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Keithley 2500 User Manual

Keithley 2500 User Manual

Photodiode meter

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Models 2500 and 2502

User's Manual

A G R E A T E R M E A S U R E O F C O N F I D E N C E

Visit us at www.TestEquipmentDepot.com

Photodiode Meter

99 Washington Street

Melrose, MA 02176

Phone 781-665-1400

Toll Free 1-800-517-8431

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Summary of Contents for Keithley 2500

Page 1 Phone 781-665-1400 Toll Free 1-800-517-8431 Visit us at www.TestEquipmentDepot.com Models 2500 and 2502 Photodiode Meter User’s Manual A G R E A T E R M E A S U R E O F C O N F I D E N C E...
Page 2 WARRANTY Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship for a period of 1 year from date of shipment. Keithley Instruments, Inc. warrants the following items for 90 days from the date of shipment: probes, cables, rechargeable batteries, diskettes, and documentation.
Page 3 Models 2500 and 2502 Photodiode Meter User’s Manual ©2000, Keithley Instruments, Inc. All rights reserved. Cleveland, Ohio, U.S.A. Third Printing, June 2002 Document Number: 2500-900-01 Rev. C Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 TestEquipmentDepot.com...
Page 4 Revision B (Document Number 2500-900-01)..............April 2001 Revision C (Document Number 2500-900-01)..............June 2002 All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc. Other brand names are trademarks or registered trademarks of their respective holders. Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176...
Page 5 Keithley products are designed for use with electrical signals that are rated Installation Category I and Installation Category II, as described in the International Electrotechnical Commission (IEC) Standard IEC 60664. Most measurement, control, and data I/O signals are Installation Category I and must not be directly connected to mains voltage or to voltage sources with high tran- sient over-voltages.
Page 6 To maintain protection from electric shock and ﬁre, replacement components in mains circuits, including the power transformer, test leads, and input jacks, must be purchased from Keithley Instruments. Standard fuses, with applicable national safety ap- provals, may be used if the rating and type are the same. Other components that are not safety related may be purchased from other suppliers as long as they are equivalent to the original component.
Page 7: Table Of Contents
Table of Contents Getting Started General information ..............Warranty information ............Contact information ............Manual addenda ..............Safety symbols and terms ........... Inspection ................Options and accessories ............Manuals ................ Triax cables and adapters ..........Interface cables ............Rack mount kits ............Carrying case ...............
Page 8 Menus ..................1-20 Main menu ................. 1-20 Rules to navigate menus ............ 1-23 Editing voltage bias values ..........1-24 Conﬁguration menus ............1-24 Connections Connection precautions .............. INPUT and OUTPUT connectors ..........Connector terminals ..............Triax INPUT connectors ............. OUTPUT connectors ............Output enable ................
Page 9 Ground connect mode ............Front panel ground connect ......... Remote command ground connect ......Basic measurement procedure ..........3-10 Output control ..............3-10 Basic measurement circuit conﬁguration ......3-10 Front panel measurement procedure ......... 3-11 Step 1. Select measurement channel and range..3-11 Step 2.
Page 10 Typical sweep applications ..........Sweep data storage .............. Bias source operating boundaries ..........Limit lines ................Loading effects ..............Data ﬂow ..................Basic readings ..............Data storage enabled ............Limit test enabled ..............Range, Digits, Speed, and Filters Range and digits ................. Measurement range .............
Page 11 Relative, Math, Ratio, and Delta Relative ..................Front panel rel ..............Enabling and disabling rel ........... Deﬁning a rel value ............Using REL in the dual-channel mode ......Remote rel programming ............ Rel commands ............. Rel programming example .......... Measurement math functions ............. Math functions ..............
Page 12 Timestamp format ............... Timestamp accuracy ............Buffer considerations ............Using :TRACe commands to store data ....... Using :READ? to store data ......... Remote command data store ............Data store commands ............Data store programming example ........Sweep Operation Sweep types ................Linear staircase sweep ............
Page 13 Trigger link ................10-8 Input trigger requirements ..........10-8 Output trigger speciﬁcations ..........10-9 External triggering example ..........10-9 Model 2500 setup ............ 10-11 Switching mainframe setup ........10-12 Operation ..............10-12 Conﬁguring triggering ............10-14 CONFIGURE TRIGGER menu ........
Page 14 Binning systems ..............11-10 Handler interface ............. 11-10 Digital I/O connector ..........11-10 Digital output lines ........... 11-10 SOT line ..............11-11 /OE line ..............11-11 Handler types ..............11-11 Category pulse component handler ......11-11 Category register component handler ...... 11-12 Basic binning systems .............
Page 15 Output enable ................12-6 Front panel output conﬁguration ..........12-8 Conﬁgure OUTPUT menu ..........12-8 Remote output conﬁguration ............ 12-9 Output conﬁguration commands ........12-9 Output conﬁguration programming example ....12-10 Remote Operations Differences: remote vs. local operation ........13-2 Local-to-remote transition ..........
Page 16 Using common and SCPI commands in the same message ............13-15 Program message terminator (PMT) ......13-15 Command execution rules ........13-15 Response messages ............13-16 Sending a response message ........13-16 Multiple response messages ........13-16 Response message terminator (RMT) ...... 13-16 Message exchange protocol ..........
Page 17 Event enable registers ............. 14-18 Programming example - program and read register set ............14-19 Queues ..................14-19 Output queue ..............14-19 Error queue ..............14-20 Programming example - read error queue ....14-21 Common Commands Command summary ..............15-2 Command reference ..............
Page 18 Set MX + B parameters ........... 17-24 MBFactor <n> ............17-24 MMFactor <n> ............17-24 MUNits <name> ............17-24 Set optical power parameters .......... 17-25 DC<n> ..............17-25 RESP<n> ..............17-25 Enable and read math function result ......17-26 STATe <b> ..............17-26 DATA? ..............
Page 19 Composite testing ............17-36 PASS:SOURce3 <NRf> | NDN ....... 17-36 FAIL:SOURce3 <NRf> | <NDN> ......17-37 BCONtrol <name> ..........17-37 MODE <name> ............17-38 Clear test results .............. 17-38 [:IMMediate] ............17-38 AUTO <b> ............... 17-38 CALCulate8 ................17-39 Select statistic ..............17-39 FORMat <name>...
Page 20 SENSe subsystem ..............17-54 Select measurement range ..........17-54 [:UPPer] <n> ............17-54 Select auto range ............. 17-55 AUTO <b> ............... 17-55 LLIMit <n> .............. 17-55 ULIMit <n> .............. 17-55 Set measurement speed ........... 17-56 NPLCycles <n> ............17-56 Conﬁgure and control ﬁlters ..........17-57 Average ﬁlter commands ..........
Page 21 STEP <n> ..............17-69 POINts <n> .............. 17-70 DIRection <name> ..........17-71 Conﬁgure list ..............17-71 VOLTage <NRf list> ..........17-71 APPend <NRf list> ..........17-72 POINts? ..............17-72 Sweep and list program examples ........17-72 Linear voltage sweep ..........17-72 List sweep ..............
Page 22 Error queue ..............17-82 [:NEXT]? ..............17-82 ALL? ................ 17-83 COUNt? ..............17-83 CODE[:NEXT]? ............17-83 CODE:ALL? ............17-83 CLEar ............... 17-83 Simulate key presses ............17-84 KEY ................. 17-84 Read version of SCPI standard ........17-85 VERSion? ..............17-85 RS-232 interface ..............
Page 23 Speciﬁcations Status and Error Messages Introduction ................Status and error messages ............Eliminating common SCPI errors ..........-113, Undeﬁned header ..........-420, Query UNTERMINATED ......... Data Flow Introduction ................SENS1 and SENS2 ............INIT ................FETCh? ............... READ? ................ CALCulate[1]:DATA? and CALCulate2:DATA? ....CALCulate3:DATA? and CALCulate4:DATA? ....
Page 24 IEEE-488 and SCPI Conformance Information Introduction ................Measurement Considerations Low current measurements ............Leakage currents ..............Noise and source impedance ..........DUT resistance ............Source capacitance ............Generated currents .............. Offset currents ............. Electrochemical effects ..........Humidity ..............Triboelectric effects ............. Piezoelectric and stored charge effects .......
Page 25 Example Programs Introduction ................Hardware requirements ............Software requirements ............General program instructions ..........Basic measurement program ............. Photodiode measurement program ..........Data store program ..............Linear sweep program ............... Limit test program ..............Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 TestEquipmentDepot.com...
Page 26 Figure 1-3 Model 2502 rear panel ............Figure 1-4 Main menu tree ..............1-22 Connections Figure 2-1 Model 2500 rear panel showing INPUT and OUTPUT connectors ............Figure 2-2 INPUT connector terminals ........... Figure 2-3 Typical photodiode connections ..........Figure 2-4 Equivalent circuit of photodiode test connections ....
Page 27 Figure 5-5 Loading effects ............... Figure 5-6 Data ﬂow front panel .............. Figure 5-7 CALC block data ﬂow ............5-10 Range, Digits, Speed, and Filters Figure 6-1 Speed conﬁguration menu tree ..........Figure 6-2 2-stage ﬁltering ............... Figure 6-3 Repeat ﬁlter (count 10) ............Figure 6-4 Median ﬁlter (rank 5) .............
Page 28 IEEE-488 and RS-232 connector location ......13-5 Figure 13-4 RS-232 interface connector ..........13-18 Status Structure Figure 14-1 Model 2500 status register structure ........14-3 Figure 14-2 16-bit status register ............. 14-5 Figure 14-3 Status byte and service request (SRQ) .........
Page 29 List of Tables Getting Started Table 1-1 Line fuses ................1-13 Table 1-2 Basic display commands ............1-15 Table 1-3 Factory default settings ............1-17 Table 1-4 Main menu ................1-20 Table 1-5 Measurement conﬁguration menus ........1-25 Table 1-6 Source conﬁguration menus ..........
Page 30 Relative, Math, Ratio, and Delta Table 7-1 Rel commands ................ Table 7-2 Rel programming example ............. Table 7-3 Measurement function conﬁguration menu ......Table 7-4 Math function commands ............Table 7-5 Math function programming example ........Table 7-6 RATIO and DELTA conﬁguration menus ......7-10 Table 7-7 RATIO and DELTA function commands ......
Page 31 Status Structure Table 14-1 Common and SCPI commands to reset registers and clear queues ..............14-4 Table 14-2 Data format commands for reading status registers ..... 14-6 Table 14-3 Status byte and service request enable register commands ................14-10 Table 14-4 Status byte programming example ........
Page 32 Table D-4 Typical addressed common command sequence ....D-12 Table D-5 IEEE command groups ............D-13 Table D-6 Model 2500 interface function codes ........D-14 IEEE-488 and SCPI Conformance Information Table E-1 IEEE-488 documentation requirements ........ Table E-2 Coupled commands ...............
Page 33: Getting Started
• General information — Covers general information that includes warranty informa- tion, contact information, safety symbols and terms, inspection, and available options and accessories. • Product overview — Summarizes the features of the Model 2500 Dual Photodiode Meter. • Familiarization — Summarizes the controls and connectors on the unit.
Page 34: General Information
General information Warranty information Warranty information is located at the front of this manual. Should your Model 2500 require warranty service, contact the Keithley representative or authorized repair facility in your area for further information. When returning the instrument for repair, be sure to fill out and include the service form at the back of this manual to provide the repair facility with the necessary information.
Page 35: Inspection
The following options and accessories are available from Keithley for use with the Model 2500. Manuals Model 2500-902-00 — This manual package includes the service manual and any perti- nent addenda. Triax cables and adapters Model 7078-TRX-1 — This low-noise 12-inch triax cable is terminated at both ends with 3-slot male triax connectors.
Page 36: Interface Cables
Model 7078-TRX-BNC Adapter — This is a 3-slot male triax to female BNC adapter. This adapter lets you connect a BNC cable to the triax input of the Model 2500. Model 237-TRX-TBC Connector — This is a 3-lug female triax bulkhead connector with cap for assembly of custom panels and interface connections.
Page 37: Product Overview
The unit has 0.1% basic measurement accuracy with up to 6 -digit resolution. At 5 -digit resolution, the Model 2500 can transfer up to 475 readings per second over the GPIB, and up to 900 read- ings per second with 4 -digit resolution.
Page 38: Front And Rear Panel Familiarization
Getting Started Model 2500 and 2502 User’s Manual Front and rear panel familiarization Front panel summary The front panel of the Model 2500 is shown in Figure 1-1. Figure 1-1 Front panel 2500 DUAL PHOTODIODE METER CHANNEL MSR1 MSR2 RATIO...
Page 39 Model 2500 and 2502 User’s Manual Getting Started Operation keys: CHANNEL SELECT Select channel 1 or channel 2 measurement for display. DISPLAY TOGGLE Toggle between channel 1/2 display (add MSR2 to display for dual display mode). LOCAL Cancel remote operation.
Page 40: Rear Panel Summary
Getting Started Model 2500 and 2502 User’s Manual Rear panel summary The rear panel of the Model 2500 is shown in Figure 1-2 and the rear panel of the Model 2502 is shown in Figure 1-3. Figure 1-2 Model 2500 rear panel WARNING: NO INTERNAL OPERATOR SERVICABLE PARTS, SERVICE BY QUALIFIED PERSONNEL ONLY.
Page 41: Figure 1-3 Model 2502 Rear Panel
8502, 8504. RS-232 connector: RS-232 Connector for RS-232 remote operation. Use a straight through (not null modem) DB-9 cable such as a Keithley Model 7009-5. GPIB connector: IEEE-488 INTERFACE Connector for GPIB remote operation. Use a shielded cable (Model 7007-1 or 7007-2).
Page 42: Power-Up
3. Reinstall the fuse holder in the power module making sure it is seated fully. Line power connection Perform the following steps to connect the Model 2500 to line power and turn it on: 1. Before plugging in the power cord make sure the front panel power switch is in the off (0) position.
Page 43: Power-Up Sequence
1-11 Power-up sequence On power-up, the Model 2500 performs self-tests on its EPROM and RAM and momentarily lights all segments and annunciators. If a failure is detected, the instrument momentarily displays an error message, and the ERR annunciator turns on. Error...
Page 44: Line Frequency Setting
50Hz operation: :SYST:LFR 50 Fuse replacement A rear panel fuse protects the power line input of the Model 2500. If the line fuse needs to be replaced, perform the steps below: WARNING Disconnect the line cord and all cables and test leads from the instru- ment before changing the line fuse.
Page 45: Display
Display Display format The Model 2500 display is used primarily to display measured readings and voltage bias source values. The top line displays measurement function readings, and the bottom line shows voltage bias values. Channel 1 measurement function readings (MSR1) are dis- played on the left, while channel 2 measurement function values (MSR2) appear on the right.
Page 46: Channel Select Key
Status and error messages Status and error messages are displayed momentarily. During Model 2500 operation and programming, you will encounter a number of front panel messages. Typical messages are either status or error in nature and are listed in...
Page 47: Remote Display Programming
Model 2500 and 2502 User’s Manual Getting Started 1-15 SWEEP — Select this option if you want the display to disable while performing a sweep. The display will disable as soon as sweep is started. The display will automatically re- enable after the sweep is completed.
Page 48: Default Settings
1-16 Getting Started Model 2500 and 2502 User’s Manual Default settings By using appropriate menu selections, you can save and recall various instrument setups, deﬁne the power-on conﬁguration, or restore factory defaults as outlined below. Saving and restoring user setups You can save and restore up to ﬁve of your own user setups using the following...
Page 49: Table 1-3 Factory Default Settings
Model 2500 and 2502 User’s Manual Getting Started 1-17 Table 1-3 Factory default settings Setting* BENCH default GPIB default A/D Controls: Auto-zero Line frequency No effect No effect Data Store No effect No effect Digital output size** 15 or 7...
Page 50 1-18 Getting Started Model 2500 and 2502 User’s Manual Table 1-3 (continued) Factory default settings Setting BENCH default GPIB default Numbers No effect No effect Optical power: Output: Output enable Disabled Disabled Power-on default No effect No effect Ranging (measure):...
Page 51: Remote Setups
Model 2500 and 2502 User’s Manual Getting Started 1-19 Table 1-3 (continued) Factory default settings Setting BENCH default GPIB default Triggering: Arm layer: Event Immediate Immediate Count Timer Input line Output trigger Line #2, Off Line #2, Off Trigger layer:...
Page 52: Menus
SAVESETUP Conﬁgure setup conditions. SAVE Save present Model 2500 setup to memory location. 0 to 4 RESTORE Return the Model 2500 to setup saved in memory. 0 to 4 POWERON Select the power-on default setup. BENCH Powers-on to BENCH defaults.
Page 53 Top level menu choices indicated in bold. Indentation identiﬁes each lower submenu level. When the remote operation interface selection (GPIB or RS-232) is changed, the Model 2500 performs a power-on reset. To check or change options of the selected interface, you must re-enter the menu structure.
Page 54: Figure 1-4 Main Menu Tree
1-22 Getting Started Model 2500 and 2502 User’s Manual Figure 1-4 Main menu tree Press MENU key (Use to select item, then press ENTER) SAVESETUP SAVE RESTORE POWERON BENCH GPIB USER-SETUP-NUMBER RESET COMMUNICATION GPIB RS-232 BAUD BITS PARITY TERMINATOR FLOW-CTRL...
Page 55: Rules To Navigate Menus
Model 2500 and 2502 User’s Manual Getting Started 1-23 Rules to navigate menus Many functions and operations are conﬁgured from the front panel menus. Use the follow- ing rules to navigate through these conﬁguration menus: • A menu item is selected by placing the cursor on it and pressing ENTER. Cursor posi- tion is denoted by the blinking menu item or option.
Page 56: Editing Voltage Bias Values
1-24 Getting Started Model 2500 and 2502 User’s Manual Editing voltage bias values Use the following keys to edit voltage bias values: • SRC1 or SRC2: selects the channel 1 (Src1) or channel 2 (Src2) source display ﬁeld on the lower line for editing. A blinking cursor will appear in the ﬁeld to be edited. If no key is pressed within a few seconds, the edit mode will be cancelled automatically.
Page 57: Table 1-5 Measurement Conﬁguration Menus
Model 2500 and 2502 User’s Manual Getting Started 1-25 These various conﬁguration menus are covered in detail in the pertinent sections of this manual. Table 1-5 Measurement conﬁguration menus Conﬁguration menu item Description CONFIG MSR1 Conﬁgure channel 1 measurement. CONFIG MSR1 BUTTON Current measurement.
Page 58: Table 1-6 Source Conﬁguration Menus
1-26 Getting Started Model 2500 and 2502 User’s Manual Table 1-6 Source conﬁguration menus Conﬁguration menu item Description CONFIG SRC1 Conﬁgure delay and ground connect mode. CONFIG SRC1 DELAY Set source delay (0 - 9999.998s). AUTO-DELAY Control source auto delay.
Page 59: Table 1-8 Limit Conﬁguration Menu
Model 2500 and 2502 User’s Manual Getting Started 1-27 Table 1-8 Limit conﬁguration menu Conﬁguration menu item Description CONFIG LIMIT Conﬁgure limit tests. CONFIG LIMITS MENU DIGOUT Program Digital I/O bit patterns for pass/fail. SIZE Select I/O number of bits.
Page 60: Table 1-9 Trigger Conﬁguration Menu
1-28 Getting Started Model 2500 and 2502 User’s Manual Table 1-9 Trigger conﬁguration menu Conﬁguration menu item Description CONFIG TRIG Conﬁgure triggering. CONFIGURE TRIGGER ARM LAYER Conﬁgure trigger model arm layer. ARM-IN Select arm layer detection event. IMMEDIATE Immediate event detection.
Page 61: Table 1-10 Sweep, Digits, Speed, And Data Store Conﬁguration Menus
Model 2500 and 2502 User’s Manual Getting Started 1-29 Table 1-10 Sweep, digits, speed, and data store conﬁguration menus Conﬁguration menu item Description CONFIG SWEEP Conﬁgure sweeps. CONFIGURE SWEEPS TYPE Select sweep type. NONE Disable sweep. STAIR Staircase sweep, program START, STOP, STEP.
Page 62: Table 1-11 Output And Display Conﬁguration Menus
1-30 Getting Started Model 2500 and 2502 User’s Manual Table 1-11 Output and display conﬁguration menus Conﬁguration menu item Description CONFIG ON/OFF OUTPUT Conﬁgure output. CONFIG OUTPUT AUTO OFF Enable disable auto off mode. DISABLE Keep output on. ENABLE Turn output off after each measurement.
Page 63: Connections
• Photodiode connections — Provides detailed diagrams for connecting the Model 2500 INPUT and OUTPUT connectors to the photodiodes in a laser diode test system. • Alternate connecting methods — Provides connecting diagrams for using the Model 2500 as a stand-alone ammeter or stand-alone voltage source.
Page 64: Connection Precautions
• VOLTAGE SOURCE CHANNEL 2 OUTPUT: A safety banana jack used to apply the channel 2 HI voltage bias source signal to the photodiode or other DUT. Figure 2-1 Model 2500 rear panel showing INPUT and OUTPUT connectors INPUT Connectors WARNING: NO INTERNAL OPERATOR SERVICABLE PARTS, SERVICE BY QUALIFIED PERSONNEL ONLY.
Page 65: Connector Terminals
Model 2500 and 2502 User’s Manual Connections Connector terminals Triax INPUT connectors The electrical conﬁguration of each triax INPUT connector is shown in Figure 2-2. Con- nector terminals are designated as follows: • Center conductor of the connector (and triax cable): input HI. This terminal connects to one terminal of the photodiode being tested.
Page 66: Output Enable
Model 2500 and 2502 User’s Manual Output enable An interlock switch can be used with the Model 2500 output enable line on the Digital I/O Port to inhibit the voltage bias source outputs. When output enable is activated, the Model 2500 outputs will turn off when the lid of the test ﬁxture is opened. However, you must ALWAYS assume that power is present until you verify that the Model 2500 output is off.
Page 67: Figure 2-3 Typical Photodiode Connections
Model 2500 and 2502 User’s Manual Connections Figure 2-3 Typical photodiode connections INPUT HI Forward Photodiode INPUT LO Laser Triax Cables Diode INPUT HI: center conductor Back INPUT LO: inner shield Photodiode INPUT HI Optional Noise Shield (Connect to INPUT LO)
Page 68: Equivalent Circuit
Connections Model 2500 and 2502 User’s Manual Equivalent circuit Figure 2-4 shows an equivalent circuit for the connection scheme shown in Figure 2-3. The circuit includes two ammeters to make current measurements and two voltage sources to bias the DUTs. Note that channel 1 and channel 2 analog common terminals are ﬂoating and independent of one another.
Page 69: Ground Connect Mode Connections
Model 2500 and 2502 User’s Manual Connections Ground connect mode connections The VOLTAGE SOURCE output jack for either channel can either be connected to chassis ground or left ﬂoating, depending on the selected ground connect mode. (See Section “Ground connect mode,”...
Page 70: Figure 2-6 Ground Connect Mode Equivalent Circuit
Connections Model 2500 and 2502 User’s Manual Figure 2-6 Ground connect mode equivalent circuit INPUT HI Channel 1 Channel 1 Analog Common V-Source Back INPUT Photodiode Outer Shield Chassis Ground Laser Diode Chassis Ground Channel 2 Forward INPUT Photodiode Outer Shield...
