Lightwave LDX-3232 User Manual

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

TABLE OF CONTENTS

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Safety Information and the Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

General Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

Safety Marking Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

Comments, Suggestions, and Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii

Chapter 1 Introduction and Specifications

Product Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Initial Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Installing Your LDX-3232 High Compliance Current Source . . . . . . . . . . . . . . 2

Grounding Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

AC Line Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

GPIB Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

The GPIB Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Tilt-Foot Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Operating the LDX-3232 Precision Current Source . . . . . . . . . . . . . . . . . . . . 3

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Available Options and Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Chapter 2 Operation

Applying Power to Your LDX-3232 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

The Power On Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

The Power On State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

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TABLE OF CONTENTS

Connecting to the Laser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Interlock Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Photodiode Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Setting the PD Bias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Grounding Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Front Panel Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

The Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Operating a Laser in Constant Current (I) Mode . . . . . . . . . . . . . . . . . . . . . . 14

Setting Up the Precision Current Source . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Conditions That Will Automatically Shut Off the LASER OUTPUT . . . . . . . . 17

Operating a Laser in Constant Power (P) Mode . . . . . . . . . . . . . . . . . . . . . . . 17

Entering Photodiode Responsivity Values . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Error Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Chapter 3 Remote Operation

Reading the GPIB Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Changing the GPIB Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Changing Operation from Local to Remote . . . . . . . . . . . . . . . . . . . . . . . . . 22

LDX-3232 Current Source Command Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Command Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Command Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

IEEE488.2 Command Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

LDX-3232 Frequently Used Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Status Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Event and Condition Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Operation Complete Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Output Off Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Command Timing and Completion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

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Chapter 4 Command Reference

LDX-3232 Device-Dependent Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

LDX-3232 Device-Dependent Command Reference . . . . . . . . . . . . . . . . . . . . 40

Chapter 5 Functions and Features

Saving and Recalling from the Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . 83

TABLE OF CONTENTS

Saving and Recalling Under Remote Operation . . . . . . . . . . . . . . . . . . . . . . . 84

Using the Laser Compliance Voltage Adjustment . . . . . . . . . . . . . . . . . . . . . 84

Using the LDX-3232 Current Source’s Trigger Function . . . . . . . . . . . . . . . . 85

Using the LDX-3232 Current Sources’s BNC Interlock Connection . . . . . . . 86

BNC Interlock Usage Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Modulating the Laser Current Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Chapter 6 Calibration and Troubleshooting

Calibration Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Recommended Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Local Calibration of the LDX-3232 Current Source . . . . . . . . . . . . . . . . . . . . 91

Current Source Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Current Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Laser Forward Voltage Measurement Calibration . . . . . . . . . . . . . . . . . . . . 94

Remote Calibration of the LDX-3232 Current Source . . . . . . . . . . . . . . . . . . 95

Current Source Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Current Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Laser Forward Voltage Measurement Calibration . . . . . . . . . . . . . . . . . . . . 98

Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

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TABLE OF CONTENTS

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iv LDX-3232

LIST OF FIGURES

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Figure 1.1 LDX-3232 Front View . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Figure 1.2 LDX-3232 Rear View . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Figure 2.1 Common Laser Cathode - Photodiode Cathode . . . . . . .11

Figure 2.2 Common Laser Cathode - Photodiode Anode . . . . . . . .11

Figure 2.3 Common Laser Anode - Photodiode Cathode . . . . . . . .11

Figure 2.4 Common Laser Anode - Photodiode Anode . . . . . . . . . .12

Figure 2.5 Back Panel LD Connector . . . . . . . . . . . . . . . . . . . . . . . .12

Figure 3.1 LDX-3232 Command Path Structure . . . . . . . . . . . . . . . .25

Figure 3.2 LDX-3232 Status Reporting Schematic Diagram . . . . . .29

Figure 3.3 LDX-3232 Output Off Register . . . . . . . . . . . . . . . . . . . .31

Figure 4.1 Command Description Format . . . . . . . . . . . . . . . . . . . .39

Figure 5.1 LDX-3232 Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . . .85

Figure 6.1 I

Calibration Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . .91

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LIST OF FIGURES

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vi LDX-3232

LIST OF TABLES

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Table 2.1 LDX-3232 Default Settings. . . . . . . . . . . . . . . . . . . . . . . . .10

Table 2.2 LDX-3232 Error Indicators . . . . . . . . . . . . . . . . . . . . . . . . .19

Table 3.1 Substitute Parameter Names. . . . . . . . . . . . . . . . . . . . . . .23

Table 3.2 LDX-3232 Often Used Commands . . . . . . . . . . . . . . . . . .27

Table 3.3 LDX-3232 Default Settings for Output Off Registers . . . . .30

Table 3.4 Error Code Classifications . . . . . . . . . . . . . . . . . . . . . . . . .33

Table 3.5 LDX-3232 Error Codes. . . . . . . . . . . . . . . . . . . . . . . . . . . .33

Table 4.1 LDX-3232 Device-Dependent Commands. . . . . . . . . . . . .35

Table 6.1 Recommended Test Equipment. . . . . . . . . . . . . . . . . . . . .90

Table 6.2 Required Calibration Components. . . . . . . . . . . . . . . . . . .90

Table 6.3 Error Code Classifications . . . . . . . . . . . . . . . . . . . . . . . .101

Table 6.4 LDX-3232 Error Codes. . . . . . . . . . . . . . . . . . . . . . . . . . .101

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LIST OF TABLES

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viii LDX-3232

SAFETY AND WARRANTY INFORMATION

The Safety and Warranty Information section provides details about cautionary symbols used in the manual, safety markings used on the instrument, and information about the Warranty including Customer Service contact information.

Safety Information and the Manual

Throughout this manual, you will see the words Caution and Warning indicating potentially dangerous or hazardous situations that, if not avoided, could result in death, serious or minor injury, or damage to the product. Specifically:

Caution indicates a potentially hazardous situation that can result in minor or moderate injury or damage to the product or equipment.

Warning indicates a potentially dangerous situation that can result in serious injury or death.

WARNING

Visible and/or invisible laser radiation. Avoid direct exposure to the beam.

General Safety Considerations

If any of the following conditions exist, or are even suspected, do not use the instrument until safe operation can be verified by trained service personnel:

• Visible damage

• Severe transport stress

• Prolonged storage under adverse conditions

• Failure to perform intended measurements or functions

If necessary, return the instrument to ILX Lightwave, or authorized local ILX Lightwave distributor, for service or repair to ensure that safety features are maintained (see the contact information on page xiii).

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SAFETY SYMBOLS

All instruments returned to ILX Lightwave are required to have a Return Authorization Number assigned by an official representative of ILX Lightwave Corporation. See Returning an Instrument on page xi for more information.

SAFETY SYMBOLS

This section describes the safety symbols and classifications. Technical specifications including electrical ratings and weight are included within

the manual. See the Table of Contents to locate the specifications and other product information. The following classifications are standard across all ILX Lightwave products:

• Indoor use only

• Ordinary Protection: This product is NOT protected against the harmful ingress of moisture.

• Class I Equipment (grounded type)

• Mains supply voltage fluctuations are not to exceed ±10% of the nominal supply voltage.

• Pollution Degree II

• Installation (overvoltage) Category II for transient overvoltages

• Maximum Relative Humidity: <80% RH, non-condensing

• Operating temperature range of 0°C to 40°C

• Storage and transportation temperature of -40°C to 70°C

• Maximum altitude: 3000 m (9843 ft.)

• This equipment is suitable for continuous operation.

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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

Earth ground Te r mi n a l

Alternating current

Visible and/or invisible laser radiation

WAR RA NT Y

Caution, risk of electric shock

On: In position of a bistable push control. The slash (I) only denotes that mains are on.

or (I)

WARRANTY

ILX LIGHTWAVE CORPORATION warrants this instrument to be free from defects in material and workmanship for a period of one year from date of shipment. During the warranty period, ILX will repair or replace the unit, at our option, without charge.

Limitations

This warranty does not apply to fuses, lamps, defects caused by abuse, modifications, or to use of the product for that it was not intended.

Protective Conductor Te r mi n a l

(O)

Caution, hot surface

Off: Out position of a bistable push control. The circle (O) only denotes that mains are off.

Frame or chassis Te r mi n a l

This warranty is in lieu of all other warranties, expressed or implied, including any implied warranty of merchantability or fitness for any particular purpose. ILX Lightwave Corporation shall not be liable for any incidental, special, or consequential damages.

If a problem occurs, please contact ILX Lightwave Corporation with the instrument's serial number, and thoroughly describe the nature of the problem.

Returning an Instrument

If an instrument is to be shipped to ILX Lightwave for repair or service, be sure to:

1 Obtain a Return Authorization number (RA) from ILX Customer Service. 2 Attach a tag to the instrument identifying the owner and indicating the required service or

repair. Include the instrument serial number from the rear panel of the instrument.

3 Attach the anti-static protective caps that were shipped with the instrument and place the

instrument in a protective anti-static bag.

4 Place the instrument in the original packing container with at least 3 inches (7.5 cm) of

compressible packaging material. Shipping damage is not covered by this warranty.

5 Secure the packing box with fiber reinforced strapping tape or metal bands.

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WAR RA NT Y

6 Send the instrument, transportation pre-paid, to ILX Lightwave. Clearly write the return

authorization number on the outside of the box and on the shipping paperwork. ILX Lightwave recommends you insure the shipment.

If the original shipping container is not available, place your instrument in a container with at least 3 inches (7.5 cm) of compressible packaging material on all sides.

Repairs are made and the instrument returned transportation pre-paid. Repairs are warranted for the remainder of the original warranty or for 90 days, thatever is greater.

Claims for Shipping Damage

When you receive the instrument, inspect it immediately for any damage or shortages on the packing list. 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.

xii LDX-3232

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WAR RA NT Y

Comments, Suggestions, and Problems

To ensure that you get the most out of your ILX Lightwave product, we ask that you direct any product operation or service related questions or comments to ILX Lightwave Customer Support. You may contact us in whatever way is most convenient:

Phone . . . . . . . . . . . . . . . . . . . . . . . . . . . (800) 459-9459 or (406) 556-2481

Fax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (406) 586-9405

Online FAQ: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . www.ilxlightwave.com

Or mail to: ILX Lightwave Corporation

P. O. Box 6310 Bozeman, Montana, U.S.A 59771 www.ilxlightwave.com

When you contact us, please have the following information:

Model Number:

Serial Number:

End-User Name:

Company:

Phone:

Fax:

Description of what is

connected to the ILX

Lightwave instrument:

Description of the problem:

If ILX Lightwave determines that a return to the factory is necessary, you are issued a Return Authorization (RA) number. Please mark this number on the outside of the shipping box.

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

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WAR RA NT 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!

xiv LDX-3232

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INTRODUCTION AND SPECIFICATIONS

Product Overview

CHAPTER 1

INTRODUCTION AND SPECIFICATIONS

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This chapter is an introduction to the LDX-3232 High Compliance Curren t Source. This chapter contains first time setup information, important safet y considerations, maintenance information, instrument specifications, and general LDX-3232 information.

If any of the following symptoms exist, or are even suspected, remove the LDX-3232 from service. Do not use the LDX-3232 until trained service personnel can verify safe operation.

Visible damage 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. The LDX-3232 current source provides a high stability output with multiple laser protection features and a fully redundant current limit. The LDX-3232 offers the added benefits of dual laser interlocks and a GPIB interface to allow full automation of testing.

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CHAPTER 1

INTRODUCTION AND SPECIFICATIONS

Initial Inspection

When you receive your LDX-3232 instrument, verify that the following items were shipped with the instrument:

• LDX-3232 High Compliance Current Source

• LDX-3232 Series Instruction Manual

• Power Cord

• Shipping Kit

Installing Your LDX-3232 High Compliance Current Source

Grounding Requirements

The LDX-3232 High Compliance Current Source comes with a three conductor AC power cable. The power cable must either be plugged into an approved threecontact electrical outlet or used with a three-contact or two-contact adapter with the grounding wire connected to an electrical ground (safety ground). The LDX-3232's power jack and supplied power cable meet IEC safety standards.

AC Line Power Requirements

You can operate the LDX-3232 instrument from a single phase power source delivering nominal line voltages of 100, 120, 220-240 VAC (all values RMS), at 50/60 Hz. The line power voltage can vary ±10% but cannot exceed 250 VAC. Maximum power consumption is 60 VA (Volt-Amps). The instrument's operational voltage is factory configurable and need not be changed before operating the instrument. However, check to be sure that the voltage printed on the back panel of the instrument matches the power-line voltage in your area.

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.

T o avoid electrical shock hazard, connect the instrument to properly earth-grounded, 3-prong receptacles only. Failure to observe this precaution can result in severe injury or death.

2 LDX-3232

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INTRODUCTION AND SPECIFICATIONS

Installing Your LDX-3232 High Compliance Current Source

CHAPTER 1

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. Using your fingers, tighten the two screws on the cable connector.

A total of 15 devices can be connected together on the same GPIB interface bus. The cables have single male/female connectors on each end so that several cables can be stacked. This allows more than one cable to be attached to any one device. However, the maximum length of the GPIB cables must not exceed 20 meters (65 feet) total or 2 meters (6.5 feet) per device.

The GPIB Address

The talk and listen addresses on the LDX-3232 High Compliance Current Source are identical. This GPIB address is read locally by pressing the (GPIB) LOCAL switch with the address displayed on the LED display . The instrument comes from the factory configured with the GPIB address set to 1. You can change the LDX-3232's GPIB address locally (via front panel). A procedure for changing the address can be found in the section "Changing the GPIB Address" in Chapter 3.

Tilt-Foot Adjustment

The LDX-3232 High Compliance Current Source comes standard with folding front legs and two rear feet for use as a bench top instrumen t. Extendin g the front feet so that the instrument front panel sits up makes it easier to view the LED displays. To use them, place the unit on a stable base and rotate the front legs downward until they lock into position.

Operating the LDX-3232 Precision Current Source

Now that the LDX-3232 High Compliance Current Source is installed and ready for use, you can begin to learn about its operation. The follo wing photos show the functional keypad groupings, back panel connectors, and so on. Use these figures to familiarize yourself with the LDX-3232. After that, use Chapter 2 for fundamentals of operating your instrument.

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Display

Power Switch

CHAPTER 1

INTRODUCTION AND SPECIFICATIONS

Installing Your LDX-3232 High Compliance Current Source

Adjust Section

GPIB Section

Fan

Parameter Selection

PD Bias Adjust

Laser Mode Selection

Figure 1.1 LDX-3232 Front View

LD Connector

Trigger Output Connector

Interlock Input Connector

Current Range Selection

GPIB Connector

Modulation Input Connector

Power Cord Connector

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Figure 1.2 LDX-3232 Rear View

INTRODUCTION AND SPECIFICATIONS

Maintenance

You may have to return your instrument to the ILX Lightwave facility at some time for repair or service whether or not it is under warranty. There is a charge for repairs after the warranty period has expired. Contact an ILX Lightwave service representative for shipping instructions prior to returning the in strument. Have th e model number, instrument serial number, and a description of the problem or request at the time of the call. All ILX Lightwave instruments are identified by a serial number located on the rear panel. The first four or five digits are the model number; the last four digits are unique to the instrument and identify your instrument specifically. A return authorization number will be given to you at the time of your request for repair or service. 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). Re-install the ESD protective caps on the rear and front panels over the connectors (9 pin D, BNC, and GPIB). Shipping damage is not covered under warranty.

