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Lightwave LDX-3232 User Manual

High compliance current source
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User's Guide
LDX-3232
High Compliance Current Source
ILX Lightwave Corporation
·
P. O. Box 6310
·
Bozeman, MT, U.S.A. 59771
·
U.S. & Canada:
1-800-459-9459 ·
International
Inquiries: 406-556-2481
·
Fax 406-586-9405
·
ilx.custhelp.com
www.ilxlightwave.com
70037800_R01_04_06

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  • Page 1 User’s Guide LDX-3232 High Compliance Current Source ILX Lightwave Corporation · P. O. Box 6310 · Bozeman, MT, U.S.A. 59771 · U.S. & Canada: 1-800-459-9459 · International Inquiries: 406-556-2481 · Fax 406-586-9405 · ilx.custhelp.com www.ilxlightwave.com 70037800_R01_04_06...

  • Page 3: Table Of Contents

    Applying Power to Your LDX-3232 ........
  • Page 4 Changing Operation from Local to Remote ......22 LDX-3232 Current Source Command Set ......22 Command Syntax .
  • Page 5 Command Reference LDX-3232 Device-Dependent Commands ......39 LDX-3232 Device-Dependent Command Reference ....40...
  • Page 6 TA B L E O F C O N T E N T S LDX-3232...
  • Page 7 Figure 1.1 LDX-3232 Front View ......4 Figure 1.2 LDX-3232 Rear View ......4 Figure 2.1 Common Laser Cathode - Photodiode Cathode .
  • Page 8 L I S T O F F I G U R E S LDX-3232...
  • Page 9 Table 3.4 Error Code Classifications ......33 Table 3.5 LDX-3232 Error Codes......33 Table 4.1 LDX-3232 Device-Dependent Commands .
  • Page 10 L I S T O F TA B L E S viii LDX-3232...

  • Page 11: Safety Information And The Manual

    (see the contact information on page xiii). 04_06 S A F E T Y A N D W A R R A N T Y I N F O R M A T I O N ARRANTY NFORMATION LDX-3232...

  • Page 12: Safety Marking Symbols

    This section provides a description of the safety marking symbols that appear on the instrument. These symbols provide information about potentially dangerous situations that can result in death, injury, or damage to the instrument and other components. Caution, refer to manual LDX-3232 Earth Alternating ground current Terminal Visible and/or...

  • Page 13: Warranty

    Secure the packing box with fiber reinforced strapping tape or metal bands. 04_06 WA R R A N T Y Protective Caution, hot Conductor surface Terminal Off: Out position of a bistable push control. The circle (O) only denotes that mains are off. Frame or chassis Terminal LDX-3232...
  • Page 14 If the instrument is damaged, file a claim with the carrier. The factory will supply you with a quotation for estimated costs of repair. You must negotiate and settle with the carrier for the amount of damage. LDX-3232...

  • Page 15: Comments, Suggestions, And Problems

    You or your shipping service are responsible for any shipping damage when returning the instrument to ILX Lightwave; ILX recommends you insure the shipment. If the original shipping container is not available, place your instrument 04_06 Phone: Fax: WA R R A N T Y LDX-3232 xiii...
  • Page 16 WA R R A N T Y in a container with at least 3 inches (7.5 cm) of compressible packaging material on all sides. We look forward to serving you even better in the future! LDX-3232...

  • Page 17: Introduction And Specifications

    Severe transport stress Prolonged storage under adverse conditions Failure to perform intended measurements or functions If necessary, return the LDX-3232 to ILX Lightwave for service and repair to ensure that safety features are maintained. Product Overview The LDX-3232 instrument is a high compliance laser diode current source intended for use with quantum cascade laser diodes and other devices requiring a high compliance output.

  • Page 18: Initial Inspection

    Before connecting the LDX-3232 High Compliance Current Source to a power source, verify that the AC power source matches the setting of the LDX-3232's voltage printed on the rear panel of the instrument.

  • Page 19: Gpib Connector

    The IEEE 488 GPIB interface connector is located on the rear panel, directly above the power input module and fuse. See Figure 1.2, LDX-3232 Rear View. Attach the GPIB cable to the 24-pin connector located on the rear panel. The connector is tapered to ensure proper orientation.

