Keithley 6487 User Manual
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Keithley 6487 User Manual

Picoammeter/voltage source
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  • Page 1 T h e t e s t & me a s u r e me n t e q u i p me n t y o u n e e d a t t h e p r i c e y o u w a n t . A l l t e s t I n s t r u me n t s , I n c .
  • Page 2 Model 6487 Picoammeter/Voltage Source 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 3 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 4 Model 6487 Picoammeter/ Voltage Source User’s Manual ©2002, Keithley Instruments, Inc. All rights reserved. Cleveland, Ohio, U.S.A. First Printing, October 2002 Document Number: 6487-900-01 Rev. A...
  • Page 5 Revision includes a revised copy of this print history page. Revision A (Document Number 6487-900-01) ...............October 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.
  • Page 6 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 7 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 8: Table Of Contents

    Table of Contents Getting Started Introduction ................Overview of this manual ............General information ..............Warranty information ............Contact information ............Safety symbols and terms ........... Unpacking and Inspection ........... Options and accessories ............User’s manual ..............Additional references ............Features ..................
  • Page 9 Basic connections to DUT ............Current measurement connections ........Ohms measurement connections ......... Noise and safety shields ............Using a test fixture ..............General purpose test fixture ..........Model 8009 resistivity test fixture ........Interlock ..................Interlock connections ............Interlock operation .............. Analog output ................
  • Page 10 Range, Units, Digits, Rate, and Filters Range, units, and digits .............. Range .................. Units ..................Digits ................... SCPI programming — range and digits ......Rate .................... Damping ..................Filters ..................Median filter ................ Digital filter ................ Filter control ................ Relative, mX+b, m/X+b (reciprocal), and log Relative ..................
  • Page 11 Remote Operation and Commands Selecting and configuring an interface ........Interfaces ................Connections ................. Front panel GPIB operation ..........Remote commands ..............General bus commands ............Common commands ............Signal oriented commands..........SCPI command subsystems ..........Programming syntax ............Specifications General Measurement Considerations Measurement considerations .............
  • Page 12 List of Illustrations Getting Started Figure 1-1 Front panel ................Figure 1-2 Rear panel ................1-10 Connections Figure 2-1 Triax input connector ............. Figure 2-2 Maximum input levels ............Figure 2-3 Basic current measurement connections ........ Figure 2-4 Basic ohms connections ............Figure 2-5 Shielding for measurements (unguarded) ......
  • Page 14 List of Tables Getting Started Table 1-1 Default settings ..............1-16 Table 1-2 MENU structure..............1-18 Connections Table 2-1 Summary of measurement considerations ......2-11 Measurements and Sourcing Voltage Table 3-1 Basic current measurement capabilities........Table 3-2 Basic voltage source output capabilities ......... Table 3-3 SCPI commands —...

  • Page 16: Getting Started

    Getting Started • Introduction — Description of the Model 6487 Picoammeter. • Overview of this manual — Provides content of this manual. • General information — Covers general information that includes warranty infor- mation, contact information, safety symbols and terms, inspection, and available options and accessories.

  • Page 17: Introduction

    The Model 6487 has the following current measurement ranges: 8 ranges (from 20mA down to the 2nA range). The Model 6487 also includes a ±500V DC voltage source and an ohms function that includes an alternating voltage mode to improve accuracy and repeatability of very high resistance measurements.

  • Page 18: Contact Information

    After removing the Model 6487 from its anti-static bag, inspect it for any obvious signs of physical damage. Report any such damage to the shipping agent immediately. • When the Model 6487 is not installed and connected, keep the unit in its anti-static bag and store it in the original packing carton.