CHAPTER 1

Attach a tag to the instrument identifying the owner and indicating the service or repair needed. Include the model number and serial number. We suggest that you insure the shipment.

In North America, contact ILX Lightwave for return authorization and shipping instructions. Outside of North America, contact your ILX distributor for shipping information.

For more information on how to obtain repair services, see the Safety and Warranty section of this manual.

If cleaning is required, use a clean dry cloth. Do not use solvents.

Potentially lethal voltages exist within the LDX-3232 High Compliance Current Source. To avoid electric shock, do not perform any of the maintenance on the instrument unless you are qualified to do so. Qualified service personnel are required to wear protective eyeglasses and anti-static wristbands while working on the LDX-3232 High Compliance Current Source circuit boards. High voltages are present on and around the instrument’s printed circuit boards.

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CHAPTER 1

INTRODUCTION AND SPECIFICATIONS

Specifications

Drive Current Output

Output Current Range 0 to 2000 mA 0 to 4000 mA Setpoint Resolution Setpoint Accuracy (% of FS) ±0.05% ±0.05% Compliance Voltage 0 - 15 V, adjustable 0 - 15 V, adjustable Temperature Coefficient <100 ppm/°C <100 ppm/°C Short Term Stability (1 hour) Long Term Stability (24 hours) Noise and Ripple (µA rms)

High Bandwidth Mode Low Bandwidth Mode

Transients

Operational 1 kV EFT/Surge

LDX-3232

40 µA 80 µA

<20 ppm <20 ppm <40 ppm <40 ppm

<20 µA <20 µA

<4 mA <8 mA

<40 µA <20 µA

<4 mA <8 mA

Compliance Voltage Adjust

Range 0 - 15 V 0 - 15 V Resolution 10 mV 20 mV Accuracy ±20% ±40%

Drive Current Limit Settings

Range 1 to 2020 mA 1 to 4040 mA Resolution 10 mA 20 mA Accuracy ±20 mA ±40 mA

Photodiode Feedback

Type Differential Differential PD Reverse Bias 0 - 5V, adjustable 0 - 5V, adjustable PD Current Range 5 to 10,000 µA 5 to 10,000 µA Output Stability Accuracy, setpoint (% of FS) ±0.05% ±0.05%

External Analog Modulation

Input 0 - 10 V, 1 kΩ 0 - 10 V, 1 kΩ Transfer Function 200 mA / V 400 mA / V

±0.02% ±0.02%

6 LDX-3232



INTRODUCTION AND SPECIFICATIONS

Specifications

LDX-3232

Bandwidth (3 dB)

High Bandwidth Low Bandwidth

Trigge r Output

Type TTL TTL Pulse Width 13 µs 13 µs

DC to 250 kHz DC to 10 kHz

CHAPTER 1

Delay 12 ms 12 ms

Measurement (Display)

Output Current Range 0 to 2000.0 mA 0 to 4000.0 mA Output Current Resolution Photodiode Current Range 0 to 10,000 µA 0 to 10,000 µA Photodiode Current Resolution 1 µA 1 µA Photodiode Current Accuracy ±4 µA ±4 µA PD Responsivity Range PD Responsivity Resolution 0.01 µA/mW 0.01 µA/mW Optical Power Range 0.00 to 5000.0 mW 0.00 to 5000.0 mW Optical Power Resolution 0.1 mW 0.1 mW Forward Voltage Range 0.000 to 10.000 V 0.000 to 10.000 V Forward Voltage Resolution 1 mV 1 mV Forward Voltage Accuracy

General

Size (H x W x D) 4” x 8.5” x 13.4”; 102 mm x 216 mm x 340 mm Weight ~ 20 pounds (9 kg) Power 100/120/230-240 V~; 2/2/1A 50/60 Hz

0.1 mA 0.1 mA

0.00 to 1000.00 µA/mW 0.00 to 1000.00 µA/mW

±2 mV ±2 mV

Temperature 0°C – 40°C operating; -40°C – 70°C storage Humidity < 90% relative humidity, non-condensing Laser Safety Features Key switch, interlock and output dela y (meets CDRH US

Display Type 5-digit, green LED

Notes

1. All values relate to a one-hour warm-up period at room temperature, 25°C.

2. Based on resolution of digital-to-analog converters used in the design.

3. Over any 1-hour period, half-scale output.

4. Over any 24-hour period, half-scale output.

5. Measured electrically with a 1 ohm load at half-scale output; evaluating spectral noise density over a 150kHz bandwidth from 125kHz to 275 kHz.

6. Maximum output current transient from normal operational situations (e.g., power on-off, current on-off), as well as accident al situations (e.g., power line plug removal).

7. Maximum output current transient resulting from a 1000 V power-line transient spike. Tested to ILX Lightwave Technical Standard #LDX-00196.

04_06 LDX-3232 7

21 CFR 1040.10)



CHAPTER 1

Available Options and Accessories

INTRODUCTION AND SPECIFICATIONS

Specifications

8. Maximum monitor photodiode current drift over any 30 minute period. Assumes zero drift in responsivity of photodiode.

9. 50% modulation at mid-scale output. Higher bandwidth is possible with smaller magnitude modulation signal.

10.Similar resolution available over GPIB.

11.Responsivity value is user-defined and is used to calculate the optical power.

12.Four wire voltage measured at the load. Voltage measurement accuracy while driving calibration load. Accuracy is dependent upon load and cable used.

Options and accessories available for the LDX-3232 High Compliance Current Sources include the following:

DESCRIPTION MODEL NUMBER

Noise Filter LNF-320 Current Source Interconnect Cable (terminated) CC-305S Current Source Interconnect Cable (unterminated) CC-306S DIL Laser Diode Mount LDM-4982 Butterfly Laser Diode Mount LDM-4894 High Power Laser Diode Mount LDM-4442 Single Rack Mount Kit RM-139 Dual Rack Mount Kit RM-140

Other laser diode mounts are available. Please contact ILX Lightwave for information on additional options for your application.

Our goal is to make the best laser diode instrumentation available anywhere. To achieve this, we need your ideas and comments on ways we can improve out products. We invite you to contact us at any time with your suggestions.

8 LDX-3232



OPERATION

Applying Power to Your LDX-3232

CHAPTER 2

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 cont ains step by step procedures that teach you how to operate your current source in Const ant Current Mode and Constant Power Mode. We recommend that you review the contents of this chapter at a minimum before operating the LDX-3232 Current Source.

Applying Power to Your LDX-3232

To turn on the LDX-3232, rotate the key in the "POWER" section of the front panel from "O" to "I". This action will initiate the power on sequence. If the LDX-3232 does not appear to turn on, verify that it is connected to line power. If line power is not the problem, remove the power cord and check the voltage selection block in addition to the line power fuse.

The Power On Sequence

During the power-up sequence, the following takes place. For about three seconds all indicators light up, and all of the 7-segment displays indicate "8". Then all lamps are turned off for three seconds. Next, the firmware version will be displayed. Then, a self-test is performed to ensure that the instrument' s hardware and processor are communicating. After this test, the instrument is ready to operate and is configured to the state it was in when the power was last shut off.

04_06 LDX-3232 9



CHAPTER 2

The Power On State

OPERATION

Connecting to the Laser

You can choose to "clear" the last saved state by recalling the default values. These values are stored in BINS to that you can save or recall instrument configurations (described in more detail in Chapter 5). "BIN 0" contains all of the default configurations listed in Table 2.1.

Note: If the instrument cannot successfully complete the power on test, an error message of E-512 or E-513 will be displayed on the Display. See Chapter 3 for a list of error codes and actions to take when your instrument indicates these errors.

Table 2.1 LDX-3232 Default Settings

GPIB mode in LOCAL via front panel, or in REMOTE via GPIB PARAMETERS not selected CAL PD = 0 µA / mW LIM I (high range) = 1000 mA LIM I (low range) = 500 mA LIM V = 15 volts LIM P = 5000 mW Output off DISPLAY enabled, in I mode Constant I, low bandwidth mode selected I setpoint = 0 mA

setpoint = 0 µA

setpoint = 0 mW

RECALL BIN number = 0

Connecting to the Laser

When connecting your laser to the LDX-3232, we recommend that the instrument be powered up with the output off. In this condition, a low impedance shunt is active across the output terminals. 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 output terminals of the instrument are left floating relative to earth ground to suppress AC power-on/power-off transients that may occur through an earthground path. If the output circuit is earth-grounded at some point (such as through the laser package and mount), the user must be careful to avoid multiple earth

10 LDX-3232



OPERATION

Connecting to the Laser

CHAPTER 2

grounds in the circuit. Multiple earth grounds may provide circuit paths that induce spurious currents in the photodiode feedback circuit and output leads.

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.

OUTPUT

LDX-3232 Current Source

Bias

P. D. L. D.

Earth Ground

Figure 2.1 Common Laser Cathode - Photodiode Cathode

P. D. L. D.

OUTPUT

LDX-3232 Current Source

Bias

5 3

Earth Ground

04_06 LDX-3232 11

Figure 2.2 Common Laser Cathode - Photodiode Anode

P. D. L. D.

OUTPUT

LDX-3232 Current Source

Bias

5 3

Earth Ground

Figure 2.3 Common Laser Anode - Photodiode Cathode



CHAPTER 2

OPERATION

Connecting to the Laser

P. D. L. D.

OUTPUT

LDX-3232 Current Source

Bias

5 3

Earth Ground

Figure 2.4 Common Laser Anode - Photodiode Anode

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. The pinout diagram for this connector is shown in Figure 2.5.

1, 2 Interlock 3 Chass is Groun d 4 Cathode Vo lta g e S ense 5 Laser Cathod e 6 PD Cathode ( + ) 7 PD A n o d e ( -)

8 Anod e Voltage Sense 9 Laser Anode

12 LDX-3232



Figure 2.5 Back Panel LD Connector

Interlock Connections

In order for the laser output to be enabled a short circuit must exist between the Interlock Pins (Pins 1 and 2) of the connector. The short can be a direct short across the pins or a switch to prevent laser operation until the switch is closed. If a short does not exist between these two pins, the INTERLOCK LED will illuminate on the front panel and the laser output will be disabled.

Note: The BNC Interlock Connection from the BNC conne ctor on the rear panel will also make the INTERLOCK LED illuminate. Please see the notes in chapter five on use of the BNC interlock connection to learn more about its operation.

The interlock terminals on the LASER connector, pins 1 and 2, must be kept isolated from all other connections including earth g round.

OPERATION

Connecting to the Laser

CHAPTER 2

Photodiode Connections

Many laser diode modules contain an internal photodiode that monitors the backfacet emission of the laser. Usually, this photodiode is internally connected to either the laser anode or cathode.

The photodiode and laser connections to the LDX-3232 are electrically isolated from ground and each other. So, if a 4 pin connection is made (no common connections), no additional jumpers are required. Figures 2.1 - 2.4 show the recommended connections and shielding for 3-pin lasers (where the common connection is internal to the device). A 4-pin laser should be connected with the same shielding as shown in Figure 2.1, but the common connection (between the photodiode and the laser) is optional.

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.

Grounding Considerations

The LASER outputs of the LDX-3232 High Compliance Current Source are isolated from chassis ground, allowing either output terminal to be grounded at the user's option. Figures 2.1 - 2.4 show the proper earth-ground shielding for laser diode/photodiode connections.

04_06 LDX-3232 13



CHAPTER 2

OPERATION

Front Pan el Operation

Front Panel Operation

This section describes fundamentals of operation for your LDX-3232 in two operating modes: Constant Current (I) and Constant Power (P).

The Display

The digital display is used to show control parameters such as laser drive current (mA), laser current limit (mA), laser forward voltage (V), voltage limit (V), monitor photodiode current (µA), and laser optical power (mW) in both setpoint and measurement modes. It will also display error codes that relate to LASER operation. Error indicators underneath the display indicate control errors and are explained in the section titled “ERROR INDICATORS”. All laser control parameters are displayed on this digital display with the appropriate annunciator illuminated.

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. In this mode a modulation input of up to 10 kHz may be used via the front panel MOD EXTERNAL connector. Follow the instructions below in the sequence presented.

14 LDX-3232



Operating a Laser in Constant Current (I) Mode

Setting Up the Precision Current Source

Set the LDX-3232 in Constant Current, low bandwid th mode by selecting I in the MODE section of the front panel. Do this by toggling the SELECT push button until the I indicator is illuminated. Repeatedly pressing the (MODE) SELECT switch cycles through the current (I), light power (P), or high-bandwidth current (I

Next, in the RANGE section set the current source range by selecting the 2000 mA range indicated by the accompanying LED. You will need to press the SELECT push button twice to change the range. It must be pressed twice quickly (within less than 1 second) to switch between ranges, and the LASER output must be off (LASER MODE ON indicator unlit) in order to change ranges.

HBW

OPERATION

) control modes.

CHAPTER 2

Configure the display so that it reads laser current in mA. Press and release the SELECT switch in the DISPLA Y section of the front panel until the mA annunciator is lit. The (DISPLAY) SELECT switch is also used to select the I µA), P display modes. When the setpoint mode is active, the corresponding annunciator will flash to indicate setpoint rather than measurement display.

To only view the setpoint, press and hold down the display SELECT switch for two or more seconds. 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 rang e, and the display is reading in mA. Next, we need to adjust the setpoint of the laser current source.

To adjust the setpoint of the current source to 1500 mA, turn the adjust knob to vary the setpoint. When the adjust knob is turned, the LDX-3232 automatically changes to setpoint mode indicated by the flashing annunciator. Adjust the setpoint to 1500 mA. After an adjustment has been made, and the adjust knob is released, the setpoint mode will time out in three seconds. The display will revert to the original measurement display mode (I, I

The instrument is still not ready to turn on the laser. One of the laser protection features our precision current sources offer is a fully independent hardware current limit. The current limit protects your laser by never allowing the laser drive current to exceed the limit independent of the setpoint and the output control mode (Constant Current or Constant Power).

(laser power, mW), or V (forward voltage, V) measurement or setpoint

, V, or PPD).

(PD current,

04_06 LDX-3232 15



CHAPTER 2

OPERATION

Operating a Laser in Constant Current (I) Mode

To set the current source limit, use the SELECT push button in the P ARAMETER se ction of the front panel to select LIM I. Press and hold the (PARAMETER) SET push button and rotate the adjust knob to vary the limit setpoint value. Set the limit to 1750 mA. Once the (PARAMETER) SET push button is released, the new parameter value is stored in non-volatile memory.