  • Page 20: Figure 1.1 Ldx-3232 Front View

    I N T R O D U C T I O N A N D S P E C I F I C A T I O N S C H A P T E R Installing Your LDX-3232 High Compliance Current Source Display...

  • Page 21: Maintenance

    Please use this number in all communications concerning your instrument. If you need to ship your LDX-3232 High Compliance Current Source back to the factory for repair, be sure that the LDX-3232 is packaged in an enclosure with cushioning material to prevent damage to the instrument during shipment (use the original shipping containers and accessories if possible).

  • Page 22: Specifications

    Type PD Reverse Bias PD Current Range Output Stability Accuracy, setpoint (% of FS) External Analog Modulation Input Transfer Function LDX-3232 0 to 2000 mA 40 µA ±0.05% 0 - 15 V, adjustable <100 ppm/°C <20 ppm <40 ppm <20 µA <20 µA...
  • Page 23 Key switch, interlock and output delay (meets CDRH US 21 CFR 1040.10) 5-digit, green LED C H A P T E R Specifications LDX-3232 DC to 250 kHz DC to 10 kHz 13 µs 12 ms 0 to 4000.0 mA 0.1 mA...

  • Page 24: Available Options And Accessories

    12.Four wire voltage measured at the load. Voltage measurement accuracy while driving calibration load. Accuracy is dependent upon load and cable used. Available Options and Accessories Options and accessories available for the LDX-3232 High Compliance Current Sources include the following: DESCRIPTION...

  • Page 25: Operation

    This chapter introduces you to the operation of the LDX-3232 High Compliance Current Source. It offers instructions for connecting your laser to the current source and describes powering up the instrument. This chapter also contains step by step procedures that teach you how to operate your current source in Constant Current Mode and Constant Power Mode.

  • Page 26: The Power On State

    When disconnecting devices, it is only necessary to turn the current source output off. It is also recommended that the connections to the LDX-3232 output be made using twisted wire pairs with an earth-grounded shield (see Figures 2.1 - 2.4). The...

  • Page 27: Figure 2.1 Common Laser Cathode - Photodiode Cathode

    Note: Cable connections to the laser must be secure! Loose connections can cause momentary open circuits that can damage the laser. Figures 2.1 - 2.4 show the possible configurations of connecting laser diodes and photodiodes with the LDX-3232 High Compliance Laser Current Source. 04_06 LDX-3232 Current Source OUTPUT P.

  • Page 28: Interlock Connections

    Connecting to the Laser The 9-pin connector marked CURRENT SOURCE on the back panel is used to connect your laser diode to the LDX-3232. There are connections provided for laser cathode and anode, photodiode cathode and anode, chassis ground and interlock.

  • Page 29: Photodiode Connections

    Setting the PD Bias The LDX-3232 provides an adjustable reverse bias of 0-5 VDC for the photodiode. To set the photodiode bias to 5 V reverse bias, turn the back panel PD BIAS ADJUST fully clockwise. To set the photodiode bias to 0 V reverse bias, turn the back panel PD BIAS ADJUST fully counter-clockwise.

  • Page 30: Front Panel Operation

    Operating a Laser in Constant Current (I) Mode Suppose you have an LDX-3232 and you want to run the instrument in Constant Current, low bandwidth mode, with a setpoint of 1500 mA and a current limit of 1750 mA. This particular mode uses a low-pass filter on the laser drive current output to significantly reduce noise.

  • Page 31: Setting Up The Precision Current Source

    When the SELECT switch is released the previous measurement mode will be restored. At this point the LDX-3232 is in Constant Current Mode, (I), in the 2000 mA range, and the display is reading in mA. Next, we need to adjust the setpoint of the laser current source.
  • Page 32 LASER output is active. An additional feature of the LDX-3232 instrument is an adjustable voltage limit. This allows an extra level of laser protection in the event of an intermittent open circuit.

  • Page 33: Conditions That Will Automatically Shut Off The Laser Output

    • LASER Open Circuit or Voltage Limit Operating a Laser in Constant Power (P) Mode Suppose you want to operate a 3 mW laser at constant 1mW level. The LDX-3232 allows you to operate the laser current source driver in a Constant Power mode.
  • Page 34 Next, configure the display so that it reads in mW by pressing and releasing the (DISPLAY) SELECT switch until the mW annunciator is lit. Adjust the Constant Power setpoint of the LDX-3232 to 1.00 mW. To do this, turn the adjust knob to vary the setpoint. When the adjust knob is turned, the LDX-3232 automatically changes to setpoint mode as indicated by the flashing annunciator.