Page 71: Alternate Connecting Methods
Connections Alternate connecting methods Although the Model 2500 is designed primarily to bias and measure photodiodes in a laser diode test system, it can also be used for stand-alone current measurements, or as a stand- alone voltage source with any suitable device.
Page 72: Voltage Source Connections
Voltage source connections Figure 2-8 shows the connecting scheme for using the Model 2500 as a stand-alone volt- age source. Note that the DUT HI terminal is connect to the OUTPUT terminal for the voltage source, while the DUT LO terminal is connected to analog common (inner ring of INPUT jack).
Page 73: Analog Output Connections (Model 2502 Only)
Model 2500 and 2502 User’s Manual Connections 2-11 Analog output connections (Model 2502 only) Analog output connector terminals Figure 2-9 shows the terminal conﬁguration of each triax ANALOG OUT connector. Output terminals are as follows: • Center conductor: analog output HI •...
Page 74: Non-Isolated Connections
2-12 Connections Model 2500 and 2502 User’s Manual Non-isolated connections Figure 2-10 shows typical non-isolated analog output connections. Note that analog output HI (center conductor) is connected to INPUT HI of the measurement instrument, while analog output LO (inner shield) is connected to INPUT LO.
Page 75: Isolated Connections
Model 2500 and 2502 User’s Manual Connections 2-13 Isolated connections To maintain proper isolation between the analog outputs and chassis ground, it is strongly recommended that you use the isolated connections shown in Figure 2-11. In this case, an Analog Devices 3B41-03 Isolated Wideband Voltage Input is used to provide isolation between the Model 2502 ANALOG OUT and the measuring instrument.
Page 76: Equivalent Circuits
2-14 Connections Model 2500 and 2502 User’s Manual Equivalent circuits Figure 2-12 shows an equivalent circuit of the analog outputs with the ground connect mode disabled. (Only one channel is shown; the other channel is identical.) Note that the analog output circuit consists of a gain/buffer ampliﬁer, and the analog output LO is con- nected to ﬂoating common.
Page 77: Figure 2-13 Analog Output Equivalent Circuit With Ground Connect Enabled
Model 2500 and 2502 User’s Manual Connections 2-15 Figure 2-13 Analog output equivalent circuit with ground connect enabled Feedback Ammeter Triax INPUT 20mA Max To A/D Converter Chassis Ground VOLTAGE SOURCE ANALOG Output Enable Ground Floating channel 1 Bias Source Connect 0 to ±10V or...
Page 78: Basic Operation
• Operation considerations — Covers warm-up, auto zero, and source delay. • Basic measurement procedure — Describes the basic procedure for setting up the Model 2500 for measurement and voltage bias operation, including choosing the mea- surement channel and range, selecting the source channel and setting output values, and turning the output on and off.
Page 79: Operation Overview
±20mA. Each channel has eight current ranges: 2nA, 20nA, 200nA, 2µA, 20µA, 200µA, 2mA, and 20mA. • Source Voltage — Each Model 2500 channel can output DC voltage from ±500µV to ±100V. Each channel has two ranges: 10V and 100V.
Page 80: Compliance
SRQ under compliance conditions over the GPIB (Section 14). Basic circuit conﬁguration The fundamental circuit conﬁguration for the Model 2500 is shown in Figure 3-1. Note that the unit has two separate channels (one channel shown), each of which includes a feedback ammeter and a 0 ±10V or 0 ±100V voltage bias source.
Page 81: Operation Considerations
Operation considerations The following paragraphs discuss warm-up period, auto zero, and source delay. Warm-up The Model 2500 must be turned on and allowed to warm up for at least one hour to achieve rated accuracies. See Appendix A for speciﬁcations.
Page 82: Source Delay
Models 2500 and 2502 User’s Manual Basic Operation Source delay The source delay options are used to set the settling time for the voltage bias source. This source delay is the delay phase of the source-delay-measure cycle. (See Section “Mea- surement Concepts,”...
Page 83: Output Slew Time
Basic Operation Models 2500 and 2502 User’s Manual Output slew time Figure 3-2 demonstrates the effect of output slew time on overall settling. Total time after changing the source value before accurate measurements can be taken includes both the slew time and the measure circuit settling time.
Page 84: Front Panel Source Delay
Models 2500 and 2502 User’s Manual Basic Operation Front panel source delay To set the manual source delay from the front panel: 1. Press CONFIG then SRC1 or SRC2. 2. Select DELAY from the displayed choices, then press ENTER. 3. Enter the desired DELAY value, then press ENTER.
Page 85: Ground Connect Mode
Basic Operation Models 2500 and 2502 User’s Manual Ground connect mode The VOLTAGE SOURCE output jack for either channel can be left ﬂoating or connected to chassis ground by selecting the appropriate ground connect mode. When ground con- nect is enabled, the VOLTAGE SOURCE terminal will be connected to chassis ground, as...
Page 86: Figure 3-3 Ground Connect Enabled
Models 2500 and 2502 User’s Manual Basic Operation Figure 3-3 Ground connect enabled Triax INPUT To Ammeter Chassis Ground SOURCE OUTPUT Floating Output Common Bias Source Ground Connect Note: One channel shown. Relay Closed Other channel is identical. Chassis Ground...
Page 87: Basic Measurement Procedure
Output control Use the ON/OFF OUTPUT key to turn both Model 2500 outputs on or off simultaneously for basic source-measure situations. With either channel 1 or channel 2 output on, the red ON/OFF OUTPUT indicator light will be on. The indicator light turns off when the out- puts are turned off.
Page 88: Front Panel Measurement Procedure
Src1 or Src2 display ﬁeld indicates that the Model 2500 is in the edit mode for that channel. If no editing operation is per- formed within six seconds, the edit mode times out and is cancelled.
Page 89: Step 3. Turn Source Outputs On
3-12 Basic Operation Models 2500 and 2502 User’s Manual • Numeric entry — When the edit mode is entered, the cursor is located on the most signiﬁcant digit of the value. From this position, you can key in the value using the number keys (0 through 9).
Page 90: Measurement Programming Example
2. Note that the steps correspond to those listed previously in “Front panel mea- surement procedure.” These commands set up the Model 2500 as follows: • Channel 2 measurement range: 2µA • Channel 2 source range: 10V • Channel 2 source output level: 10V...
Page 91: Using The Analog Outputs (Model 2502 Only)
3-14 Basic Operation Models 2500 and 2502 User’s Manual Table 3-7 Basic measurement command sequence Step Action Commands Comments *RST Restore GPIB defaults. Select channel 2 measure range. :SENS2:CURR:RANG 2e-6 Select 2µA range. Select channel 2 current reading. :FORM:ELEM CURR2 Return channel 2 reading.
Page 92: Photodiode Measurements
Photodiode Measurements • Conﬁguring measurements — Outlines the conﬁguration menu that allows you to set up various channel 1 and channel 2 measurement aspects and covers a conﬁguration procedure. • Front panel photodiode measurements — Provides a detailed procedure for making photodiode measurements from the front panel.
Page 93: Conﬁguring Measurements
Photodiode Measurements Models 2500 and 2502 User’s Manual Conﬁguring measurements Measurement conﬁguration menu Press CONFIG then MSR1 or MSR2 to access channel 1 or channel 2 conﬁguration menu shown in Table 4-1. In Section 1 use the “Rules to navigate menus”...
Page 94: Conﬁguring Measurements
4. After conﬁguring all parameters, press EXIT to return to normal display. Optical power The Model 2500 has a built-in function for converting photodiode current to optical power. 1. Press CONFIG then MSR1 or MSR2 to select the conﬁguration menu for channel 1 or channel 2.
Page 95: Front Panel Photodiode Measurements
Photodiode Measurements Models 2500 and 2502 User’s Manual Front panel photodiode measurements Photodiode measurement circuit conﬁguration The basic circuit conﬁguration for the photodiode measurement procedures in this section is shown in Figure 4-2. This example shows channel 1 connections to one photodiode.
Page 96: Step 2. Set Bias Voltage Source Values
Models 2500 and 2502 User’s Manual Photodiode Measurements Step 2. Set bias voltage source values. Set up channel 1 and channel 2 voltage sources as follows: 1. Press SRC1 to edit the channel 1 source. 2. Use the RANGE keys to select the source range that will accommodate the value you want to set.
Page 97: Table 4-2 Photodiode Measurement Commands
Photodiode Measurements Models 2500 and 2502 User’s Manual Table 4-2 Photodiode measurement commands Command Description :CALCulate[1]:FORMat <name> Deﬁne channel 1 math (name = MXB[1], COND[1], POWER[1], RES[1], or OP[1]). :CALCulate[1]:DATA? Request channel 1 math reading. :CALCulate[1]:STATe <state> Enable/disable channel 1 math (state = ON or OFF).
Page 98: Photodiode Measurement Programming Example
Section 2 for detailed connection information. These commands set up the Model 2500 as follows: • Channel 1 measurement: current measurement, auto range • Channel 2 measurement: optical power • Channel 2 responsivity constant (R) of detector for wavelength of interest: 1 •...
Page 99: Table 4-3 Basic Measurement Command Sequence
Photodiode Measurements Models 2500 and 2502 User’s Manual Table 4-3 Basic measurement command sequence Step Action Commands Comments *RST Restore GPIB defaults. Conﬁgure channel 1 :FORM:ELEM CURR1 Select channel 1 reading. measurement. Conﬁgure channel 2 :CALC2:FORM OP2 Optical power on chan. 2.
Page 100: Measurement Concepts
Measurement Concepts • Source-delay-measure cycle — Describes the various phases of the source-delay- measure cycle. • Sweep waveforms — Covers the various types of sweeps that can be performed. • Bias source operating boundaries — Covers voltage output and current limit operat- ing boundaries for the voltage bias sources.
Page 101: Source-Delay-Measure Cycle
Measurement Concepts Models 2500 and 2502 User’s Manual Source-delay-measure cycle Overview Model 2500 voltage bias and measurements operation for each channel can consist of a series of source-delay-measure (SDM) cycles (Figure 5-1). During each SDM cycle, the following occurs: 1. Set the voltage bias source output level.
Page 102: Delay Phase
Models 2500 and 2502 User’s Manual Measurement Concepts Figure 5-2 Simpliﬁed trigger model Idle Event Trig Layer Source Delay Measure Trigger Event Trig Layer See Section 10 for trigger model details. S D M Delay phase The delay phase of the SDM cycle allows the source to settle before the measurement is performed.
Page 103: Sweep Waveforms
Measurement Concepts Models 2500 and 2502 User’s Manual Sweep waveforms There are three basic sweep types to select from: linear staircase, logarithmic staircase, and custom, as shown in Figure 5-3. Staircase sweeps The linear staircase sweep goes from the start level to the stop level in equal linear steps.
Page 104: Sdm Cycle During Sweeps
Models 2500 and 2502 User’s Manual Measurement Concepts SDM cycle during sweeps An SDM cycle is performed on each step (or point) of the sweep. Thus, one measurement will be performed at each step (level). The time spent at each step (level) depends on how the SDM cycle is conﬁgured (i.e., source delay, measure speed) and the trigger delay (if...
Page 105: Bias Source Operating Boundaries
DUT load line for 400Ω intersects the 20mA current compliance limit line placing the Model 2500 in compliance. In compliance, the Model 2500 will not be able to source its programmed voltage (10V). For the 400Ω DUT, the unit will output only 8V (at the ﬁxed 20mA limit).
Page 106: Figure 5-5 Loading Effects
Models 2500 and 2502 User’s Manual Measurement Concepts Regardless of the load, current will never exceed the ﬁxed compliance of 20mA. Figure 5-5 Loading effects Current Limit Load Line 20mA Output Current (I) Operating 10mA Point Voltage Source Load Line...
Page 107: Data Flow
Basic readings With data store and limit tests disabled (Figure 5-6A), the Model 2500 simply displays the selected measurement function readings (MSR1, MSR2, RATIO, or DELTA). No data storage or limit test is performed when those two functions are disabled.
Page 108: Figure 5-6 Data Flow Front Panel
Models 2500 and 2502 User’s Manual Measurement Concepts Figure 5-6 Data ﬂow front panel MSR1 MSR2 Display Readings RATIO Displayed readings depend on selected DELTA function. A. Data store and limit tests disabled MSR1 MSR2 Data Recalled Store Readings All functions...
Page 109: Figure 5-7 Calc Block Data Flow
5-10 Measurement Concepts Models 2500 and 2502 User’s Manual Figure 5-7 CALC block data ﬂow READ?, FETC? DATA? CALC1:DATA? CALC3:DATA? Bypass if CALC1 disabled SENS1 CALC1 CALC3 (Sample (R,G,P,M) (REL) Buffer) CHANNEL 1 CALC5 CALC7 CALC6 Data Store (RATIO) (LIMITS)
Page 110: Range, Digits, Speed, And Filters
Range, Digits, Speed, and Filters • Range and digits — Discusses available ranges, maximum readings, ranging limita- tions, manual and autoranging, and display resolution. • Speed — Discusses speed settings, which are used to control the integration period of the A/D converter. •...
Page 111: Range And Digits
Range, Digits, Speed, and Filters Models 2500 and 2502 User’s Manual Range and digits Measurement range The selected measurement range affects the accuracy of the measurements as well as the maximum signal that can be measured. Available ranges Table 6-1 lists the available current measurement ranges, resolution values, and maximum readings for each Model 2500 channel.
Page 112: Auto Ranging
Models 2500 and 2502 User’s Manual Range, Digits, Speed, and Filters Auto ranging Press the MSR1 or MSR2 key, then press AUTO RANGE to enable auto ranging on chan- nel 1 or channel 2 respectively. The AUTO annunciator turns on when auto ranging is selected.
Page 113: Digits
Range, Digits, Speed, and Filters Models 2500 and 2502 User’s Manual Digits The display resolution of the measured reading depends on the DIGITS setting. This set- ting is global, which means the digits setting selects display resolution for both channels.
Page 114: Range And Digits Programming Example
Models 2500 and 2502 User’s Manual Range, Digits, Speed, and Filters Range and digits programming example Table 6-3 shows a programming example for controlling range and digits. The Model 2500 is set up as follows: • Channel 1 auto range: ON •...
Page 115: Setting Speed
Range, Digits, Speed, and Filters Models 2500 and 2502 User’s Manual Setting speed Speed is set from the SPEED ACCURACY MENU and is structured as follows. Use Section “Rules to navigate menus,” to check and/or change the speed setting. SPEED-ACCURACY MENU...
Page 116: Remote Speed Programming
Filters Filtering stabilizes noisy measurements caused by noisy input signals. However, the more ﬁltering that is used, the slower the measurement process becomes. The Model 2500 uses two stages of ﬁltering: average and median. The displayed, stored, or transmitted reading is simply the result of the ﬁltering processes.
Page 117: Repeat Filter
Range, Digits, Speed, and Filters Models 2500 and 2502 User’s Manual Each ﬁlter stage uses a stack to temporarily store readings to be ﬁltered. The size of a stack, which is set by the user, determines how many readings will be ﬁltered. A stack size of one disables that ﬁlter.
Page 118: Figure 6-4 Median Filter (Rank 5)
Models 2500 and 2502 User’s Manual Range, Digits, Speed, and Filters The number of reading samples (stack size) for the Median Filter is determined by the selected rank (0 to 5) as follows: Sample readings = 2n + 1 Where: n is the selected rank (0 to 5) From the above equation, it can be seen that the minimum number of sample readings is 1 (n=0) and the maximum number is 11 (n=5).
Page 119: Moving Filter
6-10 Range, Digits, Speed, and Filters Models 2500 and 2502 User’s Manual Moving ﬁlter The moving average ﬁlter uses a ﬁrst-in, ﬁrst-out stack. When the stack (ﬁlter count) becomes full, the readings are averaged, yielding a ﬁltered reading. For each subsequent reading placed into the stack, the oldest reading is discarded.
Page 120: Filter Conﬁguration
Models 2500 and 2502 User’s Manual Range, Digits, Speed, and Filters 6-11 Advanced ﬁlter — The Advanced Filter is part of the Moving Filter. With the Advanced Filter enabled, a user-programmable noise “window” is used with the Moving Filter. The noise window, which is expressed as a percentage of range (0-105%), allows a faster response time to large signal step changes.
Page 121: Filter Control
6-12 Range, Digits, Speed, and Filters Models 2500 and 2502 User’s Manual Filter control When ﬁltering is being applied to the input signal, the FILT annunciator will be on. The FILTER key is used to control ﬁltering. Pressing FILTER turns on the FILT annunciator to indicate that the ﬁlter conﬁguration is being applied to the input.
Page 122: Remote Filter Programming
Models 2500 and 2502 User’s Manual Range, Digits, Speed, and Filters 6-13 Remote ﬁlter programming Filter commands Table 6-6 summarizes ﬁlter commands. See Section 17 for more details. Table 6-6 Filter commands Commands* Description for Average Filter: [:SENSe[1]]:AVERage:COUNt <n> Set Ch. 1 average ﬁlter count (n = count, 1 to 100).
Page 123: Filter Programming Example
6-14 Range, Digits, Speed, and Filters Models 2500 and 2502 User’s Manual Filter programming example Table 6-7 summarizes the command sequence to program channel 1 ﬁlter aspects as follows: • Average ﬁlter off • Median ﬁlter state: on • Median ﬁlter rank: 5 •...
Page 124: Relative, Math, Ratio, And Delta
Relative, Math, Ratio, and Delta • Relative — Discusses the relative (REL) mode that can be used to null offsets or sub- tract a baseline value from readings. • Measurement Math Functions — Provides detailed information on the following math functions: I/V, V/I, MX + B, electrical power (V × I), and optical power. •...
Page 125: Relative
“Rules to navigate menus,” for details. 4. With the desired rel value displayed, press ENTER. The Model 2500 will return to the normal display with rel enabled. The reading will reﬂect the deﬁned rel value. Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176...
Page 126: Using Rel In The Dual-Channel Mode
Models 2500 and 2502 User’s Manual Relative, Math, Ratio, and Delta Using REL in the dual-channel mode The REL key does not function while the display is in the dual-channel, RATIO, or DELTA display modes. To view two rel readings simultaneously: 1.
Page 127: Rel Programming Example
:CALC3:DATA? Get reading. :OUTP1 OFF Turn off output. Measurement math functions Math functions Each Model 2500 channel has built-in math functions to calculate the following: • I/V • V/I • MX + B • Electrical power • Optical power NOTE Math function uses the current and voltage from the same channel for calculations.
Page 128: Mx + B
Responsivity = amps/watt When you select this math function, you will be prompted to enter responsitivity (R) and dark current (D) values in amps per watt and amps respectively. The Model 2500 will then display optical power in watts. NOTE Zero is not an acceptable value for responsivity, as this value would cause an inﬁnite result.
Page 129: Front Panel Math Functions
Relative, Math, Ratio, and Delta Models 2500 and 2502 User’s Manual Front panel math functions Using Table 7-3 as a guide, conﬁgure measurement math functions as follows: 1. Press CONFIG then MSR1 or MSR2 to select channel 1 or channel 2 respectively.
Page 130: Remote Math Functions
Models 2500 and 2502 User’s Manual Relative, Math, Ratio, and Delta Remote math functions Table 7-4 summarizes commands to control the measurement math functions by remote. See the :CALC1 and :CALC2 subsystems in Section 17 for detailed information. Table 7-4...
Page 131: Math Function Programming Example
Request Ch. 2 MX + B result. :OUTP2 OFF Output 2 off. RATIO and DELTA RATIO functions The Model 2500 has built-in RATIO functions to calculate the following: • MSR1/MSR2 • MSR2/MSR1 MSR1/MSR2 This function computes the ratio between the channel 1 measurement function (MSR1)
Page 132: Msr2/Msr1
RATIO = MSR2/MSR1 where: MSR1 = channel 1 measurement function MSR2 = channel 2 measurement function DELTA functions The Model 2500 has built-in RATIO functions to calculate the following: • MSR1-MSR2 • MSR2-MSR1 MSR1-MSR2 This function computes the difference between the channel 1 measurement function and...
Page 133: Front Panel Ratio And Delta Conﬁguration
7-10 Relative, Math, Ratio, and Delta Models 2500 and 2502 User’s Manual Front panel RATIO and DELTA conﬁguration Using Table 7-6 as a guide, conﬁgure RATIO and DELTA functions as follows: 1. Press CONFIG then RATIO or DELTA to select the function to be conﬁgured.
Page 134: Remote Ratio And Delta
Models 2500 and 2502 User’s Manual Relative, Math, Ratio, and Delta 7-11 Remote RATIO and DELTA Table 7-7 summarizes commands to control the RATIO and DELTA function via remote. See the :CALC5 and :CALC6 subsystems in Section 17 for detailed information.
Page 135: Ratio And Delta Function Programming Example
7-12 Relative, Math, Ratio, and Delta Models 2500 and 2502 User’s Manual RATIO and DELTA function programming example Table 7-8 summarizes commands that program the following RATIO and DELTA functions: • RATIO function: CALC3/CALC4 • DELTA function: CALC4-CALC3 Table 7-8...
Page 136: Data Store
Data Store • Data store overview — Outlines basic data store (buffer) capabilities. • Storing readings — Discusses the procedure for storing readings in the internal buffer. • Recalling readings — Provides detailed information for recalling readings stored in the buffer. •...
Page 137: Data Store Overview
Models 2500 and 2502 User’s Manual Data store overview The Model 2500 has a data store (buffer) to store from 1 to 3000 voltage bias source val- ues and measurement readings for both channels. Each reading includes the buffer loca- tion number and a timestamp.
Page 138: Buffer Location Number
Models 2500 and 2502 User’s Manual Data Store Buffer location number The buffer location number indicates the memory location of the source-measure reading. Location #0000 indicates that the displayed source-measure reading is stored at the ﬁrst memory location. If limit testing was performed, a “P” or an “F” will precede the buffer location number to indicate the pass/fail result of the test.
Page 139: Buffer Statistics
With the data store in the recall mode, buffer statistics are displayed by using the DIS- PLAY TOGGLE key. Use the DISPLAY TOGGLE key to sequence through the statistics and return the Model 2500 to the normal data store recall state. Pressing EXIT at any time returns the instrument to the normal display state.
Page 140: Timestamp Format
Models 2500 and 2502 User’s Manual Data Store Timestamp format Buffer readings can be recalled using the absolute timestamp format or the delta format. For the absolute format, readings are referenced to zero seconds. For the delta format, the timestamp indicates the time between the displayed reading and the previous reading.
Page 141: Using :Read? To Store Data
Data Store Models 2500 and 2502 User’s Manual Using :READ? to store data Use :TRIG:COUN <n> to set the number of readings to be stored (n = number of read- ings; 3000 maximum). Use the :FORM:ELEM CURR1 | CURR2 to select the channel.
Page 142: Data Store Programming Example
Models 2500 and 2502 User’s Manual Data Store Data store programming example Table 8-2 summarizes the commands for basic data store operation. These commands set up the Model 2500 as follows: • Number of points: 10 • Trigger count: 10 •...
Page 143: Sweep Operation
Sweep Operation • Sweep types — Describes the three basic sweep types: Linear staircase, logarithmic staircase, and custom sweep. • Conﬁguring and running a sweep — Discusses the procedure for setting up and per- forming sweeps including selecting and conﬁguring a sweep, setting the delay, and performing a sweep.
Page 144: Sweep Types
Sweep Operation Models 2500 and 2502 User’s Manual Sweep types The three basic sweep types described in the following paragraphs include: • Linear staircase • Logarithmic staircase • Custom Linear staircase sweep As shown in Figure 9-1, this sweep steps from a start voltage source value to an ending (stop) voltage source value.
Page 145: Logarithmic Staircase Sweep
Models 2500 and 2502 User’s Manual Sweep Operation Logarithmic staircase sweep This sweep is similar to the linear staircase sweep. The steps, however, are done on a loga- rithmic scale as shown in the example sweep in Figure 9-2. This is a 5-point log sweep from 1 to 10V.