When the LASER current limit is reached, the CURRENT LIMIT error indicator flashes. The current limit setting is independent of the voltage drop of the device connected to the LASER output, and therefore, no dummy load is required for precise adjustment of the current limit. Furthermore, since the current limit circuitry is fully independent of the main current control, the current limit can be adjusted safely, even while the 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. For maximum protection via the fastest open-circuit detection, the voltage limit should be set to a value slightly greater than the intended operating voltage.

To set the LASER voltage limit, use the SELECT push button in the PARAMETER section of the front panel to select COMP V and then press and hold the (P ARAMETER) SET push button. While holding the (PARAMETER) SET push button, adjust the voltage limit using the adjust knob.

Now you are ready to enable the current source output for your laser diode.

In the MODE section of the front panel, press the push button labeled OUTPUT. The accompanying LED labeled ON will illuminate, indicating that the laser current source's output is enabled. The instrument will drive the current source to the value set by the corresponding MODE setpoint. When the LASER output is off, an internal short is placed across the LASER output. The OUTPUT switch has a toggling action. Pressing the switch again will disable the current source output and the ON LED will not be illuminated. The default condition for the current source output is off when the instrument is first powered up. With the laser output enabled, the LASER display should be indicating measured laser current. If the output won't function, check the following conditions:

16 LDX-3232



OPERATION

Operating a Laser in Constant Power (P) Mode

Conditions That Will Automatically Shut Off the LASER OUTPUT

The following conditions will automatically cause the instrument to disable the current source output:

• LASER High Power Limit

• LASER Interlock / Key Lock Turned Off

• 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. In this mode, the LDX-3232 drives current to the laser to reach a setpoint power value (in mW). The control loop feedback parameter is photodiode current that the LDX-3232 converts to optical power via a user-defined photodiode responsivity number. If laser power changes due to internal or environmental conditions, the LDX-3232 will increase/decrease the current to the laser to maintain the power setpoint. The following paragraphs detail the instrument configuration in Constant Power Mode.

CHAPTER 2

To set the LDX-3232 in Constant Power mode, select P in the MODE section of the front panel by toggling the SELECT push button. Repeatedly pressing the (MODE) SELECT switch cycles through the current (I), light power (P), or high bandwidth current (I mode.

) control modes. The LED indicator shows the selected

HBW

Entering Photodiode Responsivity Values

The photodiode responsivity, CAL photodiode, is used to convert between photodiode current and optical power of the laser diode. To enter the CAL photodiode parameter, select CAL PD with the (PARAMETER) SELECT push button by toggling down past LIM P. The indicator becomes lit when CAL PD is selected and the display indicates the responsivity parameter in µA/mW (not annunciated). Rotate the adjust knob while holding the (PARAMETER) SET push button to enter a new value for responsivity. When the correct value is displayed, store the number by releasing the (PARAMETER) SET pushbutton.

04_06 LDX-3232 17



CHAPTER 2

OPERATION

Operating a Laser in Constant Power (P) Mode

A method to calculate the responsivity is suggested below.

1 Measure (with a calibrated detector) the output power of the device. 2 Measure the corresponding photodiode current. 3 Calculate the responsivity by dividing the photodiode current by the optical power noting

the units required are µA/mW.

The LDX-3232 High Compliance Current Source can be put into a special mode with the CAL PD parameter set to zero. When the CAL PD value is zero, the LASER output will be controlled to the I instrument is in Constant I "-.-" for the power measurement.

Next, configure the display so that it reads in mW by pressing and releasing the (DISPLAY) SELECT switch until the mW annunciator is lit.

setpoint value. Therefore, the

mode. The display will indicate

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. Adjust the setpoint to 1.00 mW. After an adjustment has been made, and the adjust knob is released, the setpoint mode will time out in three seconds. The display will then return to the measurement display mode (I, I

Before the laser output is enabled, the power limit for the laser under test should be set. In Constant Power mode, this is accomplished by setting a Power limit, LIM P value. The LDX-3232 uses the responsivity value entered to calculate a power limit as a function of monitor current (I

To set the Constant Power limit, use the SELECT push button in the PARAMETER section to select LIM P. When the LIM P is indicated by the accompanying LED, the display will indicate the limit setpoint in mW. Press and hold the (PARAMETER) SET push button and rotate the adjust knob to set the limit to 1.50 mW. When the desired value is reached, release the (PARAMETER) SET push button to store the new limit value.

The LIM P is the absolute limit of optical power, as detected by the unit via the monitor photodiode feedback loop. In order for this limit to be meaningful, the monitor photodiode responsivity (CAL PD) must be adjusted correctly. This limit is a software limit only. The LASER output is normally turned off if this limit is reached (See LASer:ENABle:OUTOFF command in Chapter 4 for instructions on disabling this function). The maximum LIM P value is 5000.0 mW.

). This is a software limit only.

, V, or PPD).

Also, in constant power mode the LASER current limit and voltage limit values are in effect. Setting of these limits is described later in this chapter.

18 LDX-3232



OPERATION

Error Indicators

Now the instrument is configured to operate in Constant Power Mode. In the MODE section, enable the output of the laser current source by depressing the OUTPUT push button once. 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.

Error Indicators

The LDX-3232 High Compliance Current Sources indicate general operational error conditions. Each error condition results in an action as shown in the table below.

Table 2.2 LDX-3232 Error Indicators

CHAPTER 2

Error Condition Action

Interlock Output off; INTERLOCK light flashes at 1 Hz Open Circuit Output off; OPEN CIRCUIT light flashes at 1 Hz; if this condition was caused by

Current Limit CURRENT LIMIT light flashes at 1 Hz Voltage Limit VOLTAGE LIMIT light flashes at 1 Hz; this indicator warns that the output is within

Optical Output Power Limit

an excessively high compliance voltage, the VOLTAGE LIMIT light will also be turned on.

0.25 V of LIM V setting; if the voltage limit (LIM V) is reached, the LASER output will shut off.

Output off; POWER LIMIT light flashes at 1 Hz

04_06 LDX-3232 19



CHAPTER 2

OPERATION

Error Indicators

20 LDX-3232



REMOTE OPERATION

CHAPTER 3

REMOTE OPERATION

                 

Everything you learned to do from the front panel can also be done remotely and in some cases, with more flexibility. For instance, in remote mode, you have access to commands for functions not found on the front panel, such as commands that will increment (INC) and decrement (DEC) the current setpoint by a pre-defined step value. The following sections show you the fundamentals of operating your LDX-3232 High Compliance Current Source remotely through the 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".

Changing the GPIB Address

Every device on the GPIB bus must have a unique address. If it is necessary to change the address, press and hold in the (PARAMETER) SET switch while displaying the GPIB address. Turn the ADJUST knob until the desired address value is displayed, then release the SET switch. The new GPIB address will then be stored in non-volatile memory . The allowable address range is 0-30 for primary GPIB addressing. Extended GPIB addressing is not implemented on the LDX-3232 at this time.

04_06 LDX-3232 21



CHAPTER 3

Changing Operation from Local to Remote

REMOTE OPERATION

LDX-3232 Current Source Command Set

Sending a command over the GPIB will automatically put the instrument in REMOTE mode. The REMOTE indicator will identify when the Current Source is in remote operation mode. When the instrument is in REMOTE mode, pressing the LOCAL switch returns the instrument to LOCAL control mode unless the Local Lockout state has been activated by the host computer. Local Lockout disables all LDX-3232 High Compliance Current Source front panel switches until this condition is changed by the host computer. When the instrument is put in Local Lockout Mode by the host computer, the REMOTE indicato r will flash at a 1Hz rate to indicate that the front panel is completely disabled by Local Lockout.

The TALK/LISTEN indicator is illuminated when the instrument is communicating over the 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 synt ax. Later in this chapter you will be introduced to the error and status registers.

Command Syntax

Any command or command query must contain all of the letters tha t a re shown in the LDX-3232 Command Path Structure, Figure 3.2. However, the Current Source's command parser is NOT CASE SENSITIVE so upper or lower case may be used in any combination. The lower case letters shown with the Device Dependent commands in Chapter 4 are optional letters and may be used for clarity. For example, the following commands are equal:

• LAS:DIS 1

• LAS:DisP 1

• LAS:DISPLAY 1

In this example, only the first three letters "DIS" are required, while the other letters, "play" are optional. These optional letters must be used in the proper sequence as shown.

22 LDX-3232



REMOTE OPERATION

LDX-3232 Current Source Command Set

CHAPTER 3

The syntax of the LDX-3232 High Compliance Current Source commands fo llows the rules laid out in the GPIB-IEEE488 standard. Colons (:) indicate the start of a new command path, while semicolons (;) indicate a separation of commands within a command string. A leading colon on a command may be used to return the LDX-3232 High Compliance Current Source command parser to the command path root (see Figure 3.1).

Sp aces or wh ite sp ace may be used to sep arate commands and /or dat a (af ter the command header or query question mark). Spaces or white space must be used to separate the command (header) from the first p arameter (or program data). The following examples show valid syntax for commands with the LDX-3232 High Compliance Current Source:

• 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 Missing colon, MODE? expected LAS:MODE:ILBW DEC Missing semicolon, DEC command generates an error LAS:DIS ? Space not allowed before question mark, DIS command

Las:LDI33;dis? Space missing between LDI command and the parameter

expected

value, 33

For further clarity in programming, the (Boolean) values of one (1) and zero (0) may be used or their names as indicated in the following table:

Table 3.1 Substitute Parameter Names

Substitute Name Value ON 1 OFF 0 OLD 1 NEW 0 TRUE 1 FALSE 0 SET 1 RESET 0

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

CHAPTER 3

REMOTE OPERATION

LDX-3232 Current Source Command Set

If multiple parameters are expected, they should be separated with commas:

LAS:INC 100,50

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). For more information, refer to your GPIB driver configuration manual.

The command structure is illustrated in Figure 3.1. Table 4.1 lists all of the LDX-3232 High Compliance Current Source’s device-dependent commands, with the full path shown for each command and a brief explanation of its usage.

24 LDX-3232



REMOTE OPERATION

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. It is recommended that the first-time user begin learning the commands by using the full path notation. Once you are familiar with the commands, you may wish to take advantage of the shortcuts allowed for command paths.

(root)

CHAPTER 3

(com. cmds) *CAL? *CLS *ESE *ESE? *ESR? *IDN?

*OPC *OPC? *PSC *PSC? *PUD *PUD? *RCL *RST *SAV *SRE *SRE? *STB? *TST? *WAI

DELAY ERR? MES MES? RAD RAD? SECURE TERM TERM? TIME? TIMER?

:CALMD :CALMD? :COND? :DEC :DIS :DIS? :EVE? :INC :LDI

:LDI? :LDV :LDV? :MDI

:MDI? :MDLN :MDLN? :MDP :MDP?

:MODE? :OUT

:OUT? :RAN

:RAN? :STEP :STEP? :TOL :TOL?

:CAL

:CONST?

:LDI :LDI?

:LDV :LDV?

:MDI :MDI?

LAS

:DIS

:LDI

:LDI?

:LDV

:LDV? :MDI :MDI?

:MDP :MDP? :SET :SET?

:PARAM

:ENAB

:COND :COND? :EVE :EVE? :OUTOFF :OUTOFF?

:LIM

:I1 :I1? :I3 :I3? :MDP :MDP? :V :V?

:MODE

:IHBW :ILBW :MDP

:SET

:LDI? :MDI? :MDP?

04_06 LDX-3232 25

Figure 3.1 LDX-3232 Command Path Structure



CHAPTER 3

REMOTE OPERATION

IEEE488.2 Command Commands

The IEEE488.2 Common Commands and Queries are distinguished by the "*" that begins each mnemonic. The diagrams below show the syntax structure for common commands, common commands with numeric data required, and command command queries.

Comm on Com m a nd

Numeric data is required with *PSC (1=on, 0=off), *RCL (0 to 10, see front panel RECALL function), *SAV (1 to 10, see front panel SAVE function), *ESE (0 to 255, see Figure 3.2), *SRE (0 to 255, see Figure 3.2), and *PUD (used at factory only).

A list of all of the GPIB-IEEE488 Common Commands supported by the LDX-3232 follows:

COMMAND

Common Command w ith Numeric Data

*CAL? *CLS *ESE *ESE? *ESR? *IDN? *OPC *OPC? *PSC *PSC? *PUD *PUD? *RCL *RST *SAV *SRE? *SRE *STB? *TST? *WAI

COMMAND

< Decimal Numer ic Prog ram Data>

Common Command Query

COMMAN D

For more information on these commands, refer to an ANSI/IEEE 488-1987 standards reference.

Note: Care should be taken to set the GPIB time-out appropriately for use with the *WAI,

26 LDX-3232



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.

REMOTE OPERATION

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. These commands are listed in Table 3.2.

Table 3.2 LDX-3232 Often Used Commands

CHAPTER 3

Name Parameters Function

ERR? NONE Returns errors generated since the last query LAS:CALMD 1 Used to set the CAL PD (monitor responsivity) constant LAS:LDI 1 Used to set the current source setpoint value LAS:LDI? NONE Used to return the constant current source measured value LAS:LDV? NONE Used to return the measured laser voltage value LAS:LIM:I2 1 Used to set the low range current limit LAS:LIM:I4 1 Used to set the high range current limit LAS:LIM:MDP 1 Used to set the constant optical power (from monitor

photodiode) limit value

LAS:LIM:V 1 Used to set the current source compliance voltage limit value

(LIM V)

LAS:MDP 1 Used to set the constant optical power setpoint LAS:MDP? NONE Returns the actual monitor photodiode power value LAS:MODE? NONE Returns the mode, ILBW, IHBW, or MDP (optical power) LAS:MODE:IHBW NONE Sets the mode to constant current, high bandwidth mode LAS:MODE:ILBW NONE Sets the mode to constant current, low bandwidth mode LAS:MODE:MDP NONE Sets the mode to constant optical power mode LAS:OUT 1 Used to enable/disable the current source output LAS:OUT? NONE Returns the current source output status LAS:RAN 1 Sets the laser current output range

04_06 LDX-3232 27



CHAPTER 3

REMOTE OPERATION

Status Reporting

This section contains information that is relevant for understanding instrument error and statu reporting. It also contains information regarding the use of the instrument status for generating interrupts for interrupt driven programs or subroutines. Understanding the Operation Complete definition for the instrument is useful for programming synchronization. The Output Off Register section also contains iformation on setting some of the conditions that will force the laser current source output off.

The following sections describe the Event and Condition registers, Operation Complete Flag, Output Off registers, and Error Messages.