  • Page 35: Error Indicators

    The accompanying LED labeled ON will illuminate indicating that the laser output is on and current is being driven to the laser. The LDX-3232 current source will drive the laser to the Constant Power setpoint and maintain closed loop control with the photodiode current measurement.
  • Page 36 O P E R A T I O N C H A P T E R Error Indicators LDX-3232...

  • Page 37: Remote Operation

    GPIB interface. Reading the GPIB Address Before you can operate the LDX-3232 instrument from a remote location, you need to know its GPIB address. Simply press the LOCAL switch in the section labeled GPIB on the front panel. The instrument will display the address. The default address from the factory is address "Adr 01".

  • Page 38: Changing Operation From Local To Remote

    GPIB bus. LDX-3232 Current Source Command Set For the most efficient and effective remote control of your LDX-3232 High Compliance Current Source, we recommend you study the following sections. You will learn about the LDX-3232 command sets, both GPIB-IEEE488 Command Commands and the most used device specific commands, and command syntax.

  • Page 39: Table 3.1 Substitute Parameter Names

    • LAS:display:ldi • Laser:limit:ldi 400 • LAS:DIS 1; las:set:ldi? • Las:MODE:Mdp; LAS:OUT 1 The following are examples of invalid syntax for the LDX-3232 High Compliance Current Source. These command strings would produce an erroneous result, as explained: LAS:MODE MDP LAS:MODE:ILBW DEC LAS:DIS ? Las:LDI33;dis?
  • Page 40 A query has no space between the mnemonic and the question mark: LAS:LDI? The LDX-3232 High Compliance Current Source uses a terminator of <NL><^END> (new line with EOI). For users whose GPIB driver defaults expect a carriage return in the terminator, <CR><NL><^END>, the TERM command may be used for convenience (see TERM command in Chapter 4).

  • Page 41: Command Paths

    Command Paths The LDX-3232 High Compliance Current Source device-dependent commands are structured into a tree format (see Figure 3.1). Each of the legal paths is listed below, followed by its list of path options, each of that is followed by the commands themselves.

  • Page 42: Ieee488.2 Command Commands

    DELAY, or *OPC? Commands. If the time for a response after one of these commands exceed the GPIB time-out period, a bus (timeout) error will occur. Usually, after this timeout error, the LDX-3232 Series Instrument will generate a query error (E302). This error code is reported via the ERR? Query.

  • Page 43: Ldx-3232 Frequently Used Commands

    LDX-3232 Frequently Used Commands The LDX-3232 High Compliance Current Source’s complete command set contains over 60 commands that allow you to operate the current source for a variety of applications. Within the command set, however, is a smaller subset of commands that will meet most of your needs.

  • Page 44: Status Reporting

    LDX-3232 High Compliance Current Source remote interface provides Event and Condition Registers for LASER operations. The Event Registers are used to report events that occur during the operation of the LDX-3232 High Compliance Current Source. Events differ from conditions in that events signal an occurrence once, and are not reset until the Event Register is queried, the status cleared by the *CLS command, or the instrument is powered off.

  • Page 45: Figure 3.2 Ldx-3232 Status Reporting Schematic Diagram

    This allows the use of the operation complete features of the LDX-3232, without the need for program looping or polling that can tie up the GPIB. Operation Complete on the LDX-3232 is defined as: No operations to the LASER current source hardware are pending.

  • Page 46: Output Off Register

    Output Off Register The Output Off Enable Register allows you to determine that conditions and events in the LDX-3232 High Compliance Current Source can cause the current source output to be turned off. This reigster is configured in a manner similar to the status reporting registers.

  • Page 47: Figure 3.3 Ldx-3232 Output Off Register

    & & 7 6 5 4 3 2 1 0 LASer:ENABle:OUTOFF <nrf> LASer:ENABle:OUTOFF? Figure 3.3 LDX-3232 Output Off Register 8 - N/A 9 - LASER Output Changed to be Out of Tolerance 10 - N/A 11 - N/A 12 - N/A...