Page 146: Custom Sweep
Sweep Operation Models 2500 and 2502 User’s Manual Thus, the ﬁve log steps for this sweep are 0, 0.25, 0.50, 0.75, and 1.00. The actual voltage bias levels at these points are listed in Table 9-1 (the voltage bias level is the anti-log of the log step).
Page 147: Custom Sweep Examples
Models 2500 and 2502 User’s Manual Sweep Operation Custom sweep examples The custom sweep can be conﬁgured to provide a 50% duty cycle pulse sweep. Figure 9-3 shows a pulse sweep that provides three 1V pulses on a 0V bias level. This pulse sweep is conﬁgured by specifying six points for the custom sweep.
Page 148: Conﬁguring And Running A Sweep
Sweep Operation Models 2500 and 2502 User’s Manual Conﬁguring and running a sweep Front panel sweep operation Conﬁguring a sweep The sweep conﬁguration menu is structured as follows and shown in Figure 9-5. Note that bullets indicate the primary items of the sweep menu and dashes indicate the options of each menu item.
Page 149: Setting Delay
• SOURCE-RANGING — Use this menu item to control voltage bias source ranging: – BEST-FIXED – With this option, the Model 2500 will select a single ﬁxed source range that will accommodate all of the source levels in the sweep. For example, if the minimum and maximum source levels in the sweep are 1V and 30V, the 100V source range will be used.
Page 150: Trigger Count And Sweep Points
Performing sweeps Procedures for the various sweep types are covered below. NOTE The following procedure assumes that the Model 2500 is already connected to the DUT as explained in Section Performing a linear staircase sweep Step 1.
Page 151: Performing A Log Staircase Sweep
Store.”) Performing a log staircase sweep Step 1. Conﬁgure channel. Conﬁgure the Model 2500 for the desired operations as follows: 1. Select the desired source channel by pressing SRC1 or SCR2. 2. Set the source level to the desired value.
Page 152 Step 4. Turn output on. Press the ON/OFF OUTPUT key to turn the output on (red OUTPUT indicator turns on). The Model 2500 will output the programmed bias level. Step 5. Run sweep. To run the sweep, press the SWEEP key. After the sweep is completed, turn the output off by pressing the ON/OFF OUTPUT key.
Page 153: Performing A Custom Sweep
9-11 Performing a custom sweep Step 1. Conﬁgure channel. Conﬁgure the Model 2500 for the desired source-measure operations as follows: 1. Select the desired source channel by pressing SRC1 or SRC2. 2. Set the source level to the desired value.
Page 154: Remote Sweep Operation
9-12 Sweep Operation Models 2500 and 2502 User’s Manual Remote sweep operation Staircase sweep commands Table 9-2 summarizes remote commands used for linear and log staircase sweep opera- tion. See Section “Conﬁgure sweeps,” for more details on these commands. Table 9-2...
Page 155: Staircase Sweep Programming Example
9-13 Staircase sweep programming example As an example of linear staircase sweep operation, assume the Model 2500 is to be used to generate the reverse-biased V-I characteristics of a photodiode. For the purposes of this test, assume the following basic sweep parameters:...
Page 156: Custom Sweep Commands
9-14 Sweep Operation Models 2500 and 2502 User’s Manual Custom sweep commands Table 9-4 summarizes remote commands used for custom sweep operation. See Section “Conﬁgure list,” for more details on these commands. Table 9-4 Custom sweep commands Command Description :SOURce[1]:VOLTage:MODE LIST Select channel 1 voltage list (custom) sweep mode.
Page 157: Custom Sweep Programming Example
Models 2500 and 2502 User’s Manual Sweep Operation 9-15 Custom sweep programming example As an example of custom sweep operation, assume a ﬁve-point sweep with the following parameters: Source and measure channel: channel 1 Voltage sweep mode: list (custom sweep)
Page 158: Triggering
Triggering • Trigger model — Discusses the trigger model, including various layers, event detec- tion, delay, and device action. • Trigger link — Discusses the trigger link, including input triggers, output triggers, and external triggering example. • Conﬁguring triggering — Details how to conﬁgure the various triggering aspects. •...
Page 159: Trigger Model (Front Panel Operation)
Idle The Model 2500 is in idle when it is not operating in the Arm Layer or Trigger Layer of the trigger model. When in idle, the ARM annunciator is off. To take the Model 2500 out of idle, turn the output ON.
Page 160: Figure 10-1 Trigger Model (Front Panel Operation)
Models 2500 and 2502 User’s Manual Triggering 10-3 Figure 10-1 Trigger model (front panel operation) Idle Turn Output ON Idle Bypass Once Arm Event Detector Immediate GPIB Never Another Layer Counter Timer Manual Arm Event Arm-In TLink Detector ⇓Stest Event ⇒...
Page 161: Event Detection
10-4 Triggering Models 2500 and 2502 User’s Manual Event detection In general, operation is held up at an Event Detector until the programmed event occurs. Note however, that if an event detector has a bypass, operation can be programmed to loop around the event detector.
Page 162: Trigger Layer
Delay Action of the SDM cycle. The Delay Action is discussed next. Source, delay, and measure actions The SDM cycle of the Model 2500 consists of three actions: Source, Delay, and Measure: SOURCE Action — Any programmed output voltage level changes are performed.
Page 163: Counters
10-point sweeps can then be performed for a total of 30 source-delay-measure actions. The maximum buffer size for the Model 2500 is 3000 readings. The product of the two counter values cannot exceed 3000. For example, if you set an arm count of two, the max- imum trigger count will be 1500 (3000 / 2 = 1500).
Page 164: Bench Defaults
• Event Detection Bypasses = Never (both layers) When the output is turned ON, the Model 2500 will run in a continuous loop around the trigger model. After each Measure Action, operation will continue at the top of the trigger model.
Page 165: Trigger Link
10-8 Triggering Models 2500 and 2502 User’s Manual Trigger link Input and output triggers are received and sent via the rear panel TRIGGER LINK connec- tor. The trigger link has four lines. At the factory, line #2 is selected for output triggers, and line #1 is selected for input triggers.
Page 166: External Triggering Example
DUT connected to that channel. This test system is shown in Figure 10-5, which uses a Model 2500 to measure 10 DUTs switched by a Model 7011 multiplexer card in a Model 7001/7002 Switch System. Figure 10-5...
Page 167: Figure 10-6 Trigger Link Connections
Figure 10-6. Trigger Link of the Model 2500 is connected to Trigger Link (IN or OUT) of the switching mainframe. Note that with the default trigger settings of the switching mainframe, line #1 is an input, and line #2 is an output.
Page 168: Model 2500 Setup
Models 2500 and 2502 User’s Manual Triggering 10-11 Model 2500 setup Step 1. Restore bench defaults. Press the MENU key, select SAVESETUP, then press the ENTER key. From the SAVESETUP menu, select RESET, then press ENTER. Select BENCH, then press ENTER.
Page 169: Switching Mainframe Setup
SCAN menu. Operation 1. To store the readings in the Model 2500 buffer, press STORE, and set the buffer size for 10. When ENTER is pressed, the asterisk (*) annunciator will turn on to indicate the buffer is enabled. See Section 8 for details.
Page 170: Figure 10-7 Operation Model For Triggering Example
Measurements Channels A) Turning the Model 2500 OUTPUT ON places it at point A in the ﬂowchart, where it waits for an external trigger. B) Pressing STEP takes the Model 7001/2 out of the idle state and places operation at point B in the ﬂowchart.
Page 171: Conﬁguring Triggering
Triggering Models 2500 and 2502 User’s Manual The trigger applied to the Model 7001/2 from the Model 2500 closes the next channel in the scan, which then triggers the Model 2500 to measure that DUT. This process continues until all 10 channels are scanned and measured.
Page 172 Models 2500 and 2502 User’s Manual Triggering 10-15 / ↑↓STEST — Event detection occurs when the SOT line of the Digital I/O port is pulsed either high or low. After selecting this arm event, you will be prompted to select the state of the event detection bypass.
Page 173: Figure 10-8 Conﬁgure Trigger Menu Tree
Triggering Models 2500 and 2502 User’s Manual • HALT — Use to return the Model 2500 to the idle state. HALT does not turn off the output. The programmed source level will still be available at the OUTPUT terminals. The following actions will take the Model 2500 out of idle: –...
Page 174: Remote Triggering
Programmable counters allow operations to be repeated, and various input and out- put trigger options are available to provide source-measure synchronization between the Model 2500 and other instruments (via the Trigger Link). Idle and initiate The instrument is considered to be in the idle state (ARM annunciator off) when it is not operating within the trigger model layers.
Page 175: Figure 10-9 Trigger Model (Remote Operation)
10-18 Triggering Models 2500 and 2502 User’s Manual Figure 10-9 Trigger model (remote operation) Note: The following commands place the Model 2500 into See Note idle: DCL, SDC, ABORt, *RST, SYSTem:PREset and *RCL INITiate Idle Layer SOURce :DIRection ARM :SOURce...
Page 176: Event Detection
The timer resets to its initial state when the instrument goes into idle. MANual — Event detection occurs when the TRIG key is pressed. The Model 2500 must be in LOCAL mode for it to respond to the TRIG key. Press the LOCAL key or send GTL over the bus to take the Model 2500 out of remote.
Page 177: Trigger Layer
10-20 Triggering Models 2500 and 2502 User’s Manual NSTest — Event detection occurs when the SOT (start of test) line of the Digital I/O port is pulsed low. This pulse is received from the handler to start limit testing. See Section PSTest —...
Page 178: Trigger Delay
Delay Action of the SDM cycle. The Delay Action is discussed next. Source, delay, and measure actions The SDM cycle of the Model 2500 consists of three actions: Source, Delay, and Measure: SOURCE action — Any programmed output voltage level changes are performed.
Page 179: Counters
(ARM:COUNt 3). Three 10-point sweeps can then be performed for a total of 30 source- delay-measure actions. The maximum buffer size for the Model 2500 is 3000 readings. The product of the ﬁnite values of the two counters cannot exceed 3000. For example, if you set an arm count of two, the maximum trigger count will be 3000 (3000 / 2 = 1500).
Page 180: Gpib Defaults
1V source level. On the second pass, three measurements will be performed at the 2V source level. After the last measurement, the Model 2500 returns to the idle state. Note that the product of the arm count (ﬁnite value) and trigger count determines the number of measurements that are performed.
Page 181: Remote Trigger Commands
Section Table 10-1 Remote trigger command Command Description :INITiate Take Model 2500 out of idle state. :ABORt Abort operation, return to idle. :ARM:COUNt <n> Set arm count (n = count). :ARM:SOURce <name> Specify arm control source. (Name = IMMediate, TLINk, TIMer, MANual, BUS, NSTest, PSTest, or BSTest.)
Page 182: Remote Trigger Example
10-25 Remote trigger example Table 10-2 summarizes the command sequence for basic trigger operation. These com- mands set up Model 2500 triggering as follows: • Arm layer source: bus • Arm layer count: 2 • Trigger layer delay: 0.1s • Trigger layer count: 10 •...
Page 183: Limit Testing
• Conﬁguring and performing limit tests — Describes how to conﬁgure the Model 2500 for limit testing and summarizes a typical test procedure. • Remote limit testing — Summarizes limit commands and provides a basic program- ming example.
Page 184: Types Of Limits
11-2 Limit Testing Models 2500 and 2502 User’s Manual Types of limits As shown in Figure 11-1, there are six limit tests that can be performed on a DUT. • Limit 1: channel 1 hardware (compliance) limit test. • Limit 2: channel 2 hardware (compliance) limit test.
Page 185: Data Flow
These hardware (H/W) tests check the voltage source compliance states of the Model 2500. Limit 1 uses the channel 1 voltage source current compliance current value (20mA) as the limit, while Limit 2 uses the channel 2 voltage source compliance current as the limit.
Page 186: Binning
If disabled, operation proceeds to the next test. The following assumes the ﬁrst three limit tests are enabled and the digital output of the Model 2500 is connected to a component handler for DUT binning. See “Binning systems,”...
Page 187: Figure 11-2 Grading Mode Limit Testing
Models 2500 and 2502 User’s Manual Limit Testing 11-5 Figure 11-2 Grading mode limit testing Start Turn Output ON and Press LIMIT key. Wait for SOT Pulse from Handler Perform Source- Measure Action Immediate Perform Display Output Limit 1/2 Binning...
Page 188: Binning Control
11-6 Limit Testing Models 2500 and 2502 User’s Manual Binning control The binning control selection determines when the testing process stops and the appropri- ate binning operation occurs. The results are communicated through the Digital I/O port based on limit test data. (See “Binning systems,”...
Page 189: Pass Condition
If programmed to perform additional tests (i.e., sweep) on the DUT package, oper- ation loops back up to perform the next source-measure action. After all programmed test cycles are successfully completed, the Model 2500 outputs the pass pattern to the compo- nent handler to perform the binning operation.
Page 190: Sorting Mode
LIMIT key. The testing process will start when the component handler sends the start-of- test (SOT) strobe pulse to the Model 2500. Note that if a handler is not used, testing will start when LIMIT is pressed. Pressing LIMIT a second time terminates the testing process.
Page 191: Figure 11-5 Sorting Mode Limit Testing
Models 2500 and 2502 User’s Manual Limit Testing 11-9 Figure 11-5 Sorting mode limit testing Start Turn Output ON and press LIMIT key. Wait for SOT Pulse from Handler Perform Source- Measure Action Perform Output Limit 1/2 Display Pass Limit 1/2 Fail Pattern “FAIL”...
Page 192: Handler Interface
“Limit test programming example,” page 11-21. Handler interface The Model 2500 is interfaced to a handler via the Digital I/O port as shown in Figure 11-6. The I/O port has four lines for output signals and one line for input signals. The output lines are used to send the test pass/fail signal(s) to the handler to perform the binning operation.
Page 193: Sot Line
If the handler requires low-going pulses, then the four digital output lines of the Model 2500 must initially be set to high. This initial HI, HI, HI, HI clear pattern on the output lines represents a no action condition for the handler since it is waiting for one of the lines to go low.
Page 194: Category Register Component Handler
Category register component handler When using this type of handler, the Model 2500 sends a bit pattern to three handler lines when a pass or fail condition occurs. This bit pattern determines the bin assignment for the DUT. With the pass/fail pattern on the output, line #4 is then pulsed. This end-of-test (EOT) pulse latches the bit pattern into the register of the handler, which places the DUT in the assigned bin.
Page 195: Figure 11-7 Binning System—Single Element Devices
Models 2500 and 2502 User’s Manual Limit Testing 11-13 Figure 11-7 Binning system—single element devices Handler OUTPUT INPUT Model 2500 Figure 11-8 Binning system—multiple element devices Switching Mainframe Handler Trigger Link DUTs Scanner Card Ch 1 Ch 2 Ch 3...
Page 196: Multiple-Element Device Binning
Trigger operations for the scanner and Model 2500 must be conﬁgured appropriately for this test. In general, the scanner must be conﬁgured to scan three channels, and the Model 2500 must be conﬁgured to perform a 3-point sweep and output a trigger to the scanner after each measurement. See Section 10 for details.
Page 197: Auto-Clear Timing
Models 2500 and 2502 User’s Manual Limit Testing 11-15 Auto-clear timing The following example timing diagram (Figure 11-9) and discussion explain the relation- ship between the digital output lines for auto-clear. This example uses the 3-bit digital out- put mode, and uses line 4 as /EOT. That is, line 4 will pulse low to signal end-of-test.
Page 198: Conﬁguring And Performing Limit Tests
11-16 Limit Testing Models 2500 and 2502 User’s Manual Conﬁguring and performing limit tests Conﬁguring limit tests Press CONFIG and then LIMIT to display the CONFIG LIMITS MENU. The limits con- ﬁguration menu is structured shown below and in Figure 11-10.
Page 199 – FAIL-MODE — Use to select the fail mode for Limit 1 and Limit 2 tests. With IN selected, the test will fail when the Model 2500 is in compliance. With OUT selected, the test will fail when not in compliance. Also use to specify the digital output bit pattern for Limit 1 and Limit 2 IN or OUT test failure (0 to 7, 3-bit;...
Page 200: Performing Limit Tests
As previously explained in Section 2, your test system could be as simple as connecting one or two DUTs to the Model 2500 or could employ the use of a handler for binning operations. Adding a scanner to the test system allows you to test multiple devices. Make sure that the Digital I/O is conﬁgured appropriately for the handler you are using.
Page 201: Step 3. Conﬁgure Limit Tests
Step 4. Turn output on. Press the ON/OFF key to turn the output on (red OUTPUT indicator turns on). The Model 2500 will output the programmed bias voltage level. Step 5. Start testing process. To enable the limit tests, press the LIMIT key. If the /SOT line of the Digital I/O is being used by a handler, the testing process will not start until the handler sends a low-going pulse.
Page 202: Remote Limit Testing
11-20 Limit Testing Models 2500 and 2502 User’s Manual Remote limit testing Limit commands Table 11-1 summarizes remote commands to control limit testing. Note that LIMitX refers to identical software limits LIMit3 through LIMit6. See Section “CALCulate7” “SOURce3,” for more details on these commands.
Page 203: Limit Test Programming Example
Models 2500 and 2502 User’s Manual Limit Testing 11-21 Table 11-1 (continued) Limit commands Command* Description :CALCulate7:CLIMits:PASS:SOURce3 <NRf> | Specify pass bit pattern. (NRf | NDN = pattern.) <NDN> Sorting mode only if Limits 3-6 enabled. :CALCulate7:CLIMits:FAIL:SOURce3 <NRf> | Specify fail bit pattern for sorting mode.
Page 204: Table 11-2 Limits Test Programming Example
11-22 Limit Testing Models 2500 and 2502 User’s Manual Table 11-2 summarizes the basic SCPI command sequence for performing a limit test for the diode current test. NOTE Appendix H for a complete program listing that includes additional pro- gramming steps necessary to test the values returned by the :CALC7:LIM3:FAIL? and :CALC7:LIM4:FAIL? queries.
Page 205: Digital I/O Port, Output Enable, And Output Conﬁguration
Digital I/O Port, Output Enable, and Output Conﬁguration • Digital I/O port — Discusses the various input/output lines on the digital I/O port as well as the +5V line that can be used to power external logic circuits. • Output enable — Describes how to use the digital I/O port output enable line to inhibit the voltage source outputs.
Page 206: Digital I/O Port
Models 2500 and 2502 User’s Manual Digital I/O port The Model 2500 has a digital input/output port that can be used to control external digital circuitry, such as a handler that is used to perform binning operations when testing limits.
Page 207: Digital Output Lines
When using a category register handler for limit testing, output line #4 is typically used for the end-of-test (EOT) or BUSY pulse. This pulse from the Model 2500 signals the handler to perform the binning operation, or indicates a busy condition. (See Section “Conﬁg-...
Page 208: Digital Output Conﬁguration
12-4 Digital I/O Port, Output Enable, and Output Configuration Models 2500 and 2502 User’s Manual Digital output conﬁguration There are two basic methods to connect external components to the digital output lines, sink operation and source operation. Sink operation Figure 12-2 shows the basic output conﬁguration for sink operation.
Page 209: Source Operation
Models 2500 and 2502 User’s Manual Digital I/O Port, Output Enable, and Output Configuration 12-5 Source operation Figure 12-3 shows the basic output conﬁguration for source operation. In this case, the external relay coil is connected between the digital output line (pins 1 to 4) and ground (pin 9).
Page 210: Remote Digital Output Control
The digital I/O port provides an output enable line for use with a test ﬁxture interlock switch. When properly used, the voltage source outputs of the Model 2500 will turn OFF when the lid of the test ﬁxture is opened.
Page 211: Figure 12-4 Using Test Fixture Output
When the output enable is activated (see “Front panel output conﬁguration,” page 12-8), the output of the Model 2500 cannot be turned on unless the output enable line is pulled low through a switch to ground as shown in Figure 12-4A.
Page 212: Front Panel Output Conﬁguration
SDM cycle. The OUTPUT turns back on at the beginning of the next SDM cycle. With ENABLE and AFTER-TRIG-COUNT, the output will remain on until the trigger count expires. When disabled, the OUTPUT stays on as long as the Model 2500 is operating within the trigger model (ARM annunciator on). With the OUTPUT enabled, pressing the ON/OFF key will disable the OUTPUT and disable auto output off.
Page 213: Remote Output Conﬁguration
Models 2500 and 2502 User’s Manual Digital I/O Port, Output Enable, and Output Configuration 12-9 Remote output conﬁguration Output conﬁguration commands Table 12-2 summarizes output conﬁguration commands. These commands include those to enable and disable the output enable line as well as commands to control output off states.
Page 214: Output Conﬁguration Programming Example
12-10 Digital I/O Port, Output Enable, and Output Configuration Models 2500 and 2502 User’s Manual Output conﬁguration programming example Table 12-3 lists the command sequence for output conﬁguration. These commands set up the Model 2500 as follows: • Output enable: on •...
Page 215: Remote Operations
• Programming syntax — Describes the basic programming syntax for both common and SCPI commands. • RS-232 interface operation — Outlines use of the RS-232 interface to control the Model 2500 via remote. Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 TestEquipmentDepot.com...
Page 216: Differences: Remote Vs. Local Operation
Differences: remote vs. local operation Local-to-remote transition When changing from local-to-remote operation the following takes place: • The Model 2500 stops taking readings and is placed into the IDLE layer of the Trigger Model. • All menus are exited. • All pending front panel commands are aborted.
Page 217: Gpib Operation
The above standards deﬁne a syntax for sending data to and from instruments, how an instrument interprets this data, what registers should exist to record the state of the instru- ment, and a group of common commands. The Model 2500 also conforms to this standard: • SCPI 1996.0 (Standard Commands for Programmable Instruments) This standard deﬁnes a command language protocol.
Page 218: Gpib Connections
13-4 Remote Operations Models 2500 and 2502 User’s Manual GPIB connections To connect the Model 2500 to the GPIB bus, use a cable equipped with standard IEEE-488 connectors as shown in Figure 13-1. Figure 13-1 IEEE-488 connector To allow many parallel connections to one instrument, stack the connectors. Two screws are located on each connector to ensure that connections remain secure.
Page 219: Figure 13-3 Ieee-488 And Rs-232 Connector Location
IEEE-488 cables. Available shielded cables from Keithley are Models 7007-1 and 7007-2. To connect the Model 2500 to the IEEE-488 bus, follow these steps: 1. Line up the cable connector with the connector located on the rear panel. The connec- tor is designed so it will ﬁt only one way.
Page 220: Primary Address
Primary address The Model 2500 ships from the factory with a GPIB primary address of 25. When the unit powers up, it momentarily displays the primary address. You can set the address to a value from 0 to 30, but do not assign the same address to another device or to a controller that is on the same GPIB bus (controller addresses are usually 0 or 21).
Page 221: Ren (Remote Enable)
• :MEASure? IFC (interface clear) The IFC command is sent by the controller to place the Model 2500 in the local, talker, lis- tener idle states. The unit responds to the IFC command by cancelling front panel TALK or LSTN lights, if the instrument was previously placed in one of these states.
Page 222: Dcl (Device Clear)