Event and Condition Registers

In addition to the required GPIB-IEEE488 status reporting structures, the 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. Conditions reflect the current state of the device and therefore may change many times during operation. Querying a Condition Register does not change its contents.

Figure 3.3 shows the status reporting scheme of the LDX-3232 High Compliance Current Source. Each of the registers that may be accessed by a command or query has the appropriate command or query written above or below the register representation. For example, the LASER Condition Register may be queried via the LASer:COND? query.

The condition or event registers are logically ANDed with their respective enable registers. These bits are then logically ORed to form a summary message in the status byte for that particular register.

Operation Complete Definition

Note that Bit 0 of the Standard Event Status Register contains the status of the Operation Complete flag. Enabling this bit via the *ESE command allows the user to update bit 5 of the status byte. Then, if the SRE ma sk has bit 5 set, and the user issues an *OPC command, the SRQ (bus) signal will be generated upon completion of the currently processed commands. This bus signal (SRQ) may be used to initiate service request routines, that depend on the completion of all previous commands.

28 LDX-3232



REMOTE OPERATION

Status Reporting

CHAPTER 3

For example, the user may turn the current source on (LAS:OUT 1), enable an SRQ on Operation Complete (set *ESE 1 and *SRE 5), and have an SRQ handling routine in the user's software, that reads a new measurement after the output on state has been reached. This allows the use of the operation complete features of the LDX-3232, without the need for program loo ping or polling that can tie up the GPIB. Operation Complete on the LDX-3232 is defined as:

1 No operations to the LASER current source hardware are pending. 2 No EEPROM (non-volatile) memory write cycles are in progress.

LOGICAL

Standard

Event Status Register

*ESR?

Standard

Event Status Enable

*ESE

*ESE?

SERVICE

REQUEST

GENERATION

QUEUE

NOT-EMPTY

{

ERROR QUEUE

0 - Operation Complete

01234567

1 - Request Control 2 - Query Error 3 - Device-Dependendent Error 4 - Execution Error

5 - Command Error

6 - User Request 7 - Power On

01234567

LOGICAL

{

Service Requ es t Enable

*SRE

*SRE?

QUEUE

NOT-EMPTY

{

OUTPUT

QUEUE

Status Byte Register

01234567

0 – N/A 1 - N/A 2 – LASER Event 3 – LASER Cond.

4 - Message Available

5 - Event Status Summary

6 - Request Service/Master Status Summary 7 - Error Available

0123457

*STB?

LOGI CA L

LASE R Cond i tion St at us Regi ster

ASer : COND?

89101112131415

15 14 13 12 11 10 9 8

ASER Condi tion St at us Enabl

LAS : ENABl e : COND

AS : ENABl e

LOGICAL

76543210

LASER Event St at us Regi ster

LASer : EVEnt ?

51413121110 9 8

LASER Event St at us Enabl e

AS : ENABl e : EVEn

LAS : ENABl e :

0 – Current Limit 1 – Voltage Limit 2 – N/A 3 – Power Limit 4 – Interlock 5 – N/A 6 – Comp. Voltage Limit 7 – Open Circuit 8 – Output Shorted 9 – Out of Tolerance 10 – Output On

11 – Ready for Calibration 12 – N/A

01234567

13 – N/A 14 – N/A 15 – N/A

89101112131415

76543210

0 – Current L imit 1 – Voltage Limit

01234567

2 – N/A 3 – Power Limit 4 – Interlock 5 – N/A 6 – Comp. Voltage Limit 7 – Open Circuit 8 – Output Shorted

9 – Tolerance Change 10 – Output On/Off change 11 – New Measurement Ready 12 – N/A 13 – N/A 14 – N/A 15 – N/A

Note: If the GPIB times out while waiting for a response, either set the GPIB time-our longer or use SRQ generated interrupts in your program. See your GPIB manual for time-out configuration or SRQ programming setup.

The *OPC, *OPC? and *WAI commands should not be used inside a calibration routine.

04_06 LDX-3232 29

Figure 3.2 LDX-3232 Status Reporting Schematic Diagram



CHAPTER 3

Output Off Register

REMOTE OPERATION

Status Reporting

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. However, the register output is not reported in the Status Byte Register. Rather, it sets the hardware that controls the output switching. The events and conditions that may be set to cause the current source output to be turned off are shown in Figure 3.3.

The default (factory) settings for this register are shown in Table 3.3. These settings are not affected by the *PSC (Power-On Status Clear) command.

Table 3.3 LDX-3232 Series Default Settings for Output Off Registers

0 - disabled 8 - N/A 1 - disabled 9 - disabled 2 - N/A 10 - N/A 3 - enabled 11 - N/A 4 - N/A 12 - N/A 5 - N/A 13 - N/A 6 - N/A 14 - N/A 7 - N/A 15 - N/A

30 LDX-3232



REMOTE OPERATION

Status Reporting

CHAPTER 3

Logical

Turn Output Off

151413 12

11 10

76543210

101112131415

LASer:ENABle:OUTOFF <nrf>

LASer:ENABle:OUTOFF?

5432

LASER Output Off

Enable Register

Figure 3.3 LDX-3232 Output Off Register

0 - LASER Current Limit 8 - N/A 1 - LASER Voltage Limit 9 - LASER Output Changed to be Out of Tolerance 2 - N/A 10 - N/A 3 - LASER Power Limit (output on) 11 - N/A 4 - N/A 12 - N/A 5 - N/A 13 - N/A 6 - N/A 14 - N/A 7 - N/A 15 - N/A

04_06 LDX-3232 31



CHAPTER 3

REMOTE OPERATION

Command Timing and Completion

This section describes, for each device-dependent command, whether that command is performed in an overlapped or sequential manner. In other words, it states whether the next command may begin while the current command is being executed, or if the next command must wait until the current command is completed before its execution begins. The conditions for setting the operation complete flag are given in the 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.

The *WAI (common command) is an example of a sequential command that forces the next command to wait until the no-operation-pending flag is true. This is essentially the same as waiting for the OPC flag to become true, because the nooperations-pending flag is used to set the OPC flag (bit 0 of the Standard Event Status Register).

Commands that change the status of the instrument limits or change its mode or current range, step value, or status enable registers will not have their OPC flag set until all current writing to non-volatile memory has been completed. This is done to ensure that the OPC flag is never set prematurely.

Whenever there is any output (response) data in the Output Queue, bit 4 is set in the Status Byte Register. Whenever there is any error message in the Error Queue, bit 7 is set in the Status Byte Register.

Error Messages

In the event of a hardware error condition, error messages will be displayed on the display. In most cases, the error message will appear for three seconds. In some cases the error code display will remain until the user changes display modes. In the case of multiple error messages, the display may sequentially show each message for three seconds. In addition to the hardware errors, GPIB errors may be read via the ERR? query. Table 3.4 lists the numerical error ranges by function. Table 3.5 contains all of the error messages that may be generated. Not all of these messages may appear on the front panel displays. Some refer to GPIB activities only.

In remote operation, the errors can be read by issuing the ERR? query. When this is done, all of the error messages that are resident in the error queue are returned

32 LDX-3232



REMOTE OPERATION

Error Messages

CHAPTER 3

(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 Area of Operation

E-001 to E-099 Internal Program Errors E-100 to E-199 Parser Errors E-200 to E-299 Execution Control Errors E-300 to E-399 GPIB Errors E-500 to E-599 LASER Control Errors

Table 3.5 LDX-3232 Series Error Codes

Error Code Explanation

E-001 Memory allocation failure E-103 <DEFINITE LENGTH ARBITRARY BLOCK PROGRAM DATA> length too long E-104 <NON-DECIMAL NUMERIC PROGRAM DATA> type not defined E-105 <DECIMAL PROGRAM DATA> exponent not valid E-106 <DECIMAL PROGRAM DATA> digit expected E-123 Command not found E-124 <program mnemonic> Lookup, failed because query/command type match failed E-126 Too few or too many program data elements

E-201 <PROGRAM DATA> value out of range E-202 <PROGRAM DATA> will not convert to valid type E-203 Security violation, command is not available without clearance E-205 <PROGRAM DATA> is not a Boolean value or word E-207 <PROGRAM DATA> will not convert to an unsigned 16-b it value E-209 <PROGRAM DATA> will not convert to an unsigned 32-b it value E-210 <PROGRAM DATA> will not convert to a floating point value E-211 <PROGRAM DATA> will not convert to a character value E-213 <PROGRAM DATA> is incorrect block data length E-214 <PROGRAM DATA> length exceeds maximum

E-302 Query error; device was addressed to talk, but GPIB controller failed to read all of the

04_06 LDX-3232 33



CHAPTER 3

REMOTE OPERATION

Error Messages

Error Code Explanation

E-501 LASER interlock disabled output E-503 LASER open circuit disabled output E-504 LASER current limit disabled output E-505 LASER voltage limit disabled output E-507 LASER power limit disabled output E-510 LASER out of tolerance disabled output E-511 LASER control error disabled output E-512 Analog section status is all 1’s or all 0’s (power down) E-513 Serial EEPROM checksum error E-515 Laser output must be off to change ranges E-516 Incorrect configuration for calibration sequence to start E-519 Setting a measurement is only valid during the calibration phase for that measurement;

user has tried to calibrate a measurement without first entering the required calibration mode.

34 LDX-3232



COMMAND REFERENCE

CHAPTER 4

COMMAND REFERENCE

                 

This chapter is a guide to all of the device-dependent commands for the 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. The commands that emulate local (front panel) operation are denoted by the solid box next to the Local label in the upper left corner of the command description.

Table 4.1 LDX-3232 Series Device-Dependent Comm a nd s

Name Parameters Function

DELAY 1 Used to create a delay in the execution of further

ERR? NONE Returns errors generated since the last query LAS:CALMD 1 Used to set the CAL PD (monitor responsivity) constant LAS:CALMD? NONE Re turns the CAL PD (monitor responsivity) constant LAS:CAL:CONST? 1 Factory use only LAS:CAL:LDI NONE Used to enter the laser current calibration mode LAS:CAL:LDI? NONE Returns the ready state for entering the laser current

LAS:CAL:LDV NONE Used to enter the laser voltage calibration mode LAS:CAL:LDV? NONE Returns the ready state for entering the laser voltage

LAS:CAL:MDI NONE Used to enter the monitor photodiode current calibration

04_06 LDX-3232 35

commands

calibration value

calibration mode

mode



CHAPTER 4

COMMAND REFERENCE

Name Parameters Function

LAS:CAL:MDI? NONE Re turns the ready state for entering the monitor

photodiode current calibration value

LAS:COND? NONE Returns the value of the LASER condition register LAS:DEC 0, 1 or 2 Used to decreate the laser current setpoint value by one

or more steps

LAS:DIS 1 Turns the LASER display on or off LAS:DIS? NONE Returns the LASER display value LAS:DIS:LDI NONE Turn on/off LASER display to show laser output current LAS:DIS:LDI? NONE Returns status of laser output current display, on/off LAS:DIS:LDV NONE Turn on/off LASER display to show laser output voltage LAS:DIS:LDV? NONE Returns status of laser output voltage display, on/off LAS:DIS:MDI NONE Turn on/off LASER display to show photodiode monitor

current

LAS:DIS:MDI? NONE Returns status of photo diode monitor current display,

on/off

LAS:DIS:MDP NONE Turns on/off LASER display to show photodiode monitor

power

LAS:DIS:MDP? NONE Re turns status of photodiode monitor power display,

on/off

LAS:DIS:PARAM NONE Enables LASER display to show parameter values LAS:DIS:SET NONE Shows the LASER display setpoint corresponding to

mode

LAS:DIS:SET? NONE Returns status of LASER setpoint display, on/off LAS:ENAB:COND 1 Sets the enable register for LASER conditions LAS:ENAB:COND? NONE Returns the value of the LAS conditions enable register LAS:ENAB:EVE 1 Sets the enable register for LAS events LAS:ENAB:EVE? NONE Returns the value of the LAS event enable register LAS:ENAB:OUTOFF 1 Sets the enable register for LAS conditions, that turn the

LAS output off

LAS:ENAB:OUTOFF? NONE Returns the value of the LAS outoff enable register LAS:EVENT? NONE Re turns the value of the LAS event register LAS:LDI 1 Used to set the LASER constant current source setpoint

value

LAS:LDI? NONE Used to return the constant current source measured

LAS:INC 0, 1, or 2 Used to increment the LASER setpoint value by one or

LAS:LDV 1 Used to set the laser voltage value for calibration LAS:LDV? NONE Used to return the measured laser voltage value

36 LDX-3232



value

more steps

COMMAND REFERENCE

Name Parameters Function

LAS:LIM:I2 1 Used to set the LASER low range current source limit LAS:LIM:I2? NONE Used to return the LASER low range current source limit LAS:LIM:I4 1 Used to set the LASER high range current source limit LAS:LIM:I4? NONE Used to return the LASER high range current source

limit

LAS:LIM:MDP 1 Used to set the constant optical power (from monitor

photodiode) limit value

LAS:LIM:MDP? NONE Used to return the optical power (from monitor

photodiode) limit value

LAS:LIM:V 1 Used to set the LASER compliance voltage limit value LAS:LIM:V? NONE Used to return the LASER compliance voltage limit

value

CHAPTER 4

LAS:MDI 1 Used to set the constant optical power setpoint, if

LAS:MDI? NONE Used to return the monitor photodiode current

LAS:MDLN 1 Used to enable/disable the front panel modulation input LAS:MDLN? NONE Used to return the status of the front panel modulation

LAS:MDP 1 Used to set the constant optical power setpoint LAS:MDP? NONE Returns the actual monitor photodiode power value LAS:MODE? NONE Returns the mode, I (current), IHBW (high bandwidth),

LAS:MODE:IHBW NONE Sets the mode to constant current, high bandwidth LAS:MODE:ILBW NONE Sets the mode to constant current, low bandwidth LAS:MODE:MDP NONE Sets the mode to constant optical power mode LAS:OUT 1 Used to enable/disable the current source outpu t LAS:OUT? NONE Returns the current source output status LAS:RAN 1 Sets the laser current output range LAS:RAN? NONE Returns the laser current output range LAS:SET:LDI? NONE Returns the laser constant I (current) setpoint

photodiode responsivity is 0

measured value

input

or P (optical power)

LAS:SET:MDI? NONE Returns the laser constant optical power setpoint LAS:SET:MDP? NONE Returns the constant P (optical power) setpoint LAS:STEP 1 Used to set the LASER setpoint step value LAS:STEP? NONE Returns the LASER setpoint step value LAS:TOL 2 Used to set the LASER setpoint tolerance value and

04_06 LDX-3232 37

time period value



CHAPTER 4

COMMAND REFERENCE

Name Parameters Function

LAS:TOL? NONE Used to return the LASER setpoint tolerance value and

time period value

MES 1 Used to enter a string message of up to 16 bits MES? NONE Returns a previously stored ASCII message RAD 1 Sets the radix type for numerical data; decimal, binary,

RAD? NONE Used to return the radix type for numerical data TERM 1 Used to add a carriage return to the device terminator TERM? NONE Returns the status of the TERM command TIME? NONE Returns the elapsed time since the instrument was last

TIMER? NONE Returns the elapsed time since the timer was last reset

octal or hexadecimal

powered up

38 LDX-3232



COMMAND REFERENCE

(

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.