  • Page 19: Options And Accessories

    3 alligator clips on the other. Model 237-TRX-T Adapter — This is a 3-slot male to dual 3-lug female triax tee adapter for use with 7078-TRX triax cables. Suitable for use with the Model 6487 V-Source in high voltage applications.
  • Page 20 CAP-31 Protective Shield /Cap — For use with 3-lug triax connectors. Interlock cables and connector Model 6517-ILC-3 Interlock Cable — Designed to connect the interlock of the Model 6487 to the Model 8009 test fixture. Model 8002-ILC-3 Interlock Cable — Designed to connect the lid interlock circuit of a test fixture to the interlock circuit of the Model 6487.

  • Page 21: User's Manual

    Getting Started Model 6487 User’s Manual Rack mount kits Model 4288-1 single fixed rack mount kit — Mounts a single Model 6487 in a standard 19-inch rack. Model 4288-2 side-by-side rack mount kit — Mounts two instruments (Models 182, 428, 486, 487, 2000, 2001, 2002, 2010, 2400, 2410, 2420, 2430, 6430, 6485, 6487, 6517A, 7001) side-by-side in a standard 19-inch rack.

  • Page 22: Front And Rear Panel Familiarization

    Digital I/O port — Four output lines and one input line to control external cir- cuitry as an interface between limit tests and component handler. (See Section 8 of the Reference Manual.) • Remote interface — Model 6487 can be controlled using the IEEE-488 interface (GPIB) or the RS-232 interface (Section •...
  • Page 23 When in Remote operation (REM annunciator lit), cancels GPIB remote mode. MENU Provides access to menu. POWER Power switch. In position turns 6487 on (I), out position turns it off (O). 2 Function keys I|Ω Use to toggle between regular current measurements and ohms.
  • Page 24 Model 6487 User’s Manual Getting Started 4 Range keys Use to select the next higher measurement range. Also use to modify the upper auto- range limit. Use to select the next lower measurement range. Also use to modify the lower auto- range limit.

  • Page 25: Rear Panel Summary

    1-10 Getting Started Model 6487 User’s Manual Rear panel summary The rear panel of Model 6487 is shown in Figure 1-2. Figure 1-2 Rear panel MADE IN U.S.A. CAT I IEEE-488 ANALOG OUT (CHANGE IEEE ADDRESS DIGITAL I/O WITH FRONT PANEL MENU)
  • Page 26 Do not connect external sources to the 6487 voltage source. External sources may damage the 6487 voltage source. 11 INTERLOCK This interlock connector provides connection of the 6487’s voltage source with an interlock connector on a test fixture. 12 Power Module Contains the AC line receptacle and power line fuse.

  • Page 27: Voltage Source

    1-12 Getting Started Model 6487 User’s Manual Voltage source The Model 6487 voltage source can source up to ±505V DC and is used for the ohms function. See “Basic connections to DUT,” page 1-4 Section 2 for full details on voltage source operation.

  • Page 28: Power-Up

    Getting Started 1-13 Power-up Line power connection Follow the procedure below to connect the Model 6487 to line power and turn on the instrument. Check to see that the line voltage indicated in the window of the fuse holder assem- (Figure 1-2) is correct for the operating voltage in your area.

  • Page 29: Power-Up Sequence

    Power-up sequence The following power-up sequence occurs when the Model 6487 is turned on: The Model 6487 performs self-tests on its EPROM and RAM with all digits and annunciators turned on. At power-up, the VOLTAGE SOURCE OPERATE LED will come on for 0.7 seconds to indicate that it is functional. If a failure is detected, the instrument momentarily displays an error message and the ERR annunciator turns on.

  • Page 30: Default Settings

    (FACT), three user-saved (USR0, USR1, and USR2), and bus default (GPIB). As shipped from the factory, Model 6487 powers up to the factory default settings. Factory default set- tings provide a general purpose setup for front panel operation, while the bus default (GPIB) settings do the same for remote operation.
  • Page 31 1-16 Getting Started Model 6487 User’s Manual Table 1-1 Default settings Factory GPIB Setting (:SYStem:PRESet) (*RST) Arm Layer (CONFIG ARM): Arm-In Source Event Arm Count Input Trigger Link Line Source Bypass NEVER Output Trigger Link Line Output Trigger Buffer (STORE):...
  • Page 32 Model 6487 User’s Manual Getting Started 1-17 Table 1-1 (continued) Default settings Factory GPIB Setting (:SYStem:PRESet) (*RST) RS-232: No effect (Off at factory) All Settings No effect Trigger Layer (CONFIG TRIG): Trig-In Source Event Trigger Count Trigger Delay Input Trigger Link Line...