DCL. GET (group execute trigger) GET is a GPIB trigger that is used as an arm event to control operation. The Model 2500 reacts to this trigger if it is the programmed arm control source. The following command...
Page 223: Front Panel Gpib Operation
Clear) command. LSTN This indicator is on when the Model 2500 is in the listener active state, which is activated by addressing the instrument to listen with the correct MLA (My Listen Address) com- mand. LSTN is off when the unit is in the listener idle state. Place the unit in the listener idle state by sending UNL (Unlisten), addressing it to talk, or sending IFC (Interface Clear) command over the bus.
Page 224: Srq
13-10 Remote Operations Models 2500 and 2502 User’s Manual You can program the instrument to generate a service request (SRQ) when one or more errors or conditions occur. When this indicator is on, a service request has been generated. This indicator stays on until the serial poll byte is read or all the conditions that caused SRQ have been cleared.
Page 225 Models 2500 and 2502 User’s Manual Remote Operations 13-11 These brackets indicate that :IMMediate is implied (optional) and does not have to be used. Thus, the above command can be sent in one of two ways: :INITiate :INITiate:IMMediate Notice that the optional command is used without the brackets. When using optional com- mand words in your program, do not include the brackets.
Page 226: Query Commands
13-12 Remote Operations Models 2500 and 2502 User’s Manual <NDN> Non-decimal numeric — This parameter is used to send values in the binary, octal, or hexadecimal format. The prefix designates the format type: #Bxx...x #B specifies the binary format. xx...x is the binary number (using 0s and 1s).
Page 227: Case Sensitivity
Models 2500 and 2502 User’s Manual Remote Operations 13-13 Case sensitivity Common commands and SCPI commands are not case sensitive. You can use upper or lower case and any case combination. Examples: *RST = *rst :DATA? = :data? :SYSTem:PRESet = :system:preset NOTE Using all upper case will result in slightly faster command response times.
Page 228: Program Messages
13-14 Remote Operations Models 2500 and 2502 User’s Manual Program messages A program message is made up of one or more command words sent by the computer to the instrument. Each common command is a three letter acronym preceded by an asterisk (*).
Page 229: Command Path Rules
Models 2500 and 2502 User’s Manual Remote Operations 13-15 Command path rules • Each new program message must begin with the root command, unless it is optional (e.g., [:SENSe[1]]). If the root is optional, simply treat a command word on the next level as the root.
Page 230: Response Messages
Model 2500 is addressed to talk. The responses are sent in the order the query commands were sent and are separated by semicolons (;). Items within the same query are separated by commas (,).
Page 231: Rs-232 Interface Operation
>11 bits). This clears any pending operation, discards any pending output, and returns a “DCL.” Baud rate The baud rate is the rate at which the Model 2500 and the programming terminal commu- nicate. Choose one these available rates: • 57600 •...
Page 232: Terminator
13-18 Remote Operations Models 2500 and 2502 User’s Manual Terminator The Model 2500 can be conﬁgured to terminate each program message that it transmits to the controller with any of the following combinations of <CR> and <LF>: <CR> Carriage return <CR+LF>...
Page 233: Error Messages
Models 2500 and 2502 User’s Manual Remote Operations 13-19 Table 13-2 RS-232 connector pinout Pin number Description Not used TXD, transmit data RXD, receive data Not used GND, signal ground Not used RTS, ready to send CTS, clear to send Not used Note: CTS and RTS are tied together.
Page 234: Programming Example
Programming example The following QuickBasic 4.5 programming example will control the Model 2500 via the RS-232 COM2 port. Place the Model 2500 into the RS-232 mode from the front panel main menu (press MENU, select COMMUNICATION, select RS-232). When the com- munication setting is changed, the Model 2500 will reset into that mode.
Page 235: Status Structure
Status Structure • Overview — Provides an operational overview of the status structure for the Model 2500. • Clearing registers and queues — Covers the actions that clear (reset) registers and queues. • Programming and reading registers — Explains how to program enable registers and read any register in the status structure.
Page 236: Overview
Queues The Model 2500 uses an output queue and an error queue. The response messages to query commands are placed in the output queue. As various programming errors and status mes- sages occur, they are placed in the error queue.
Page 237: Figure 14-1 Model 2500 Status Register Structure
Models 2500 and 2502 User’s Manual Status Structure 14-3 Figure 14-1 Model 2500 status register structure Questionable Event Questionable Questionable Condition Event Enable Register Register Register & & & & & & & Logical & Calibration Summary & & &...
Page 238: Clearing Registers And Queues
Models 2500 and 2502 User’s Manual Clearing registers and queues When the Model 2500 is turned on, the bits of all registers in the status structure are cleared (reset to 0), and the two queues are empty. Commands to reset the event and event...
Page 239: Programming And Reading Registers
Models 2500 and 2502 User’s Manual Status Structure 14-5 Programming and reading registers Programming enable registers The only registers that can be programmed by the user are the enable registers. All other registers in the status structure are read-only registers. The following explains how to ascertain the parameter values for the various commands used to program enable registers.
Page 240: Reading Registers
14-6 Status Structure Models 2500 and 2502 User’s Manual format) parameter type is used to send decimal values, and does not use a header. The following examples show the proper parameter syntax for setting Bits B5, B3, and B2: #b101100 Binary format (<NDN>...
Page 241: Status Byte And Service Request (Srq)
Models 2500 and 2502 User’s Manual Status Structure 14-7 Status byte and service request (SRQ) Service request is controlled by two 8-bit registers; the status byte register and the service request enable register. Figure 14-3 shows the structure of these registers.
Page 242: Status Byte Register
Depending on how it is used, Bit B6 of the Status Byte Register is either the Request for Service (RQS) bit or the Master Summary Status (MSS) bit: • When using the serial poll sequence of the Model 2500 to obtain the status byte (a.k.a. serial poll byte), B6 is the RQS bit. See “Serial polling and SRQ”...
Page 243: Service Request Enable Register
Typically, SRQs are managed by the serial poll sequence of the Model 2500. If an SRQ does not occur, bit B6 (RQS) of the status byte register will remain cleared, and the pro- gram will simply proceed normally after the serial poll is performed.
Page 244: Status Byte And Service Request Commands
14-10 Status Structure Models 2500 and 2502 User’s Manual Status byte and service request commands The commands to program and read the status byte register and service request enable reg- ister are listed in Table 14-3. For details on programming and reading registers, see “Pro-...
Page 245: Status Register Sets
Status register sets As shown in Figure 14-1, there are four status register sets in the status structure of the Model 2500: Standard Event Status, Operation Event Status, Measurement Event Status, and Questionable Event Status. NOTE Appendix B for details on which register bits are set by speciﬁc error and status conditions.
Page 246 • Bit B6, User Request (URQ) — Set bit indicates that the LOCAL key on the Model 2500 front panel was pressed. • Bit B7, Power ON (PON) — Set bit indicates that the Model 2500 has been turned off and turned back on since the last time this register has been read.
Page 247: Operation Event Register
TLINK trigger event to occur. • Bit B6, Waiting for Arm Event (Arm) — Set bit indicates that the Model 2500 is in the arm layer waiting for an arm event to occur.
Page 248: Measurement Event Register
• Bit B7, Reading Overﬂow (ROF) — Set bit indicates that the current reading exceeds the selected measurement range of the Model 2500. • Bit B8, Buffer Available (BAV) — Set bit indicates that there are at least two readings in the buffer.
Page 249: Figure 14-6 Measurement Event Status
Models 2500 and 2502 User’s Manual Status Structure 14-15 Figure 14-6 Measurement event status — Measurement stat:meas:cond? (B15) (B14) (B13) (B12) (B11) (B10) (B9) (B8) (B7) (B6) (B5) (B4) (B3) (B2) (B1) (B0) Condition Register — Measurement Event stat:meas? (B15)
Page 250: Questionable Event Register
14-16 Status Structure Models 2500 and 2502 User’s Manual Questionable event register The used bits of the questionable event register (Figure 14-7) are described as follows: • Bits B0 through B7 — Not used. • Bit B8, Calibration Summary (Cal) — Set bit indicates that an invalid calibration constant was detected during the power-up sequence.
Page 251: Condition Registers
For example, while the Model 2500 is in the idle state, bit B10 (Idle) of the operation condition register will be set. When the instrument is taken out of idle, bit B10 clears.
Page 252: Event Enable Registers
14-18 Status Structure Models 2500 and 2502 User’s Manual Event enable registers Figure 14-1 shows, each status register set has an enable register. Each event register bit is logically ANDed (&) to a corresponding enable bit of an enable register. Therefore,...
Page 253: Programming Example - Program And Read Register Set
An empty output queue clears the MAV bit in the status byte register. A message is read from the output queue by addressing the Model 2500 to talk after the appropriate query is sent.
Page 254: Error Queue
When empty, the message “0, No Error” is placed in the queue. Messages in the error queue are preceded by a code number. Negative (-) numbers are used for SCPI-deﬁned messages, and positive (+) numbers are used for Keithley-deﬁned messages. The messages are listed in Appendix B.
Page 255: Programming Example - Read Error Queue
Models 2500 and 2502 User’s Manual Status Structure 14-21 Table 14-9 Error queue commands Command Description Default STATus STATus Subsystem: :QUEue Read error queue: Note 1 [:NEXT]? Read and clear oldest error/status (code and message). :ENABle <list> Specify error and status messages for error queue.
Page 256: Common Commands
Common Commands • Command summary — Lists the IEEE-488.2 common commands used by the Model 2500. • Command reference — Provides a detailed reference for all common commands except for those associated with the status structure, which are discussed in Section Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176...
Page 257: Command Summary
Places an ASCII “1” into the output queue when all pending selected device operations have been completed. *OPT? Option query Query Model 2500 for list of installed options. *RCL <NRf> Recall command Returns the Model 2500 to the user-saved setup. *RST...
Page 258: Command Reference
The identiﬁcation code includes the manufacturer, model number, serial number, and ﬁrm- ware revision levels and is sent in the following format: KEITHLEY INSTRUMENTS INC., MODEL 2500, xxxxxxx, yyyyy/zzzzz /a/d Where: xxxxxxx is the serial number. yyyyy/zzzzz is the ﬁrmware revision levels of the digital board ROM and display board ROM, including date and time of build.
Page 259: Opc Programming Example
* Additional code required to test for “1” in output queue. *OPT? — option query Return list of installed options When *OPT? is sent, Model 2500 returns a list of any installed options. *SAV <NRf> — save Save present setup in memory *RCL <NRf>...
Page 260: Sav, *Rcl Programming Example
*TRG — trigger Send bus trigger to Model 2500 Use the *TRG command to issue a GPIB trigger to the Model 2500. It has the same effect as a group execute trigger (GET). Use the *TRG command as an event to control operation. The Model 2500 reacts to this trigger if BUS is the programmed arm control source.
Page 261: Trg Programming Example
Use this query command to perform a checksum test on ROM. The command places the coded result (0 or 1) in the output queue. When the Model 2500 is addressed to talk, the coded result is sent from the output queue to the computer.
Page 262: Scpi Signal-Oriented Measurement Commands
SCPI Signal-Oriented Measurement Commands • Command summary — Summarizes those commands used to conﬁgure and acquire readings. • Conﬁguring measurement function — Provides detailed information on commands to conﬁgure the measurement function. • Acquiring readings — Describes commands to acquire post-processed readings, both trigger and acquire readings, and to perform a single measurement.
Page 263: Command Summary
This command conﬁgures the instrument to measure DC current. The :READ? command is then typically used to trigger a speciﬁed number of measurements. See “READ?,” page 16-4. When this command is sent, the Model 2500 will be conﬁgured as follows: • Select current function. •...
Page 264: Acquiring Readings
Appendix C for a detailed explanation on how data ﬂows through the vari- ous operation blocks of the Model 2500. It clariﬁes the types of readings that are acquired by the various commands to read data. Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176...
Page 265: Data[:Latest]
Appendix C for a detailed explanation on how data ﬂows through the vari- ous operation blocks of the Model 2500. It clariﬁes the type of readings that are acquired by the various commands to read data. Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176...
Page 266: Measure[:Current[:Dc]]
Models 2500 and 2502 User’s Manual SCPI Signal-Oriented Measurement Commands 16-5 MEASure[:CURRent[:DC]]? Parameters CURRent[:DC] Amps function Description This command combines other signal-oriented measurement commands to perform a “one-shot” measurement and acquire the reading. When this command is sent, the following commands execute in the order that they are presented.
Page 267: Scpi Command Reference
SCPI Command Reference • Reference tables — Summarizes each SCPI command subsystem. • SCPI subsystems — Provides detailed information on all commands in each SCPI subsystem. Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 TestEquipmentDepot.com...
Page 268: Reference Tables
17-2 SCPI Command Reference Models 2500 and 2502 User’s Manual Reference tables Table 17-1 through Table 17-10 summarize the commands for each SCPI subsystem. The following list includes the SCPI subsystem commands and the table number where each command is summarized.
Page 269 Models 2500 and 2502 User’s Manual SCPI Command Reference 17-3 Table 17-1 CALCulate command summary Default Command Description parameter SCPI :CALCulate[1] Subsystem to control CALC1 (channel 1) math: :FORMat <name> Select math format (MXB[1], COND[1], MXB[1] POWER[1], RES[1], or OP[1]).
Page 270 17-4 SCPI Command Reference Models 2500 and 2502 User’s Manual Table 17-1 (continued) CALCulate command summary Default Command Description parameter SCPI :CALCulate3 Subsystem to control CALC3 (channel 1 REL): :FEED <name> Select input path (SENSe[1] or CALCulate[1]). SENS1 :FEED? Query CALC3 feed.
Page 271: Table 17-1 Calculate Command Summary
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-5 Table 17-1 (continued) CALCulate command summary Default Command Description parameter SCPI :CALCulate7 Path to CALC7 (limit tests): :DATA? Return all CALC7 results. :LATest? Return most recent CALC7 result. :FEED <name>...
Page 272 17-6 SCPI Command Reference Models 2500 and 2502 User’s Manual Table 17-1 (continued) CALCulate command summary Default Command Description parameter SCPI :CALCulate7 CALC7 limit tests (continues): :LIMitX Path to software limits. LIMitX = LIMit3...LIMit6. :UPPer Conﬁgure upper limit: [:DATA] <n>...
Page 273 Models 2500 and 2502 User’s Manual SCPI Command Reference 17-7 Table 17-1 (continued) CALCulate command summary Default Command Description parameter SCPI :CALCulate7 CALC7 limit tests (continues): :CLEar Clear test results: [:IMMediate] Clear latest limit test result and reset Digital I/O port back to :SOURce3:TTL settings.
Page 274: Table 17-2 Display Command Summary
17-8 SCPI Command Reference Models 2500 and 2502 User’s Manual Table 17-2 DISPlay command summary Default Command Description parameter SCPI :DISPlay :ENABle <b> Turn on or turn off front panel display. Note 1 :ENABle? Query state of display. :MODE <name>...
Page 275: Table 17-3 Format Command Summary
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-9 Table 17-3 FORMat command summary Default Command Description parameter SCPI :FORMat :SREGister <name> Select data format for reading status event registers ASCii (ASCii, HEXadecimal, OCTal or BINary). :SREGister? Query format for reading status event registers.
Page 276: Table 17-4 Output Command Summary
17-10 SCPI Command Reference Models 2500 and 2502 User’s Manual Table 17-4 OUTPut command summary Default Command Description parameter SCPI :OUTPut[1] Path to control output 1. [:STATe] <b> Turn source 1 on or off. [:STATe]? Query state of source 1.
Page 277: Table 17-5 Sense Command Summary
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-11 Table 17-5 SENSe command summary Default Command Description parameter SCPI [:SENSe[1]] Sense 1 subsystem to control channel 1 measurement: :CURRent[:DC] Path to conﬁgure current: :RANGe Conﬁgure measurement range: [:UPPer] <n>...
Page 278 17-12 SCPI Command Reference Models 2500 and 2502 User’s Manual Table 17-5 (continued) SENSe command summary Default Command Description parameter SCPI :SENSe2 Sense 2 subsystem to control channel 2 measurement: :CURRent[:DC] Path to conﬁgure current: :RANGe Conﬁgure measurement range: [:UPPer] <n>...
Page 279: Table 17-6 Source Command Summary
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-13 Table 17-6 SOURce command summary Default Command Description parameter SCPI :SOURce[1] Path to control channel 1 source: :CLEar Path to clear source: [:IMMediate] Turn selected source off. :AUTO Automatically turn source on/off.
Page 280 17-14 SCPI Command Reference Models 2500 and 2502 User’s Manual Table 17-6 (continued) SOURce command summary Default Command Description parameter SCPI :SOURce[1] Path to conﬁgure channel 1 source (continued): :VOLTage :STARt <n> Specify start level for V-sweep; -100 to 100.
Page 281 Models 2500 and 2502 User’s Manual SCPI Command Reference 17-15 Table 17-6 (continued) SOURce command summary Default Command Description parameter SCPI :SOURce2 Path to control channel 2 source: :CLEar Path to clear source: [:IMMediate] Turn selected source off. :AUTO Select source auto on/off mode source.
Page 282 17-16 SCPI Command Reference Models 2500 and 2502 User’s Manual Table 17-6 (continued) SOURce command summary Default Command Description parameter SCPI :SOURce2 Path to conﬁgure channel 2 source (continued): :VOLTage :STARt <n> Specify start level for V-sweep; -100 to 100.
Page 283 Models 2500 and 2502 User’s Manual SCPI Command Reference 17-17 Table 17-6 (continued) SOURce command summary Default Command Description parameter SCPI :SOURce3 Path to control digital output lines: :BSIZe <n> Set Digital I/O bit size (3, or 4). No effect :BSIZe? Query Digital I/O bit size.
Page 284: Table 17-7 Status Command Summary
17-18 SCPI Command Reference Models 2500 and 2502 User’s Manual Table 17-7 STATus command summary Default Command Description parameter SCPI :STATus Note 1 :MEASurement Control measurement event registers: [:EVENt]? Read the event register. Note 2 :ENABle <NDN> Program the enable register.
Page 285: Table 17-8 System Command Summary
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-19 Table 17-8 SYSTem command summary Default Command Description parameter SCPI :SYSTem :PRESet Return to :SYSTem:PRESet defaults. :POSetup <name> Select power-on setup (RST, PRESet or SAV 0-4). :POSetup? Query power-on setup.
Page 286: Table 17-9 Trace Command Summary
17-20 SCPI Command Reference Models 2500 and 2502 User’s Manual Table 17-9 TRACe command summary Default Command Description parameter SCPI :TRACe|:DATA Use :TRACe or :DATA as root command: Note :DATA? Read the contents of the buffer (data store). :CLEar Clear readings from buffer.
Page 287: Table 17-10 Trigger Command Summary
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-21 Table 17-10 TRIGger command summary Default Command Description parameter SCPI :INITiate[:IMMediate] Initiate source and measure cycle(s). :ABORt Reset trigger system. Goes to idle state. :ARM Path to program Arm Layer:...
Page 288: Calculate Subsystems
Appendix C for a detailed explanation on how data ﬂows through the vari- ous CALC operation blocks of the Model 2500. It clariﬁes the type of readings that are acquired by the various commands to read data. Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176...
Page 289: Calculate[1] And Calculate2
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-23 CALCulate[1] and CALCulate2 Conﬁgure and control math functions The CALC1 and CALC2 commands control math functions for channel 1 and channel 2 respectively. They perform the remote equivalents to the front panel CONFIG MSR1 and CONFIG MSR2 conﬁguration menus.
Page 290: Set Mx + B Parameters
17-24 SCPI Command Reference Models 2500 and 2502 User’s Manual Set MX + B parameters MBFactor <n> :CALCulate[1]:KMATh:MBFactor <n> Select channel 1 B (offset) value :CALCulate2:KMATh:MBFactor <n> Select channel 2 B (offset) value Parameters <n> = -9.99999e20 to Specify B (offset) value for MX + B +9.99999e20...
Page 291: Set Optical Power Parameters
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-25 Set optical power parameters DC<n> :CALCulate[1]:KMATh:DC<n> Set channel 1 dark current value :CALCulate2:KMATh:DC<n> Set channel 2 dark current value Parameters <n>=-9.999999e20 to +9.999999e20 Specify dark current in amps DEFault MINimum -9.999999e20...
Page 292: Enable And Read Math Function Result
2500 is triggered to perform the programmed source and measure operations. After the Model 2500 returns to idle, you can read the result of the selected math function using the :CALC1:DATA? or :CALC2:DATA? command. (See below). When disabled, the :CALC1:DATA? and CALC2:DATA? command will return the NAN (not a number) value of +9.91e37.
Page 293: Calculate3 And Calculate4
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-27 CALCulate3 and CALCulate4 Conﬁgure and control relative functions The CALC3 and CALC4 commands control relative for channel 1 and channel 2 respec- tively. They perform the remote equivalents to the front panel REL and CONFIG REL conﬁguration menu.
Page 294: Set Or Acquire Relative Value
17-28 SCPI Command Reference Models 2500 and 2502 User’s Manual Set or acquire relative value OFFSet <n> :CALCulate3:NULL:OFFSet <NRf> Specify null offset (REL) for channel 1 :CALCulate4:NULL:OFFSet <NRf> Specify null offset (REL) for channel 2 Parameters <NRf> = -9.999999e20 to Specify null offset value 9.999999e20...
Page 295: Calculate5
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-29 CALCulate5 Conﬁgure and control RATIO function The CALC5 commands control the RATIO function. They perform the remote equivalents to the front panel RATIO and CONFIG RATIO conﬁguration menu. Select RATIO calculation mode FORMat <name>...
Page 296: Calculate6
17-30 SCPI Command Reference Models 2500 and 2502 User’s Manual CALCulate6 Conﬁgure and control DELTA function The CALC6 commands control the delta function. They perform the remote equivalents to the front panel DELTA and CONFIG DELTA conﬁguration menu. Select DELTA calculation mode FORMat <name>...
Page 297: Calculate7
• Limit 2: channel 2 compliance (hardware) limit test • Limit 3 through Limit 6: software limits When used with a handler to provide binning operations, communication between the Model 2500 and the handler is provided via the Digital I/O port. (See Section 11 for com- plete details.) Many control aspects of the digital output lines are performed from the...
Page 298: Read Limits Data
These commands are used to specify the condition that will cause the Limit 1 and Limit 2 tests to fail. With IN speciﬁed, the test will fail when the Model 2500 goes into compliance (ﬁxed 20mA current limit for each voltage source). With OUT speciﬁed, the test will fail when the Model 2500 comes out of compliance.
Page 299: Source3 |
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-33 Query :UPPer? Query speciﬁed upper limit :UPPer? DEFault Query *RST default upper limit :UPPer? MINimum Query lowest allowable upper limit :UPPer? MAXimum Query largest allowable upper limit :LOWer? Query speciﬁed lower limit...