Command Path:Na m e

uired letters are shown in

Re u

er case; lower case letters

tional.

are o

CHAPTER 4

Front Panel/ Remote Execution

A solid box means the command can be executed in that mode. Comm and mnemonics in front

anel (local) mode may vary.

Command Descri S

ntax Diagram

tion

For Remote Commands)

Parameters

Tells what ex

ected, and their type.

arameters are

refers to a

flexible numeric notation

IEEE-488.2). Integer,

onential, or floating point

ex ma

be used with the decimal radix. Alternate radices ma selecte d in remote o

eration.

Points of Interest

ecial information

Has s about the comm an d.

Front Panel

Remote

The LASer:LIMit:I2 command sets the laser current limit value.

SYNTAX DIAGRAM

PARAMETERS

POINTS OF INTEREST

LAS

An <nrf value> that represents the LASER limit current, in mA.

The current limit is in effect in all modes of operation of the laser output. In local operation, the limit current is entered by selecting the LIM I parameter, pressing and holdi ng in the ( PARAMETER) S ET switch, adjusting the ADJ US T knob until the desire d v alue is displayed, and then releasing the SET switch.

LASer:LIMit:I

<white

space>

LIM

< nrf value >

les

Exam

Shows t

ical statements

using the command.

04_06 LDX-3232 39

EXAMPLES

"Las:Lim:I2 100" - action: the LASER current limit

is set to 100.0 mA.

"LAS : LIM:I 4 3000" - action: the LASER current limit

is set to 3000.0 mA.

Figure 4.1 Command Description Format



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

The following pages contain a reference for the device-dependent commands of the LDX-3232 High Compliance Current Source. This reference contains useful information for both local and remote operation of the LDX-3232.

References to the front panel labels are capitalized in the following reference pages (as is done throughout this manual). Therefore, a reference to the LOCAL switch is meant to signify the actual switch labeled LOCAL on the front panel of the LDX-3232.

In some reference, parentheses are used to signify the labeled are for a particular switch or LED indicator on the front panel. For example, (PARAMETER) SET refers to the switch labeled “SET” in the PARAMETER area of the front panel.

DELAY

The DELAY command causes the execution of commands to be delayed by a userdefined time. This command is similar to the *WAI common command, except that execution resumes after the specified number of miliseconds, instead of waiting for the Operation-Complete flag to be set.

Syntax Diagram

Parameters An <nrf value> that represents the delay time in milliseconds. Notes The Operation-Complete flag is held false until the delay period elapses, but the *OPC?

query will not execute until the delay period has elapsed. This command is useful for creating delays that don't require a lot of program code and

don't tie up the GPIB during execution. The delay time is approximate, with an error of about ±10%.

Examples "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.

Note: Care should be taken to set the GPIB time-out appropriately for use with the Delay command.

DELAY

<white

space>

<nrf

value>

FRONT PANEL

REMOTE

40 LDX-3232



COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

ERRors?

The ERRors? query returns a list of command and device errors that have occurred since the last query. These errors are notated by a number that corresponds to the type of error that occurred. See Chapter 3 for information regarding error handling.

Syntax Diagram

Parameters None. Notes The response data will be a list of the current errors. The errors are represented by

numbers and are separated by commas. A response of 0 indicates that no errors were reported. The response data is sent as character data. Up to 10 error codes are stored between error queries.

Examples "ERR?" -response: 0, means no errors reported.

"Errors?" -response: 201, means that the <PROGRAM DATA> (parameter) value out of range error was reported since the last ERR? query.

ERR

LASer:CALMD

The LASer:CALMD command sets the laser's photodiode feedback responsivity (the CAL PD parameter).

Syntax Diagram

FRONT PANEL

REMOTE

FRONT PANEL REMOTE

CALMD

Parameters An <nrf value>, in mA/mW. The range is 0 to 1000. Notes 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.

Examples "LAS:CALMD 0" -action: sets the CAL PD parameter to 0. This enables the constant I

mode of operation. "Laser:Calmd 1" -action: sets the CAL PD parameter to 1.00 mA/mW. Therefore, a

photodiode feedback current of 1 mA will cause the P

04_06 LDX-3232 41

LAS

CALPD

operation modes. Otherwise, the value of this

and PPD values. The units of this parameter are

<white

space>

display to read 1 mW.

<nrf

value>

mode, when



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:CALMD?

The LASer:CALMD? query returns the value of the laser's photodiode feedback responsivity (CAL PD parameter) setting.

Syntax Diagram

CALMD

Notes 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

If this value is 0, the front panel P

Examples "LASER:CALMD?" -response: 0, means the LDX-3232 is set for operation in constant

mode (if P mode is also selected).

"Las:Calmd?" -response: 1.1, means the LDX-3232 is set for operation in constant PPD mode (if P mode is also selected) and the responsivity is set to 1.1 µA/mW. 1.1 µA of photodiode feedback current represents 1 mW of optical power.

LAS

mode, and the PPD setpoint value will be in effect.

CALPD

will display "-.-” and no PPD value can be calculated.

FRONT PANEL REMOTE

mode, and the IPD

LAS:CAL:CONST?

The LAS:CAL:CONST? query returns a stored calibration value. It is intended for factory use only.

FRONT PANEL

REMOTE

42 LDX-3232



COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

LASer:CAL:LDI

The LASer:CAL:LDI command is used to enter the LASER current setpoint, measurement, and limit (in low bandwidth mode) calibration mode.

Syntax Diagram

Parameters None Notes Since the limit circuit is the same for both high and low bandwidth modes, it is only

calibrated when low bandwidth mode is selected. After this command is issued, the LDX-3232 High Compliance Current Source will allow

calibration of the current setpoint, measurement, and limit (if low bandwidth mode is selected). This procedure is outlined in Chapter 6.

The calibration defaults to the selected bandwidth setting. Therefore, it is necessary to select the desired bandwidth (I or I the calibration for that bandwidth.

Calibration is performed at the current setpoint, wherever it is set. If the LASER output is not on, 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.

Examples "Las:CAL:LdI" -action: the LDX-3232 enters calibration mode for LASER current.

"Las:Cal:LDI" -action: the LDX-3232 enters calibration mode for LASER current.

LAS

: :

HBW

CAL

) and turn the LASER output on before performing

FRONT PANEL REMOTE

LDI

04_06 LDX-3232 43



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:CAL:LDI?

The LASer:CAL:LDI? query is used to determine that the LDX-3232 is ready for a value to be entered during the calibration cycle of the LASer:CAL:LDI mode.

Syntax Diagram

Notes After this query is issued and a response of 1 is received, the LDX-3232 will be ready for

Examples "LASer:CAL:LDI?" -response: 1, means the LDX-3232 is ready for the user to enter a

LAS

the user to enter a current value via the LASer:LDI command (see Chapter 6).

current value via the LASer:LDI command. “LASer:Cal:LdI?” -response: 0, means the LDX-3232 is not yet ready for the user to enter

a LASER current value

CAL

LASer:CAL:LDV

The LASer:CAL:LDV command is used to enter the LASER voltage measurement calibration mode.

Syntax Diagram

FRONT PANEL REMOTE

LDI

FRONT PANEL REMOTE

Parameters None Notes After this command is issued, the LDX-3232 will allow calibration of the laser voltage

Examples "Las:CAL:Ldv" -action: the LDX-3232 enters calibration mode for LASER voltage.

44 LDX-3232



measurement. This procedure is outlined in Chapter 6. The LASer:CAL:LDV? query may be used to determine if the LDX-3232 is ready for the

user to enter a value.

"Las:Cal:LDV" -action: the LDX-3232 enters calibration mode for LASER voltage.

LAS

: :

CAL

LDV

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

FRONT PANEL REMOTE

LDV

FRONT PANEL REMOTE

LASer:CAL:LDV?

The LASer:CAL:LDV? query is used to determine that the LDX-3232 is ready for a value to be entered during the calibration cycle of the LASer:CAL:LDV mode.

Syntax Diagram

Notes 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).

Examples "LASer:CAL:LDV?" -response: 1, means the LDX-3232 is ready for the user to enter a

voltage value via the LASer:LDV command. "LASer:Cal:LdV?" -response: 0, means the LDX-3232 is not yet ready for the user to

enter a LASER voltage value.

LAS

CAL

LASer:CAL:MDI

The LASer:CAL:MDI command is used to enter the LASER photodiode current calibration mode.

Syntax Diagram

IPD

Parameters None Notes After this command is issued, the LDX-3232 will automatically enter the LASER

photodiode current calibration mode. When the LDX-3232 is ready, the user should enter the true measured value. This procedure is outlined in Chapter 6.

If the LASER output is not ON or if the P mode is not selected, error code E-516 will be generated.

In remote operation, the LASer:CAL:MDI? query may be used to determine if the LDX-3232 is ready for the user to enter a value via the LASer:MDI command.

Examples "Las:CAL:MDI" -action: the LDX-3232 enters the LASER photodiode current calibration

mode. "LAS:Cal:MDI" -action: the LDX-3232 enters the LASER photodiode current calibration

mode.

LAS

: :

CAL

MDI

04_06 LDX-3232 45



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:CAL:MDI?

The LASer:CAL:MDI? query is used to determine that the LDX-3232 is ready for a value to be entered during the calibration cycle of the LASer:CAL:MDI mode.

Syntax Diagram

Notes After this query is issued and a response of 1 is received, the LDX-3232 be ready for the

Examples "LAS:CAL:MDI?" -response: 1, means the LDX-3232 is ready for the user to enter a

LAS

user to enter a photodiode current value via the LASer:MDI command (see Chapter 6).

photodiode current value via the LASer:MDI command.

CAL

LASer:COND?

The LASer:COND? query returns the value of the status condition register of the LASER operations.

Syntax Diagram

FRONT PANEL REMOTE

MDI

IPD

FRONT PANEL

REMOTE

46 LDX-3232



-where the response is the sum of the following:

1 LASER Current Limit 256 Output is shorted 2 LASER Voltage Limit 512 Output is outside tolerance limit 4 N/A 1024 Output on/off state 8 Power limit 2048 Ready for calibration data state 16 Interlock disabled 4096 N/A 32 N/A 8192 N/A 64 Compliance Voltage Limit 16384 N/A 128 Open circuit 32768 N/A

Notes The LASER conditions that are reported to the status byte are set via the

LASer:ENABle:COND command. The Open circuit condition is only present while the LASER output is on, and when the

hardware detects this condition, it will turn the LASER output off. Therefore, the Open

LAS

COND

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

Circuit condition is fleeting and may be missed via the LAS:COND? query . Therefore, the user should test for the Open Circuit Event via the LAS:EVEnt? query.

The LASER condition status is constantly changing, while the event status is only cleared when the event status is read or the *CLS command is issued.

Examples "LAS:COND?" -response: 513, means that the LASER limit current and out of tolerance

LASER conditions currently exist. "Radix Hex; Laser:Cond?" -response: #H108, means that the LASER Output shorted

and Power limit conditions currently exist.

CHAPTER 4

<nrf

value>

FRONT PANEL

REMOTE

<nrf

value>

LASer:DEC

The LASer:DEC command decrements the selected laser control mode setpoint by one or more steps. Optional parameters allow multiple steps to be decremented and the time (in milliseconds) between decrements to be set, respectively. This is an overlapped command. Other commands may be executed while this function is in progress.

Syntax Diagram

Parameters 0, 1, or 2. The first optional parameter is the number of steps, and the second optional

Notes The decremental default amount is one step. The step size can be edited via the

Examples "LAS:MODE:I; LAS:STEP 3; LAS:DEC" -action: The laser source current setpoint is

LAS

parameter is the number of milliseconds between steps.

LAS:STEP command. LDX-3232 default values are 0. 1 mA, 0.1 mW, or 1 µA (if CALMD = 0).

If the first optional parameter is used, but not the second, the user may decrement the LASER setpoint by a multiple of the LAS:STEP size, without changing the LAS:STEP size.

If the both optional parameters are used, the user may create an automated stepping ramp function for the LASER output.

If the first optional parameter is entered as zero, "LAS:DEC 0", the command will do nothing.

The minimum time to complete one decrement is about 20 ms. Therefore, values for the second optional parameter (time between decrements) have a practical minimum of 20.

decremented by 0.3 mA. "LAS:MODE:I; LAS:STEP 3; LAS:DEC 3" -action: The laser source current setpoint is

decremented by three times the amount described in the first example. "LAS:MODE:I; LAS:STEP 3; LAS:DEC 3,5000" -action: The laser source current

setpoint is decremented by the amount described in the first example, three times, with five seconds between decremental steps.

DEC

<white

space>

04_06 LDX-3232 47

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CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

<white

space>

FRONT PANEL

REMOTE

<nrf

value>

FRONT PANEL

REMOTE

LASer:DISplay

The LASer:DISplay command enables or disables (turns off) the display and some LEDs

Syntax Diagram

Parameters An <nrf value>; -where 1 = on, 0 = off. Notes T urning the display and LEDs off means that a message of all blank spaces is sent to the

display, and most of the LEDs will be turned off.

Examples "las:dis 1" -action: turns the LASER display on and enables the LASER indicator LEDs.

"Laser:dis Off" -action: turns the LASER display and disables the LASER indicator LEDs.

LAS DIS

LASer:DISplay?

The LASer:DISplay? query returns the value shown on the display.

Syntax Diagram

Notes Returns the actual (6-character) string from the output buffer to the display. If the display

is disabled, it returns " .".

Examples "LAS:DIS?" -response: "- 99.9", means the LASER display shows "- 99.9".

"Laser:DISp?" -response: " 0.6", means the LASER display shows " 0.6".

LAS DIS

48 LDX-3232



COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

LASer:DISplay:LDI

The LASer:DISplay:LDI command sets the laser display to show the constant current measurement.

Syntax Diagram

Parameters None. Notes The LDI measurement display mode is turned off automatically when another display

selection is enabled.

Examples "LAS:DIS:LDI" -action: enables the display for current values.

LAS

: :

DIS

LASer:DISplay:LDI?

The LASer:DISplay:LDI? query returns the status of the LDI measurement display mode.

Syntax Diagram

FRONT PANEL REMOTE

LDI

FRONT PANEL

REMOTE

LDI

Notes In local operation, the status of the LDI measurement display mode is indicated by the

Examples "LAS:DIS:LDI?" -response: 0, means that the LDI measurement is not displayed.

LAS

- where the response is 0 or 1.

enunciator next to the display (mA will be illuminated and not blinking when the display is in LDI measurement mode).

