User’s GuideHigh Power Laser Diode Controller Mainframe
LDC-3926

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
70035601 January 2010

Table of Contents

List of Figures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
List of Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Safety and Warranty Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Safety Information and the Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
General Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Safety Symbols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x
Safety Marking Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Returning an Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Claims for Shipping Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Comments, Suggestions, and Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . .xii

Chapter 1

Introduction and Specifications
Product Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Initial Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Installing the LDC-3926 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Grounding Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
AC Line Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
RS-232 Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
GPIB Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
The GPIB Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Tilt-Foot Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Rack Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Front and Back Panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

LDC-3926



iTable of Contents

Chapter 2

Operations
Front Panel Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Display Section Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Hard Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Soft Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Adjust Section Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Numeric Keypad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Adjust Knob . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Increment and Decrement Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Applying Power to the Mainframe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
The Power On Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
The Power On State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Laser Enable Key Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Using the Menu Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Main Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Channel Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
System Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Communications Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Display Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Save and Recall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
All Channel Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Status Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Displaying the Summary Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Displaying the Status Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Modulating the Laser Current Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Modulation Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Chapter 3

Remote Operations
GPIB Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Data and Interface Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Talkers, Listeners, and Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
GPIB Cable Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
The GPIB Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Reading the GPIB Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Changing the GPIB Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
RS-232 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Reading the Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Changing the Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Changing Operation from Local to Remote . . . . . . . . . . . . . . . . . . . . . . . . 24
GPIB vs. RS-232 Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Mainframe Command Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

ii

LDC-3926

Table of Contents

Command Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Letters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
White Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Terminators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Command Separators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Command Tree Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Syntax Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
IEEE 488.2 Common Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
LDC-3926 Mainframe Specific Commands . . . . . . . . . . . . . . . . . . . . . . . . . 30
Status Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Event and Condition Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Operation Complete Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Command Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Sequential/Overlapped Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Query Response Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Chapter 4

Command Reference
GPIB Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Command Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Chapter 5

Troubleshooting
Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Testing for Errors in Remote Operation . . . . . . . . . . . . . . . . . . . . . . . . . 54
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Index-i

01_10

LDC-3926



iii

Table of Contentsiv

LDC-3926

List of Figures

Figure 1.1 Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 1.2 Mainframe Rear View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 2.1 Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 2.2 Display Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure 2.3 Adjust Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 2.4 Initialization Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 2.5 Main Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 2.6 Channel Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 2.7 System Configuration Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 2.8 Communications Configuration Menu . . . . . . . . . . . . . . . . . . . . 13
Figure 2.9 Display Configuration Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 2.10 Calibration Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 2.11 Save and Recall Configuration Menu . . . . . . . . . . . . . . . . . . . 15
Figure 2.12 All Channel Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure 2.13 Status Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 2.14 Summary Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 2.15 Status Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 2.16 LDC-3926 Back Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 3.1 GPIB Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 3.2 GPIB Connector Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 3.3 Command Path Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 3.4 Status Reporting Schematic Diagram . . . . . . . . . . . . . . . . . . . . 31

LDC-3926

v

List of FiguresviLDC-3926

List of Tables

Table 1.1 General Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Table 3.1 Substitute Parameter Names. . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Table 3.2 Invalid Syntax Command Strings . . . . . . . . . . . . . . . . . . . . . . . . . 29
Table 3.3 Mainframe Error Code Classifications . . . . . . . . . . . . . . . . . . . . . 33
Table 3.4 Mainframe Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 4.1 GPIB Command Summary Reference List . . . . . . . . . . . . . . . . . . 35
Table 5.1 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Table 5.2 Mainframe Error Code Classifications . . . . . . . . . . . . . . . . . . . . . 55
Table 5.3 Mainframe Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

LDC-3926

 vii

List of Tablesviii 

LDC-3926

SAFETY AND WARRANTY INFORMATIONThe 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 which, if not avoided, could result in death, serious or minor
injury, or damage to the product. Specifically:! CAUTION
Caution indicates a potentially hazardous situation which can result in minor ormoderate injury or damage to the product or equipment.

WARNING
Warning indicates a potentially dangerous situation which 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, forservice or repair to ensure that safety features are maintained (see the contact information on pagex).
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 ix for more information.

LDC-3926



vii

SAFETY SYMBOLSSAFETY SYMBOLSThis 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 followingclassifications 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)• Pollution Degree II• Installation (overvoltage) Category II for transient overvoltages• Maximum Relative Humidity: <80% RH, non-condensing• Operating temperature range of 0 oC to 40 oC• Storage and transportation temperature of -40 oC to 70 oC• Maximum altitude: 3000 m (9843 ft)• This equipment is suitable for continuous operation.

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 which can result in death,injury, or damage to the instrument and other components.

or(I)viii 

LDC-3926

Caution,refer tomanualEarthgroundTerminal

Alternating
current

Visible and/or
invisible laser
radiation

Caution, riskof electric
shock

Protective
Conductor
Terminal

Caution, hot
surface

Frame orchassisTerminal

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

or(O)

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

WA R R A N T Y

WARRANTY
ILX LIGHTWAVE CORPORATION warrants this instrument to be free from defects in material andworkmanship 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 which it was not intended.
This warranty is in lieu of all other warranties, expressed or implied, including any implied warrantyof 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 orrepair. 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 theinstrument in a protective anti-static bag.

4

Place the instrument in the original packing container with at least 3 inches (7. 5 cm) ofcompressible packaging material. Shipping damage is not covered by this warranty.

5

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

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 theremainder of the original warranty or for 90 days, whichever is greater.

Claims for Shipping Damage
When you receive the instrument, inspect it immediately for any damage or shortages on thepacking list. If the instrument is damaged, file a claim with the carrier. The factory will supply you witha quotation for estimated costs of repair. You must negotiate and settle with the carrier for theamount of damage.

LDC-3926



ix

WA R R A N T Y

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

In the United States:
Phone . . . . . . . . . . . . . . . . . . . . . . . . . . . (800) 459-9459 or (406) 586-1244
Fax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (406) 586-9405
Online: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . http://ilx.custhelp.com
Email: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . support@ilxlightwave.com
Or mail to:
ILX Lightwave Corporation
P. O. Box 6310
Bozeman, Montana, U.S.A 59771
www.ilxlightwave.com

In Europe:
Optical Test and Calibration Ltd.
Listerhills Science Park
Bradford, BD7 1HR United Kingdom
Phone: (44) 1274 393857
Fax: (44) 1274 393336
Online: www.otc.co.uk
Email: sales@otc.co.uk

In China:
ETSC Technologies Co.
9/F Building 1
SBI Street
Dongxin Road
East Lake High-Tech Development Zone
Wuhan, Hubei, 430074 PRC China
Phone: (86) 27 8717 0152; (86) 27 8741
2681; (86) 27 8780 7925
Fax: (86) 27 8780 7133
Online: www.etsc-tech.com
Email: sales@etsc-tech.comxLDC-3926

In Japan:
Kyosai Technos
424, Shimo-Ongata-Machi
Hachioji-Shi
Tokyo, 192-0154 Japan
Phone: (81) 426 521 388
Fax: (81) 426 513 270

In China:
Kyosai Technos
3F Bldg G, No.21 Changjiang Road, Wuxi
National Hi-Tech Development Zone
Jiangsu, P.R. China
Phone: (86) 510 522 1707
Fax: (86) 510 522 1679
Email: ilx-service-china@kyosaitec.co.jp

WA R R A N T Y

When you contact us, please have the following information:
Model Number:
Serial Number:End-user Name:
Company:
Phone:
Fax:
Description of what isconnected to the ILX
Lightwave instrument:

Description of the problem:

If ILX Lightwave determines that a return to the factory is necessary, you areissued a Return Authorization (RA) number. Please mark this number on theoutside of the shipping box.
You or your shipping service are responsible for any shipping damage whenreturning the instrument to ILX Lightwave; ILX recommends you insure theshipment. 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.
We look forward to serving you even better in the future!

LDC-3926

xi

WA R R A N T Y

xii 

LDC-3926

CHAPTER1INTRODUCTION AND SPECIFICATIONS

Chapter 1 is an introduction to the LDC-3926 Laser Diode Controller. It contains unpacking
information, installation instructions, and basic instruction about how to apply power. It also contains
some maintenance information and specifications.

If any of the following symptoms exist, or are even suspected, remove the LDC-3926
from service. Do not use the LDC-3926 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 for service and repair to ensure thatsafety features are maintained.

Product Overview
The LDC-3926 Laser Diode Controller mainframe holds up to 16 modules for controlling laser diodecurrent and temperature, with the capability of providing 6 A of current per module bay. The currentsource modules provide high stability output with fully redundant current limits and multiple laser
protection features. The temperature control modules are compatible with most thermistor-typetemperature sensors and TEC modules to deliver precise laser temperature control over a wide
range of temperatures.
The LDC-3926 accepts all LDC-3908, LDC-3916 and LDC-3926 modules.

LDC-3926

1

CHAPTER1INTRODUCTION AND SPECIFICATIONS
Installing the LDC-3926

Initial Inspection
Visually inspect the mainframe and its packaging for damage or signs of mishandling. Verify that thepower cord was shipped with the mainframe.
When unpacking the instrument, make sure to save the packaging and the protective Electro Static
Discharge (ESD) caps on the rear of the instrument, in case you have to return the instrument to ILX
Lightwave. Shipping damage is not covered under the standard instrument warranty.

Installing the LDC-3926
This section provides information about the necessary requirements to install the LDC-3926 andhow to begin operating the instrument.

Grounding Requirements
The LDC-3926 comes with a three-conductor AC power cable. The power cable must be plugged
into an approved three-contact electrical outlet or used with a three-contact to two-contact adaptor
with the grounding wire connected to an electrical ground (safety ground). The power cordconnector and power cable meet IEC safety standards.

The instrument must be connected to properly earth-grounded receptacles.

AC Line Power Requirements
You can operate the mainframe from a single-phase power source delivering nominal line voltagesof 100, 120, 200-240 VAC (all values RMS) from 50 to 60 Hz. The line power voltage can vary +10%.
The instrument must be connected to properly earth-grounded receptacles.
The LDC-3926 is factory configured with a 20 A mains fuse for regions or locations with a nominalline voltage of 100 VAC and 15 A mains fuse for regions with nominal line voltages of 120, 200-240
VAC. The instrument must be reconfigured with the correct fusing if it is moved to a region or
physical location with different nominal supply voltages than intended at shipment. Contact ILX
Customer Service (see Comments, Suggestions, and Problems on page xii of the Safety andWarranty section for contact information) for more information.

At supply voltages below 110 volts, a fully-loaded LDC-3926 can approach 15 amps of
current draw and compromise the safety limits of some AC line power sources.
Current draw increases as supply voltage drops. For example, an LDC-3926 that is fullyloaded with six-amp laser current source modules, consumes 1285 volt-amps with all
modules running at 6.0 amps of output current. If line voltage is 90 volts, the instrument
draws up to 14.78 amps; at 110 volts, the mainframe draws up to 11.68 amps.

2LDC-3926

INTRODUCTION AND SPECIFICATIONS
Installing the LDC-3926

CHAPTER1

RS-232 Connectors
The RS-232 interface consists of two 9-pin, D-sub connectors, located on the rear panel (see Figure
1.2 on page 4). The A connector is used to connect to the host computer with a standard straightthrough cable. The B connector is not enabled at this time.