  • Page 48: Command Timing And Completion

    Chapter 3 section titled Operation Complete Definition. All LDX-3232 device-dependent commands are executed in an overlapped manner, except the DELAY command that is sequential. The operation complete flag is set after the conditions outlined in the Operation Complete Definition have been satisfied.

  • Page 49: Table 3.4 Error Code Classifications

    (up to 10 may be stored). Reading the error queue via GPIB clears the error queue. Table 3.4 Error Code Classifications Error Code Range E-001 to E-099 E-100 to E-199 E-200 to E-299 E-300 to E-399 E-500 to E-599 Table 3.5 LDX-3232 Series Error Codes Error Code E-001 E-103 E-104 E-105 E-106 E-123 E-124...
  • Page 50 E-507 E-510 E-511 E-512 E-513 E-515 E-516 E-519 LDX-3232 Explanation LASER interlock disabled output LASER open circuit disabled output LASER current limit disabled output LASER voltage limit disabled output LASER power limit disabled output LASER out of tolerance disabled output LASER control error disabled output Analog section status is all 1’s or all 0’s (power down)

  • Page 51: Command Reference

    LDX-3232 High Compliance Current Source. This chapter is divided into two parts. The first part contains an overview of the remote commands used by the LDX-3232 High Compliance Current Source. The second part contains all of the LDX-3232 commands in alphabetical order. Figure 4.1 shows the format for the device command descriptions in this chapter.
  • Page 52 LAS:ENAB:EVE? LAS:ENAB:OUTOFF LAS:ENAB:OUTOFF? LAS:EVENT? LAS:LDI LAS:LDI? LAS:INC LAS:LDV LAS:LDV? LDX-3232 Parameters Function NONE Returns the ready state for entering the monitor photodiode current calibration value NONE Returns the value of the LASER condition register 0, 1 or 2 Used to decreate the laser current setpoint value by one...
  • Page 53 Returns the constant P (optical power) setpoint Used to set the LASER setpoint step value NONE Returns the LASER setpoint step value Used to set the LASER setpoint tolerance value and time period value C H A P T E R LDX-3232...
  • Page 54 Name LAS:TOL? MES? RAD? TERM TERM? TIME? TIMER? LDX-3232 Parameters Function NONE Used to return the LASER setpoint tolerance value and time period value Used to enter a string message of up to 16 bits NONE Returns a previously stored ASCII message Sets the radix type for numerical data;...

  • Page 55: Ldx-3232 Device-Dependent Commands

    LDX-3232 Device-Dependent Commands This section contains all of the device-dependent commands for the LDX-3232 High Compliance Current Source, listed in alphabetical order. Sub-sections for each path are presented, listing the commands that are legal for that path. See Figure 3.1 for command path tree structure.