"Las:dis:ldI?" -response: 1, means that the LDI measurement is displayed.

DIS

04_06 LDX-3232 49



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:DISplay:LDV

The LASer:DISplay:LDV command sets the laser display to show the laser forward voltage measurement.

Syntax Diagram

Parameters None Notes The LDV measurement mode is turned off automatically when another display selection

is enabled.

Examples "LAS:DIS:LDV" -action: enables the display for LDV measurement mode.

LAS

: :

DIS

LASer:DISplay:LDV?

The LASer:DISplay:LDV? query returns the status of the LDV (laser diode voltage) measurement display mode.

Syntax Diagram

FRONT PANEL REMOTE

LDV

FRONT PANEL

REMOTE

50 LDX-3232



LDV

Notes In local operation, the status of the LDV measurement mode is indicated by the

Examples "LAS:DIS:LDV?" -response: 0, means that laser voltage measurement is not displayed.

LAS

- where the response is 0 or 1.

enunciator next to the display (V will be illuminated when the display is in LDV measurement mode).

"LAS: DIS:LDV?" -response: 1, means that the laser voltage measurement is displayed.

DIS

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

LASer:DISplay:MDI

The LASer:DISplay:MDI command sets the laser display to show the monitor photodiode current measurement.

Syntax Diagram

Parameters None Notes The MDI measurement display is turned off automatically when another display selection

is enabled.

Examples "LAS:DIS:MDI" -action: enables the display for photodiode current measurement values.

Laser:Disp:Mdi" -action: enables the LASER display for photodiode current measurement values.

LAS

: :

DIS

LASer:DISplay:MDI?

The LASer:DISplay:MDI? query returns the status of the (LASER DISPLAY) I

Syntax Diagram

FRONT PANEL REMOTE

IPD

MDI

FRONT PANEL

REMOTE

switch.

MDI

Notes In local operation, the status of the MDI measurement mode is indicated by the

Examples "LAS:DIS:MDI?" -response: 0, means that the laser photodiode monitor current

04_06 LDX-3232 51

LAS

- where the response is 0 or 1

enunciator next to the display (µA will be illuminated and not blinking when the display is in MDI measurement mode).

measurement is not displayed. "Las:dis:MDI?" -response: 1, means that the monitor photodiode current measurement

is displayed.

DIS

IPD



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:DISplay:MDP

The LASer:DISplay:MDP command sets the display to show the monitor photodiode power measurement.

Syntax Diagram

Parameters None Notes The MDP measurement display is turned off automatically when another display

selection is enabled.

Examples "Las:Display:MDp" -action: enables the display for photodiode power measurement

values. "Laser:Disp:MDP" -action: enables the display for photodiode power measurement

values.

LAS

: :

DIS

LASer:DISplay:MDP?

The LASer:DISplay:MDP? query returns the status of the MDP (monitor diode power) measurement display mode.

Syntax Diagram

FRONT PANEL REMOTE

PPD

MDP

FRONT PANEL

REMOTE

52 LDX-3232



MDP

Notes In local operation, the status of the MDP measurement mode is indicated by the

Examples "LAS:DIS p:MDp?" -response: 0, means that the MDP measurement is not displayed.

LAS

- where the response is 0 or 1.

enunciator next to the display (mW will be illuminated and not blinking when the display is in MDP measurement mode).

"Las:dis:MDP?" -response: 1, means that the MDP measurement is displayed.

DIS

PPD

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

LASer:DISplay:PARAM

The LASer:DISplay:PARAM command enables the display to show the parameter values.

Syntax Diagram

Parameters None Notes This command has the same effect as pressing the (PARAMETER) SELECT switch

while in LASER mode. The selected parameter will be displayed for three seconds. The actual LASER PARAM display is turned off automatically when a display selection is enabled.

Each time the command is issued, the next LASER parameter will be selected, see Chapter 2 for more information.

Examples "Laser:Display:Param" -action: selects a parameter and displays its value.

"LAS:DIS:PARAM" -action: selects a parameter and displays its value.

LAS

: :

DIS

LASer:DISplay:SET

The LASer:DISplay:SET command sets the display to show the setpoint of the selected display mode.

Syntax Diagram

FRONT PANEL REMOTE

PARAM

FRONT PANEL REMOTE

Parameters None Notes Using this command has the same ef fect as physically holding the (DISPLAY) SELECT

switch down continuously.

Examples "Las:Dis:Set" -action: enables the display for the setpoint of the selected mode: LDI,

MDI (I "LAS:Dis:Set" -action: enables the display for the setpoint of the selected display mode.

04_06 LDX-3232 53

) or MDP (PPD)

LAS

: :

DIS

SET



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

FRONT PANEL

REMOTE

SET

FRONT PANEL

REMOTE

LASer:DISplay:SET?

The LASer:DISplay:SET? query returns the status of the setpoint display mode.

Syntax Diagram

- where the response is 0 or 1.

Notes The setpoint display will not time out when REMOTE operation is used. (It will be

continuously displayed.)

Examples "LAS:DISPLAY:SET?" -response: 0, means the setpoint is not shown on the display.

"Las:Dis:Set?" -response: 1, means the setpoint value is shown on the display.

LAS

DIS

LASer:ENABle:COND

The LASer:ENABle:COND command sets the condition status enable register of the LASER operations for summary (in bit 3 of the status byte) and generation of service requests.

Syntax Diagram

Parameters An <nrf value> whose sum represents the enabled bits:

Notes The enabled or disabled LASER conditions can be read by using the

LAS

LASer:ENABle:COND? query. The LASER condition status can be monitored by the LASer:COND? query. If any of the

enabled LASER conditions are true, bit 3 of the status byte register will be set. The enable registers normally retain their values at power-up (as they were at power-

down) unless the power-on status clear flag is set true (for more information see the *PSC definition, in the GPIB-IEEE488 specification).

ENAB

COND

<white

space>

<nrf

value>

54 LDX-3232

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COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

Examples "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).

Laser:Enable:Cond #H0F9B" - action: enables the LASER status condition register so that any and all of the above conditions will be reported in the status byte register (bit 3).

CHAPTER 4

FRONT PANEL

REMOTE

COND

LASer:ENABle:COND?

The LASer:ENABle:COND? query returns the value of the status condition enable register of the LASER operations.

Syntax Diagram

- where the response is the sum of the following:

1 LASER Current Limit 256 Output is shorted 2 LASER Voltage Limit 512 Output changed to be in/out of tolerance 4 N/A 1024 Output on/off state 8 Power limit 2048 Ready for calibration data state 16 Interlock disabled 4096 N/A 32 N/A 8192 N/A 64 Compliance Voltage Limit 16384 N/A 128 Open circuit 32768 N/A

Notes The enabled LASER conditions can be set by using the LASer:ENABle:COND

command. The LASER condition status can be monitored by the LASer:COND? query.

Examples "LAS:ENAB:COND?" -response: 17, means that the Laser Current Limit and Interlock

disabled LASER conditions will be reported (in summarized form) to the status byte (bit 3).

"Radix Hex; Laser:Enable:Cond?" -response: #H0F9B, means that all of the above conditions will be reported (in summarized form) to the status byte (bit 3).

LAS

ENAB

04_06 LDX-3232 55

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CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:ENABle:EVEnt

The LASer:ENABle:EVEnt command sets the status event enable register of the LASER operations. These events are summarized in bit 2 of the status byte register.

Syntax Diagram

Parameters An <nrf value> whose sum represents the bits that are enabled:

1 LASER Current Limit 256 Output is shorted 2 LASER Voltage Limit 512 Output changed to be in/out of tolerance 4 N/A 1024 Output on/off state changed 8 Power limit 2048 New measurements taken 16 Interlock changed state 4096 N/A 32 N/A 8192 N/A 64 Compliance Voltage Limit 16384 N/A 128 Open circuit 32768 N/A

Notes The enabled LASER events can be read by using the LASer:ENABle:EVEnt? query. The

Examples "LAS:ENAB:EVENT 136" -action: enables the LASER status event register so that the

LAS

LASER event status can be monitored by the LASer:EVEnt? query. The enable registers normally retain their values at power-up (as they were at power-

down) unless the power-on status clear flag is set true (for more information see the *PSC definition, in the GPIB-IEEE488 specification).

Open circuit and Power limit events will be reported (in summarized form) to the status byte (bit 2).

"Laser:Enable:Event #H0F9B" -action: enables the LASER status event register so all of the above events will be reported (in summarized form) to the status byte (bit 2).

ENAB

: EVE

FRONT PANEL

REMOTE

<white

space>

<nrf

value>

56 LDX-3232



COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

FRONT PANEL

REMOTE

EVE

LASer:ENABle:EVEnt?

The LASer:ENABle:EVEnt? query returns the value of the status event enable register of the LASER operations.

Syntax Diagram

- where the response is the sum of the following:

1 LASER Current Limit 256 Output is shorted 2 LASER Voltage Limit 512 Output changed to be in/out of tolerance 4 N/A 1024 Output on/off state 8 Power limit 2048 New measurements taken 16 Interlock state changed 4096 N/A 32 N/A 8192 N/A 64 Compliance Voltage Limit 16384 N/A 128 Open circuit 32768 N/A

Notes The enabled LASER events can be set by using the LASer:ENABle:EVEnt command.

The LASER event status can be monitored by the LASer:EVEnt? query.

Examples "LAS:ENAB:EVE?" -response: 1040, means that the Output on/off state change and

Interlock changed LASER events will be reported (in summarized form) to the status byte register (bit 2).

"Radix Hex; Las:Enab:Eve?" -response: #HFDB, means that all of the above events will be reported (in summarized form) to the status byte register (bit 2).

LAS

ENAB

04_06 LDX-3232 57



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:ENABle:OUTOFF

The LASer:ENABle:OUTOFF command sets the status outoff enable register of the LASER operations (things that will turn the LASER output off).

Syntax Diagram

Parameters An <nrf value> whose sum represents the enabled bits:

1 LASER Current Limit 256 N/A 2 LASER Voltage Limit 512 Output is out of tolerance* 4 N/A 1024 N/A 8 Power limit (with output on) 2048 N/A 16 N/A 4096 N/A 32 N/A 8192 N/A 64 N/A 16384 N/A 128 N/A 32768 N/A

Notes The enabled LASER outoff bits can be read by using the LASer:ENABle:OUTOFF?

Examples "LAS:ENAB:OUTOFF 9" -action: enables the LASER status outoff register so that Power

LAS

query. The enable registers normally retain their values at power-up (as they were at power-

down) unless the power-on status clear flag is set true (for more information see the *PSC definition, in the GPIB-IEEE488 specification).

The factory default value for this register is #B0000100000001000, #H808, or 2056 decimal.

limit and LASER current limit conditions will cause the LASER output to be turned off. "Las:Enab:Outoff #HE0B" -action: enables the LASER status outoff register so that any

or all of the above conditions will cause the LASER output to be turned off.

ENAB

OUTOFF

FRONT PANEL

REMOTE

<white

space>

<nrf

value>

58 LDX-3232



COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

FRONT PANEL

REMOTE

OUTOFF

LASer:ENABle:OUTOFF?

The LASer:ENABle:OUTOFF? query returns the value of the status outoff enable register of the LASER operations.

Syntax Diagram

-where the response is the sum of the following:

1 LASER Current Limit 256 N/A 2 LASER Voltage Limit 512 Output if out of tolerance 4 N/A 1024 N/A 8 Power limit (with output on) 2048 N/A 16 N/A 4096 N/A 32 N/A 8192 N/A 64 N/A 16384 N/A 128 N/A 32768 N/A

Notes The enabled LASER events can be set by using the LASer:ENABle:OUTOFF c ommand.

The LASER output status can be monitored by the LASer:EVEnt? query.

Examples "LAS:ENAB:OUTOFF?" -response: 1, means that Current Limit Condition will cause the

LASER output to be turned off. "Radix Hex; Las:Enab:Eve?" -response: #H20B, means that all of the above conditions

will cause the LASER output to be turned off.

LAS

ENAB

04_06 LDX-3232 59



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:EVEnt?

The LASer:EVEnt? query returns the value of the status event register of the LASER operations.

Syntax Diagram

-where the response is the sum of the following:

1 LASER Current Limit 256 Output is shorted 2 LASER Voltage Limit 512 Output changed to be in/out of tolerance 4 N/A 1024 Output on/off state changed 8 Power limit 2048 Measurement ready 16 Interlock disabled 4096 N/A 32 N/A 8192 N/A 64 Compliance Voltage Limit 16384 N/A 128 Open circuit 32768 N/A

Notes The LASER conditions that are reported in the status byte can be set by using the

LASer:ENABle:EVEnt command. The LASER event status is only cleared when the event status is read or by the *CLS

command while the condition status is constantly changing.

Examples "LAS:EVE?" -response: 513, means that the LASER output tolerance changed and

current limit events have occurred since the last LASer:EVEnt? query. "Radix Hex; Laser:Event?" -response: #H88, means that the LASER Power limit and

Open circuit events have occurred since the last LASer:EVEnt? query.

LAS EV E

FRONT PANEL

REMOTE

60 LDX-3232

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COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

<nrf

value>

FRONT PANEL

REMOTE

<nrf

value>

LASer:INC

The LASer:INC command increments the selected laser control mode setpoint by one or more steps. Optional parameters allow multiple steps to be incremented and the time (in ms) between increments to be set, respectively. This is an overlapped command. Other commands may be executed while this function is in progress.

Syntax Diagram

Parameters 0, 1, or 2. The first optional parameter is the number of steps, and the second optional

Notes The decremental default amount is one step. The step size can be edited via the

Examples “LAS:MODE:I; LAS:STEP 3; LAS:INC” -action: The laser source current setpoint is

LAS

parameter is the number of ms between steps.

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. The second optional parameter is the time, in ms, between steps.

If both optional parameters are used, the user may create an automated stepping ramp function for the LASER output.

If the first optional parameter is entered as zero, “LAS:INC 0”, the command will do nothing.

The minimum time to complete one increment is about 20 ms. Therefore, values for the second optional parameter (time between increments) have a practical minimum of 20.

This command should not be overlapped with “LAS:DEC” or other “LAS:INC” commands.

incremented by 0.03 mA. “LAS:MODE:I; LAS:STEP 3; LAS:INC 3” -action: The laser source current setpoint is

incremented by three times the amount described in the first example. “LAS:MODE:I; LAS:STEP 3; LAS:INC 3,5000” -action: The laser source current setpoint

is incremented by the amount described in the first example, three ti mes, with fiveseconds between incremental steps.

“LAS:STEP 1; LAS:Mode:P; Las:INC” -action: The power setpoint is incremented by

0.01 mW.

INC

<white

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CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:LDI

The LASer:LDI command sets the laser control current.