GPIB Connector
A total of 15 devices can be connected together on the same GPIB interface bus. The GPIB
interface connector is located on the rear panel, to the left of the power input module (see Figure 1.2
on page 4). The 24-pin GPIB interface connector is tapered to ensure proper orientation. Finger
tighten the two screws on the cable connector.
The cables have single male/female connectors on each end so that several cables can be stacked.
This permits more than one cable to be attached to any one device. 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 LDC-3926 are identical. The mainframe comes from the factory
configured with the GPIB address set to 1. You can change the GPIB address locally (via the front
panel). The procedure for changing the address is found in Changing the GPIB Address on page 23.

Tilt-Foot Adjustment
The LDC-3926 comes standard with folding front legs and two rear feet for use as a benchtop
instrument. Extend the front legs to tilt the front panel upward, making it easier to read the vacuum
fluorescent display.

Rack Mounting
The LDC-3926 can be mounted in a standard 19-inch rack with one of two available rack mounting
kits. These kits contain support brackets that fasten to the inside of a rack enclosure to support themainframe along each side. There are two kits available from ILX. Each kit comes with thenecessary hardware, including fasteners and instructions for their use. Refer to the ILX Lightwave
product catalogue or contact Customer Service (see page xii for contact information) for ordering
information.

Do not rack mount instruments directly on top of one another. There must be at least a
1.75-inch (44 mm, 1 u) open space between instruments to ensure airflow for propercooling. Make sure that all air-vents are open and free from obstruction.

01_10

LDC-3926



3

CHAPTER1INTRODUCTION AND SPECIFICATIONS
Front and Back Panels

Front and Back Panels
Figure 1.1 and Figure 1.2 show front and rear views of the instrument. The figures identify functional
keypad groupings, rear panel connectors, and switches. Please refer to Chapter 2, Operations for
operating fundamentals of the LDC-3926.

Laser Enable
Key Swicth

Menu Soft Keys:
F1, F2, F3, F4

Menu Control
Keys: MAIN,
CHAN, PREV,NEXT

Parameter Adjust
Keys
Adjust Knob

Power Switch

Vacuum Flourescent
Display

Numeric Keypad

Figure 1.1 Front Panel
Only the 16 module bays are user-accessible. Do not attempt to remove the Microprocessor module
or power module.
Channel 1

Modulation Input
BNC Connector

GPIB Connector

Channel 16

Microprocessor
ModulePower
ModulePower Cord
Connector

RS-232 B Inactive

RS-232 A Input

Figure 1.2 Mainframe Rear View

4



LDC-3926

GroundConnector

INTRODUCTION AND SPECIFICATIONSSpecifications

CHAPTER

1

Specifications
The LDC-3926 is factory configured with a 20 A mains fuse for regions or locations with a nominalline voltage of 100 VAC and 15 A mains fuse for regions with nominal line voltages of 120, 200-240
VAC. The instrument must be reconfigured with the correct fusing if it is moved to a region or
physical location with different nominal supply voltages than intended at shipment. Contact ILX
Customer Service (see Comments, Suggestions, and Problems on page xii of the Safety andWarranty section for contact information) for more information.

Potentially lethal voltages exist within the LDC-3926 Laser Diode Controller. To avoid
electric shock, do not perform any maintenance on the instrument unless you arequalified to do so. Qualified service personnel are required to wear protective eyewear
and anti-static wrist bands while working on the LDC-3926 Laser Diode Controller circuitboards. High voltages are present on and around the printed circuit boards.
Only the 16 module bays are user-accessible. Do not attempt to remove theMicroprocessor module or power module.

Table 1.1 General Specifications
Specification

Description

Chassis Ground

4 mm Banana JackGPIB Connector

24-pin IEEE-488.2

RS-232 Interface connector

9-pin, D-connector

Power Requirements1

50 Hz to 60 Hz
100 VAC +10%, 15 A
120 VAC +10%, 12 A
200-240 VAC +10%, 6 A

Size (H x W x D)

133 mm x 432 mm x 609 mm (5.25" x 17" x 24")

Weight (typical)
Mainframe only

20 kg (44 lbs)

With modules

27 kg (59 lbs)

Operating Temperature

0 oC to 40 oC

Storage Temperature-40 oC to +70 oC

Humidity220-85% non-condensing

Laser Safety Features

Keyswitch, Interlock, Output Delay: (Meets CDRH US21, CFR 1040.10)

Display

Vacuum Fluorescent
64 x 128 pixels
83 mm x 41 mm

1.
2.

01_10

All channels driving 6 amps.
Based on the vacuum fluorescent display specification.

LDC-3926



5

CHAPTER

6



LDC-3926

1

INTRODUCTION AND SPECIFICATIONSSpecifications

CHAPTER

2

OPERATIONS

This chapter introduces you to the operation of the LDC-3926. It offers instructions for connecting
your laser to the current source and temperature control modules and describes powering up the
instrument. The chapter also provides a description of the front panel controls, including both display
and adjust controls.
This chapter also provides a description of the LDC-3926 Menu Structure and has instructions about
selecting each menu and performing the operations relevant to the menu selected.

LDC-3926



7

CHAPTER

2

OPERATIONS
Front Panel Controls

Front Panel Controls
All key operating parameters for the laser and temperature control modules can be set, adjusted,and displayed through established menus. See the respective module manual for further information
on each module.
Soft Keys
Display
Section

Display
ScreenLaser Enable
Key Swicth

Primary Menu
Controls

AdjustSectionPower Switch

Figure 2.1 Front Panel

Display Section Controls
All key operating parameters for the LAS (laser) and TEC modules can be set, adjusted, anddisplayed through established menus. (See the respective module manual for further information oneach module.) The menus on the display are controlled by using the keys (pushbuttons) to the rightof the display box. There are two kinds of keys, the hard keys and soft keys. The hard keys have
only one function, while the function of the soft keys varies with each menu on the display.

Hard KeysEnter the menu structure using one of the primary Menu Control keys. These keys provide directaccess to the Main and Channel menus as well as movement within the screens used most often for
instrument control. They are located in the second column to the right of the display window. They
are labeled (from top to bottom): MAIN (for Main Menu), CHAN (Channel), PREV (Previous), andNEXT. Pressing the MAIN key provides direct access to the Main Instrument screen. The CHAN key
provides direct access to the Channel screen, where the instrument displays channel information
about operating parameters for the laser and TEC modules. The CHAN key also allows access tocomplete laser and TEC configuration screens. The PREV/NEXT keys move the cursor around thescreen to select operating parameters only.

8LDC-3926

OPERATIONS
Front Panel Controls

CHAPTER

2

Soft Keys
The four keys closest to the display window are used as soft keys. They perform menu-specificfunctions within each menu. When you have accessed a menu, the soft key identification for thismenu appears on the right side of the display, next to the corresponding key. Soft keys can be used
to initiate another menu or to change/edit a parameter. For example, in the LAS section of the CHAN
menu, the word On designates the state of the output. Pressing the associated soft key changes thestate from On to Off. If the LAS soft key is pressed, the laser setup menu appears.
Soft Keys

Hard Keys

Figure 2.2 Display Section

Adjust Section Controls
The Adjust section of the front panel provides various means of entering or modifying instrument
parameters. These include a 12-key numeric keypad, a rotary knob (digital encoder), and incrementand decrement keys.

Numeric Keypad
The numeric keypad provides direct entry of values for set-points and numeric data. When an
editable field is highlighted or selected from the menu screens, you can type the desired value using
the keypad, then accept by pressing the Enter key within five seconds. If an incorrect value isentered, press the CLEAR key to reset the field to its previous value. The keypad supports decimal
entry as well as negative values for some constants and temperature set-points.

Adjust Knob
When the cursor in a menu is positioned on a parameter that can be adjusted, the Adjust Knob isused to increase or decrease the parameter values. When the Adjust Knob is turned, the new values
are updated automatically. The Adjust Knob can be disabled from the System Configuration menu.

Increment and Decrement Keys
The Increment and Decrement keys are used, in addition to the Adjust Knob, to adjust values on anyof the screens where a numeric value is required. Holding down either of the keys increases or

01_10

LDC-3926



9

CHAPTER

2

OPERATIONSApplying Power to the Mainframe

decreases the number via a time-based acceleration algorithm. When the Arrow keys are pressed,
the new values are updated automatically.
Numeric
KeypadEnter and
Clear Keys

AdjustKnob

Increment andDecrement
Keys

Figure 2.3 Adjust Section

Applying Power to the Mainframe
To turn on the LDC-3926, push the button in the Power section of the front panel to change thesetting from zero (0) to one (1). This initiates the Power-on sequence. If the LDC-3926 does notappear to turn on, verify that it is connected to line power.

The Power On Sequence
When power is applied to the LDC-3926, the following takes place:• The initialization screen is displayed, showing the company name and logo, the name of
instrument, and firmware version.
• A self test is performed to ensure that the mainframe processor is communicating with theprocessor(s) of any module(s) connected to the mainframe and identifying which module
model is present. After this test, the instrument is ready to operate and is configured to thestate it was in when the power was last shut off.

Figure 2.4 Initialization Screen

10 

LDC-3926

OPERATIONSUsing the Menu Structure

CHAPTER

2

The Power On StateThe controller defaults to the Channel menu and the first channel with a module when power isapplied. It is configured to the state when power was last shut off, and according to the type ofmodule in each bay. You can choose to clear the last saved state by recalling the default values.
These values are stored in BINS that you can use to save or recall configurations (See Save and
Recall on page 15). BIN 0 contains all of the default configurations. The default configuration
information for each module is found in the each module instruction manual.
Note: If the instrument cannot successfully complete the power on test, that is, cannot
identify a module (or modules) inserted into the mainframe, that module (or modules) are
not identified in the Status Screen. Power down the instrument and check if the modules
are correctly seated and fastened to the mainframe. If you continue to experience power-up
problems, power down the instrument and contact an ILX Lightwave Customer Service
Representative.

Laser Enable Key Switch
The LDC-3926 is equipped with a laser enable key switch. This ensures that the laser current isturned on only if the key is inserted and in the On position.
Laser current sources installed in the LDC-3926 have remote interlock capability. The interlock
capability allows you to connect the interlock circuit to an external switch for safety. If the interlock isremoved, the laser current output is disabled. Refer to the appropriate laser module User's Guide fordetails about the interlock function.

Using the Menu StructureThis section describes the menus, how they are structured, and how to navigate through them.

Main Menu
The Main menu is the primary set-up and configuration screen for the instrument. Pressing thecorresponding soft keys to the right of the display leads to Channel selection, System configuration,
All Channel control features, and system Status displays. It also allows a soft key path directly backto the Channel menu.

Figure 2.5 Main Menu

01_10

LDC-3926

 11

CHAPTER

2

OPERATIONSUsing the Menu Structure

Channel Menu
The Channel menu provides standard user information, along with soft-key assignments forconfiguring a module further or for turning the output On or Off. Pressing the CHAN key allows you
to jump directly to the default Channel menu. The channel number is changed by rotating the Adjust
Knob or pressing the INC/DEC keys. Pressing the LAS or TEC soft key calls up the menu for editing
Laser or TEC control parameters for each of the active modules.
The output state for each module is changed by pressing the associated soft key, which isaccompanied by a configurable audible tone. When the output is on, the screen indicates measured
laser output current and forward voltage, measured temperature, thermoelectric module current,
sensor resistance, or other measurements depending on the module installed.