Page 300 H = High (>+3V) * OUT 4 not used in 3-bit mode (values = 0 to 7) The Model 2500 can be conﬁgured to place the deﬁned fail bit pattern on the digital output immediately when a fail condition occurs, or it can wait until all testing on a device package is completed (operation leaves trigger layer).
Page 301: Pass:source3 | Ndn
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-35 PASS:SOURce3 <NRf> | NDN :CALCulate7:LIMitx:PASS:SOURce3 <NRf> | <NDN> Set sorting mode pass pattern (x = 3-6) Parameters <NRf> = 0 to 7 (3-bit) Decimal value 0 to 15 (4-bit) Decimal value <NDN>...
Page 302: Fail
The Model 2500 can be conﬁgured to place the deﬁned pass bit pattern on the digital output immediately when the pass condition occurs, or it can wait until all testing on a device package is completed (operation leaves trigger layer).
Page 303: Fail:source3 |
With END selected, the digital output will not update to the pass or fail bit pattern until the Model 2500 completes the sweep or list operation. This allows multiple test cycles to be performed on DUT. With the use of a scanner card, multi-element devices can be tested.

Page 304: Mode
17-38 SCPI Command Reference Models 2500 and 2502 User’s Manual MODE <name> :CALCulate7:CLIMits:MODE <name> Control digital I/O port pass/fail output Parameters <name> = GRADing Output graded pass/fail pattern SORTing Output sorted pass/fail pattern Query :MODE? Query digital I/O pass/fail mode...

Page 305: Calculate8
3. See Appendix C for a detailed explanation on how data ﬂows through the various operation blocks of the Model 2500. It clariﬁes the types of readings that are acquired by the various commands to read data. Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176...
Page 306: Display Subsystem
17-40 SCPI Command Reference Models 2500 and 2502 User’s Manual DISPlay subsystem The display subsystem controls the display of the Model 2500 and is summarized in Table 17-2. Control display DIGits <n> :DISPlay:DIGits <n> Set display resolution Parameters <n> = 3.5 digit resolution...
Page 307: Mode
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-41 MODE <name> :DISPlay:MODE <name> Select CALC block for display Parameters <name> = CALCulate3 Display CALC3 (Ch. 1 REL) CALCulate4 Display CALC4 (Ch. 2 REL) CALCulate5 Display CALC5 (RATIO) CALCulate6 Display CALC6 (DELTA)

Page 308: Read Display
These query commands are used to read what is currently being dis- played on the top and bottom displays. After sending one of these com- mands and addressing the Model 2500 to talk, the displayed data (message or reading) will be sent to the computer.
Page 309: State
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-43 STATe <b> :DISPlay[:WINDow[1]]:TEXT:STATe <b> Control message; top display :DISPlay:WINDow2:TEXT:STATe <b> Control message; bottom display Parameters <b> = 0 or OFF Disable message for speciﬁed display 1 or ON Enable message for speciﬁed display...

Page 310: Figure 17-1 Ascii Data Format
MEASure?, TRACe:DATA?, CALCx:DATA? over the GPIB. All other queries are returned in the ASCII format. NOTE Regardless of which data format for output strings is selected, the Model 2500 will only respond to input commands using the ASCII format. ASCII format The ASCII data format is in a direct readable form for the operator.
Page 311: Figure 17-2 Ieee-754 Single Precision Data Format (32 Data Bits)
NOTE The Model 2500 terminates the binary data string with LF + EOI. If your pro- gram is set to terminate on CR and/or LF, data transfer may terminate prema- turely because one or more data bytes has a CR or LF value. To avoid the problem, set your computer program to terminate on EOI only.
Page 312: Data Elements
17-46 SCPI Command Reference Models 2500 and 2502 User’s Manual Data elements ELEMents <item list> :FORMat:ELEMents [SENSe] <item list> Specify data elements for data string Parameters <item list> = CURRent[1] Includes channel 1 current reading CURRent2 Includes channel 2 current reading...
Page 313 STATus — A status word is available to provide status information con- cerning Model 2500 operation. The 24-bit status word is sent in a deci- mal form and must be converted by the user to the binary equivalent to determine the state of each bit in the word. For example, if the status value is 65, the binary equivalent is 0000000000001000001.
Page 314 17-48 SCPI Command Reference Models 2500 and 2502 User’s Manual Grading mode status bit values: Meas. Event Result Bit #: 12 11 10 Status All limit tests passed Bit 5 (LP) Limit test 1 failed Bit 0 (L1) Limit test 2 failed...
Page 315: Source3
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-49 SOURce3 <name> :FORMat:SOURce3 <name> Set SOUR3 and TTL response formats Parameters <name> = ASCii ASCII format HEXadecimal Hexadecimal format OCTal Octal format BINary Binary format Query :SOURce3? Query response format...

Page 316: Trace Data Elements
17-50 SCPI Command Reference Models 2500 and 2502 User’s Manual TRACe data elements TRACe <item list> :FORMat:ELEMents:TRAce <item list> Specify data elements for buffer Parameters <item list> = CURRent[1] Includes channel 1 current reading CURRent2 Includes channel 2 current reading...
Page 317: Byte Order
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-51 Byte order BORDer <name> :FORMat:BORDer <name> Specify binary byte order Parameters <name> = NORMal Normal byte order for binary formats SWAPped Reverse byte order for binary formats Query :BORDer? Query byte order...
Page 318: Output Subsystem
These commands are used to turn the channel 1 and channel 1 source outputs on or off. Turning a source off places the Model 2500 in the idle state. The only exception to this is when source auto clear is enabled. In this mode, the source turns on during each source phase of the SDM cycle and then turns off after each measurement.
Page 319: Output Enable Control
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-53 Output enable control ENABle[:STATe] <b> :OUTPut[1]:ENABle[:STATe] <b> Control output enable for both sources Parameters <b> = 0 or OFF Disable output enable 1 or ON Enable output enable Query :ENABle[:STATe]?
Page 320: Sense Subsystem
SENSe subsystem The SENSe subsystem is used to conﬁgure and control the measurement functions of the Model 2500. SENSe[1] controls channel 1 measurement functions, and :SENSe2 controls channel 2 functions. Some of the commands are global, where a single command affects both channels.
Page 321: Llimit
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-55 Select auto range AUTO <b> [:SENSe[1]]:CURRent[:DC]:RANGe:AUTO <b> Control auto ranging for channel 1 :SENSe2:CURRent[:DC]:RANGe:AUTO <b> Control auto ranging for channel 2 Parameters <b> = 0 or OFF Disable auto range...

Page 322: Set Measurement Speed
17-56 SCPI Command Reference Models 2500 and 2502 User’s Manual Set measurement speed NPLCycles <n> [:SENSe[1]]:CURRent[:DC]:NPLCycles <n> Set channel 1 speed (PLC) :SENSe2:CURRent[:DC]:NPLCycles <n> Set channel 2 speed (PLC) Parameters <n> = 0.01 to 10 Power-line cycles per integration DEFault MINimum 0.01...
Page 323: Conﬁgure And Control Filters
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-57 Conﬁgure and control ﬁlters NOTE Detailed information on the average and median ﬁlters are provided in Section “Filters.” All ﬁlter commands are global and commands affect both channels simultaneously. Average ﬁlter commands COUNt <n>...
Page 324: Tcontrol
17-58 SCPI Command Reference Models 2500 and 2502 User’s Manual TCONtrol <name> [:SENSe[1]]:AVERage:TCONtrol <name> Set average ﬁlter type :SENSe2:AVERage:TCONtrol <name> Set average ﬁlter type Parameters <name> = MOVing Moving average ﬁlter REPeat Repeat average ﬁlter Query :TCONtrol? Query type of average ﬁlter Description These commands are used to control the type of average ﬁlter.

Page 325: Median Filter Commands
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-59 Median ﬁlter commands MEDian:RANK <NRf> [:SENSe[1]]:MEDian:RANK <n> Set median ﬁlter rank :SENSe2:MEDian:RANK <n> Set median ﬁlter rank Parameters <n> = 0 to 5 Specify rank value for median ﬁlter DEFault...
Page 326: Source Subsystem
17-60 SCPI Command Reference Models 2500 and 2502 User’s Manual SOURce subsystem This subsystem is used to conﬁgure and control the two voltage sources, and to set the logic level (high or low) of each digital output line. The commands for this subsystem are...
Page 327: Select Sourcing Mode
SWEep — In this mode, the source will perform a voltage sweep. See “Conﬁgure sweeps,” page 17-66, for commands to deﬁne the sweep. NOTE The sourcing mode will default to FIXed whenever the Model 2500 goes to the local state. Select range RANGe <n>...
Page 328: Auto
Auto range will be disabled if a ﬁxed range is selected. See the previous command. Both *RST and :SYSTem:PREset enables source auto range. When the Model 2500 goes into the local state, source auto range disables. Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 TestEquipmentDepot.com...

Page 329: Set Amplitude For Fixed Source
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-63 Set amplitude for ﬁxed source [:IMMediate][:AMPLitude] <n> :SOURce[1]:VOLTage[:LEVel][:AMPLitude] <n> Set ﬁxed source 1 amplitude :SOURce2:VOLTage[:LEVel][:AMPLitude] <n> Set ﬁxed source 2 amplitude Parameters <n> = -100 to 100 Set source amplitude (volts)
Page 330: Triggered[:Amplitude]
These commands perform the same as the [:IMMediate][:AMPLitude] commands except that the source amplitude is not updated immediately. With this command, the amplitude is updated when the Model 2500 is triggered to perform a source and measure operation. For example, if the...

Page 331: Set Delay
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-65 Set delay NOTE All SOURx:DEL commands are global and affect both simultaneously. DELay <n> :SOURce[1]:DELay <n> Manually set source delay :SOURce2:DELay <n> Manually set source delay Parameters <n> = 0 to 999.998...
Page 332: Select Ground Connect Mode
These commands are used to select the source ranging mode for sweeps using the channel 1 and channel 2 voltage sources. With BEST selected, the Model 2500 will select a single ﬁxed source range that will accom- modate all the source levels in the sweep. For front panel operation, this is the BEST FIXED option.
Page 333: Spacing
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-67 With AUTO selected, the Model 2500 will automatically go to the most sensitive source range for each source level in the sweep. For front panel operation, this is the AUTO RANGE option.

Page 334: Center
17-68 SCPI Command Reference Models 2500 and 2502 User’s Manual (best ﬁxed range). You can use source auto range if sweeping through one or more source ranges. When the sweep is started, the source will output the speciﬁed start level and, after the delay period of the SDM cycle, a measurement is per- formed.

Page 335: Step
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-69 For example, assume you are testing a device that operates at 10V, and you want to sweep from 8 to 12 volts. To do this, you would specify the center to be 10V and the span to be 4 volts (12 - 8).

Page 336: Points
17-70 SCPI Command Reference Models 2500 and 2502 User’s Manual POINts <n> :SOURce[1]:SWEep:POINts <n> Set number of points for source 1 :SOURce2:SWEep:POINts <n> Set number of points for source 2 Parameters <n> = 1 to 3000 Specify number of source-measure...

Page 337: Direction
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-71 DIRection <name> :SOURce[1]:SWEep:DIRection <name> Set direction of source 1 sweep :SOURce2:SWEep:DIRection <name> Set direction of source 2 sweep Parameters <name> = Run sweep from start to stop DOWN Run sweep from stop to start...

Page 338: Points
17-72 SCPI Command Reference Models 2500 and 2502 User’s Manual APPend <NRf list> :SOURce[1]:LIST:VOLTage:APPend <NRf list> Add value(s) to source 1 list :SOURce2:LIST:VOLTage:APPend <NRf list> Add value(s) to source 2 list Parameters <NRf list> = NRf, NRf … NRf NRf =...
Page 339: Logarithmic Sweep
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-73 Logarithmic sweep Logarithmic sweep from 10V to 100V in 20 points: *RST SOUR1:SWE:SPAC LOG SOUR1:VOLT:STAR 1 SOUR1:VOLT:STOP 100 SOUR1:SWE:POIN 20 TRIG:COUN 20 SOUR1:VOLT:MODE SWE OUTP1 ON INIT To determine the source values that will be generated:...
Page 340: Source3
17-74 SCPI Command Reference Models 2500 and 2502 User’s Manual SOURce3 The following commands are used to set the logic level of the digital output lines, and con- trol the pulse width of limit test output patterns that are sent to component handlers. Limit tests are conﬁgured and controlled from the CALCulate7 Subsystem.
Page 341: Actual
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-75 Use the following table to determine the parameter value for the desired decimal digital output pattern: Decimal OUT 4 OUT 3 OUT 2 OUT 1 value* L = Low (Gnd) H = High (>+3V)
Page 342: Bstate
17-76 SCPI Command Reference Models 2500 and 2502 User’s Manual BSTate <b> :SOURce3:TTL4:BSTate <b> Control BUSY and EOT polarity Parameters <b> = Set EOT/BUSYpolarity high Set EOT/BUSY polarity low Query :BSTate? Query EOT/BUSY polarity Description This command sets the polarity of the EOT or BUSY signal in the 3-bit mode.

Page 343: Delay
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-77 Description This command is used to enable or disable auto-clear for the digital out- put lines. When enabled, the output pattern will clear automatically after the pass or fail output bit pattern of a limit test is sent to a handler via the digital output lines.

Page 344: Status Subsystem
17-78 SCPI Command Reference Models 2500 and 2502 User’s Manual STATus subsystem The STATus subsystem is used to control the status registers of the Model 2500. The com- mands in this subsystem are summarized in Table 17-7. NOTE These registers and the overall status structure are fully explained in...
Page 345: Read Condition Registers
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-79 Read condition registers CONDition? :STATus:MEASurement:CONDition? Read Measurement Condition :STATus:QUEStionable:CONDition? Read Questionable Register :STATus:OPERation:CONDition? Read Operation Condition Description These query commands are used to read the contents of the condition registers.
Page 346: Enable
17-80 SCPI Command Reference Models 2500 and 2502 User’s Manual ENABle <list> :STATus:QUEue:ENABle <list> Enable messages for error queue Parameters <list> = (numlist) where numlist is a speciﬁed list of messages that you wish to enable for the Error. Query...

Page 347: System Subsystem
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-81 SYSTem subsystem The SYSTem subsystem contains miscellaneous commands that are summarized in Table 17-8. Default conditions PRESet :SYSTem:PRESet Return to :SYSTem:PRESet defaults Description This command returns the instrument to states optimized for front panel operation.
Page 348: Control Auto Zero
The error queue is a ﬁrst-in, ﬁrst-out (FIFO) register that can hold up to 10 messages. After sending this command and addressing the Model 2500 to talk, the oldest message is sent to the computer and is then removed from the queue.
Page 349: All
Description This query command is similar to the [:NEXT]? command except that all messages in the error queue are sent to the computer when the Model 2500 is addressed to talk. All messages are removed from the queue. COUNt? :SYSTem:ERRor:COUNt?
Page 350: Simulate Key Presses
17-84 SCPI Command Reference Models 2500 and 2502 User’s Manual Simulate key presses :SYSTem:KEY <NRf> Simulate key-press Parameters <NRf> = RANGE EDIT EDIT MENU key DELTA key FILTER key SPEED key CHANNEL SELECT key AUTO key EDIT EXIT key SRC1 key...
Page 351: Read Version Of Scpi Standard
17-85 The queue for the :KEY? query command can only hold one key-press. When :KEY? is sent over the bus, and the Model 2500 is addressed to talk, the key-press code number for the last key pressed (either physi- cally or with :KEY) is sent to the computer.
Page 352: Rwlock
Description This action command is used to reset the absolute timestamp to 0 sec- onds. The timestamp also resets to 0 seconds every time the Model 2500 is turned on. Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176...
Page 353: Trace Subsystem
:FORMat subsystem. NOTE Appendix C for a detailed explanation on how data ﬂows through the vari- ous operation blocks of the Model 2500. It clariﬁes the types of readings that are acquired by the various commands to read data. CLEar :TRACe:CLEar...
Page 354: Conﬁgure And Control Buffer
Description This command is used to read the status of storage memory. After send- ing this command and addressing the Model 2500 to talk, two values separated by commas are sent to the computer. The ﬁrst value indicates how many bytes of memory are available, and the second value indi- cates how many bytes are reserved to store readings.
Page 355: Control
This command is used to select the buffer control. When NEXT is selected, the asterisk (*) annunciator turns on to indicate that the buffer is enabled. The storage process starts when Model 2500 is taken out of idle to perform source-measure operations.

Page 356: Trigger Subsystem
Description This command is used to initiate source and measure operation by tak- ing the Model 2500 out of idle. The :READ? and :MEASure? com- mands also perform an initiation. Command processing will halt until the trigger model returns to the idle state, with the following exceptions: •...
Page 357: Program Trigger Model
For example, assume the arm count is set to 2 and the trigger counter is set to 10, the Model 2500 is conﬁgured to perform 10 source-measure operations twice for a total of 20 source-measure operations.
Page 358: Delay
17-92 SCPI Command Reference Models 2500 and 2502 User’s Manual DELay <n> :TRIGger[:SEQuence[1]]:DELay <n> Set trigger layer delay Parameters <n> = 0 to 999.9999 Specify delay in seconds DEFault 0 second delay MINimum 0 second delay MAXimum 999.9999 second delay...

Page 359: Timer
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-93 source occurs immediately. Subsequent arm events will then occur every 30 seconds. The interval for the timer is set using the :TIMer command. With MANual selected, the event occurs when the TRIG key is pressed.

Page 360: Input
17-94 SCPI Command Reference Models 2500 and 2502 User’s Manual INPut <event list> :TRIGger[:SEQuence[1]][:TCONﬁgure][:ASYNchronous]:INPut <event list> Enable event detectors Parameters <event list> = SOURce Enable Source Event Detector DELay Enable Delay Event Detector SENSe Enable Measure Event Detector NONE Disable all event detectors in Trigger...

Page 361: Iline
Models 2500 and 2502 User’s Manual SCPI Command Reference 17-95 ILINe <NRf> :ARM[:SEQuence[1]][LAYer[1]][:TCONﬁgure]:ILINe <NRf> Select input line; arm layer :TRIGger[:SEQuence[1]][:TCONﬁgure]:ILINe <NRf> Select input line; trigger layer Parameters <NRf> = Line #1 Line #2 Line #3 Line #4 Line #5 Line #6...

Page 362: Output
17-96 SCPI Command Reference Models 2500 and 2502 User’s Manual OUTPut <event list> :ARM[:SEQuence[1]][LAYer[1]][:TCONﬁgure]:OUTPut <event list>Arm layer event :TRIGger[:SEQuence[1]][:TCONﬁgure]:OUTPut <event list> Trigger layer events Parameters Arm Layer Trigger <event list> = TRIGger Trigger on exiting trigger layer NONE Disable arm layer output trigger Trigger Layer Triggers <event list>...

Page 363 Speciﬁcations Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 TestEquipmentDepot.com...
Page 364 2500 and 2502 Dual Photodiode Meters The Models 2500 and 2502 Dual Photodiode Meters can measure and display GENERAL either photodiode current or optical power for two photodiodes with appro- Typical Noise Floor Measurement Specification priate user-supplied optical power gain/wavelength calibration factors.
Page 365 Models 2500 and 2502 User’s Manual Specifications Accuracy calculations The following information discusses how to calculate accuracy for both current measure- ment and voltage bias functions. Current measurement accuracy Current measurement accuracy is calculated as follows: Accuracy = ±(% of reading + offset) As an example of how to calculate the actual reading limits, assume that you are measur- ing 1mA on the 2mA range.
Page 366: Status And Error Messages
Status and Error Messages Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 TestEquipmentDepot.com...
Page 367 Each message is preceded by a code number. Negative (-) numbers are used for SCPI- deﬁned messages, and positive (+) numbers are used for Keithley-deﬁned messages. Note that error and status conditions will also set speciﬁc bits in various status registers, as sum-...
Page 368 Models 2500 and 2502 User’s Manual Status and Error Messages Table B-1 Status and error messages Number Error message Event Status register -440 Query UNTERMINATED after Standard Event indeﬁnite response -430 Query DEADLOCKED Standard Event -420 Query UNTERMINATED Standard Event...
Page 369 Status and Error Messages Models 2500 and 2502 User’s Manual Table B-1 (continued) Status and error messages Number Error message Event Status register -178 Expression data not allowed Standard Event -171 Invalid expression Standard Event -170 Expression error Standard Event...
Page 370 Models 2500 and 2502 User’s Manual Status and Error Messages Table B-1 (continued) Status and error messages Number Error message Event Status register +000 No error Measurement events: +100 Limit 1 failed Measurement Event +101 Low limit 2 failed Measurement Event...
Page 371 Status and Error Messages Models 2500 and 2502 User’s Manual Table B-1 (continued) Status and error messages Number Error message Event Status register Calibration errors: +500 Date of calibration not set Standard Event +501 Next date of calibration not set...
Page 372 Models 2500 and 2502 User’s Manual Status and Error Messages Table B-1 (continued) Status and error messages Number Error message Event Status register +822 Too small for sense range Standard Event +824 Cannot exceed compliance range Standard Event +830 Invalid with INF ARM:COUNT...
Page 373: Eliminating Common Scpi Errors
Status and Error Messages Models 2500 and 2502 User’s Manual Eliminating common SCPI errors There are three SCPI errors that occur more often than any others: • -113, Undeﬁned header • -410, Query INTERRUPTED • -420, Query UNTERMINATED The following paragraphs discuss the causes for these errors and methods for avoiding them.
Page 374: 420, Query Unterminated
(program message units) within one command string (program message). When the Model 2500 detects an error in a program message unit, it discards all further program message units until the end of the string; for example: :SENS1:DATE?;...
Page 375: Data Flow
Data Flow Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 TestEquipmentDepot.com...
Page 376: Introduction
Data Flow Models 2500 and 2502 User’s Manual Introduction Data ﬂow for remote operation is summarized by the block diagram shown in Figure C-1. Refer to this block diagram for the following discussion. Figure C-1 Data ﬂow block diagram READ?,...
Page 377: Sens1 And Sens2
“FORMat subsystem,” for details. After all source and measure operations are completed, the Model 2500 returns to the idle state. The data stored in the sample buffer will remain there until data from another source-measure cycle overwrites the buffer. Data in the sample buffer is lost if the Model goes to the local state (REM annunciator off).
Page 378: Calculate[1]:Data? And Calculate2:Data
Data Flow Models 2500 and 2502 User’s Manual CALCulate[1]:DATA? and CALCulate2:DATA? If CALCulate1 or CALCulate2 is enabled, SENS1 or SENS2 data is fed to the CALC1 (channel 1) or CALC2 (channel 2) block where the results for the selected math function are calculated.
Page 379: Ieee-488 Bus Overview
IEEE-488 Bus Overview Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 TestEquipmentDepot.com...
Page 380: Introduction
IEEE-488 Bus Overview Models 2500 and 2502 User’s Manual Introduction Basically, the IEEE-488 bus is a communication system between two or more electronic devices. A device can be either an instrument or a computer. When a computer is used on the bus, it serves to supervise the communication exchange between all the devices and is known as the controller.
Page 381: Bus Description
The IEEE-488 standards also include another addressing mode called secondary address- ing. Secondary addresses lie in the range of #H60-#H7F. Note, however, that many devices, including the Model 2500, do not use secondary addressing. Once a device is addressed to talk or listen, the appropriate bus transactions take place. For example: if the instrument is addressed to talk, it places its data string on the bus one byte at a time.
Page 382: Figure D-1 Ieee-488 Bus Conﬁguration
IEEE-488 Bus Overview Models 2500 and 2502 User’s Manual Figure D-1 IEEE-488 bus conﬁguration To Other Devices Device 1 Able to Talk, Listen and Control (Computer) Data Bus Device 2 Able to Talk and Listen Data Byte (2500) Transfer Control...
Page 383: Bus Lines
Models 2500 and 2502 User’s Manual IEEE-488 Bus Overview Bus lines The signal lines on the IEEE-488 bus are grouped into three different categories: data lines, management lines, and handshake lines. The data lines handle bus data and com- mands, while the management and handshake lines ensure that proper data transfer and operation takes place.
Page 384 IEEE-488 Bus Overview Models 2500 and 2502 User’s Manual NRFD (Not Ready For Data) — The acceptor controls the state of NRFD. It is used to signal to the transmitting device to hold off the byte transfer sequence until the accepting device is ready.
Page 385: Bus Commands
Models 2500 and 2502 User’s Manual IEEE-488 Bus Overview Bus commands The instrument may be given a number of special bus commands through the IEEE-488 interface. This section brieﬂy describes the purpose of the bus commands which are grouped into the following four categories.
Page 386: Uniline Commands
IEEE-488 Bus Overview Models 2500 and 2502 User’s Manual Uniline commands ATN, IFC, and REN are asserted only by the controller. SRQ is asserted by an external device. EOI may be asserted either by the controller or other devices depending on the direction of data transfer.
Page 387: Addressed Multiline Commands
ORing the address with #H40. Talk commands are used to address devices to talk. SCG (Secondary Command Group) — Commands in this group provide additional addressing capabilities. Many devices (including the Model 2500) do not use these commands. Unaddress commands The two unaddress commands are used by the controller to remove any talkers or listeners from the bus.
Page 388: Common Commands
D-10 IEEE-488 Bus Overview Models 2500 and 2502 User’s Manual Common commands Common commands are commands that are common to all devices on the bus. These com- mands are designated and deﬁned by the IEEE-488.2 standard. Generally, these commands are sent as one or more ASCII characters that tell the device to perform a common operation, such as reset.
Page 389: Command Codes
Models 2500 and 2502 User’s Manual IEEE-488 Bus Overview D-11 Figure D-3 Command codes Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 TestEquipmentDepot.com...
Page 390: Table D-3 Typical Addressed Multiline Command Sequence
D-12 IEEE-488 Bus Overview Models 2500 and 2502 User’s Manual Typical command sequences For the various multiline commands, a speciﬁc bus sequence must take place to properly send the command. In particular, the correct listen address must be sent to the instrument before it will respond to addressed commands.
Page 391: Ieee Command Groups
Models 2500 and 2502 User’s Manual IEEE-488 Bus Overview D-13 IEEE command groups Command groups supported by the Model 2500 are listed in Table D-5. Common com- mands and SCPI commands are not included in this list. Table D-5 IEEE command groups...
Page 392: Interface Function Codes
The interface function codes for the Model 2500 are listed in Table D-6. The codes deﬁne Model 2500 capabilities as follows: Table D-6 Model 2500 interface function codes Code Interface function Source Handshake capability.
Page 393: Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, Ma
DC (Device Clear Function) — DC1 deﬁnes the ability of the instrument to be cleared (initialized). DT (Device Trigger Function) — DT1 deﬁnes the ability of the Model 2500 to have readings triggered. C (Controller Function) — The instrument does not have controller capabilities (C0).
Page 394 IEEE-488 and SCPI Conformance Information Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 TestEquipmentDepot.com...
Page 395: Ieee-488 And Scpi Conformance Information
IEEE-488 and SCPI Conformance Information Models 2500 and 2502 User’s Manual Introduction The IEEE-488.2 standard requires speciﬁc information about how the Model 2500 imple- ments the standard. Paragraph 4.9 of the IEEE-488.2 standard (Std 488.2-1987) lists the documentation requirements. Table E-1 provides a summary of the requirements, and pro- vides the information, or references the manual for that information.
Page 396 Requirements Description or reference IEEE-488 Interface Function Codes. Appendix Behavior of Model 2500 when the address is set outside Cannot enter an invalid address. the range 0-30. Behavior of Model 2500 when valid address is entered. Address changes and bus resets.
Page 397: Table E-2 Coupled Commands
IEEE-488 and SCPI Conformance Information Models 2500 and 2502 User’s Manual Table E-2 Coupled commands Command* Also changes* :SENSe[1]:CURRent:RANGe:UPPER :SENSe[1]:CURRent:RANGe:AUTO :SENSe[1]:CURRent:NPLC NPLC for other channel :SOURce[1]:VOLTage:RANGe :SOURce[1]:VOLTage:RANGe:AUTO :SOURce[1]:VOLTage:STARt :SOURce[1]:VOLTage:STEP :SOURce[1]:VOLTage:CENTer :SOURce[1]:VOLTage:SPAN :SOURce[1]:VOLTage:STOP :SOURce[1]:VOLTage:STEP :SOURce[1]:VOLTage:CENTer :SOURce[1]:VOLTage:SPAN :SOURce[1]:VOLTage:STEP :SOURce[1]:VOLTage:POINts :SOURce[1]:VOLTage:POINts :SOURce[1]:VOLTage:STEP :SOURce[1]:VOLTage:CENTer...
Page 398: Measurement Considerations
Measurement Considerations Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 TestEquipmentDepot.com...
Page 399: Low Current Measurements
Models 2500 and 2502 User’s Manual NOTE This appendix summarizes considerations to make accurate measurements using the Model 2500. For comprehensive information on these and additional mea- surement considerations, refer to the Low Level Measurements handbook, which is available from Keithley.
Page 400: Source Capacitance
1Ω to 100Ω Source capacitance DUT source capacitance will also affect the noise performance of the Model 2500 amme- ters. In general, as source capacitance increases, the noise gain also increases. The elements of interest for this discussion are the capacitance (C...
Page 401: Generated Currents
As long as the internal and external offsets remain stable for a reasonable period of time, the relative feature of the Model 2500 can be used to zero out offset current. With the source current (I ) set to zero, the ammeter will only measure and display the offset cur- rent reading.
Page 402: Electrochemical Effects
Models 2500 and 2502 User’s Manual Measurement Considerations Electrochemical effects Error currents also arise from electrochemical effects when ionic chemicals create weak batteries on a circuit board. These batteries could generate a few nanoamps of current between conductors. Ionic contamination may be the result of body oils, salts, or solder ﬂux.
Page 403: Dielectric Absorption
Measurement Considerations Models 2500 and 2502 User’s Manual Dielectric absorption Dielectric absorption in an insulator can occur when a voltage across that insulator causes positive and negative charges within the insulator to polarize because various polar mole- cules relax at different rates. When the voltage is removed, the separated charges generate a decaying current through circuits connected to the insulator as they recombine.
Page 404: General Measurement Considerations
Models 2500 and 2502 User’s Manual Measurement Considerations General measurement considerations The following measurement considerations apply to all precision measurements. Ground loops Ground loops that occur in multiple-instrument test setups can create error signals that cause erratic or erroneous measurements. The conﬁguration shown in...
Page 405: Light
Measurement Considerations Models 2500 and 2502 User’s Manual Figure F-3 Eliminating ground loops Instrument 1 Instrument 2 Instrument 3 Power Line Ground Light Some components, such as semiconductor junctions and MOS capacitors on semiconduc- tor wafers, are excellent light detectors. Consequently, these components must be tested in a light-free environment.
Page 406: Electrostatic Interference
Models 2500 and 2502 User’s Manual Measurement Considerations Electrostatic interference Electrostatic interference occurs when an electrically charged object is brought near an uncharged object, thus inducing a charge on the previously uncharged object. Usually, effects of such electrostatic action are not noticeable because low impedance levels allow the induced charge to dissipate quickly.
Page 407: Magnetic Fields
Electromagnetic Interference (EMI) The electromagnetic interference characteristics of the Model 2500 comply with the elec- tromagnetic compatibility (EMC) requirements of the European Union as denoted by the CE mark. However, it is still possible for sensitive measurements to be affected by exter- nal sources.
Page 408: Gpib 488.1 Protocol
GPIB 488.1 Protocol Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 TestEquipmentDepot.com...
Page 409: Introduction
When using the 488.1 protocol, throughput is enhanced up to 10 times for data sent to the Model 2500 (command messages) and up to 20 times for data returned by the Model 2500 (response messages). The speed of readings sent over the GPIB is also increased.
Page 410: Protocol Differences
Interface Clear (IFC) must be performed to reset the query. • When sending a command or query, do not attempt to read data from the Model 2500 until the terminator has been sent (usually Line Feed with EOI). Otherwise, a DCL or IFC must be sent to reset the input parser.
Page 411: Bus Hold-Off
GPIB operation. • If the unit is in REMote, the GTL command may not put the Model 2500 into the local mode. Only the front panel LOCAL key is guaranteed to operate, if not in local lockout (LLO).
Page 412: Example Programs
Example Programs Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 TestEquipmentDepot.com...
Page 413: Introduction
Be sure to use a shielded IEEE-488 cable for bus connections. 2. Turn on the computer and the Model 2500. 3. Make sure the Model 2500 is set for its default primary address of 25. (Use the front panel MENU/COMMUNICATIONS/GPIB selection to check or change the address.) 4.
Page 414: Basic Measurement Program
Models 2500 and 2502 User’s Manual Example Programs Basic measurement program The program listing below performs basic single-channel DUT measurement as covered in Section 3. This program sets up the following operating modes: • Channel 2 measurement range: 2µA • Channel 2 source range: 10V •...
Page 415: Photodiode Measurement Program
Example Programs Models 2500 and 2502 User’s Manual Photodiode measurement program The program listing below performs photodiode measurements as covered in Section 4. This program sets up the following operating modes: • Channel 1 measurement: current measurement, auto range • Channel 2 measurement: optical power, R = 1, D = 0.
Page 416: Data Store Program
Models 2500 and 2502 User’s Manual Example Programs Data store program The program listing below performs data storage as covered in Section 8, and it also dem- onstrates how to use SRQs to determine when storage is complete. This program sets up the following operating modes: •...
Page 417: Linear Sweep Program
Example Programs Models 2500 and 2502 User’s Manual Linear sweep program The program listing below performs a linear sweep as covered in Section 9. This program sets up the following operating modes: • Source and measure channel: channel 2 • Source mode: sweep •...
Page 418: Limit Test Program
Models 2500 and 2502 User’s Manual Example Programs Limit test program The program listing below performs a limits test as covered in Section 11. This program sets up the following operating modes: • Source and measure channel: channel 1 • Source voltage: 1V •...
Page 419 Index CALCulate[1] 17-23 CALCulate2 17-23 CALCulate3 17-27 CALCulate4 17-27 CALCulate5 17-29 Accessories CALCulate6 17-30 Acquiring readings 16-3 CALCulate7 17-31 Amplitude CALCulate8 17-39 Setting for fixed source 17-63 Circuit configuration Annunciators Basic Arm layer 10-4 10-19 Photodiode measurement Auto delay period Clearing registers and queues 14-4 Auto range...
Page 420 Common commands 15-1 Ground connect mode *CLS 14-4 Handler interface 11-10 *ESE 14-18 IEEE-488 13-4 *ESE? 14-18 Photodiode *ESR? 14-17 Precautions *IDN? 15-3 RS-232 13-18 *OPC 15-3 Voltage source 2-10 *OPC? 15-3 Connector *OPT? 15-4 ANALOG OUT (Model 2502 only) *RCL 15-4 Digital I/O...
Page 421 Delay Examples Auto *OPC programming example 15-4 Manual *SAV, *RCL programming example 15-5 Phase *TRG programming example 15-6 Setting 17-65 Custom sweep examples Trigger 10-5 10-21 Custom sweep programming example 9-15 DELTA function Data store programming example Commands 7-11 External triggering example 10-9 Enable and read result 17-30...
Page 422 Menus 1-26 Ground connect mode Moving filter 6-10 Commands Programming example 6-14 Connections Remote programming 6-13 Selecting 17-66 Repeat filter Ground loops Stages GTL (go to local) 13-7 Flow control 13-18 FORMat subsystem 17-43 Front panel Handler Front panel operation Category pulse component 11-11 Auto zero...
Page 423 Limit tests Photodiode Clear results 17-38 Programming example 3-13 Commands 11-20 Range Compliance 11-3 Remote command procedure 3-12 Composite testing 17-36 Time Configure and control 17-32 Measurement range Configuring 11-16 Select 17-54 Feeds 11-3 Measurement speed Grading mode 11-4 Setting 17-56 Modes 11-3...
Page 424 Operating boundaries Queues 14-2 14-19 Bias source Clearing 14-4 Loading effects Error 14-20 17-79 17-82 Operation Output 14-19 Front panel GPIB 13-9 GPIB 13-3 Local-to-remote transition 13-2 Rack mount kits Overview 11-4 Range Remote-to-local transition 13-2 Auto RS-232 13-17 Limits Optical power Commands Optical power conversion...
Page 425 DATA[:LATest]? 16-4 Commands FETCh? 16-3 Defining a value MEASure[:CURRent[:DC]]? 16-5 Dual-channel mode READ? 16-4 Enable and read result 17-28 SDC (selective device clear) 13-8 Enabling and disabling Select input path 17-27 17-31 Menus 1-26 SENSe subsystem 17-54 Programming example Serial number identification 1-11 1-12 Remote programming...
Page 426 Speed Timestamp Commands Accuracy Menus 1-29 Format Programming example Resetting 17-86 Remote programming Select format 17-89 Setting TRACe subsystem 17-87 Statistics Trigger Aquire 17-39 Commands 10-24 Select 17-39 Configure 10-14 Status and error messages 1-14 13-9 Delay 10-5 10-21 Status byte and SRQ 14-2 14-7 External triggering example...
Page 427 Service Form Model No. _______________ Serial No. __________________ Date _________________ Name and Telephone No. ____________________________________________________ Company _______________________________________________________________________ List all control settings, describe problem and check boxes that apply to problem. _________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ Intermittent Analog output follows display Particular range or function bad; specify _______________________________ IEEE failure Obvious problem on power-up...
Page 428 Specifications are subject to change without notice. All Keithley trademarks and trade names are the property of Keithley Instruments, Inc. All other trademarks and trade names are the property of their respective companies. Keithley Instruments, Inc. 28775 Aurora Road • Cleveland, Ohio 44139 • 440-248-0400 • Fax: 440-248-6168 1-888-KEITHLEY (534-8453) •...

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