  • Page 56: Ldx-3232 Device-Dependent Command Reference

    "DELAY 500" -action: Further commands and queries are not executed until about 0.5 seconds have elapsed from the time this command is executed. “LAS:LDI 22;Delay 2000;LAS:LDI?” -actions: The current is set to 22.0 mA, then the LDX-3232 High Compliance Current Source waits for about 2.0 seconds before returning the measured current. RONT...
  • Page 57 (the CAL PD parameter). An <nrf value>, in mA/mW. The range is 0 to 1000. If the parameter is set to 0, the LDX-3232 will operate in a constant I Constant P (MDP) mode is selected. The parameter should be set to 0 for I parameter is used to convert between I mA/mW.
  • Page 58 (CAL PD parameter) setting. If this value is 0, the LDX-3232 will be set to operate in constant I setpoint value will be in effect. If this value is non-zero, the LDX-3232 will be set to operate in constant P...
  • Page 59 E516 is displayed. In remote operation, the LASer:CAL:LDI? query may be used to determine if the LDX-3232 High Compliance Current Source is ready for the user to enter a value. "Las:CAL:LdI" -action: the LDX-3232 enters calibration mode for LASER current.
  • Page 60 LASer:CAL:LDI mode. After this query is issued and a response of 1 is received, the LDX-3232 will be ready for the user to enter a current value via the LASer:LDI command (see Chapter 6).
  • Page 61 LASer:CAL:LDV mode. After this query is issued and a response of 1 is received, the LDX-3232 will be ready for the user to enter a voltage value via the LASer:LDV command (see Chapter 6).
  • Page 62 LASer:CAL:MDI mode. After this query is issued and a response of 1 is received, the LDX-3232 be ready for the user to enter a photodiode current value via the LASer:MDI command (see Chapter 6).
  • Page 63 The decremental default amount is one step. The step size can be edited via the LAS:STEP command. LDX-3232 default values are 0.1 mA, 0.1 mW, or 1 µA (if CALMD = 0).
  • Page 64 C O M M A N D R E F E R E N C E C H A P T E R LDX-3232 Device-Dependent Command Reference LASer:DISplay Syntax Diagram Parameters Notes Examples LASer:DISplay? Syntax Diagram Notes Examples LDX-3232 The LASer:DISplay command enables or disables (turns off) the display and some LEDs An <nrf value>;...
  • Page 65 Notes Examples 04_06 C O M M A N D R E F E R E N C E LDX-3232 Device-Dependent Command Reference The LASer:DISplay:LDI command sets the laser display to show the constant current measurement. None. The LDI measurement display mode is turned off automatically when another display selection is enabled.
  • Page 66 C O M M A N D R E F E R E N C E C H A P T E R LDX-3232 Device-Dependent Command Reference LASer:DISplay:LDV Syntax Diagram Parameters Notes Examples LASer:DISplay:LDV? Syntax Diagram Notes Examples LDX-3232 The LASer:DISplay:LDV command sets the laser display to show the laser forward voltage measurement.
  • Page 67 Notes Examples 04_06 C O M M A N D R E F E R E N C E LDX-3232 Device-Dependent Command Reference The LASer:DISplay:MDI command sets the laser display to show the monitor photodiode current measurement. None The MDI measurement display is turned off automatically when another display selection is enabled.
  • Page 68 C O M M A N D R E F E R E N C E C H A P T E R LDX-3232 Device-Dependent Command Reference LASer:DISplay:MDP Syntax Diagram Parameters Notes Examples LASer:DISplay:MDP? Syntax Diagram Notes Examples LDX-3232 The LASer:DISplay:MDP command sets the display to show the monitor photodiode power measurement.
  • Page 69 Notes Examples 04_06 C O M M A N D R E F E R E N C E LDX-3232 Device-Dependent Command Reference The LASer:DISplay:PARAM command enables the display to show the parameter values. None This command has the same effect as pressing the (PARAMETER) SELECT switch while in LASER mode.
  • Page 70 C O M M A N D R E F E R E N C E C H A P T E R LDX-3232 Device-Dependent Command Reference LASer:DISplay:SET? Syntax Diagram Notes Examples LASer:ENABle:COND Syntax Diagram Parameters Notes LDX-3232 The LASer:DISplay:SET? query returns the status of the setpoint display mode.
  • Page 71 04_06 C O M M A N D R E F E R E N C E LDX-3232 Device-Dependent Command Reference "LAS:ENAB:COND 129" -action: enables the LASER status condition register so that the Open circuit and LASER current limit conditions will be summarized in the status byte (bit 3).
  • Page 72 C O M M A N D R E F E R E N C E C H A P T E R LDX-3232 Device-Dependent Command Reference LASer:ENABle:EVEnt Syntax Diagram Parameters Notes Examples LDX-3232 The LASer:ENABle:EVEnt command sets the status event enable register of the LASER operations.
  • Page 73 Examples 04_06 C O M M A N D R E F E R E N C E LDX-3232 Device-Dependent Command Reference The LASer:ENABle:EVEnt? query returns the value of the status event enable register of the LASER operations. - where the response is the sum of the following:...
  • Page 74 C O M M A N D R E F E R E N C E C H A P T E R LDX-3232 Device-Dependent Command Reference LASer:ENABle:OUTOFF Syntax Diagram Parameters Notes Examples LDX-3232 The LASer:ENABle:OUTOFF command sets the status outoff enable register of the LASER operations (things that will turn the LASER output off).
  • Page 75 Examples 04_06 C O M M A N D R E F E R E N C E LDX-3232 Device-Dependent Command Reference The LASer:ENABle:OUTOFF? query returns the value of the status outoff enable register of the LASER operations. -where the response is the sum of the following:...
  • Page 76 C O M M A N D R E F E R E N C E C H A P T E R LDX-3232 Device-Dependent Command Reference LASer:EVEnt? Syntax Diagram Notes Examples LDX-3232 The LASer:EVEnt? query returns the value of the status event register of the LASER operations.
  • Page 77 The decremental default amount is one step. The step size can be edited via the LAS:STEP command. LDX-3232 default values are 0.1 mA, 0.1 mW, or 1 µA. If the first optional parameter is used, but not the second, the LASER setpoint is incremented by a multiple of the LAS:STEP size without changing the LAS:STEP size.
  • Page 78 C O M M A N D R E F E R E N C E C H A P T E R LDX-3232 Device-Dependent Command Reference LASer:LDI Syntax Diagram Parameters Notes Examples LASer:LDI? Syntax Diagram Notes Examples LDX-3232 The LASer:LDI command sets the laser control current.
  • Page 79 Examples 04_06 C O M M A N D R E F E R E N C E LDX-3232 Device-Dependent Command Reference The LASer:LDV command sets the laser voltage for calibration of the laser voltage measurement. An <nrf value> that represents the (laser) output voltage, in volts.
  • Page 80 C O M M A N D R E F E R E N C E C H A P T E R LDX-3232 Device-Dependent Command Reference LASer:LIMit:I2 Syntax Diagram Parameters Notes Examples LASer:LIMit:I2? Syntax Diagram Notes Examples LDX-3232 The LASer:LIMit:I2 command sets the LASER current limit value for the 2000 mA range on the LDX-3232.
  • Page 81 Examples 04_06 C O M M A N D R E F E R E N C E LDX-3232 Device-Dependent Command Reference The LASer:LIMit:I4 command sets the LASER current limit value for the 4000 mA range on the LDX-3232. An <nrf value> that represents the LASER limit current, in mA.
  • Page 82 C O M M A N D R E F E R E N C E C H A P T E R LDX-3232 Device-Dependent Command Reference LASer:LIMit:MDP Syntax Diagram Parameters Notes Examples LASer:LIMit:MDP? Syntax Diagram Notes Examples LDX-3232 The LASer:LIMit:MDP command sets the laser monitor photodiode power limit value.
  • Page 83 04_06 C O M M A N D R E F E R E N C E LDX-3232 Device-Dependent Command Reference The LASer:LIMit:V command sets the LASER compliance voltage limit value. An <nrf value> that represents the LASER limit voltage, in volts.
  • Page 84 C O M M A N D R E F E R E N C E C H A P T E R LDX-3232 Device-Dependent Command Reference LASer:MDI Syntax Diagram Parameters Notes Examples LASer:MDI? Syntax Diagram Notes Examples LDX-3232 The LASer:MDI command sets the value of the optical power setpoint, in µA, if the CALMD (CAL PD) responsivity is 0.
  • Page 85 Examples 04_06 C O M M A N D R E F E R E N C E LDX-3232 Device-Dependent Command Reference The LASer:MDLN command enables or disables (turns off) the front panel modulation input (BNC). An <nrf value> - where 1=on, 0=off.
  • Page 86 C O M M A N D R E F E R E N C E C H A P T E R LDX-3232 Device-Dependent Command Reference LASer:MDP Syntax Diagram Parameters Notes Examples LASer:MDP? Notes Examples LDX-3232 The LASer:MDP command sets the value of the optical power setpoint in mW if the CALMD (CAL PD) responsivity is greater than 0.
  • Page 87 04_06 C O M M A N D R E F E R E N C E LDX-3232 Device-Dependent Command Reference The LASer:MODE? query returns the selected laser control mode. mode is the same as I mode (low bandwidth), except that the output low bandpass filter is disabled in I mode.
  • Page 88 C O M M A N D R E F E R E N C E C H A P T E R LDX-3232 Device-Dependent Command Reference LASer:MODE:ILBW Parameters Notes Examples LASer:MODE:MDP Parameters Notes Examples LDX-3232 The LASer:MODE:ILBW command selects laser constant current mode.
  • Page 89 Examples 04_06 C O M M A N D R E F E R E N C E LDX-3232 Device-Dependent Command Reference The LASer:OUTput command turns the laser output on or off. An <nrf value>; 1=on, 0=off. There is a two-second delay after the output is turned on before the output shorting relay is opened.
  • Page 90 This range setting effects the Laser Drive Current output current range only. The Laser Drive Current output should be “off” when this command is issued. If the Laser Diode Current output is “on” when this command is issued, the LDX-3232 will generate error E515, and the range will not be changed.
  • Page 91 Examples 04_06 C O M M A N D R E F E R E N C E LDX-3232 Device-Dependent Command Reference The LASer:SET:LDI? query returns the constant I value that is used for both output ranges and both bandwidths.
  • Page 92 C O M M A N D R E F E R E N C E C H A P T E R LDX-3232 Device-Dependent Command Reference LASer:SET:MDP? Notes Examples LASer:STEP Parameters Notes Examples LDX-3232 "LAS:Set:MDI?" -response: 100.0 means the laser monitor photodiode current is setpoint is 100 µA, for use in constant P mode with CALMD=0.
  • Page 93 0.1 to 100.0 mA; and the second represents the time window, in seconds, with a range of 0.001 to 50.000 seconds. The LDX-3232 defaults to a tolerance of 1.0 mA for three seconds, unless changed by the LASer:TOLerance command. If the LDX-3232 is operated in P mode, the current tolerance parameter is not used.
  • Page 94 - where the response consists of two values, the first is the current tolerance in mA and the second is the time window, in seconds. The tolerance of the LDX-3232 LASER current may be used to delay programming after an "LASer:OUTput 1" command is issued or the setpoint is changed.
  • Page 95 04_06 C O M M A N D R E F E R E N C E LDX-3232 Device-Dependent Command Reference The MESsage? query returns the previously stored message. This message will always be 16 bytes long and enclosed in quotes. The message is entered via the MESsage command.
  • Page 96 - where the character response data of DEC means decimal, BIN means binary, HEX means hexadecimal, and OCT means octal. DEC is the default type. The LDX-3232 defaults to this radix at power-up. The RADix command is used to select the desired radix. Once it is changed, the new radix will remain in effect until the power is shut off or a new RADix command is issued.
  • Page 97 An altered terminator will be in the form <CR><NL><^END>. This termination will be sent with all output until the "TERM 0" command is sent, or the LDX-3232 is powered off. "Term?" -response: 1, means that the <CR><NL><^END> terminator is temporarily being used.
  • Page 98 The timer counter is initially set at power-up, the same as the TIME? counter. So the first time the TIMER? is issued its response will be the same as if a TIME? query's response. "Timer?" -response: 00:02:00.31, means the LDX-3232 has been on for two minutes and 0.31 seconds since the last TIMER? query was issued.