Figure 2.6 Channel Menu

System Configuration
The System Configuration menu is accessed from the Main menu. Pressing the appropriate soft key
provides access to:• The Communications Configuration menu (Comm.) for GPIB and RS-232 setup• Display Configuration (Display) menu for interface settings• Calibration (Cal.) menu for module calibration• Save/Recall (Sav/Rec) menu for system-wide parameter storage and retrieval

Figure 2.7 System Configuration Menu

12 

LDC-3926

OPERATIONSUsing the Menu Structure

CHAPTER

2

Communications Configuration
To operate your LDC-3926 remotely, via the General Purpose Information Bus (GPIB) or through a
serial RS-232 link, select Comm. from the System Configuration menu to access the Config. Commmenu. The Config. Comm menu allows you to view and change the GPIB address and the RS-232
baud rate. Press the Up soft key (F3) to return to the Sys. Config. menu. See Chapter 3, Remote
Operations, or your module manual, for complete information on remote control operation.

Figure 2.8 Communications Configuration Menu

Display Configuration
Selecting Display from the System Configuration menu accesses the Display Config. menu. Here,you can adjust the display brightness, initiate a display self-test, enable or disable an audible tone
whenever pushbuttons are pressed, and enable or disable the Adjust Knob. Use the PREV andNEXT keys to select the desired function. Pressing the Up Arrow soft key (F3) returns you to theprevious menu.
You can adjust the display brightness in four levels. A bar graph is displayed next to the Brightenunciator. One, two, three or no sections of the bar graph are back-lit, indicating the level of display
brightness. You can adjust the brightness with the Adjust Knob or the INC/DEC keys. Display
brightness increases from right to left. Each step increases the brightness 12.5% from minimum tomaximum brightness.
If there is a problem with the graphic display, you can inititiate a display self-test from this menu
using the Display Test function. Select Display Test function using the PREV/NEXT keys, then use
the Adjust Knob or the INC/DEC keys to select "Yes". Press ENTER to activate the test. The display
is instructed to light all pixels; perform a visual inspection of the display to ensure that all of the pixels
are illuminated. If you find a display problem, contact the Customer Service Department of ILX
Lightwave (see Comments, Suggestions, and Problems on page xii for more information). Press theMAIN or CHAN keys to return to those specific menus or press any other key to return to theprevious menu.
The Audible Beep function allows you to enable or disable an audible tone when any key (either
hard or soft key) is pressed or when the Adjust knob increments or decrements a value. The On or
Off enunciator (depending on the current state of this function) is highlighted when selected. Use the
Adjust Knob or INC/DEC keys to turn the tone on or off. You must press Enter after making thedesired selection to execute the change.
You can enable or disable the Adjust Knob from the Display Configuration menu. Once the Lockout
dial function is selected, the On or Off enunciator is highlighted. Use the Adjust Knob or INC/DEC

01_10

LDC-3926

 13

CHAPTER

2

OPERATIONSUsing the Menu Structure

keys to turn the Adjust Knob on or off. Press ENTER after making the desired selection to executethe change.
Enter KeyINC/DEC Keys

Figure 2.9 Display Configuration Menu

Calibration
The Calibration Menu allows you to calibrate, from the front panel, all Laser and TEC functions foreach of the modules loaded into the LDC-3926. Remote calibration through the IEEE488.2 GPIB or
serial RS-232 interface is provided as well.
ILX recommends that the modules be calibrated every 12 months, or whenever performanceverification indicates that calibration is necessary, such as any difference between the displayed
laser current and the actual laser current. Calibrate the modules under laboratory conditions;typically, 23 oC (±3.0 oC). If possible, calibrate the LDC-3926 at its intended use temperature (if thisis within the specified operating temperature range of 0 oC to 40 oC). For specific calibration
information, see the module instruction manual.

Figure 2.10 Calibration Menu

14 

LDC-3926

OPERATIONSUsing the Menu Structure

CHAPTER

2

Save and Recall
The Save and Recall feature is used to alternate between particular instrument configurations. The
Save feature allows you to store front panel settings for any given configuration. These settings,
which are stored in one of ten memory bins, are retrieved at any time with the Recall function. This
saves setup time and reduces the chance of setup error for tests that are repeated periodically. See
the relevant module manual for information on instrument configuration setup.

Figure 2.11 Save and Recall Configuration Menu
To save a configuration:1

Select Sav/Rec from the System Configuration menu to access the Save/Recall Config.
menu.

2

Select the desired bin number using the Adjust Knob or the INC/DEC keys.

3

Press the Save soft key to save the configuration.

The instrument saves/recalls up to 16 channel settings in a bin location. Each channel can be
configured differently and saved or recalled from a bin for future use. A module must be present
within the mainframe to save the settings. To recall a configuration:1

Select the desired bin number using the Adjust Knob or the INC/DEC keys.

2

Press the Recall soft key.

3

To restore the factory default settings, press the Default soft key. Bin 0 contains thefactory default settings.
Note: A checksum from each module is used to ensure the recalled setup matches theuser's expectation (in case a module was changed or fails to restore properly). A warning isdisplayed if a checksum error is found.

See Chapter 3, Remote Operations for remote execution of the Save and Recall functions.

01_10

LDC-3926

 15

CHAPTER

2

OPERATIONSUsing the Menu Structure

All Channel Menu
The All Channel menu allows you to configure all 16 channels of the instrument (or any number ofchannels from 2 to 16) simultaneously. Once the modules are configured, all of the lasers and/or
TEC modules can be turned on simultaneously by pressing the ON soft key. All of the modules must
be the same model number for this feature to operate. See the specific module User's Guide for
information about configuring the modules.

Figure 2.12 All Channel Menu

16 

LDC-3926

OPERATIONSUsing the Menu Structure

CHAPTER

2

Status Menu
The Status menu allows you to view information about module status, adjust setpoints, turn on
outputs and view module error codes. There are two status pages to choose from:• The Summary status page lists all channels, up to sixteen, present in the mainframe and thecondition of the output;• The Status page lists four channels at a time, totaling up to sixteen.

Figure 2.13 Status Menu

Displaying the Summary Screen
From the Status menu, press the Summary soft key (F3) to display the Summary page. Next to eachchannel number is a channel designation LAS or TEC, depending on the module. If the designation
is highlighted, the output is turned on for that respective channel. Blanks indicate that there is no
module present in that bay.

Figure 2.14 Summary Screen

01_10

LDC-3926

 17

CHAPTEROPERATIONSUsing the Menu Structure2

Displaying the Status Screen
The Status screen provides instant access to multiple channel status information. You can alsochange laser and TEC setpoints and turn on the laser or TEC from the status screen.
1

Press the Status soft key (F4) from the Status menu. Multiple channel status information isdisplayed.
Note: With the PREV/NEXT keys, you can scroll through all of the modules loaded, one
channel at a time.

2

To change the laser or TEC setpoint:
2aPress F1 to highlight the top line and change it from measurement to setpoint.

Pressing F1 cycles through the values.
2b

Adjust the setpoint using the Adjust Knob or numeric keypad.

3

Press F1 again to highlight and change the second line from measurement to setpoint.

4

Adjust the setpoint using the Adjust Knob or numeric keypad.

5

Press F1 again to highlight first-line Off or On. Use the Adjust Knob or INC/DEC keys toturn the channel output On or Off.

6

Press F1 again to highlight and adjust the next the next value (if applicable to themodule).

7

Press the corresponding softkeys (F2, F3, and F4) to adjust the other displayed channels.

8

Press MAIN or CHAN to exit the Status screen.

Figure 2.15 Status Screen
The default measurements shown on the Status Screen are configureable by sending a GPIB
command. These two lines can be configured to display any laser or TEC measurement by sending
the appropriate GPIB command. For example, sending the command STATMENU:LINE2:IPD
displays the photodiode monitor current on the second line. See the Command Reference chapter ofthe module User's Guide for more information.

18 

LDC-3926

OPERATIONSUsing the Menu Structure

CHAPTER

2

Modulating the Laser Current Sources
The LDC-3926 allows a modulated signal to be superimposed on the laser current of any or all
current source modules. The modulation connector (BNC) on the back panel is the input for themodulated signal.
Note: The modulation input is terminated into 50 .
Modulation
input

Figure 2.16 LDC-3926 Back Panel
Each module uses an instrumentation amplifier to buffer the modulation signal. This signal may be
applied to more than one module (channel) at a time.
Laser protection is assured, even while modulating, via the current limit parameter set on eachindividual module. Refer to the appropriate module manual for details on current limit settings andlaser diode protection.
The allowable bandwidth of the modulated signal, defined as the 3 dB roll-off point, depends on thecurrent source module used and the mode (constant current: low bandwidth, high bandwidth). See
the laser current source specifications in the appropriate module User's Guide for external analog
modulation bandwidth specifications.

Modulation Setup

01_10

1

Press CHAN or press the Channel soft key from the Main menu to view the channel
menu.

2

Press the LAS softkey to view the laser setup screen.

3

Press F4, the down arrow softkey, until LAS p.3 (laser page 3) is displayed.

4

Press PREV or NEXT to highlight the modulation toggle.

5

Using the the Adjust knob or INC/DEC keys, turn on or turn off the modulation.

LDC-3926

 19

CHAPTER

20 

LDC-3926

2

OPERATIONSUsing the Menu Structure

CHAPTER

3

REMOTE OPERATIONS

GPIB (General Purpose Interface Bus) is the common name for ANSI/IEEE Standard 488.2-1987,
an industry standard for interconnecting test instruments in a system. Everything you can do fromthe 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. The
following sections show you the fundamentals of operating your LDC-3926 Laser Diode Controller
remotely through the General Purpose Interface Bus (GPIB) and RS-232 interfaces.

GPIB Configuration
Before you can operate the LDC-3926 from a remote location with the GPIB, you need to know its
GPIB address. The following sections describe reading and changing the GPIB address of the
LDC-3926.

Data and Interface Messages
GPIB devices communicate with each other by sending data and interface messages. Data contains
device-specific information such as programming instructions, measurement results, and instrument
status. Each device has an address number, and ignores all data traffic not addressed to it.
Depending on its content, data is often called a "device dependent message" or a "device
dependent command". Interface messages manage the bus, with functions such as initializing thebus and addressing or unaddressing devices. In addition, some individual bus lines are designatedfor this purpose.

Talkers, Listeners, and Controllers
Every GPIB system consists of one or more "talkers" and "listeners", and at least one controller.
Talkers supply data. Listeners accept data. A system can consist of simply a talker and listener, forexample a meter connected to a datalogger or chart recorder. Controllers designate talkers andlisteners. A controller is necessary when the active talkers or listeners must be changed. When thecontroller is a computer, it often also designates itself as a listener so it can collect data fromdesignated talkers.
If there is more than one controller, only one is the Controller In Charge (CIC). Control is passed
from one controller to another. In a multiple controller system, there can be one System Controller
capable of asserting control (becoming CIC).

LDC-3926



21

CHAPTER

3

REMOTE OPERATIONSGPIB Configuration

GPIB Cable Connections
Standard GPIB connectors can be linked together (daisy-chained), allowing you to configure thesystem linearly or in a star configuration.
Device B

Device A

Device B

Device C

Device D

Device A

Device C

linear configuration

Device Dstar configuration

Figure 3.1 GPIB Connections

The GPIB Connector
The standard GPIB connector consists of 16 signal lines in a 24-pin stackable connector. The extra
pins are used for some twisted-pair wires. There are eight data input/output (IO) lines, threehandshake lines, and five interface management lines.
Eight data input/output (DIO) lines carry both data (including device dependent commands) andinterface messages. The ATN interface management line determines whether these lines containdata or interface messages.
Three handshake lines ensure that all data and messages are reliably transferred:• NRFD (not ready for data) indicates whether a device can receive the next byte of data or
message.
• NDAC (not data accepted) indicates whether a receiving device has accepted a byte ofdata or message.
• DAV (data valid) indicates that the signal levels on the data lines are stable and available
for the receiving device(s) to accept.
Five interface management lines control the flow of information:• ATN (attention) is set by the controller in charge to define the I/O lines for data or interface
messages.
• IFC (interface clear) is set by the system controller to initialize the bus and assert itself as
controller in charge.
• REN (remote enable) is set by the controller to place addressed devices into remote or
local (front panel) control mode.
• SRQ (service request) can be set by any device in the system to request service from thecontroller.
• EOI (end or identify) is used by talkers to identify the end of a message.

22 

LDC-3926

REMOTE OPERATIONSGPIB Configuration

DIO1
DIO2
DIO3
DIO4
EOI
DAV
NRFD
NDAC
IFC
SRQ
ATN
SHIELD

1
2
3
4
5
6
7
8
9
10
11
12

13
14
15
16
17
18
19
20
21
22
23
24

CHAPTER

3

DIO5
DIO6
DIO7
DIO8
REN
GND (Twisted pair with DAV)GND (Twisted pair with NRFD)
GND (Twisted pair with NDAC)
GND (Twisted pair with IFC)GND (Twisted pair with SRQ)GND (Twisted pair with ATN)
SIGNAL GROUND

Figure 3.2 GPIB Connector Diagram

Reading the GPIB Address
1

Press MAIN from the front panel to recall the Main Menu.

2

Press the Sys. Config soft key, to reach the System Configuration menu.

3

Press the Comm. soft key to access the Config. Comm menu. The mainframe displays
the GPIB Address on the Config. Comm menu.

Changing the GPIB Address
Every device on the GPIB bus must have a unique address. The default address from the factory isaddress "01".
1

Press Main from the front panel to recall the Main Menu.

2

Press the Sys. Config soft key, to reach the System Config. menu.

3

Using the PREV/NEXT keys, highlight GPIB Address.

4

Select the desired address using the Adjust Knob.

The new GPIB address is stored in non-volatile memory. The allowable address range is 0-30 forprimary GPIB addressing. Extended GPIB addressing is not implemented on the LDC-3926 at this
time.

01_10

LDC-3926

 23

CHAPTERREMOTE OPERATIONSGPIB Configuration3

RS-232 Configuration
The baud rate setting must match the baud rate used by the serial RS-232 interface, which istypically a serial COMM port on your PC. This section describes reading and changing the baud rateof the LDC-3926.
The RS-232 is configured for 8-bit, no parity. This is not adjustable. Only the baud rate may bealtered.

Reading the Baud Rate
1

Press Main from the front panel to recall the Main Menu.

2

Press the Sys. Config soft key, to reach the System Config. menu.

3

Press the Comm. soft key to access the Config. Comm. menu. The instrument displays
the baud rate on the Config. Comm. menu.

Changing the Baud Rate
The factory default baud rate is 19200.
1

Press Main from the front panel to recall the Main Menu.

2

Press the Sys. Config soft key, to reach the System Config. menu.

3

Using the PREV/NEXT keys, highlight Baud rate.

4

Select the desired baud rate using the Adjust Knob.

The new baud rate is stored in non-volatile memory. The allowable baud rates are 1200, 2400, 4800,
9600, and 19200. Refer to the serial port configuration of your PC (if used) for the appropriate baudrate.

Changing Operation from Local to Remote
Sending a command over the GPIB or RS-232 interface automatically puts the instrument in Remotemode. The Remote indicator on the lower right of the front panel illuminates when the controller is inremote operation mode.
When the instrument is in Remote mode, press the Local button from the front panel to return the
instrument to Local Control mode unless a Local Lockout state has been activated by the low level
GPIB command LLO from the host computer (GPIB only). Local Lockout disables all LDC-3926 front
panel operations until it is changed from the host computer. In this condition, the REMOTE indicator
will flash at a 1 Hz rate. Menu changes are allowed by using the soft keys in Remote mode.
Changing channels is allowed by using the Adjust Knob or Increment/Decrement keys. Other items
in menus such as setpoint adjustments, mode changes, cursor movements or turning the TEC/laser
on or off are not allowed.
The Talk/Listen indicator on the front panel illuminates when the instrument is communicating overthe GPIB or RS-232 interface.
For more information on low level commands such as LLO, refer to the IEEE488.1 specification.

24 

LDC-3926

REMOTE OPERATIONS
Mainframe Command Set

CHAPTER

3

GPIB vs. RS-232 Communications
The LDC-3926 must not be run remotely via GPIB and RS-232 at the same time. When using the
RS-232 interface, the remote GPIB command set is fully operable. Command syntax does not vary
between GPIB and RS-232 usage. However, the commands which affect GPIB hardware operation
will not be useful. For example, the user could send the "*SRE" command via RS-232. However, any
service request (SRQ) via GPIB would not be visible since RS-232 has no hardware to support it.
This is because SRQ is a function of the GPIB interface hardware and is not available via RS-232.

Mainframe Command Set
This section contains information about the LDC-3926 mainframe command set, command syntax,
as well as error and status registers. For module-specific commands, refer to the module's User's
Guide.

Command Syntax
This section describes command syntax and structure. You need this information to effectively write
GPIB control programs. The syntax of GPIB commands follow the rules defined in the ANSI/IEEE
488.2-1987 standard.

Letters
Any GPIB command or query must contain all of the letters that are shown in upper case in thecommand definition. Some of the device dependent commands include additional optional lettersshown in lower case in the command reference (Chapter 4, Command Reference). Upper or lower
case does not matter, it is used in this manual to identify optional letters; although, the optional
letters must be in the correct sequence. Some examples of what does, and does not, work:
Okay

Not Okay

DIS

DS

Disp

dsp

Displ

dply

DisplaDSPLY

Display

displyWhite SpaceWhite space is normally the space character (space bar). A single white space must separate acommand from its parameters or data. For example:
Okay

Not Okay

DELAY 500

DELAY500

To enhance readability, you can use one or more white spaces before a comma, semicolon, or
terminator. Since a computer normally puts the terminator at the end of each command string (line),an extra space character at the end of the command line does not affect the command string.

01_10

LDC-3926

 25

CHAPTER

3

REMOTE OPERATIONS
Mainframe Command Set

A query has no space between the mnemonic and the question mark. For example:
Okay

Not Okay

TIMER?

TIMER ?

Note: Too many consecutive white spaces can overflow the 80-byte data I/O buffer.

Terminators
A program message terminator identifies the end of a command string. These are the valid
terminator sequences:• <NL>• <^END>• <NL><^END>
Many computers terminate with <CR><NL><^END> (Carriage Return - New Line - EOI). A carriage
return (<CR>)is read as a white space.
The LDC-3926 terminates its responses with <CR><NL><^END>, unless you use the TERM
command to change it. See TERM on page 50 for more information.
If you encounter problems with GPIB communications, the terminator string can sometimes be thecause.

Command Separators
You can put more than one command on the same line (same command string) if you separate themwith a semicolon.
Note: The semicolon can be preceded by one or more spaces. Examples:
TEC:DIS 1; tec:set:t?;
TEC:MODE:t ; TEC:T 25 ; TEC:Const 1, 2, 3.5 ; TEC:OUT

Parameters
Some commands require a parameter. The parameter must be separated from the command by atleast one space.
The syntax symbol <nrf value> refers to the flexible numeric representation defined by the GPIB
standard. It means that you can represent numbers in integer or floating point form, or inengineering/scientific notation. The IEEE-488.2 standard uses the names NR1, NR2, and NR3
respectively to denote "integer", "floating point", and "scientific notation". For example the number"twenty" may be represented by any of the following ASCII strings:

26 

LDC-3926

Integer

20

+20

NR1

Floating point

20.0

+20.0

NR2

Scientific notation

2.0E+12.0e+1+2.0E+1+2.0e+1

NR3

REMOTE OPERATIONS
Mainframe Command Set

CHAPTER

3

There are no default values for omitted parameters. If a command is expecting a parameter andnone is entered, an error is generated.
For further clarity in programming, the (Boolean) values of one (1) and zero (0) may be used or theirnames 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

If multiple parameters are expected, they must be separated with commas. For example, to set theSteinhart-Hart constants (C1, C2, and C3) on a TEC module, the following command may be sent:
TEC:CONST 1.111, 2.004, 0.456
Figure 4.1 lists the LDC-3926 device-dependent commands, with the full path shown for eachcommand and a brief explanation of its usage. Device-dependent commands for each module arelisted in the module's instruction manual.

01_10

LDC-3926

 27

CHAPTER

3

REMOTE OPERATIONS
Mainframe Command Set

Command Tree Structure
The LDC-3926 commands require the full path notation.

(root)

Commands

Generic Module Commands*CAL?

ALLCOND?

MODERR?

*CLS

ALLEVE?

MODIDN?

*ESE

BEEP

*ESE?
*ESR?

BEEP?
CHAN

*IDN?

CHAN?

*OPC

CHECKSUM?

*OPC?

DELAY

*PSC
*PSC?

ERR?
MENU

*PUD

MES

*PUD?

MES?

*RCL
*SAV

RAD
RAD?
SECURE

*SRE

SCR

*SRE?

SCR?

*STB?

TERM

*TST?

TERM?

*WAI

TIME?
TIMER?

*RST

Module-specific commands:
see the module instruction manual

Figure 3.3 Command Path Structure

Syntax Summary
GPIB commands must contain all of the letters shown in upper case in the command definition.
Optional letters shown in lower case for some device dependent commands in the commandreference are useful for clarity, but must be in the correct sequence.
A single white space must separate a command from its parameters or data. White space isnormally the space character (space bar). Other control characters are also interpreted as whitespace. Do not use white space before the question mark in a query command.
If you encounter problems with GPIB communications, the terminator string can be the cause. Referto your GPIB interface (controller) manual. The instrument accepts <NL>, or <^END>, or<NL><^END> as a command line terminator. Many computers terminate with <CR> <NL> <^END>(Carriage Return - New Line - EOI). The instrument ignores the <CR> (Carriage Return) and treats
it as white space. The LDC-3926 terminates its responses with <CR><NL><^END>, unless you use
the TERM command to change it.

28 LDC-3926

REMOTE OPERATIONS
Mainframe Command Set

CHAPTER3

You can put more than one command on the same line (same command string) if you separate themwith a semicolon.
GPIB uses a flexible representation for numeric parameters: integer, floating point, orengineering/scientific notation. There are no default values for omitted parameters.
Some device-dependent GPIB commands are compound commands, in which the first mnemonic
opens a path to a set of commands relating to that path. The second mnemonic then defines theactual command.
Table 3.2 shows examples of invalid syntax command strings that produce errors:

Table 3.2 Invalid Syntax Command Strings
COMMANDCOMMENT

TEC:MODE T

Missing colon, MODE? expected.

TEC:MODE:R DEC

Missing semicolon, DEC command generates an error.

LAS:DIS ?

Space not allowed before question mark, DIS command
expected.

Las:LDI33;dis?

Space missing between LDI command and the parametervalue, 33.

IEEE 488.2 Common Commands
IEEE 488.2 Common Commands and Queries are distinguished by the "*" which begins eachmnemonic. The diagrams below show the syntax structure for common commands, common
command queries, and common commands with numeric data required.
Numeric data is required with *PSC (1 = on, 0 = off), *RCL (0 to 10, see Save and Recall on page15), *SAV (1 to 10, see Save and Recall on page 15), *ESE (0 to 255, see Table 3.3 on page 28),
*SRE (0 to 255, see Table 3.3 on page 28), and *PUD (used at factory only).
The *CAL? query returns "1" if all LDC-3926 modules' self-calibration routines are completed
properly, otherwise "0" is returned.
The *TST? query returns "1" if all LDC-3926 modules that were working at power-up (or at the timeof the last *TST? query) have responded to the LDC-3926 mainframe within the past 15 seconds. If
any modules fail to respond to the mainframe, *TST? returns "0", and those modules are no longer
recognized by the system.
A list of all of the IEEE 488.2 Common Commands supported by the LDC-3926 follows.
*CAL?

*CLS

*ESE

*ESE?

*ESR?

*IDN?

*OPC

*OPC?

*PSC

*PSC?

*PUD

*PUD?

*RCL

*RST

*SAV

*SRE?

*SRE

*STB?

*TST?

*WAI

The IEEE 488.2 common commands and LDC-3926 mainframe commands are documented in
Chapter 4, Command Reference.

01_10

LDC-3926

 29

CHAPTER

3

REMOTE OPERATIONS
Status Reporting

LDC-3926 Mainframe Specific Commands
The LDC-3926 command set can be divided into three categories: IEEE 488.2 common commands,
LDC-3926 mainframe commands, and module-dependent commands. The IEEE 488.2 common
commands and LDC-3926 mainframe commands are documented in this manual. The commands
that apply to each module are found in that module's instruction manual.

Status Reporting
This section contains information for understanding instrument error and status reporting. It also
contains information regarding the use of the instrument status for generating interrupts for interruptdriven programs or subroutines. Understanding the Operation Complete definition for the instrument
is useful for programming synchronization. The Output Off Register section also contains
information about setting some of the conditions that force the laser current source and/or TEC
output to turn 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 IEEE 488.2 status reporting structures, the LDC-3926 remote interface
provides Event and Condition registers for module operations. The ALLEVE register is used toreport events that occur during the operation of the LDC-3926 and that are enabled to be passed tothe status byte. The ALLEVE register contains summary bits from each of the sixteen modules.
Likewise, the ALLCOND register is used to report conditions which occur during the operation of the
LDC-3926, and are enabled to be passed on to the status byte. The ALLCOND register contains
summary bits from each of the sixteen modules.
The bits in the ALLCOND and ALLEVE registers are logically ORed to form a summary message inthe status byte for that particular register.
Events are different from conditions. Events signal one-time occurrences and are not reset until
either the corresponding module's Event Register(s) is queried, the *CLS command is issued, or the
LDC-3926 is powered off. Conditions reflect the current state of the device and therefore may
change many times during operation.
Figure 3.4 on page 31 shows the status reporting scheme of the LDC-3926 Laser Diode Controller.

Operation Complete Definition
Bit 0 of the Standard Event Status register contains the status of the Operation Complete flag.
Enabling this bit via the *ESE command allows you to update Bit 5 of the status byte. Then, if theSRE mask has bit 5 set, and the user issues an *OPC command, the SRQ signal is generated uponcompletion of the currently processed commands. This is used to initiate service request routinesthat depend on the completion of all previous commands.
The LDC-3926 defines operation completeness as the state when all sequential and overlappedcommands are completed. Most commands are sequential; only a few are overlapped. See
Sequential/Overlapped Commands on page 32 and refer to the module manual for a list ofoverlapped commands.

30 

LDC-3926

REMOTE OPERATIONS
Status ReportingStandard
Event Status*ESR?
7 6 5 4 3&

LOGICAL
OR

&

&

&

&

7 6 5 4 3

2

&

2

1 0

&

&

1 0

Standard
Event Status
Register*ESE <nrf>
*ESE

{

{
OUTPUT
QUEUE

Status Byte
*STB
0 − TEC EventM
1 − TEC Cond.
&
2 − LASER Event&&
3 − LASER Cond.
&&
4 − Message&&
5 − Event Status
6 − Request Service / Master Status7
5 4 3 2 1 0
7 − Error
Available
Service Request Enable*SRE<nrf>
*SRE?

{

{

15 14 13 12 11 10 9 8

QUEUE
NOT−EMPTY

LOGICALOR

QUEUE
NOT−EMPTY

Condition Status Summary Register
ALLCOND?

0 − Operation
1 − Request
2 − Query3 − Device−Dependent
4 − Execution
5 − Command
6 − User
7 − Power

SERVICEREQUEST
GENERATION

R

7 6

E

M

3 2

1 0

CHAPTER7 6 5 4

3 2

1 0

LOGICAL
OR

Event Status Summary Register
ALLEVE?
15 14 13 12 11 10 9 8

7 6 5 4LOGICAL OR

ERROR
QUEUE

3 2

1 0

3

0 − Channel 1
1 − Channel 2
2 − Channel 3
3 − Channel 4
4 − Channel 5
5 − Channel 6
6 − Channel 7
7 − Channel 8
8 − Channel 9
9 − Channel 10
10− Channel 11
11− Channel 1212 − Channel 13
13 − Channel 14
14 − Channel 15
15 − Channel 16

0 − Channel 1
1 − Channel 2
2 − Channel 3
3 − Channel 4
4 − Channel 5
5 − Channel 6
6 − Channel 7
7 − Channel 8
8 − Channel 9
9 − Channel 10
10− Channel 11
11− Channel 1212 − Channel 13
13 − Channel 14
14 − Channel 15
15 − Channel 16

Figure 3.4 Status Reporting Schematic Diagram
Care must be taken when using the *OPC, *OPC?, and *WAI commands with the LAS:OUT ON
command, due to the two-second turn-on delay. In some cases operation completion can far exceed
the standard GPIB time-out setting.
If the GPIB times out while waiting for a response, either set the GPIB time-out to be longer, or use
SRQ-generated interrupts in your program. See your GPIB manual for time-out configuration or
SRQ programming setup.

01_10

LDC-3926

 31

CHAPTER

3

REMOTE OPERATIONS
Error Messages

Command TimingThis section describes, for each device-dependent command, whether that command is performed
in an overlapped or sequential manner. Command timing states whether the next command canbegin while another command is being executed, or if the next command must wait until thiscommand is completed before its execution begins. See Operation Complete Definition on page 30
for conditions about setting the operation complete flag.

Sequential/Overlapped Commands
All device-dependent commands are executed in an overlapped manner: subsequent commands
can begin before the current command is completed. Some common commands are sequential; thenext command must wait until this command is completed. All device-dependent commands are
executed in an overlapped manner, except the "DELAY" command which is sequential. The
operation complete flag is set after the conditions outlined in the Operation Complete Definition havebeen satisfied.
The *WAI (common command) is an example of a sequential command which 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 no-operations-pending flag is used to set the OPC flag(bit 0 of the Standard Event Status Register).
Commands which 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 nonvolatile memory has been completed. This ensures the OPC flag is never set prematurely.

Query Response Timing
Query responses are evaluated at the time the query request is parsed, and not at the time theresponse message is sent. In most cases this does not create a problem since the time between
parsing a query and sending its response is small.

Error Messages
In the event of a hardware error condition, error messages are displayed on the channel menu
screens. In addition to mainframe errors, GPIB errors from the channel (module) may be read via
the MODERR? query. Mainframe Errors and a binary representation of channel errors may be readover GPIB using the ERR? query. For example, a response from ERR? might look like:
0,0000000010001000
This indicates that there are no Mainframe Errors, and that channel 4 and channel 8 both haveerrors. Read those error codes by sending:
CHAN 4;ERR?;CHAN 8;ERR?
Table 3.3 lists the numerical error ranges by function. Table 3.4 on page 33 contains all of the error
messages which may be generated. Not all of these messages may appear on the front panel
displays. Some refer to GPIB activities only.

32 

LDC-3926

REMOTE OPERATIONS
Error Messages

CHAPTER3

In remote operation, the errors can be read by issuing the ERR? query. When this is done, all of theerror messages which are resident in the error queue are returned (up to 10 may be stored).
Reading the error queue via GPIB clears the error queue.
Note: Errors codes not listed are reserved for future design use.

Table 3.3 Mainframe Error Code Classifications
Error Code Range

Area of Operation

E-100 to E-199

Parser Errors

E-200 to E-299

Execution Control Errors

E-300 to E-399

GPIB Errors

E-700 to E-799

Mainframe Errors

E-900 to E-999

Mainframe-to-Module
Communication Errors

Table 3.4 Mainframe Error Codes

01_10

Error CodeExplanation

E-124

Command not recognized by mainframe.

E-125

Common command not recognized by mainframe.

E-126

Too few or too many program data elements.

E-201<PROGRAM DATA> ó Value out of range.

E-202<PROGRAM DATA> ó Will not convert to valid type.

E-203

Security violation; command is not available without clearance.

E-225

No modules are present.

E-226

Arbitrary Block data header not valid.

E-227

Invalid channel selection.

E-228

String delimiter not found.

E-229"Channel All" command not valid; all modules in mainframe must be the same model.

E-301

A <RESPONSE MESSAGE> was ready, but the mainframe failed to address the device to
talk.

E-302

Device was addressed to talk, but mainframe failed to read all of the message.

E-710

AC Power Low Error detected.

E-711

AC Power Low Error detected.

E-712

Over-Temperature Error detected on internal sensor.

E-713

Power Brown-out Error detected.

E-714

Internal error waiting to display

E-9xx

Internal communications warnings.

LDC-3926

 33

CHAPTER

34 

LDC-3926

3

REMOTE OPERATIONS
Error Messages

CHAPTER

4

COMMAND REFERENCE


This chapter is a reference to all of the GPIB commands for the LDC-3926 Laser Diode Controller. It
contains an overview of the remote commands used by the LDC-3926, as shown in Table 4.1, and it
contains the command descriptions, listed in alphabetical order.

GPIB Commands
Table 4.1 GPIB Command Summary Reference List
Name

Parameters

Function

ALLCOND?

NONE

Returns the summary of all 16 channels' condition bits which are further
summarized in the Status Byte.

ALLEVE?

NONE

Returns the summary of all 16 channels' event bits which are further
summarized in the Status Byte.

BEEP

1

Enables the beeper, or beeps once.

BEEP?

NONE

Returns the enable status of the beeper.

*CAL?

NONE

Used for the A/D calibration procedure.

CHAN

1

Selects a channel (or all channels) for further commands.

CHAN?

NONE

Returns the selected channel.

CHECKSUM?

NONE

Returns a value which is the checksum of the 3926 setup parameters.

*CLS

NONE

Resets the Standard Event Register, Status Byte and Error Queue to zero.

DELAY

1

Used to create a delay in the execution of further commands.

ERR?

NONE

Returns errors generated since the last query.

*ESE

1

Used to load the Standard Event Status Enable Register.

*ESE?

NONE

Returns the value of hte STANDARD EVENT STATUS ENABLE REGISTER

*ESR?

NONE

Returns the value of the STANDARD EVENT REGISTER.

*IDN?

NONE

Returns the DEVICE IDENTIFICATION string.

MENU

1

Selects a menu for the front panel display.

MES

1

Enters a string message of up to 16 bits.

MES?

NONE

Returns a previously stored ASCII message.

MODERR?

NONE

Returns the error codes of the selected channel(s).

LDC-3926



35

CHAPTER

4

COMMAND REFERENCE
GPIB Commands

Table 4.1 GPIB Command Summary Reference List

36 

LDC-3926

Name

Parameters

Function

MODIDN?

NONE

Returns the model number, serial number, and firmware version of theselected channel(s).

*OPC

NONE

Generates the OPERATION COMPLETE message in the Standard Event
Status Register .

*OPC?

NONE

Places an ASCII character 1 into the Output Queue.

*PSC

1

Used to avoid any undesirable service requests.

*PSC?

NONE

Queries the power-on-status-clear flag.

*PUD

1

Stores data unique to the instrument.

*PUD?

NONE

Retrieves the contents of the *PUD storage area.

RAD

1

Sets the radix for integer data. Decimal, binary, octal, or hexadecimal.

RAD?

NONE

Returns the radix type for numerical data.

*RCL

1

Recall a stored setup configuration

*RST

NONE

Performs a device reset.

*SAV

1

Save the current setup configuration

SECURE

1

Used to gain access to protected data.

SCR

1

Enables or disables auto-scrolling in the status menu.

SCR?

NONE

Returns the status of the auto-scrolling feature.

*SRE

NONE

Sets the Service Request Enable Register bits to allow generation of theuser-selectable service requests.

*SRE?

NONE

Determines the current contents of the Service Request Enable Register.

*STB?

NONE

Reads the Status Byte.

TERM

1

Adds 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 powered up.

TIMER?

NONE

Returns the elapsed time since the timer was last reset.

*TST?

NONE

Initiates an internal self-test and returns a response when complete.

*WAI

NONE

Prevents executing any further commands until the No-Operation-Pending
flag is true.

COMMAND REFERENCE
Command Reference

CHAPTER

4

Command ReferenceThis section presents the mainframe commands for both local and remote operation of the LDC3926, listed in alphabetical order. Also included in this section are the descriptions of the Generic
Module Commands, see Figure 3.3 on page 28. Refer to the appropriate module manual for details
on each specific module. Sub-sections for each path are presented, listing the commands which arelegal for that path.

ALLCOND?

COMMONFRONT PANELREMOTEThe ALLCOND? query returns the status summary of enabled conditions from each channel of the
LDC-3926 Laser Diode Controller.
Parameters

None. The response is the sum of the following:
1 - Channel 1 conditions

Notes

256 - Channel 9 conditions

2 - Channel 2 conditions

512 - Channel 10 conditions

4 - Channel 3 conditions

1024 - Channel 11 conditions

8 - Channel 4 conditions

2048 - Channel 12 conditions

16 - Channel 5 conditions

4096 - Channel 13 conditions

32 - Channel 6 conditions

8192 - Channel 14 conditions

64 - Channel 7 conditions

16384 - Channel 15 conditions

128 - Channel 8 conditions

32768 - Channel 16 conditions

Each channel's conditions that are summarized here represent that channel's contribution to the
Status Byte Register. All of the "bits" of the ALLCOND register are logically ORed to set or clear bit
0 of the Status Byte Register.
The value of the ALLCOND register is not cleared until it is read using the ALLCOND? query. Thus,
if an SRQ is generated from any of the condition "bits" of the ALLCOND register, it is necessary to
use the ALLCOND? query in the user's interrupt service routine to reset the interrupt-enabledcondition. Otherwise, multiple interrupts would occur.
Typical use of the ALLCOND? query would be in conjunction with the *STB? query. For example, if
you first read the status byte with *STB? and find bit 0 is set, then you can read the ALLCOND? tofind out which channel(s) generated the change. If more information is still required, then you canquery the contributing channel(s) for the appropriate conditions (e.g. "CHAN 3;LAS:COND?" or"CHAN 12;TEC:COND?", etc.). For more information, see the appropriate condition-enablecommands, e.g. "LAS:ENAB:COND" or "TEC:ENAB:COND". Refer to the appropriate module
instruction manual for details on each specific module.

Examples

ALLCOND?óresponse: 0, means the no channels have any enabled conditions to pass to the Status
Byte register.
ALLCOND?óresponse: 9, means that channels 1 and 4 have enabled conditions. Bit 0 of the Status
Byte register is set.
RAD BIN;ALLCOND?óresponse: #B10001, means that channels 1 and 5 have enabled conditions.
Bit 0 of the Status Byte register is set.

01_10

LDC-3926

 37

CHAPTER

4

COMMAND REFERENCE
Command Reference

ALLEVE?

COMMONFRONT PANELREMOTEThe ALLEVE? query returns the status summary of enabled events from each channel of the
LDC-3926 Laser Diode Controller.

Parameters

Notes

None. The response is the sum of the following:
1 - Channel 1 events

256 - Channel 9 events

2 - Channel 2 events

512 - Channel 10 events

4 - Channel 3 events

1024 - Channel 11 events

8 - Channel 4 events

2048 - Channel 12 events

16 - Channel 5 events

4096 - Channel 13 events

32 - Channel 6 events

8192 - Channel 14 events

64 - Channel 7 events

16384 - Channel 15 events

128 - Channel 8 events

32768 - Channel 16 events

Each channel's events which are summarized here represent that channel's contribution to the
Status Byte Register. All of the "bits" of the ALLEVE register are logically ORed to set or clear bit 1of the Status Byte Register.
The value of the ALLEVE register is not cleared until it is read using the ALLEVE? query. Thus, if an
SRQ is generated from any of the event "bits" of the ALLEVE register, it is necessary to use the
ALLEVE? query in the user's interrupt service routine to reset the interrupt-enabled condition.
Otherwise, multiple interrupts would occur.
Typical use of the ALLEVE? query would be in conjunction with the *STB? query. For example, if
you first read the Status Byte with *STB? and find that bit 1 is set, then you can read the ALLEVE?
to find out which channel(s) generated the change. If more information is required, then you canquery the contributing channel(s) for the appropriate events (i.e. "CHAN 11;LAS:EVE?" or "CHAN
3;TEC:EVE?", etc.). For more information, see the appropriate event-enable commands,e.g.
"LAS:ENAB:EVE" or "TEC:ENAB:EVE".

Examples

ALLEVE? - response: 0, means the no channels have any enabled events to pass to the Status Byte
register.
ALLEVE? - response: 19, means that channels 1, 2, and 5 have enabled conditions. Bit 0 of the
Status Byte register is set.
RAD BIN;ALLEVE? - response: #B100001, means that channels 1 and 6 have enabled events. Bit 0
of the Status Byte register is set.

BEEP

COMMONFRONT PANELREMOTE
The BEEP command controls the LDC-3926 Laser Diode Controller's beeper. The beeper can beused to signal error or warning conditions.

Parameters

An <nrf value>, 0 = Off (totally disabled); 1 = On, enabled for normal operation; and 2 = beep once.

Notes

Disabling the BEEP will prevent the audible beeper signal from working during front panel operation,
including calibration signals. The parameter must be a numeric value (0, 1, or 2), and not acharacter data substitute (such as On or Off).

Examples

BEEP 0 - action: The beeper is disabled.
BEEP 1 - action: The beeper is enabled for normal operation.
BEEP 2 - action: The beeper is beeped once.

38 

LDC-3926

COMMAND REFERENCE
Command Reference

BEEP?

CHAPTER

4

COMMONFRONT PANELREMOTE
The BEEP? query returns the enable status of the LDC-3926 Laser Diode Controller's beeper.

Parameters

None. A response of 0 = Off (totally disabled); 1 = On, enabled for normal operation.

Notes

Disabling the BEEP will prevent the audible beeper signal from working during front panel operation,
including calibration signals.
The beeper is normally enabled, unless it is specifically disabled via the "BEEP 0" remotecommand.

Examples

BEEP? - response: 0, means the beeper is disabled.
BEEP? - response: 1, means the beeper is enabled for normal operation.

*CAL?

COMMONDEVICE DEPENDENTFRONT PANEL

ActionAdjusts the internal analog to digital (A/D) converter to reference points, then reports results.

Results

Zero = OK

Note

A/D referencing is performed each 10 minutes of inactive time.

Example*CAL?

Non-zero = calibration error

CHANnelCOMMONFRONT PANELREMOTEThe CHANnel command selects the modules that will receive subsequent channel-basedcommands.

Parameters

An <nrf value>, a list of comma-separated <nrf values>, or "ALL".
-where the <nrf value> (1 - 16) represents an LDC-3926 channel number.

Notes

The modules in the selected channels will receive all channel-based commands until the next"channel" command.
Selecting a channel remotely does not affect the front panel display. To change the front panel
display remotely, see "Menu" command.
If an invalid (missing) module is selected, an "E227" error will be generated, and the channel will not
be changed.

Examples

CHAN 1 - action: selects the module in channel 1 for further channel-based commands (assuming a
module exists in the channel).
CHAN 1,3,4,8 - action: selects the modules in channels 1, 3, 4,and 8 for further channel-basedcommands.
CHANnel ALL - action: selects all available modules for further channel-based commands

01_10

LDC-3926

 39

CHAPTER

4

COMMAND REFERENCE
Command Reference

CHANnel?

COMMONFRONT PANELREMOTEThe CHANnel? query returns the channel numbers of the modules that have been selected toreceive channel-based commands.
Parameters

None. The response will be the channel numbers of the selected modules.

Notes

If no channels are found by the mainframe, the response will be 0.

Examples

CHAN? - response: "12", means the module in channel 12 is selected for channel-basedcommands.
:CHAN? - response: "3;4;16", means the modules in channels 3, 4, and 16 are selected for channelbased commands.
CHANnel? - response: "ALL", means that channel-based commands will be sent to all available
modules.

CHECKSUM?

COMMONFRONT PANELREMOTEThe CHECKSUM? query returns an integer value which is the summation of all pertinent
parameters of the present configuration.
Parameters

None. The response consists of an integer value.

Notes

The response value may be stored and compared at a later time to verify that the present
configuration of the instrument is the same as expected. This feature works well with the *RCL
(recall) command as a means of verifying a stored setup.
The checksum does not test the functionality of the instrument or which modules are present.

Examples

CHECKSUM? - response: 3812, is the checksum of the present configuration of parameters on the
instrument.

*CLS

COMMONDEVICE DEPENDENTFRONT PANEL

Action40 LDC-3926

Clears status event registers: Event Status, Event Status Enable, and Error Queue.

Note

Useful to clear registers before enabling service requests (SRQ).

Example*CLSCOMMAND REFERENCE
Command Reference

DELAY

CHAPTER

4

COMMONFRONT PANELREMOTEThe DELAY command causes the execution of commands to be delayed by a user-defined timeinterval. This command is similar to the *WAI common command, except that execution resumes
after the specified number of milliseconds, instead of waiting for the Operation-Complete flag to be
set.

Parameters

An <nrf value> which represents the delay time, in milliseconds.

Notes

Further commands are held off until the delay period elapses.
This command is useful for creating delays which do not require very much program code and do
not tie up the GPIB during execution.

Examples

DELAY 500 - action: Further commands and queries are not executed until 0.5 second has elapsed
from the time this command is executed.
Tec:T 22;Delay 2000;Tec:T? - actions: The TEC is set to 22.0C, then the LDC-3926 Laser Diode
Controller waits for about 2.0 seconds before displaying the measured temperature.

ERRors?

COMMONFRONT PANELREMOTEThe "ERRors?" query returns a list of "mainframe" device and command errors, followed by a binary
representation of the occurrence of "module" device and command errors. The "mainframe" errors
are those which have occurred since the last "ERR?" query. The "module" errors are not cleared
until the "MODERR?" query is sent to each module which reports an error. The errors are notated bya number (code) which corresponds to the type of error which occurred. See Chapter 3, Error
Messages, for information regarding error handling.

Parameters

None. The response consists of one or more "mainframe" error code values, separated by commas
and a 16-bit binary representation of errors which exist on each channel.

Notes

A response of 0,0000000000000000 indicates that no errors were reported. The first zero indicatesno "mainframe" errors, and the second (16-bit) zero indicates no "module" errors. The response
data is sent as character data.

Examples

ERR? - response: 0,0000000000000001 means no "mainframe" errors reported, but channel #1 has
an error. Use "CHAN 1;MODERR?" to retrieve the error code(s) from channel 1.
ERRors? - response: 219,1111111100000000, means that the LDC-3926 was unable to restore thesetup parameters (at power-up) because of a change in modules. Also, there are errors present onchannels 9 - 16.

01_10

LDC-3926

 41

CHAPTER

4

COMMAND REFERENCE
Command Reference*ESE <nrf value>

COMMONDEVICE DEPENDENT

Event Status Enable

FRONT PANEL

ActionEnables bits in the standard event status enable register.

Response

The value must be between 0 and 255.

7 6 5 4 3 2 1 0 Standard Event Status Register&&&
Logical OR

&
&

&
&

&

7 6 5 4 3 2 1 0 Standard Event Status Enable Register
Bit Reference
0- Operation Complete

4- Execution Error

1- N/A

5- Command Error

2- Query Error

6- User Request

3- Device Dependent Error

7- Power On

Notes

Bit 5 of the status byte register is set if any enabled conditions are true.
Setting bit 0 allows you to generate service requests from overlapped commands as previous operations complete. This may be useful for ensuring that an operation is complete before starting ameasurement.

42 

LDC-3926

COMMAND REFERENCE
Command Reference*ESE?

CHAPTER

4

COMMONDEVICE DEPENDENT

Event Status Enable?

FRONT PANEL

ActionRequests the value in the standard event status enable register.

Response

The value must be between 0 and 255.

7 6 5 4 3 2 1 0 Standard Event Status Register&&&
Logical OR

&
&

&
&

&

7 6 5 4 3 2 1 0 Standard Event Status Enable Register
Bit Reference
0- Operation Complete

4- Execution Error

1- N/A

5- Command Error

2- Query Error

6- User Request

3- Device Dependent Error

7- Power On

Notes

Bit 5 of the status byte register is set if any enabled conditions are true.
Response is the sum of the enabled bits.

01_10

LDC-3926

 43

CHAPTER

4

COMMAND REFERENCE
Command Reference*ESR?

COMMON

Standard Event Status Register?

DEVICE DEPENDENTFRONT PANEL

ActionRequests the value in the standard event status register.

Response

The value must be between 0 and 255.

7 6 5 4 3 2 1 0 Standard Event Status Register&&&
Logical OR

&
&

&
&

&

7 6 5 4 3 2 1 0 Standard Event Status Enable Register
Bit Reference
0- Operation Complete

4- Execution Error

1- N/A

5- Command Error

2- Query Error

6- User Request

3- Device Dependent Error

7- Power On

Notes

Response is the sum of the enabled bits.
This command allows you to determine which type of error has occurred.

*IDN?

COMMONDEVICE DEPENDENTFRONT PANEL

ActionRequests the instrument to identify itself.

Response

Returns a comma delimited standard format ASCII identification string, from information stored in
the instrument during manufacture.

MENU

COMMONFRONT PANELREMOTE
The MENU command changes the displayed menu on the front panel.

Parameters

An <nrf value> which represents the front panel menu selections. 1 = Channel Menu, 2 = Status
Menu, or 3 = Summary Menu.

Notes

This command is useful for visually monitoring activity from the front panel while in remote
operation.
The channel used (when the parameter is 1) is the remotely selected channel, not the last front
panel selected channel (see CHANnel on page 39).

Examples

MENU 1 - action: sets the front panel display to the remotely selected channel's main menu.
MENU 2 - action: sets the front panel display to the Status menu.

44 

LDC-3926

COMMAND REFERENCE
Command Reference

MESsage

CHAPTER

4

COMMONFRONT PANELREMOTE
The MESsage command allows the user to enter an ASCII string of up to 16 non-zero characters.
This command may be useful for storing messages which relate to a test or configuration.

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 nullterminate 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.

MESsage?

COMMONFRONT PANELREMOTE

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.
Parameters

None. 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, theresponse 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."

MODERR?

COMMONFRONT PANELREMOTE
The MODERR? query returns a list of "module" device and command errors. The "module" errors
are those which have occurred since the last "MODERR?" query. The errors are notated by anumber (code) which corresponds to the type of error which occurred. See the appropriate module
instruction manual for information regarding error handling for each specific module.

Parameters

None. The response consists of one or more "module" error code values, separated by commas.

Notes

A response of (0) indicates that no errors were reported. The response data is sent as character
data.

Examples

MODERR? - response: 0 means no "module" errors reported.
MODERR? - response: 501, means that the module has a LASER interlock error which prevented
the LAS output from being turned on.

01_10

LDC-3926

 45

CHAPTER

4

COMMAND REFERENCE
Command Reference

MODIDN?

COMMONFRONT PANELREMOTE
The MODIDN? query returns the module model name and serial number.

Parameters

None. The response consists of the module's model number, serial number, and version number,separated by commas.

Notes

The serial number may also be found by removing the module from the mainframe and viewing theserial number information on the side of the module.

Examples

MODIDN? - response: "3926374,03740001,v1.00", for example.

*OPC

COMMON

Operation Complete

DEVICE DEPENDENTFRONT PANEL

Sets the operation complete bit in the Event Status Register when all pending overlappedcommands have been completed.
Response

None.

Example

*OPC

*OPC?

COMMON

Operation Complete Query

DEVICE DEPENDENTFRONT PANEL

Places an ASCII character 1 into the Output Queue when all pending operations have been
finished.
Response

1 - when all overlapped commands are complete.

Example*OPC?

*PSC <nrf value>
Power-on Status Clear

COMMONDEVICE DEPENDENTFRONT PANEL

Sets automatic power-on clearing of the enable registers.
Values0 = disable power-on clearing
1 = enable power-on clearing

Notes

Any non-zero value is interpreted as 1.
Registers affected:
Condition Status Enable
Service Request Enable
Event Status Enable
Standard Event Status Enable
Factory default condition: disabled.
In the disabled state, the values of the enable registers are saved through power OFF/ON. The
power-on status clear flag (see PSC?) is set false, disallowing service request interrupts after
power-on.
In the enabled state, the enable registers are cleared during power ON. The power-on status clear
flag (see PSC?) is set true, allowing service request interrupts after power-on.

Examples*PSC 0 - Disable automatic power-on clearing of the enable registers.
*PSC 1 - Enable automatic power-on clearing of the enable registers.

46 

LDC-3926

COMMAND REFERENCE
Command Reference*PSC?

CHAPTER

4

COMMONDEVICE DEPENDENTPower-on Status Clear?

FRONT PANEL

ActionRequests the state of the power-on status clear flag.

Response0óThe enable registers are saved through power OFF/ON.
1óThe enable registers are cleared during power ON.
Registers affected:
Condition Status Enable:
Event Status Enable:

Service Request Enable
Standard Event Status Enable

See Chapter Three for more information on register structure.
Example*PSC? - Request state of power-on status clear flag.

*PUD

COMMONDEVICE DEPENDENTFRONT PANEL

ActionStores data unique to the instrument, such as calibration date and serial number. This data is
protected from change by the "SECURE <nrf>" command and is usually entered by the factory.

Notes

The arbitrary block program data is exactly 25 bytes long.

*PUD?

COMMONDEVICE DEPENDENTFRONT PANEL

ActionRequests the stored identification string.

RADix

COMMONFRONT PANELREMOTEThe 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.

Parameters

Character program data is expected, as shown above.

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 newradix.
In cases where the radix is not DECimal, the flexible numeric type <nrf value> (as shown in theCommand 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; *ESR? - action: the hexadecimal radix is selected; -response: #H80, means power-on
was detected.

01_10

LDC-3926

 47

CHAPTER

4

COMMAND REFERENCE
Command Reference

RADix?

COMMONFRONT PANELREMOTEThe RADix? query allows the programmer to determine which radix type for status, condition, andevent query response data is currently selected. Decimal, binary, octal, and hexadecimal areallowed.

Parameters
Notes

None. The response will be character data. A response of DEC means decimal, BIN means binary,
HEX means hexadecimal, and OCT means octal.
DEC is the default type. The LDC-3926 Laser Diode Controller defaults to this radix at power-up.
The RADix command is used to select the desired radix. Once it is changed, the new radix willremain in effect until the power is shut off or a new RADix command is issued.

ExamplesRAD? - 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.

*RCL <nrf value>

COMMONDEVICE DEPENDENT

RecallFRONT PANEL

ActionRecalls a stored setup configuration from memory.

Value range

0 through 10

Notes

Setup 0 has a factory-set default configuration.
If you use GPIB to recall setup 0 (*RCL 0), GPIB mode is set to REMOTE. If you recall setup "0" by
the front panel, GPIB mode is set to LOCAL.
Same function as RECALL on the front panel.
Use *SAV to store various setup configurations for convenient recall.
The current setup is automatically stored and recalled at next power-ON, unless you use *PSC totell the instrument not to do so.

Example*RCL 0 - Recall the factory default setup.

*RST

COMMONDEVICE DEPENDENT

Reset
ActionFRONT PANEL
Performs a device reset and the following:
Sets OCIS state
Sets OQIS state

Notes

OCIS = Operation-complete Command Idle State. This is the same state as after *OPC: no further
operations to complete.
OQIS = Operation-complete Query Idle State. This is the same state as after *OPC?: no further
operations to complete.
These idle states allow the mainframe to complete its reset process (no operations pending) before
con-tinuing with other operations.

Example48 LDC-3926*RSTCOMMAND REFERENCE
Command Reference*SAV <nrf value>

CHAPTER

4

COMMONDEVICE DEPENDENT

Save

FRONT PANEL

ActionSaves the current setup configuration in memory.

Value range

1 through 10

Notes

Configuration 0 is reserved for a factory-set default configuration. See *RCL.
It is normally not necessary to save the current setup for next power-ON. The current setup is
automatically stored for recall at next power-ON unless you use *PSC not to do so.

Example*SAV 2 - Save the current setup configuration as #2.

SCRollCOMMONFRONT PANELREMOTEThe SCRoll command enables or disables the auto-scrolling feature of the ALL status screen.

Parameters
Notes

A Boolean value, 0 = FALSE (disabled), 1 = TRUE (enabled).
This command affects the Status screen only.
The scrolling rate is not adjustable.
When the auto-scrolling feature is enabled it is in effect until it is disabled or the LDC-3926 ispowered off.

ExamplesSCR 1 - Enables the auto-scrolling feature of the Status screen.
SCRol 0 - Disables the auto-scrolling feature of the Status screen.

SCRoll?

COMMONFRONT PANELREMOTEThe SCRoll? query allows the programmer to determine the status of the auto-scrolling feature for
the Status Menu.

Parameters

None. The response is an <nrf value>, 1 = TRUE (enabled), 0 = FALSE (disabled).

Notes

In local operation, the user must select the Status screen in order to determine if the auto-scrollingfeature is in use.

Examples

SCRoll? - response: 1, means that auto-scrolling is enabled for the Status screen.
SCR? - response: 0, means that auto-scrolling is disabled for the Status screen.

*SRE <nrf value>
Service Request Enable

COMMONDEVICE DEPENDENTFRONT PANEL

Enables bits in the service request enable register.

01_10

Notes

Response is the sum of the enabled bits.

Example*SRE 136 - Enable the service request enable register condition summary and error message bits
(8 + 128 = 136).

LDC-3926

 49

CHAPTER

4

COMMAND REFERENCE
Command Reference*SRE?

COMMON

Service Request Enabled?

DEVICE DEPENDENTFRONT PANEL

Requests the value in the service request enable register.
Notes

Response is the sum of the enabled bits.
See Chapter Three for more information about register structure.

Example*SRE? - Response 136 means the service request enable register condition summary and error
message bits are enabled (8 + 128 = 136).

*STB?

COMMONDEVICE DEPENDENT

Status Byte?

FRONT PANEL
Requests the value in the status byte register.

Notes

Response is the sum of the enabled bits.
See Chapter Three for more information about register structure.

Example*STB? - Response 200 means the status byte condition and master status summary bits, and error
message bits, are enabled. (8 + 64 + 128 = 200)TERM

COMMONFRONT PANELREMOTEThe TERM command allows the programmer to change the default (IEEE488.2 standard) terminatorto include the carriage return.

Parameters

An <nrf value>, 0 = FALSE, 1 = TRUE

Notes

An altered terminator will be in the form <CR><NL><^END>. Technically this takes the LDC-3926
out of IEEE488.2 specification, but this command may be used for convenience when using nonstandard GPIB controllers. This termination issent with all output until the TERM 0 command is sentor the LDC-3926 is powered off.

ExamplesTERM 1 - temporarily sets <CR><NL><^END> as the output terminator.

TERM?

COMMONFRONT PANELREMOTEThe TERM? query allows the programmer to determine whether the default (IEEE488.2 standard)terminator has been altered to include a carriage return.

Parameters

None. The response is an <nrf value>, 1 = TRUE, 0 = FALSE.

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 LDC-3926 Laser Diode Controller is powered off.

ExamplesTERM? - response: 1, means that the <CR><NL><^END> terminator is temporarily being used.
TERM? - response: 0, means that the <NL><^END> terminator (IEEE 488.2 standard) is being
used.

50 

LDC-3926

COMMAND REFERENCE
Command Reference

TIME?

CHAPTER

4

COMMONFRONT PANELREMOTEThe TIME? query allows the programmer to determine how much time has passed since the
LDC-3926 Laser Diode Controller was last powered up.

Parameters

None. The response is character data in the form: hours:minutes:seconds.

Notes

The TIME clock is independent of the TIMER clock.

Examples

TIME? - response: 00:01:02.36, means that 1 minute, 2.36 seconds have passed since the
LDC-3926 Laser Diode Controller was powered up.
TIME? - response: 00:32:00.76, means that 32 minutes, 0.76 second have passed since the
LDC-3926 Laser Diode Controller was powered up.

TIMER?

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

Parameters

None. The response is character data in the form: 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.

Examples

TIMER? - response: 00:02:00.31, means the LDC-3926 Laser Diode Controller has been on for 2
minutes, 0.31 seconds since the last TIMER? query was issued.
TIMER? - response: 00:00:12.03, means the LDC-3926 Laser Diode Controller has been on for12.03 seconds since the last TIMER? query was issued.

*TST?

COMMONDEVICE DEPENDENTTest?

FRONT PANEL
Performs internal self-test, then reports results.

Response

0 = test completed with no errors.
Non-zero = test not completed, or was completed with errors.

Example

TST?

*WAI

COMMON

Wait to Continue

DEVICE DEPENDENTFRONT PANEL

Prevents the instrument from executing any further commands until OPC (operation complete)status is true.
Note

This command can be used to make the instrument wait until an operation is complete before
continuing.
Care should be taken to set the GPIB time-out appropriately for use with the *WAI command. After
this command (or the Delay) command is sent, the controller may receive up to 20 more commands
before the wait period is over. If more than 20 commands are sent before the delay or wait period isover, the additional commands will be ignored and an error E220 will be generated.

Example01_10*WAI - Wait until OPC status is true.

LDC-3926

 51

CHAPTER

52 

LDC-3926

4

COMMAND REFERENCE
Command ReferenceCHAPTER

5

TROUBLESHOOTING

This chapter is to help you resolve problems quickly. If you need help, contact ILX Lightwave
Customer Service. See page xii for contact information.
ILX Lightwave Corporation provides in-house and on-site calibration services for ILX instruments.
Although the LDC-3926 does not require calibration, most ILX instruments require yearly calibration
to ensure performance to published specifications. ILX factory calibrations employ NIST traceable
measurement instrumentation, and our calibration engineers and technicians use automated test
equipment to accurately and efficiently capture and record calibration data. An original certificate ofcalibration authenticity is provided with all instrument calibrations, and a detailed report showing any
pre-calibration out-of-tolerance conditions is available upon request. Calibration turn-times arenormally five business days or less. On-site calibrations can be performed around your production
schedule, night or day, seven days a week. Please contact ILX Customer Support (see Comments,
Suggestions, and Problems on page xii for contact information) for additional calibration information.
For further assistance with technical solutions and troubleshooting, visit the www.ilxlightwave.com
Support page (www.ilxlightwave.com/support/index.html), and the Library page(www.ilxlightwave.com/library/index.html) for Application Notes and Technical Notes.

LDC-3926



53

CHAPTERTR OUBLESHOOTING
Troubleshooting Guide

5

Troubleshooting Guide
This section is a guide to troubleshooting the LDC-3926. Some of the more common symptoms arelisted here, and the appropriate troubleshooting actions are given. If problems persist, contact ILX
Customer Service (see page xii for contact information). Also check the www.ilxlightwave.com
Support page, and the Library page for Application Notes and Technical Notes.

Table 5.1 Troubleshooting
Symptom

Corrective Action

LDC-3926 will not power up•

Check AC Power line voltage and power cordconnection.

•

There maybe a problem with the internal fusing.
Contact ILX Customer Service•

This may occur if the instrument loses power (AC line)
briefly or line voltage drops below specification. If the
instrument is locked−up, cycle the power.

Power on, but outputs have been shut off.
Instrument is locked up or instrument resets
itself.

Error Messages
In the event of a mainframe error condition, error messages are displayed on the channel menu
screens. Refer to the module User's Guide for information about module-specific errors.

Testing for Errors in Remote Operation
This section contains error codes that the LDC-3926 reports in response to the ERR? query. For
more information about specific GPIB commands, see Chapter 4, Command Reference.
1

Send the query ERR? to read the system errors and module error summary.
This allows you to error-check the LDC-3926 as a whole. If any module errors arepresent, the corresponding bit of the module error summary is set. For example, suppose
the mainframe responds to an ERR? query with the string 0,0000000001100000. The
zero to the left of the comma indicates that there are no mainframe errors, and the binary
representation to the right of the comma indicates that there are errors on channels 7 and6. (Module 16 is on the left, module 1 is on the right).

2

Send the query MODERR? to read the module errors.

For example, type CHAN 7;MODERR? to return the errors in module 7, and CHAN 6;MODERR?
returns any errors in module 6. For more information about module errors, refer to the module's
User's Guide.
Note: Errors codes not listed are reserved for future design use.

54 

LDC-3926

TROUBLESHOOTING
Error Messages

CHAPTER

5

Table 5.2 Mainframe Error Code Classifications
Error Code Range

Area of Operation

E-100 to E-199

Parser Errors

E-200 to E-299

Execution Control Errors

E-300 to E-399

GPIB Errors

E-700 to E-799

Mainframe Errors

E-900 to E-999

Mainframe-to-Module Communication Errors

Table 5.3 Mainframe Error Codes

01_10

Error CodeExplanation

E-124

Command not recognized by mainframe.

E-125

Common command not recognized by mainframe.

E-126

Too few or too many program data elements.

E-201<PROGRAM DATA> ó Value out of range.

E-202<PROGRAM DATA> ó Will not convert to valid type.

E-203

Security violation; command is not available without clearance.

E-225

No modules are present.

E-226

Arbitrary Block data header not valid.

E-227

Invalid channel selection.

E-228

String delimiter not found.

E-229"Channel All" command not valid; all modules in mainframe must be the same model.

E-301

A <RESPONSE MESSAGE> was ready, but the mainframe failed to address the device to talk.

E-302

Device was addressed to talk, but mainframe failed to read all of the message.

E-710

AC Power Low Error detected.

E-711

AC Power Low Error detected.

E-712

Over-Temperature Error detected on internal sensor.

E-713

Power Brown-out Error detected.

E-714

Internal error waiting to display

E-9xx

Internal communications warnings.

LDC-3926

 55

CHAPTER

56 

LDC-3926

5

TR OUBLESHOOTING
Error Messages