Syntax Diagram

Parameters An <nrf value> that represents the (laser) output current in mA. Notes setpoint is the same for both low and high bandwidth output modes. Examples "Las:LDI 400" -action: sets the laser output current to 400.00 mA.

"LAS:ldi 100" -action: sets the laser output current to 100.0 mA.

LAS

LDI

LASer:LDI?

The LASer:LDI? query returns the value of the measured laser current.

Syntax Diagram

FRONT PANEL REMOTE

<white

space>

FRONT PANEL REMOTE

<nrf

value>

- where the response is the most recent laser current measurement.

Notes Response is the measured laser output current for either low or high bandwidth modes.

This measurement is updated approximately once every 600 ms.

Examples "LAS:ldi?" -response: 30.0, means the measured laser output current is 30.0 mA.

"Laser:LDI?" -response: 100.0, means the measured laser output current is 100.0 mA.

LAS

LDI

62 LDX-3232

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LDX-3232 Device-Dependent Command Reference

CHAPTER 4

<white

space>

FRONT PANEL

REMOTE

<nrf

value>

FRONT PANEL

REMOTE

LASer:LDV

The LASer:LDV command sets the laser voltage for calibration of the laser voltage measurement.

Syntax Diagram

Parameters An <nrf value> that represents the (laser) output voltage, in volts. Notes setpoint is the same for both low and high bandwidth output modes and is entered only

for LDV calibration.

Examples "Las:LDV 4" -action: enters a value of 4.000 V.

"LAS:ldv 1.025" -action: enters a value of 1.025 V.

LAS LDV

LASer:LDV?

The LASer:LDV? query returns the value of the measured laser voltage.

Syntax Diagram

- where the response is the measured laser output voltage for either low or high

bandwidth modes. Notes This measurement is updated approximately once every 600 ms. Examples "LAS:ldv?" -response: 3.03, means the measured laser output voltage is 3.03 V.

"Laser:LDV?" -response: 1.0, means the measured laser output voltage is 1.000 V.

LAS

LDV

04_06 LDX-3232 63



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:LIMit:I2

The LASer:LIMit:I2 command sets the LASER current limit value for the 2000 mA range

on the LDX-3232. Syntax Diagram

Parameters An <nrf value> that represents the LASER limit current , in mA . Notes The current limit is in effect in all modes of operation (ILBW, IHBW , or P). The current

Examples "LAS:LIM:I2 180" -action: the LASER current limit is set to 180 mA.

LAS

limit in use depends on the LASER output range selection.

":Laser:Limit:I2 160" -action: the LASER current limit is set to 160 mA.

LIM

LASer:LIMit:I2?

The LASer:LIMit:I2? query returns the value of the LASER current limit for the 2000 mA

range on the LDX-3232. Syntax Diagram

FRONT PANEL REMOTE

<white

space>

FRONT PANEL REMOTE

<nrf

value>

- where the response is the current limit value for the 2000 mA range.

Notes The current limit is in effect in all modes of operation (ILBW, IHBW , or P). The current

limit in use depends on the LASER output range selection. Examples "LAS:LIM:I2?" -response: 40, means the laser current limit is 40 mA.

"Laser:LIM:I2?" -response: 50, means the laser current limit is 50 mA .

LAS

LIM

64 LDX-3232



COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

LASer:LIMit:I4

The LASer:LIMit:I4 command sets the LASER current limit value for the 4000 mA range

on the LDX-3232. Syntax Diagram

Parameters An <nrf value> that represents the LASER limit current , in mA . Notes The current limit is in effect in all modes of operation (ILBW, IHBW , or P). The current

Examples "LAS:LIM:I4 1800" -action: the LASER current limit is set to 1800 mA.

LAS

limit in use depends on the LASER output range selection.

In local operation, the limit current is entered by selecting LIM I parameter, pressing and

holding in the (PARAMETER) SET switch, adjusting the knob until the desired value is

displayed, and then releasing the SET switch.

":Laser:Limit:I4 160" -action: the LASER current limit is set to 160 mA.

LIM

LASer:LIMit:I4?

The LASer:LIMit:I4? query returns the value of the LASER current limit for the 4000 mA

on the LDX-3232. Syntax Diagram

FRONT PANEL REMOTE

<white

space>

FRONT PANEL REMOTE

<nrf

value>

- where the response is the current limit value for the 4000 mA range.

Notes The current limit is in effect in all modes of operation (ILBW, IHBW , or P). The current

limit in use depends on the LASER output range selection. Examples "LAS:LIM:I4?" -response: 400, means the laser current limit is 400 mA.

"Laser:LIM:I4?" -response: 1500, means the laser current limit is 1500 mA.

LAS

LIM

04_06 LDX-3232 65

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CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:LIMit:MDP

The LASer:LIMit:MDP command sets the laser monitor photodiode power limit value. Syntax Diagram

MDP

Parameters An <nrf value> that represents the laser monitor photodiode power limit in mW. Notes When constant MDP mode is used, the output level is limited only by the LIM Ix value.

Examples "LAS:LIM:MDP 10" -action: sets the laser output power limit to a value that corresponds

LAS

Exceeding the powere limit will either cause the output to shut off (default) or generate a

warning (see LAS:ENAB:OUTOFF command).

to producing 10.00 mW of photodiode feedback (optical) power.

"Las:Limit:MDp 5" -action: sets the laser output power limit to a value that corresponds to

producing 5.00 mW of photodiode feedback (optical) power .

: :

LIM

LASer:LIMit:MDP?

The LASer:LIMit:MDP? query returns the value of the laser monitor photodiode power

limit. Syntax Diagram

FRONT PANEL REMOTE

<white

space>

FRONT PANEL REMOTE

<nrf

value>

66 LDX-3232



MDP

Notes The (LASER) MDP limit is in effect for both laser output current ranges.

Examples "LAS:LIM:MDP?" -response: 3.0, means the monitor photodiode power limit is set to

LAS

- where the response is the LASER power limit setting.

The MDP limit is not in effect when CALMD=0. In this case, the monitor current

measurement is not converted to power.

3.0 mW.

":LAS:Limit:MDP?" -response: 10.0, means the monitor photodiode power limit is set to

10.0 mW.

LIM

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

LASer:LIMit:V

The LASer:LIMit:V command sets the LASER compliance voltage limit value. Syntax Diagram

Parameters An <nrf value> that represents the LASER limit voltage, in volts. Notes The voltage limit setting is useful for laser protection. When the maximum operating

Examples "LAS:LIM:V 5.0" -action: the LASER compliance voltage limit is set to 5.0 V.

LAS

voltage of a laser is known, the user may set the voltage limit to a value slightly higher

than the maximum operating voltage. Then, if the laser is accidentally disconnected, the

current source will quickly sense the over-voltage and shut off.

In local operation, the voltage limit is entered by selecting the COMP V parameter,

pressing and holding in the (PARAMETER) SET switch. Turn the adjust knob until the

desired value is displayed and then release the SET switch.

":Laser:Limit:V 4.60" -action: the LASER compliance voltage limit is set to 4.6 V.

LIM

LASer:LIMit:V?

The LASer:LIMit:V? query returns the value of the LASER compliance voltage limit

setting. Syntax Diagram

FRONT PANEL REMOTE

<white

space>

FRONT PANEL REMOTE

<nrf

value>

- where the response is the LASER limit voltage setpoint.

Notes The voltage limit is valid for all modes of Laser operation.

In local operation, the voltage limit is seen by selecting the COMP V parameter , pressing

and holding in the (PARAMETER) SELECT switch. Examples "LAS:LIM:V?" -response: 4.5, means the laser compliance voltage limit is 4.5 V.

"Laser:LIM:V?" -response: 10.0, means the laser compliance voltage limit is set to

10.0 V.

04_06 LDX-3232 67

LAS

LIM



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:MDI

The LASer:MDI command sets the value of the optical power setpoint, in µA, if the

CALMD (CAL PD) responsivity is 0. Syntax Diagram

MDI

Parameters An <nrf value> that represents the photodiode feedback current, in µA. Notes If the CALMD (CAL PD) parameter is not set to 0, the LAS:MDI value will not be used. In

this case, the measured MDI would be converted to MDP (P

and the MDP (P Examples "Las:Mdi 40" -action: The LASER output is controlled so that the photodiode feedback

current remains constant at 40 µA.

"Laser:MDI 200" -action: The LASER output is controlled so that the photodiode

feedback current remains constant at 200 µA.

LAS

) setpoint would be used.

IPD

LASer:MDI?

The LASer:MDI? query returns the value of the laser photodetector current measurement

in µA. Syntax Diagram

FRONT PANEL REMOTE

<white

space>

, by the CAL PD factor),

FRONT PANEL REMOTE

<nrf

value>

Notes The response is in µA. The response is valid, even when the unit is not in constant P

Examples "Las:Mode:MDP; Las:Calmd 0; Las:MDi?" -response: 100.0, means 100 µA of

68 LDX-3232



MDI

- where the response is the most recent LASER monitor current measurement.

mode.

This measurement is updated approximately once every 600 ms.

photodetector current. This feedback is controlling the laser current output.

"LAS:MODE:IHBW; LAS:MDI?" -response: 20.0, means 20 µA of photodetector current,

but photodiode monitor current is not controlling the laser output current.

LAS

IPD

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

LASer:MDLN

The LASer:MDLN command enables or disables (turns off) the front panel modulation

input (BNC). Syntax Diagram

Parameters An <nrf value> - where 1=on, 0=off. Notes After turning the modulation off, it will remain off until turned back on via this command or

by resetting the instrument. Examples “las:mdln 1” -action: turns the modulation input on and enables modulation via the front

panel BNC connector.

“Laser:mdln 0” -action: turns the modulation input off. Modulation signals at the front

panel BNC will not effect the LAS output.

LAS MDLN

LASer:MDLN?

The LASer:MDLN? query returns that status of the LAS modulation control. When

disabled, a modulation signal at the front panel BNC will not effect the LAS output. Syntax Diagram

FRONT PANEL

REMOTE

<white

ace>

FRONT PANEL

REMOTE

<nrf

value>

- where the response of 1=on, 0=off.

Notes The LASER modulation control switches the front panel BNC in and out of the LAS

control circuit. At power up or after reset, modulation is enabled by default. Examples “LAS:MDLN?” -response: 1, means that the LAS modulation input is enabled.

“las:mdln?” -response: 0, means that the LAS modulation input is disabled.

04_06 LDX-3232 69

LAS

MDLN



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:MDP

The LASer:MDP command sets the value of the optical power setpoint in mW if the

CALMD (CAL PD) responsivity is greater than 0. Syntax Diagram

MDP

Parameters An <nrf value> that represents the photodiode feedback power in mW. Notes If the CALMD (CAL PD) parameter is set to 0, the LAS:MDP value will not be used. In

this case, the measured MDP would be invalid, and the MDI (I Examples "Las:Mdp 40" -action: The LASER output is controlled so that the photodiode feedback

power remains constant at 40 mW.

"Laser:MDP 200" -action: The LASER output is controlled so that the photodiode

feedback power remains constant at 200 mW.

LAS

LASer:MDP?

The LASer:MDP? query returns the value of the laser photodetector power measurement

in mW.

FRONT PANEL REMOTE

<white

space>

) setpoint would be used.

FRONT PANEL REMOTE

<nrf

value>

70 LDX-3232



MDP

- where the response is the most recent LASER power measurement.

Notes The response is in mW. The response is valid, even when the unit is not in constant P

mode. This measurement is updated approximately once every 600 ms. Examples "Las:Mode:MDP; Las:Calmd 460; Las:MDp?" -response: 100.0, means 100 mW of

photodetector power. This feedback is controlling the laser current output.

"LAS:MODE:IHBW; LAS:MDP?" -response: 20.0, means 20 mW of photodetector

power, but photodiode monitor current is not controlling the laser output current.

LAS

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

LASer:MODE?

The LASer:MODE? query returns the selected laser control mode.

Notes I

Examples "LAS:MODE?" -response: ILBW, means that constant I (current) mode is in effect for the

mode is the same as I mode (low bandwidth), except that the output low bandpass

HBW

filter is disabled in I

laser output.

":Las:Mode?" -response: MDP, means that constant P (power) mode is in effect for the

laser output, and CALMD>0.

"Las:Mode?" -response: MDI, means that constant P (power) mode is in effect for the

laser output, and CALMD=0.

"Laser:MODE?" -response: IHBW, means that constant I

mode is in effect for the laser output.

HBW

LAS

mode.

MODE

LASer:MODE:IHBW

The LASer:MODE:IHBW command selects laser high bandwidth constant current mode.

FRONT PANEL REMOTE

(current, high bandwidth)

HBW

FRONT PANEL REMOTE

Parameters None Notes This mode of operation is constant I mode with the output lowpass filter disabled. Examples "LAS:Mode:Ihbw" -action: enables the laser high bandwidth constant current mode.

04_06 LDX-3232 71

LAS

: :

MODE

IHBW



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:MODE:ILBW

The LASer:MODE:ILBW command selects laser constant current mode.

Parameters None Notes Constant I mode (low bandwidth) enables the output low bandpass filter. Examples "LAS:MODE:ILBW" -action: sets the laser output for constant I mode (low bandwidth).

LAS

: :

MODE

LASer:MODE:MDP

The LASer:MODE:MDP command selects laser constant power mode.

FRONT PANEL REMOTE

ILBW

FRONT PANEL REMOTE

Parameters None Notes This mode of laser operation requires the laser's monitor photodiode feedback to

maintain constant optical power or constant monitor current.

In this mode, the displayed parameter will be either I

CALMD>0) in mW. Examples "LAS:MODE:MDP" -action: sets the laser output mode of operation to constant optical

power mode.

LAS

: :

MODE

(if CALMD=0) in µA, or PPD (if

MDP

72 LDX-3232



COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

<white

space>

FRONT PANEL REMOTE

<nrf

value>

FRONT PANEL REMOTE

LASer:OUTput

The LASer:OUTput command turns the laser output on or off.

Parameters An <nrf value>; 1=on, 0=off. Notes There is a two-second delay after the output is turned on before the output shorting relay

is opened. Following this, the output current ramps up to the current setpoint slowly to

protect the laser. Therefore, the time to turn the output on and reach the setpoint current

varies from two to about three seconds.

After the output is turned on, it may be useful to wait until the output is stable (within

tolerance) before performing further operations, but it is not necessary . When the LASER

output is off, it is safe to connect or disconnect devices to the LASER output terminals.

When the LASER output is off, an internal short is placed across the output terminals. Examples "LAS:I 20; LAS:OUT ON" -action: sets the laser output current to 20 mA and then turns

the output on.

LAS OUT

LASer:OUTput?

The LASer:OUTput? query returns the status of the laser output switch.

- where the response is 0 or 1

Notes Although the status of the switch is on, the output may not have reached the setpoint

value. Examples "Las:OUT?" -resp on se : 0, mea ns tha t the output switch is disabled, devices may be

safely disconnected or connected at the LASER output terminals.