  • Page 33: Menu

    NOTE SCPI tables in this manual are abridged. That is, they do NOT include most optional command words and query commands. See the Section 14 of the Model 6487 Reference Manual for a complete listing of SCPI commands.

  • Page 34: Optional Command Words

    (?) that follows the command word. A query command requests (queries) the pro- grammed status of that command. When a query command is sent and Model 6487 is addressed to talk, the response message is sent to the computer.
  • Page 35 1-20 Getting Started Model 6487 User’s Manual...

  • Page 36: Connections

    Connections • Connection fundamentals — Covers fundamental information about connecting test circuits to the picoammeter. • Basic connections to DUT — Details connecting test circuits to the picoammeter for both current and ohms measurements. • Using a test fixture — Discusses using general test fixtures as well as the Model 8009 test fixture.

  • Page 37: Connection Fundamentals

    DUT. The voltage source is primarily used for ohms measurements. See “Ohms measurement connections,” page 2-4 for details. Maximum input levels The maximum input levels to the Model 6487 are summarized in Figure 2-2.

  • Page 38: Connecting Cables And Test Leads

    Model 6487 User’s Manual Connections WARNING The maximum safe voltage between the voltage source or ammeter common and chassis ground (common mode voltage) is 505V peak. Exceeding this voltage can create a shock hazard. Figure 2-2 Maximum input levels Input HI...

  • Page 39: Basic Connections To Dut

    Current limiting resistors are required for DUTs capable of forcing voltages 505V or greater. Damage to the instrument may result if volt- ages greater than 505V are forced on the Model 6487 INPUT HI. Ohms measurement connections Basic connections for ohms measurements are shown in Figure 2-4;...

  • Page 40: Noise And Safety Shields

    LO. Additionally, Figure 2-5(B) shows an added safety shield con- nected to earth ground and Model 6487 chassis. This type of shielding should be used whenever hazardous voltages will be present in the test circuit. WARNING The maximum safe voltage between picoammeter LO and chassis ground (common mode voltage) is 505V peak.

  • Page 41: Using A Test Fixture

    Model 8009 resistivity test fixture Ω-cm and surface This test fixture allows volume resistivity in the range from 10 to 10 Ω/sq. For typical connections to the Model 6487, resistivity in the range from 10 to 10 refer to Figure...
  • Page 42 Model 6487 User’s Manual Connections Figure 2-6 General purpose test fixture connections Metal Chassis To Voltage Insulated Source Terminal Post (6) To 6487 Input To 6487 COMMON Metal Guard Plate Safety Earth Ground Banana Jacks 3-Lug Female Triax Connector Figure 2-7 Typical connections for measurements using the Model 8009 test fixture...

  • Page 43: Interlock

    Model 6487 User’s Manual Interlock The Model 6487 has a built-in interlock that works in conjunction with the voltage source. The interlock prevents the voltage source from being placed in operate on the 50V and 500V ranges, and optionally on the 10V range, to assure safe operation.

  • Page 44: Analog Output

    Pin 2 Interlock Analog output The Model 6487 has an analog output on the rear panel. The ANALOG OUT provides a scaled, inverting ±2V output. A full-scale reading corresponds to ±2V output. CAUTION Connecting COMMON or ANALOG OUT to earth while floating the input may damage the instrument.

  • Page 45: Measurement Considerations

    There are a variety of factors to consider when making low-level measurements. These con- siderations are summarized in Table 2-1 and are detailed in Appendix G of the Model 6487 Reference Manual and Appendix B of this manual. For comprehensive information on all measurement considerations, refer to the Low Level Measurements handbook, which is available from Keithley Instruments.
  • Page 46 Input bias current Offset current of Model 6487 could affect low current measurements. Voltage burden Offset voltage of Model 6487 could cause errors if it is high in relation to the voltage of the measured circuit. Noise Noise generated by source resistance and source capacitance.
  • Page 47 2-12 Connections Model 6487 User’s Manual...

  • Page 48: Measurements And Sourcing Voltage

    Measurements and Sourcing Voltage • Measurement overview — Explains the basic measurement and voltage source capabilities of Model 6487. • Performance considerations — Covers warm-up period, voltage offset correction, auto zero, zero check, and zero correct. • Current measurements — Provides a basic procedure to measure current.

  • Page 49: Measurement Overview

    ±10fA to ±21mA 2nA, 20nA, 200nA, 2µA, 20µA, 200µA, 2mA, and 20mA Voltage source The basic voltage source output capabilities of the Model 6487 are summarized in Table 3-2. Accuracy specifications are shown in Appendix Table 3-2 Basic voltage source output capabilities...

  • Page 50: Performance Considerations

    Performance considerations Warm-up period The Model 6487 can be used within one minute after it is turned on. However, the instru- ment should be turned on and allowed to warm up for at least one hour before use to achieve rated accuracy. If the instrument has been exposed to extreme temperatures, allow extra time for the internal temperature to stabilize.
  • Page 51 Measurements and Sourcing Voltage Model 6487 User’s Manual The Model 6487 has a zero correct feature to algebraically subtract the voltage offset term from the measurement. Perform the following steps to algebraically zero correct the measurement: Enable zero check by pressing ZCHK (“ZEROCHK” message displayed).

  • Page 52: Current Measurements

    LO not exceed 505V. CAUTION The maximum input voltage and current to Model 6487 is 505V peak and 21mA. Exceeding either of these values may cause damage to the instrument that is not covered by the warranty.
  • Page 53 NOTE When not making floating measurements, it is recommended that you ground measurement LO at only one place in the circuit, such as with the ground link connection on the rear panel of the 6487. (See “Ground loops,” page B-2.)

  • Page 54: Scpi Programming - Current Measurements

    Table 3-3. Programming example — current measurements The following command sequence will perform one zero corrected current measurement: *RST ' Return 6487 to GPIB defaults. FUNC ‘CURR’ ' Select current function. SYST:ZCH ON ' Enable zero check. RANG 2e-9 ' Select the 2nA range.

  • Page 55: Ohms Measurements

    Measurements and Sourcing Voltage Model 6487 User’s Manual Ohms measurements Overview To measure ohms with the Model 6487, you must set up the voltage source to the desired range, value, and current limit (see “Voltage source operation,” page 3-11), choose an appropriate current measurement range (or use auto range), and enable the ohms function.
  • Page 56 Model 6487 User’s Manual Measurements and Sourcing Voltage Step 4. Connect the resistance to be measured to the picoammeter Basic connections for ohms measurements are shown in Figure 3-2. Note that both the picoammeter INPUT and the V-SOURCE OUTPUT jacks are connected to the resistance under test.

  • Page 57: Scpi Programming - Ohms Measurements

    3-10 Measurements and Sourcing Voltage Model 6487 User’s Manual Figure 3-2 Connections for ohms measurements Red (HI) Metal Noise Shield Green Metal Safety Shield (Chassis) Safety Earth 237-ALG-2 Ground Cable Black (LO) DUT = Device Under Test. V-SOURCE OUTPUT MADE IN U.S.A.

  • Page 58: Programming Example - Ohms Measurements

    Measurements and Sourcing Voltage 3-11 Programming example — ohms measurements The following command sequence will perform one zero-corrected resistance measurement: *RST ' Return 6487 to GPIB defaults. FORM:ELEM READ,UNIT ' Measurement, units elements only. SYST:ZCH ON ' Enable zero check. RANG 2e-9 ' Select the 2nA range.

  • Page 59: Sourcing Voltage

    6487 voltage source. Turning source on and off The OPER key will toggle the voltage source state (on/off). The Model 6487 will output the configured voltage, and the VOLTAGE SOURCE OPERATE indicator will turn on. OPER (operate) key...

  • Page 60: Open Interlock Indication

    Programming example — voltage The following command sequence will output 5V on the 10V range with a 2.5mA limit: *RST ' Return 6487 to GPIB defaults. SOUR:VOLT:RANG 10 ' Select 10V source range. SOUR:VOLT 5 ' Set voltage source output to 5.
  • Page 61 3-14 Measurements and Sourcing Voltage Model 6487 User’s Manual...

  • Page 62: Range, Units, Digits, Rate, And Filters

    Range, Units, Digits, Rate, and Filters • Range, units, and digits — Provides details on measurement range, reading units, and display resolution selection. Includes the SCPI commands for remote operation. • Rate — Provides details on reading rate selection. Includes the SCPI commands for remote operation.

  • Page 63: Range, Units, And Digits

    Range, Units, Digits, Rate, and Filters Model 6487 User’s Manual Range, units, and digits Range The ranges for current measurements are listed in Table 4-1. Table 4-1 Measurement ranges µA 2µA 20nA 20µA 20mA 200nA 200µA The full scale readings for every measurement range are 5% over range. For example, on the 20µA range, the maximum input current is ±...

  • Page 64: Units

    Scientific notation provides more resolution on small values than engineering units. Digits The DIGITS key sets display resolution for Model 6487. Display resolution can be set from 3 to 6 digits. This single global setting affects display resolution for all measure- ment ranges.

  • Page 65: Rate

    filters. Filters Filtering stabilizes noisy measurements caused by noisy input signals. The Model 6487 uses two types of filters: median and digital. The displayed, stored or transmitted reading is simply the result of the filtering processes. Note that both the median and digital filters can be in effect at the same time.

  • Page 66: Median Filter

    Model 6487 User’s Manual Range, Units, Digits, Rate, and Filters Median filter The median filter is used to determine the "middle-most" reading from a group of readings that are arranged according to size. For example, assume the following readings: 20mA, 1mA, 3mA...

  • Page 67: Filter Control

    Range, Units, Digits, Rate, and Filters Model 6487 User’s Manual Filter control Front panel Both the median and average filters are controlled by pressing CONFIG then FILT. Select MEDIAN or AVERAGE, then set appropriate parameters. For the MEDIAN selection, you can choose ON or OFF and set the RANK. For the AVERAGE filter, you can choose ON or OFF, COUNT, MOVING or REPEAT.

  • Page 68: Relative, Mx+B, M/X+B (Reciprocal), And Log

    Relative, mX+b, m/X+b (reciprocal), and log • Relative — Explains how to null an offset or establish a baseline value. Includes the SCPI commands for remote operation. • mX+b, m/X+b (reciprocal), and Logarithmic — Covers these three basic math operations and includes the SCPI commands for remote operation.

  • Page 69: Relative

    Relative, mX+b, m/X+b (reciprocal), and log Mode 6487 User’s Manual Relative Relative (Rel) nulls an offset or subtracts a baseline reading from present and future read- ings. When a Rel value is established, subsequent readings will be the difference between the actual input and the Rel value.

  • Page 70: Mx+B, M/X+B (Reciprocal), And Logarithmic

    This calculation converts input readings to logarithm base 10 values. The calculation is performed as follows: where: X is the input reading y is the logarithmic result For example: Assume that exactly 1mA is being measured by the Model 6487. 3 – 1.000000mA NOTE This calculation uses the absolute value of the normal input reading as the log of a negative number cannot be computed.

  • Page 71: Configuring Math Functions

    Relative, mX+b, m/X+b (reciprocal), and log Mode 6487 User’s Manual Configuring math functions To select and configure math functions from the front panel, press CONFIG then MATH. Select the math function to configure, then enter the required parameters for mX + b and m/X + b (m, b, and units).

  • Page 72: Buffer And Sweeps

    Buffer and Sweeps • Buffer operations — Explains how to store and recall readings including buffer statistics. • Voltage sweeps — Discusses how to generate sweeps using the voltage source.

  • Page 73: Buffer Operations

    Model 6487 User’s Manual Buffer operations The Model 6487 has a buffer to store from one to 3,000 readings. It also stores overflow readings. Each reading includes the voltage source value and a timestamp. The timestamp for each reading is referenced to the time the measure/store process is started. In addition, recalled data includes statistical information (maximum, minimum, peak-to-peak, average and standard deviation).

  • Page 74: Clear

    Model 6487 User’s Manual Buffer and Sweeps Clear To clear the buffer, press CONFIG followed by STORE, then set the reading count to 0 (pressing AUTO will clear the display quickly). Press ENTER with a reading count of 0 displayed to finish clearing the buffer.

  • Page 75: Scpi Programming - Buffer

    When programming the buffer via remote, the trigger count set with the TRIG:COUN command should normally equal the number of buffer readings to store set with TRAC:POIN. See Section 7 of the Model 6487 Reference Manual for details on triggering.

  • Page 76: Voltage Sweeps

    Buffer and Sweeps Voltage sweeps The Model 6487 voltage source can be used to generate voltage sweeps from a start volt- age to a stop voltage at discrete step voltages. The Model 6487 stores readings in the buffer for later recall, one set of readings per voltage step.

  • Page 77: Programming Example

    Model 6487 User’s Manual Programming example The following command sequence performs a sweep from 1V to 10V in 1V increments: *RST ' Return 6487 to RST defaults. SOUR:VOLT:SWE:STAR 1 ' Start voltage = 1V. SOUR:VOLT:SWE:STOP 10 ' Stop voltage = 10V.

  • Page 78: Remote Operation And Commands

    Remote Operation and Commands • Selecting and configuring an interface — Explains how to select and configure an interface; GPIB or RS-232. • Remote commands — Lists the following types of bus commands: general bus commands, common commands, signal oriented commands, and SCPI subsystems.

  • Page 79: Selecting And Configuring An Interface

    (SCPI, DDC, or 488.1). The primary address must be the same as that specified in the computer program, but be sure to avoid address conflicts. Use the SCPI language setting for most applications. See the Model 6487 Reference Manual for information on the DCC and 488.1 programming languages.

  • Page 80: Front Panel Gpib Operation

    REM shows when the instrument is in the remote state, TALK is on when the instrument is in the talker active state, and LSTN is on when the Model 6487 is in the listener active state. SRQ shows when the instrument has generated a service request.

  • Page 81: Remote Commands

    Goes into remote when next addressed to listen. Reset interface; all devices go into talker and listener idle states. LOCAL key locked out. Cancel remote; restore front panel operation for Model 6487. Returns all devices to known conditions. Returns Model 6487 to known conditions.

  • Page 82: Signal Oriented Commands

    Returns model number of any installed options. *RCL <NRf> Recall command Returns Model 6487 to the user-saved setup. *RST Reset command Returns Model 6487 to the *RST default conditions. *SAV <NRf> Save command Saves the present setup as the user-saved setup. *SRE <NRf>...

  • Page 83: Scpi Command Subsystems

    Model 6487 User’s Manual SCPI command subsystems Table 7-4 summarizes the various SCPI subsystems used to program most Model 6487 operations. Detailed lists of commands associated with these subsystems are located in Section 14 of the Model 6487 Reference Manual.
  • Page 84 Model 6487 User’s Manual Remote Operation and Commands The query command requests the presently programmed status. It is identified by the ques- tion mark (?) at the end of the fundamental form of the command. Most commands have a query form.
  • Page 85 Remote Operation and Commands Model 6487 User’s Manual...

  • Page 86: Specifications

    Specifications...
  • Page 87 DEFAULT ±(% RDG. + OFFSET) TYPICAL DAMPING DDC (IEEE-488.1). RANGE RESOLUTION 18°–28°C, 0–70% RH RMS NOISE LANGUAGE EMULATION: Keithley Model 486/487 emulation via 2 nA 10 fA 0.3 % + 400 fA 20 fA 4 ms 80 ms DDC mode.

  • Page 88: General Measurement Considerations

    General Measurement Considerations...

  • Page 89: Measurement Considerations

    The configu- ration that results in the lowest noise signal is the one that should be used. A convenient way to make this connection uses the ground link at the rear of the Model 6487.

  • Page 90: Triboelectric Effects

    Triboelectric currents can be minimized as follows: • Use “low noise” cables. These cables are specially designed to minimize charge generation and use graphite to reduce friction. The Keithley Model 237 and 7078 cables are low noise. • Use the shortest cables possible and secure them (i.e., taping or tying) to a non-vibrating surface to keep them from moving.

  • Page 91: Electrochemical Effects

    Areas to check for light leaks include doors and door hinges, tubing entry points, and connectors or connector pan- els. With this in mind, the Model 6487 display may be turned off by sending the :DISP:ENAB OFF command.

  • Page 92: Magnetic Fields

    Electromagnetic Interference (EMI) The electromagnetic interference characteristics of the Model 6487 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 93 General Measurement Considerations Model 6487 User’s Manual The effect on instrument performance can be considerable if enough of the unwanted sig- nal is present. The effects of EMI can be seen as an unusually large offset, or, in the case of impulse sources, erratic variations in the displayed reading.

  • Page 94: Example Programs

    Example Programs...

  • Page 95: Programming Examples

    This section contains example programs (pseudo-code) to achieve speed and buffer size specifications. 1000 readings/second into internal buffer NOTE This program configures the Model 6487 to 0.01 PLC, digital filters off, front panel off, auto-zero off, as well as takes and stores 2000 readings. *RST ' Return 6487 to RST defaults.

  • Page 96: 900 Readings/Second To Ieee-488 Bus

    NOTE This program configures the Model 6487 to 0.01 PLC, digital filters off, front panel off, auto-zero off, binary transfer, and IEEE-488.1 (language). Model 6487 must be set to IEEE-488.1 operation from the front panel. Press CONFIG then COMM, select LANG: 488.1, then press ENTER.

  • Page 97: 3000 Readings Into Internal Buffer

    Due to memory limitations, the maximum product of the trigger count times the arm count is 2,048. Consequently, two triggers are required to completely fill the buffer to its 3,000 reading maximum. See Section 7 of the Model 6487 Reference Manual for triggering details.
  • Page 98 Index Digital 1-12, 4-5 filter filter control Symbols DIGITS Digits * (asterisk) DISP (more) Display 1-9, 1-12 Numerics , , , and Electrochemical effects Electromagnetic Interference (EMI) Electrostatic interference Additional references engineering Analog 1-12 units 1-12 analog 2-10 ENTER ANALOG OUTPUT 1-11 AUTO Error...
  • Page 99 IEEE Noise and safety shields IEEE-488 1-11 IEEE-488.2 common commands and queries Open interlock indication 3-13 Input 1-10 OPER 3-12 cables, connectors and adapters Operation keys connector Optional command words 1-19 Inspection for damage Options and accessories Instruction Manual Overview of this manual Interface available INTERLOCK...
  • Page 100 safety shield 3-6, 3-9 TALK Safety symbols and terms Test fixture SAVE TIMER Saving 1-15 timestamps scientific (SCI) Triax scientific notation 1-12 Triboelectric effects SCPI 3-10, 3-13, 4-6, 6-5, 7-6 TRIG 1-8, 1-9 SCPI commands TRIGGER LINK 1-11 amps function 3-7, 3-10 buffer SCPI programming...
  • Page 102 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 105 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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