  • Page 99: Saving And Recalling From The Front Panel

    1750 mA, a laser current setpoint of 1500 mA, and Display Mode I. Once this setup is saved, the LDX-3232 Current Source may be configured for another unique setup. You can recall the original setup for the first experiment any time using the RECALL function.

  • Page 100: Saving And Recalling Under Remote Operation

    LASER compliance voltage limit. The closer the LASER voltage limit shut off point is to the operating voltage of your laser, the faster the circuit will work in the event of an open circuit. Some experimentation may be necessary for optimum results. LDX-3232...

  • Page 101: Using The Ldx-3232 Current Source's Trigger Function

    Using the LDX-3232 Current Source’s Trigger Function For applications where you need to synchronously initiate a measurement task from a remote instrument with the LDX-3232 Current Source, the Current Source offers a trigger output signal. The TTL pulse is initiated with any remote change in setpoint of the laser current source.

  • Page 102: Using The Ldx-3232 Current Sources's Bnc Interlock Connection

    Linking the LDX-3232 Current Source to a temperature controller* with the ability to signal when its temperature control has gone outside of some tolerance window will allow the LDX-3232 to safely shutoff its output before thermal damage occurs to the laser diode.
  • Page 103 The modulation port input impedance is 1 k Ω . The transfer function for the low and high current ranges of the LDX-3232 are 200 mA/V and 400 mA/V. Set the LDX-3232 in Constant Current High Bandwidth Mode by selecting I panel.
  • Page 104 This short will prevent the modulation signal from reaching the LED in our example experiment. Thus, it is safe to disconnect the test device (LED) when the LDX-3232's output is off, regardless of the presence of the modulation signal.

  • Page 105: Troubleshooting

    The current limits are calibrated internally by the instrument as part of the calibration process. Your LDX-3232 Current Source can be calibrated with the case closed. It should be calibrated every 12 months or whenever performance verification indicates that calibration is necessary, such as differences between setpoint and measurement display values that exceed the accuracy specification.

  • Page 106: Recommended Equipment

    C A L I B R A T I O N A N D T R O U B L E S H O O T I N G C H A P T E R Recommended Equipment Finally, the LDX-3232 Current Source should be allowed to warm up for at least one hour before calibration. Recommended Equipment Recommended test equipment for calibrating the LDX-3232 Current Source is listed in Table 6.1.

  • Page 107: Local Calibration Of The Ldx-3232 Current Source

    Local Calibration of the LDX-3232 Current Source There are three calibration adjustments required for the LASER current source of the LDX-3232 Current Source. They are calibration of the constant current source for both bandwidths and ranges, calibration of the laser voltage measurement,...

  • Page 108: Ipd Current Calibration

    (PARAMETER) SET switch is released, the Current Source will calculate the calibration constants and store them to nonvolatile memory. In low bandwidth calibration mode, the LDX-3232 Series Current Source will also perform current limit calibration, indicated by the CURRENT LIMIT LED flashing.
  • Page 109 After a few seconds the display will show the I After the value on the display is stable (has not changed by more than one digit for several seconds) the LDX-3232 Current Source is ready for the actual I entered.

  • Page 110: Laser Forward Voltage Measurement Calibration

    Once the second actual voltage value is entered, the Current Source will store the new calibration constants. This ends the section on front panel calibration of your LDX-3232 Current Source. The next section discusses calibration through the GPIB/IEEE488 interface. LDX-3232...

  • Page 111: Remote Calibration Of The Ldx-3232 Current Source

    However, the *OPC, *WAI command, or *OPC? query should not be issued until after the expected calibration value is entered, or the system will "hang". This happens because the LDX-3232 Current Source will wait indefinitely for an input, yet not allow any input until the calibration is finished.

  • Page 112: Ipd Current Calibration

    LDX-3232 Series Current Source is ready to receive it. The Current Source will be ready to receive the new measured value when, after a LAS:CAL:LDI? query is sent, the response from the Current Source is "1".
  • Page 113 04_06 C A L I B R A T I O N A N D T R O U B L E S H O O T I N G Remote Calibration of the LDX-3232 Current Source State I (constant current low bandwidth)

  • Page 114: Laser Forward Voltage Measurement Calibration

    Enter the measured voltage (in volts) via the LAS:LDV <nrf value> command. The measured value of the voltage should not be entered until the LDX-3232 Current Source is ready to receive it. The current source will be ready to receive the voltage value when, after a LAS:CAL:LDV? query is sent, the response from the Current Source is "1".

  • Page 115: Troubleshooting Guide

    Troubleshooting Guide This section is a guide to troubleshooting the LDX-3232 Current Sources. Some of the more common symptoms are listed here, and the appropriate troubleshooting actions are given. We recommend that the user start at the beginning of this guide. Read the symptom descriptions, and follow the steps for the corrective actions that apply.
  • Page 116 This indicates a voltage limit error; check laser connections. A high impedance may cause this condition. The LDX-3232 instruments have an adjustable laser compliance voltage. Check to see if the LASER voltage limit setting is too low (Chapter 2); check laser connections.

  • Page 117: Error Messages

    (up to 10 may be stored). Reading the error queue via GPIB clears the error queue. Table 6.3 Error Code Classifications Error Code Range E-001 to E-099 E-100 to E-199 E-200 to E-299 E-300 to E-399 E-500 to E-599 Table 6.4 LDX-3232 Series Error Codes Error Code E-001 E-103 E-104 E-105 E-106 E-123 E-124...
  • Page 118 E-512 E-513 E-515 E-516 E-519 LDX-3232 Explanation Security violation, command is not available without clearance <PROGRAM DATA> is not a Boolean value or word <PROGRAM DATA> will not convert to an unsigned 16-bit value <PROGRAM DATA> will not convert to an unsigned 32-bit value <PROGRAM DATA>...

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