"LAS:OUT?" -response: 1, means that the LASER output switch is enabled, LASER

output is present.

04_06 LDX-3232 73

LAS

OUT



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

<white

space>

FRONT PANEL REMOTE

<nrf

value>

FRONT PANEL REMOTE

LASer:RANge

The LASer:RANge command selects the laser's drive current output range.

Parameters An <nrf value> that represents the laser current output range.

2 = 2000 mA, and 4= 4000 mA range Notes 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. Examples "LAS:RAN 4" -action: sets the laser output drive current range to 4000 mA.

"Laser:range 2" -action: sets the laser output drive current range to 2000 mA.

LAS RAN

LASer:RANge?

The LASer:RANge? query returns the value of the Laser Drive Current range.

- where the response is in integer; 2 means 2000 mA range and 4 means 4000 mA

range. Notes The resolution and accuracy of the laser limit current are dependent on the Laser Drive

Current output range. Examples "LAS:RAN?" -response: 2, means that the Laser Drive Current range is 2000mA.

"LAS:range?" -response: 4, means that the Laser Drive Current range is 4000mA.

LAS

RAN

74 LDX-3232



COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

LASer:SET:LDI?

The LASer:SET:LDI? query returns the constant I value that is used for both output

ranges and both bandwidths.

- where the response is the constant I setpoint value, in mA.

Notes In local operation, the constant I setpoint is read by selecting I or I

pressing and holding down the SELECT switch in the DISPLAY area of the front panel.

When the mA indicator is blinking, the display will show the LDI setpoint. Examples "LAS:SET:LDI?" -response: 50.0, means the laser output current setp oi n t val u e i s

50.0 mA.

"Laser:set:ldi?" -response: 120.0 means the laser output current setpoint value is

120.0 mA.

LAS

LDI

SET

FRONT PANEL REMOTE

mode, then

HBW

LASer:SET:MDI?

The LASer:SET:MDI? query returns the laser monitor photodiode current setpoint value

(when CALPD=0), in µA.

- where the response is the constand I

Notes In local operation, the MDI setpoint is read by selecting P mode, then pressing and

holding down the SELECT switch in the DISPLAY area of the front panel. When the µA

indicator is blinking, the display will show the MDI setpoint.

The monitor photodiode current is directly proportional to the laser optical output power.

Therefore, the MDI (I Examples "las:set:mdi?" -response: 30.0, means the laser monitor photodiode current is setpoint is

30 µA, for use in constant P mode with CALPD = 0.

LAS

MDI

) setpoint may be used to control optical output of the laser.

SET

IPD

setpoint value, in µA.

FRONT PANEL REMOTE

04_06 LDX-3232 75

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CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

"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.

LASer:SET:MDP?

The LASer:SET:MDP? query returns the laser monitor photodiode power setpoint value

(when CALMD [CAL PD] is not zero), in mW.

- where the response is the constand P

Notes In local operation, the MDP setpoint is read by selecting P mode, then pressing and

holding down the SELECT switch in the DISPLAY area of the front panel. When the mW

indicator is blinking, the display will show the MDP setpoint. This setpoint is used in

constand MDP mode only. Examples "LAS:Set:MDP?" -response: 10.0, means the laser monitor photodiode feedback

setpoint is 10.0 mW (CALPD>0).

"Laser:Set:MDP?" -response: 25.0, means the laser monitor photodiode feedback

setpoint is 25.0 mW (CALPD>0).

LAS

MDP

setpoint, in mW.

SET

FRONT PANEL REMOTE

76 LDX-3232



LASer:STEP

The LASer:STEP command is used to increment or decrement the selected laser control

mode setpoint by the given amount, when used with the LASer:INC or LASer:DEC

command.

Parameters An integer value of the step amount, in the range 1 to 9999. Notes The step of one corresponds to the smallest display resolution for the mode. For

example, a step of one means 0.1 mA, 0.1 mW, or 1 µA (if CALPD=0). Examples "Las:Mode:i; Las:ldi 20; Las:Step 100; Las:Inc; Las:set:ldi?" -action: sets the step to

10.0 mA, so the Las:set:ldi? query will return a value of 21.0 mA.

"LAS:STEP 100" -action: sets the step size to 100; could mean 10.0 mA , 10.0 mW, or

100 µA.

LAS

STEP

FRONT PANEL

REMOTE

<white

space>

<nrf

value>

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

LASer:STEP?

The LASer:STEP? query is used to read back the LASer STEP value. This value is used

to increment or decrement the selected laser control mode setpoint by the given amount

when used with the LASer:INC or LASer:DEC command.

- where the response is an integer value.

Examples "Las:Mode:LDI; Las:Step?" -response: 1 means the step size is 0.1 mA, since Const I

mode is in effect.

"LAS:MODE:MDP; LAS:CALMD 1; LAS:STEP?" -response: 10 means the step size is

1.0 mW, since Const P mode is in effect.

LAS

STEP

LASer:TOLerance

The LASer:TOLerance command allows the programmer to determine the LASER

current tolerance and time window for it to occur, in order that the operation complete flag

be set after a "LASer:OUTput 1" command is issued or the LASER setpoint is changed.

: :

LAS

TOL

<white

space>

<nrf

value>

FRONT PANEL

REMOTE

FRONT PANEL

REMOTE

<nrf

value>

Parameters Two <nrf values>; the first represents the LASER current tolerance in mA with a range of

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.

Notes 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.

Instead a fixed value of 50 µA is used for the I

PPD power, and only the time window parameter may be adjusted.

Note: If the tolerance is set too tight it may never be achieved. This is due to the calibration

of the setpoint and measurement values.

Examples "Las:Tol 0.5,10" -action: the LDX-3232's LASER current source will be in tolerance when

the LASER current is within 0.5 mA for 10.000 seconds.

04_06 LDX-3232 77

current. A fixed value of 1 mW is used for



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

LASer:TOLerance?

The LASer:TOLerance? query allows the programmer to determine how the LASER

current tolerance is set.

- where the response consists of two values, the first is the current tolerance in mA and

the second is the time window, in seconds. Notes 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.

A change of the output into or out of tolerance flag sets a flag in the LASER status event

service requests. Examples "Las:Tol?" -response: "0.2,5.0", means the LDX-3232 has a LASER current tolerance

setting of 0.2 mA with a time window of 5.000 seconds.

"LASER:TOL?" -response: "1.0,20.0", means the LDX-3232 has a LASER current

tolerance setting of 1.0 mA with a time window of 20.000 seconds.

LAS

TOL

MESsage

The MESsage command allows the user to enter an ASCII string of up to 16 non-NULL

characters. This command may be useful for storing messages that relate to a test or

configuration.

FRONT PANEL

REMOTE

FRONT PANEL

REMOTE

78 LDX-3232



Parameters An ASCII string that is 1 - 16 bytes in length. Notes The message may contain any ASCII character, but will be terminated when a NULL

terminator character is received. If the message has less than 16 bytes, the software will

fill the remaining message space with the space character. After 16 bytes have been

entered, the software will null-terminate the string. Examples MESSAGE "This is a test." -action: The string, "This is a test. " will be stored in

non-volatile memory.

Mes "Test 3" -action: The string, "Test 3 " will be stored in non-volatile memory.

MES

<white

space>

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

MESsage?

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.

- where the response is a 16-byte long character string.

Notes The response data will be a 16-byte long string. If there is no previously stored message,

the response will be " ", all spaces. Examples "MES?" -response: "Test 3 ", means the previously stored message was "Test 3".

"Message?" -response: "This is a test. ", means the previously stored message was

"This is a test."

MES

RADix

The RADix command allows the programmer to select the radix type for status,

condition, and event query response data. Decimal, binary, hexadecimal, and octal are

allowed.

FRONT PANEL

REMOTE

FRONT PANEL

REMOTE

DEC

Parameters As shown above, character program data is expected. Notes DECimal is the default type. Only the first three letters of the words decimal,

hexadecimal, binary, or octal are required.

When the RADIX is selected, all status, condition, and event queries will return values in

the new radix.

In the cases where the radix is not DECimal, the flexible numeric type <nrf value> (as

shown in the Command Reference diagrams) will be replaced by HEX, BIN, or OCT

representation.

All of the above radixes may be used to enter program data at any time, without the need

for issuing the RADix command. The proper prefix must also be used with Hex (#H),

binary (#B), or octal (#Q).

This command may be useful for setting up status reporting blocks. The bit-wise status

representation may be more easily read in BIN, HEX, or OCT. Examples "RAD dec" -action: the decimal radix is selected.

RAD

HEX

<white

space>

BIN

OCT

04_06 LDX-3232 79



CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

"rad hex; *ESR?" -action: the hexadecimal radix is selected; -response: #H80, means

power-on was detected.

RADix?

The RADix? query allows the programmer to determine that radix type for status,

condition, and event query response data is currently selected. Decimal, binary, octal,

and hexadecimal are allowed.

- where the character response data of DEC means decimal, BIN means binary, HEX

means hexadecimal, and OCT means octal. Notes 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. Examples "RAD?" -response: Dec, means the selected radix is decimal.

"rad?" -response: Hex, means the selected radix is hexadecimal.

"RADIX?" -response: Oct, means the selected radix is octal.

RAD

SECURE

The SECURE command allows the service technician access to the protected user data

command, *PUD, that is a common command. This data is normally changed only at the

factor, and therefore the SECURE command is not needed by the user.

FRONT PANEL

REMOTE

FRONT PANEL

REMOTE

80 LDX-3232



TERM

The TERM command allows the programmer to change the default

(GPIB/IEEE488 standard) terminator to include the carriage return.

Parameters An <nrf value>, 0=FALSE, non-z ero =TRUE Notes An altered terminator will be in the form <CR><NL><^END>. This technically takes the

LDX-3232 out of GPIB/IEEE488 specification, but may be done for convenience when

using non standard GPIB controllers. This termination will be sent with all output until the

"TERM 0" command is sent or the LDX-3232 is powered off. Examples "Term 1" -temporarily sets <CR><NL><^END> as the output terminator.

"Term 0" -sets the GPIB/IEEE488 standard <NL><^END>terminator. This is the

LDX-3232 default value.

TERM

<white

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FRONT PANEL

REMOTE

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

CHAPTER 4

TERM?

The TERM? query allows the programmer to determine whether the default

(IEEE488.2 standard) terminator has been altered to include a carriage return.

- where the response is 0 or 1.

Notes 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. Examples "Term?" -response: 1, means that the <CR><NL> <^END> terminator is temporarily

being used.

"Term?" -response: 0, means that the <NL><^END> terminator (GPIB/IEEE488

standard) is being used.

?TERM

TIME?

The TIME? query allows the programmer to determine how much time has passed since

the LDX-3232 was last powered up.

FRONT PANEL

REMOTE

FRONT PANEL

REMOTE

- where the response is character data in the form: hours:minutes:seconds. Notes The TIME clock is independent of the TIMER clock. Examples "Time?" -response: 1:02.36, means that one minute and 2.36 seconds have passed

since the LDX-3232 was powered up. "TIME?" -response: 32:00:76, means that 32 minutes and 0.76 seconds have passed

since the LDX-3232 was powered up.

?TIME

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CHAPTER 4

COMMAND REFERENCE

LDX-3232 Device-Dependent Command Reference

TIMER?

The TIMER? query allows the programmer to determine how much time has passed since the last TIMER? query was issued.

- where the response is character data that represents hours:minutes:seconds. Notes Each time the TIMER? query is issued, the timer is reset to 0 and the elapsed time since

the last TIMER? query is returned. 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.

Examples "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.

"TIMER?" -response: 00:00:12.03, means the LDX-3232 has been on for 12.03 seconds since the last TIMER? query was issued.

?TIMER

FRONT PANEL

REMOTE

82 LDX-3232

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FUNCTIONS AND FEATURES

Saving and Recalling from the Front Panel

CHAPTER 5

FUNCTIONS AND FEATURES

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This chapter introduces you to the LDX-3232 High Compliance Current Source functions and operating features such as event triggering, analog modulation of laser injection current, and Save and Recall.

Saving and Recalling from the Front Panel

For applications where you might need to alternate between pa rticu lar inst rumen t configurations, the LDX-3232 Current Source offers a unique SAVE and RECALL feature. The SA VE feature allows you to easily store all front panel settings for any given instrument configuration. These settings, that are stored in one of ten memory bins, can be retrieved at any time with the RECALL function. This saves setup time, and it reduces the chance of setup error for tests that are periodically repeated. For example, using the configuration described in Chapter 2 where the Current Source is operating in Constant Current mode, the instrument parame ters saved by using the SAVE function would be Constant Current Mode, 2000 mA range, a limit setpoint of 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.

To enter the SAVE/RECALL mode, press the SELECT switch in the PARAMETER section until the SAVE indicator LED becomes lit and the unit displays the SAVE "bin" on the display. If another bin number is desired, press and hold the SET switch and rotate the adjust knob until the desired bin number is displayed. Releasing the SET switch completes the SA VE operation and all of the instrument parameters are saved to the indicated bin number as they appear on the front panel.

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CHAPTER 5

FUNCTIONS AND FEATURES

Saving and Recalling Under Remote Operation

To recall a previously saved instrument setup, press the SELECT switch until the RECALL indicator led becomes lit. The instrument will display a RECALL "bin" number on the display. If you desire to change the RECALL bin, press and hold the SET switch and rotate the adjust knob until the desired bin number is displayed. Releasing the SET switch completes the RECALL operation. The instrument is restarted and the front panel parameters are reconfigured to th e new parameters saved under that bin number.

The factory default values for front panel parame ters may be restored by recalling "bin" zero (0). See Table 2.1 for the default settings.

Saving and Recalling Under Remote Operation

For saving under remote operation, use the command *SAV x, where x is the desired "bin" number (1-10). For a recall under remote operation, use the command

*RCL x, where x is the desired "bin" number (0 - 10).

Using the Laser Compliance Voltage Adjustment

For applications where you need to have critical protection of the laser, we recommend the following. Using a 1 LASER voltage limit as described in Chapter 2.

Then with the LASER output on, slowly increase the LASER current and watch the LASER voltage measurement. Press the (DISPLAY) SELECT push button to see the voltage. At about 0.25 V below the LASER voltage limit value, the VOLTAGE LIMIT warning indicator will become lit on the display. Continue to adjust the current upwards until the voltage limit is reached and the output is shut off. Record the voltage at that the LASER output shuts off. It should be within the specification of the LASER voltage limit accuracy. However, there is typically some offset error. For example, if the LASER voltage limit is set to 5.0 V, the actual voltage where it shuts off may be 4.9 V. This error term of 0.1 V should be considered when setting the 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.

Ω resistor or other non-critical load, set the

84 LDX-3232

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Lightwave LDX-3232 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual