Newport LDX-3232 User Manual
User’s Guide
High Compliance Current Source
LDX-3232
70037802 November 2017
Table of Contents
Safety and Warranty Information .......................................................................... 5
Chapter 1 : Introduction and Specifications .......................................................... 9
Product Overview ................................................................................................................. 9
Initial Inspection ............................................................................................................................ 9
Installing the LDX-3232 High Compliance Current Source ................................................. 10
Grounding Requirements ............................................................................................................ 10
AC Line Power Requirements .................................................................................................... 10
GPIB Connector .......................................................................................................................... 10
The GPIB Address ...................................................................................................................... 10
Tilt-Foot Adjustment .................................................................................................................... 10
Operating the LDX-3232 Precision Current Source ............................................................ 11
Specifications ...................................................................................................................... 12
Available Options and Accessories ............................................................................................ 14
Chapter 2 : Operation ......................................................................................... 15
Applying Power to the LDX-3232 ........................................................................................ 15
The Power On Sequence ........................................................................................................... 15
Connecting to the Laser ...................................................................................................... 15
Interlock Connections ................................................................................................................. 17
Photodiode Connections ............................................................................................................. 17
Setting the PD Bias ..................................................................................................................... 18
Grounding Considerations .......................................................................................................... 18
Front Panel Operation ........................................................................................................ 18
The Display ................................................................................................................................. 18
Setting Up the LDX-3232 Precision Current Source ........................................................... 19
Mode Selection ........................................................................................................................... 19
Range Selection ......................................................................................................................... 19
Display Selection ........................................................................................................................ 19
Adjust Knob ................................................................................................................................ 19
Parameter Selection ................................................................................................................... 20
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Using the LDX-3232 in Constant Power (P) Mode ..................................................................... 20
Error Indicators ........................................................................................................................... 20
Automatic Laser Output Shut Off Conditions .............................................................................. 21
Chapter 3 : Remote Operation ............................................................................ 23
Reading the GPIB Address ......................................................................................................... 23
Changing the GPIB Address ....................................................................................................... 23
Changing Operation from Local to Remote ................................................................................ 23
LDX-3232 Current Source Command Set .......................................................................... 24
Command Syntax ....................................................................................................................... 24
Command Paths ......................................................................................................................... 26
IEEE488.2 Command Commands ...................................................................................... 27
Status Reporting ................................................................................................................. 28
Event and Condition Registers ................................................................................................... 28
Operation Complete Definition .................................................................................................... 29
Output Off Register ..................................................................................................................... 30
Command Timing and Completion ............................................................................................. 30
Error Messages .......................................................................................................................... 31
Chapter 4 : Command Reference ....................................................................... 33
LDX-3232 Device Dependent Command Reference .......................................................... 36
Chapter 5 : Functions and Features ................................................................... 51
Saving and Recalling from the Front Panel ........................................................................ 51
Saving and Recalling Under Remote Operation ......................................................................... 52
Using the Laser Compliance Voltage Adjustment ............................................................... 52
Using the LDX-3232 Current Source’s Trigger Function ..................................................... 52
Using the LDX-3232’s BNC Interlock Connection ............................................................... 53
BNC Interlock Usage Example ................................................................................................... 53
Entering Photodiode Responsivity Values .......................................................................... 53
Modulating the Laser Current Source ................................................................................. 54
Chapter 6 : Calibration and Troubleshooting ...................................................... 55
Calibration Overview ........................................................................................................... 55
Recommended Equipment ......................................................................................................... 56
Calibration of the LDX-3232 Current Source ...................................................................... 57
Current Source Calibration ......................................................................................................... 57
I
Laser Forward Voltage Measurement Calibration ...................................................................... 61
Troubleshooting Guide ....................................................................................................... 62
Current Calibration ................................................................................................................ 59
PD
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List of Figures
Figure 1.1 LDX-3232 Front View ................................................................................................ 11
Figure 1.2 LDX-3232 Rear View ................................................................................................ 11
Figure 2.1 Common Laser Cathode & Photodiode Cathode ...................................................... 16
Figure 2.2 Common Laser Cathode & Photodiode Anode ......................................................... 16
Figure 2.3 Common Laser Anode & Photodiode Cathode ......................................................... 16
Figure 2.4 Common Laser Anode & Photodiode Anode ............................................................ 17
Figure 2.5 Back Panel LD Connector ......................................................................................... 17
Figure 2.6 LDX-3232 Front Panel .............................................................................................. 18
Figure 3.1 LDX-3232 Command Path Structure ........................................................................ 26
Figure 3.2 Common Command Structure .................................................................................. 27
Figure 3.3 LDX-3232 Status Reporting Schematic Diagram ...................................................... 29
Figure 3.4 LDX-3232 Output Off Register & Defaults ................................................................ 30
Figure 6.1 IPD Calibration Circuit ............................................................................................... 56
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List of T ables
Table 1.1 Specifications ............................................................................................................ 12
Table 1.2 Accessories List ........................................................................................................ 14
Table 2.1 LDX-3232 Error Indicators ........................................................................................ 20
Table 3.1 Substitute Parameter Names .................................................................................... 25
Table 3.2 Error Code Classifications......................................................................................... 31
Table 3.3 LDX-3232 Error Codes.............................................................................................. 31
Table 4.1 Remote Command Summary Reference List ........................................................... 33
Table 5.1 LDX-3232 Default Settings (Bin 0) ............................................................................ 51
Table 6.1 Recommended Test Equipment ................................................................................ 56
Table 6.2 Calibration Circuit Components ................................................................................ 56
Table 6.3 Current Calibration Configuration Setup ................................................................... 57
Table 6.4 Power Calibration Configuration Setup ..................................................................... 59
Table 6.5 Voltage Calibration Configuration Setup ................................................................... 61
Table 6.6 Troubleshooting Guide .............................................................................................. 62
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Safety and Warranty Information
The Safety and Warranty Information section provides details about cautionary symbols used in the manual,
safety markings used on the instrument, and the information about the Warranty including Customer Service
contact information.
Safety Information and the Manual
Throughout this manual, the words Caution and Warning indicate potentially dangerous or hazardous situations
which, if not avoided, could result in death, serious or minor injury, or damage to the product. Specifically:
Indicates a potentially hazardous situation which can result in minor or moderate injury or damage to the
product or equipment.
Indicates a potentially dangerous situation which can result in serious injury or death.
Indicates 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
Prolong storage under adverse conditions
Failure to perform intended measurements or functions
If necessary, return the instrument to ILX Lightwave, or authorized local ILX Lightwave distributor, for service or
repair to ensure that safety features are maintained (see the contact information on page 6).
All instruments returned to ILX Lightwave are required to have a Return Material Authorization (RMA) number
assigned by an official representative of ILX Lightwave Corporation. See “Returning an Instrument” on page 5 for
more information.
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Safety Symbols
This section describes the safety symbols and classifications.
Technical specifications including electrical ratings and weight are included within the manual. See the Table of
Contents to locate the specifications and other product information. The following classifications are standard
across all ILX Lightwave products:
Indoor use only.
Ordinary protection: This product is NOT protected against the harmful ingress of moisture.
Class I Equipment (grounded type).
Mains supply voltage fluctuations are not to exceed ±10% of the nominal supply voltage.
Pollution Degree II
Installation (overvoltage) Category II for transient overvoltages
Maximum Relative Humidity: <80% RH, non-condensing
Operating temperature range of 0°C to 40°C
Storage and transportation temperature of -40°C to 70°C
Maximum altitude of 3000m (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.
Caution:
Refer to
manual
Caution:
Risk of Electric
Shock
Earth Ground
Terminal
Protective
Conductor
Terminal
On: In position of push control.
The (I) denotes that the mains
are on.
Alternating
Current
Caution:
Hot Surface
Of: Out position of push control.
The (O) denotes that the mains
are on.
Visible and/or
invisible laser
radiation
Frame or
Chassis
Terminal
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Warranty
ILX Lightwave warrants this instrument to be free from defects in material and workmanship for a period of one
year from the date of shipment. During the warranty period, ILX Lightwave will repair or replace the unit, at our
option, without charge.
Limitations
This warranty does not apply to fuses, lamps, defects cause by abuse, modifications, or 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 warranty of
merchantability or fitness for any particular purpose. ILX Lightwave shall not be liable for an incidental, special, or
consequential damages.
If a problem occurs, please contact ILX Lightwave 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 Material Authorization number (RMA) from ILX Lightwave Customer Service.
2. Attach a tag to the instrument identifying the owner and indicating the required service or repair. Include
the instrument serial number from the rear panel of the instrument.
3. Attach the anti-static protective caps that were shipped with the instrument and place the instrument in a
protective anti-static bag.
4. Place the instrument in the original packing container with at least 3 inches (7.5cm) of compressible
packaging material. Shipping damage is not covered by this warranty.
5. Secure the packing box with fiber reinforced strapping tape or metal bands.
6. Send the instrument, transportation pre-paid, to ILX Lightwave. Clearly write the Return Material
Authorization number on the outside of the box and on the shipping paperwork. ILX Lightwave
recommends the shipment be insured.
If the original shipping container is not available, place the instrument in a container with at least 3 inches
(7.5cm) of compressible packaging material on all sides.
Repairs are made and the instrument returned transportation pre-paid. Repairs are warranted for the
remainder of the original warranty or for 90 days, whichever is greater.
Claims for Shipping Damage
Upon receiving the instrument, inspect it immediately for any damage or shortages on the packing list. If the
instrument is damaged, file a claim with the carrier. The factory will supply a quotation for estimated costs of
repair. The customer is responsible for negotiation and settlement with the carrier for the amount of damage.
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Comments, Suggestions, and Problems
To ensure getting the most out of ILX Lightwave products, direct any product operation, service related
questions, or comments to ILX Lightwave Customer Support. Contact ILX Lightwave in whatever way is most
convenient:
Phone (800) 459-9459 or (406) 586-1244
Fax (406) 586-9405
Email sales@ilxlightwave.com
Mailing Address:
ILX Lightwave
31950 Frontage Road
Bozeman, Montana, USA 59715
When contacting ILX Lightwave, please have the following information:
Model Number
Serial Number
End-User Name
Company
Phone Number
Email Address
Description of the problem
If ILX Lightwave determines that a return to the factory is necessary, a Return Material Authorization (RMA) will
be issued. Please mark this number on the outside of the shipping box.
The customer or carrier is responsible for any shipping damage when returning an instrument to ILX Lightwave.
ILX Lightwave recommends insuring the shipment. If the original shipping container is not available, place the
instrument in a container with at least 3 inches (7.5cm) of compressible packaging material on all sides.
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Chapter 1 :
Introduction and Specifications
This chapter is an introduction to the LDX-3232 High Compliance Current Source:
Setup Information
Safety Considerations
Maintenance Information
Instrument Specifications
If any of the following symptoms exist, or are even suspected, remove the LDX-3232 from service. Do not
use the LDX-3232 until trained service personnel can verify safe operation.
-
Visible damage
-
Severe transport stress
-
Prolonged storage under adverse conditions
-
Failure to perform intended measurements or functions
If necessary, return the LDX-3232 to ILX Lightwave for service and repair to ensure that safety features are
maintained.
Product Overview
The LDX-3232 instrument is a high compliance voltage laser diode current source. The LDX-3232 current
source provides a high stability output with multiple laser protection features and a fully redundant current
limit. The LDX-3232 offers the added benefits of dual laser interlocks and a GPIB interface to allow full
automation of testing.
Initial Inspection
Upon receiving the LDX-3232 instrument, verify that the following items were shipped with the instrument:
LDX-3232 High Compliance Current Source
USB Flash Drive containing LDX-3232 User Manual
Power Cord
Shipping Kit
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Installing the LDX-3232 High Compliance Current Source
Grounding Requirements
The LDX-3232 High Compliance Current Source comes with a three conductor AC power cable. The
power cable must either be plugged into an approved three-contact electrical outlet or used with a threecontact or two-contact adapter with the grounding wire connected to an electrical ground (safety ground).
The LDX-3232's power jack and supplied power cable meet IEC safety standards.
AC Line Power Requirements
The LDX-3232 instrument can be operated from a single phase power source delivering nominal line
voltages of 100, 120, or 220-240 VAC (all values RMS), at 50/60 Hz. The line power voltage can vary
±10% but cannot exceed 250 VAC. Maximum power consumption is 60 VA (Volt-Amps). Setting operating
voltage can only be done at the factory. Before operating the instrument, verify that the voltage indicated
on the back panel of the instrument matches the power-line voltage used in the operating environment.
Before connecting the LDX-3232 High Compliance Current Source to a power source, verify that the AC
power source matches the setting of the LDX-3232's voltage printed on the rear panel of the instrument.
To avoid electrical shock hazard, connect the instrument to properly earth-grounded, 3-prong receptacles
only. Failure to observe this precaution can result in severe injury or death.
GPIB Connector
The IEEE 488 GPIB interface connector is located on the rear panel, directly above the power input
module and fuse (See Figure 1.2). Attach the GPIB cable to the 24-pin connector located on the rear
panel. The connector is tapered to ensure proper orientation. The two screws on the cable connector need
only be finger tightened.
A total of 15 devices can be connected together on the same GPIB interface bus. The cables have single
male/female connectors on each end so that several cables can be stacked. This allows more than one
cable to be attached to any one device. However, the maximum length of the GPIB cables must not
exceed 20 meters (65 feet) total or 2 meters (6.5 feet) per device.
The GPIB Address
The talk and listen addresses on the LDX-3232 High Compliance Current Source are identical. This GPIB
address is read locally by pressing the (GPIB) LOCAL button with the address displayed on the LED
display. The instrument comes from the factory configured with the GPIB address set to 1. The LDX-3232's
GPIB address can be changed locally (via front panel). A procedure for changing the address can be found
in the section Changing the GPIB Address in Chapter 3.
Tilt-Foot Adjustment
The LDX-3232 High Compliance Current Source comes standard with folding front legs and two rear feet
for use as a bench top instrument. Extending the front feet so that the instrument front panel sits up makes
it easier to view the LED displays. To use them, place the unit on a stable base and rotate the front legs
downward until they lock into position.
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Operating the LDX-3232 Precision Current Source
The following photos show the functional keypad groupings, back panel connectors, and so on. Use these
figures to become familiar with the LDX-3232. After that, use Chapter 2 for fundamentals of instrument
operation.
Figure 1.1 LDX-3232 Front View
Figure 1.2 LDX-3232 Rear View
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Specifications
Table 1.1 Specifications
2000mA Range 4000mA Range
Output Current Range 0 to 2000 mA 0 to 4000 mA
Setpoint Resolution
Setpoint Accuracy ±0.15% of SP +2 mA
Compliance Voltage 0 - 15 V, adjustable
Temperature Coefficient <100 ppm/°C
Short Term Stability (1 hour)
Long Term Stability (24 hours)
Noise and Ripple (µA rms)
High Bandwidth Mode
Low Bandwidth Mode
Transients
Operational
1 kV EFT/Surge
Range 0 - 15 V
Resolution 60 mV
Accuracy ±2.5%
Range 1 to 2020 mA 1 to 4040 mA
Resolution 10 mA 20 mA
Accuracy ±20 mA ±40 mA
Type Differential
PD Reverse Bias 0 - 5V, adjustable
PD Current Range 5 to 10,000 µA
Output Stability
Accuracy, setpoint (% of FS) ±0.05%
Input
Transfer Function 200 mA / V 400 mA / V
Bandwidth (3 dB)
High Bandwidth Low Bandwidth
Drive Current Output
2
3
4
5
40 µA 80 µA
<20 ppm
<40 ppm
<20 µA
<20 µA
1
<40 µA
<20 µA
6
7
8
9
<4 mA
<8 mA
Compliance Voltage Adjust
Drive Current Limit Settings
Photodiode Feedback
±0.02%
External Analog Modulation
0 - 10 V, 1 k
DC to 250 kHz
DC to 10 kHz
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Trigger Output
Type TTL
Pulse Width 13 µs
Delay 12 ms
Measurement (Display)
Output Current Range 0 to 2000.0 mA 0 to 4000.0 mA
Output Current Resolution10
0.1 mA
Photodiode Current Range 0 to 10,000 µA
Photodiode Current Resolution 1 µA
Photodiode Current Accuracy ±4 µA
PD Responsivity Range11
0.00 to 1000.00 µA/mW
PD Responsivity Resolution 0.01 µA/mW
Optical Power Range 0.00 to 5000.0 mW
Optical Power Resolution 0.1 mW
Forward Voltage Range 0.000 to 10.000 V
Forward Voltage Resolution 1 mV
Forward Voltage Accuracy12
±2 mV
General
Size (H x W x D) 4” x 8.5” x 13.4”; 102 mm x 216 mm x 340 mm
Weight ~ 20 pounds (9 kg)
Power 100/120/230-240 V~; 2/2/1A 50/60 Hz
Temperature 0°C – 40°C operating; -40°C – 70°C storage
Humidity < 90% relative humidity, non-condensing
Laser Safety Features Key switch, interlock and output delay (meets CDRH US
21 CFR 1040.10)
Display Type 5-digit, green LED
Notes
1.
All values relate to a one-hour warm-up period at room temperature, 25°C.
2.
Based on resolution of digital-to-analog converters used in the design.
3.
Over any 1-hour period, half-scale output.
4.
Over any 24-hour period, half-scale output.
5.
Measured electrically with a 1 ohm load at half-scale output; evaluating spectral noise density over a 150kHz bandwidth from 125kHz to 275 kHz.
6.
Maximum output current transient from normal operational situations (e.g., power on-off, current on-off), as well as accidental situations (e.g., power line
plug removal).
7.
Maximum output current transient resulting from a 1000 V power-line transient spike. Tested to ILX Lightwave Technical Standard #LDX-00196.
8.
Maximum monitor photodiode current drift over any 30 minute period. Assumes zero drift in responsivity of photodiode.
9.
50% modulation at mid-scale output. Higher bandwidth is possible with smaller magnitude modulation signal.
10.
Similar resolution available over GPIB.
11.
Responsivity value is user-defined and is used to calculate the optical power.
12.
Four wire voltage measured at the load. Voltage measurement accuracy while driving calibration load. Accuracy is dependent upon load and cable used.
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Available Options and Accessories
Options and accessories available for the LDX-3232 High Compliance Current Source include the
following:
Table 1.2 Accessories List
DESCRIPTION MODEL NUMBER
Low Noise CW Filter, 9-pin DSUB LNF-320
Driver to Mount Cable, 5 Amp, DB9 Male to DB9 Male CC-305S
Driver to Unterminated Cable, 5 Amp, DB9 Male to Bare Wire CC-306S
Laser Diode Mount, 14-pin DIL LDM-4982
Laser Diode Mount, 14-pin Butterfly LDM-4894
Laser Diode Mount, Requires Mounting Kit, High Power LDM-4442
Single Rack Mount Kit, LDX-3200 Series & LDT-5900 Series RM-139
Dual Rack Mount Kit, LDX-3200 Series & LDT-5900 Series RM-140
Please contact ILX Lightwave or visit www.newport.com/ilxlightwave for information on additional options for
applications.
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Chapter 2 :
Operation
This chapter introduces the operation of the LDX-3232 High Compliance Current Source. It
offers instructions for connecting a laser diode to the current source and describes powering up
the instrument. This chapter also includes:
Operation Procedures
Interlock Information
Applying Power to the LDX-3232
To turn on the LDX-3232, rotate the key in the POWER section of the front
panel from O to I. This action will initiate the power on sequence. If the LDX3232 does not appear to turn on, verify that it is connected to line power. If
line power is not the problem, remove the power cord and check the voltage
selection block in addition to the line power fuse.
The Power On Sequence
During the power-up sequence, the following takes place:
For about three seconds all indicators are lit up; all of the 7-segment displays indicate 8.
All indicator lights are turned off for three seconds.
Firmware version will be displayed.
Instrument performs a communications self-test between the hardware and processor.
After this test, the instrument is ready to operate and is configured to the state it was in
when the power was last shut off.
Connecting to the Laser
When connecting a laser to the LDX-3232, it is recommended that the instrument be powered
up with the output off. In this condition, a low impedance shunt is active across the output
terminals. When disconnecting devices, it is only necessary to turn the current source output off.
It is also recommended that the connections to the LDX-3232 output be made using twisted wire
pairs with an earth-grounded shield (see Figures 2.1 - 2.4). The output terminals of the
instrument are left floating relative to earth ground to suppress AC power-on/power-off
transients that may occur through an earth- ground path. If the output circuit is earth-grounded
at some point (such as through the laser package and mount), the user must be careful to avoid
multiple earth grounds in the circuit. Multiple earth grounds may provide circuit paths that induce
spurious currents in the photodiode feedback circuit and output leads.
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Note: Cable connections to the laser must be secure. Loose connections can cause
momentary open circuits that can damage the laser.
Figures 2.1 – 2.4 show the possible configurations of connecting laser diodes and photodiodes
with the LDX-3232 High Compliance Laser Current Source.
Figure 2.1 Common Laser Cathode & Photodiode Cathode
Figure 2.2 Common Laser Cathode & Photodiode Anode
Figure 2.3 Common Laser Anode & Photodiode Cathode
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Figure 2.4 Common Laser Anode & Photodiode Anode
The 9-pin connector marked CURRENT SOURCE on the back panel is used to connect the
laser diode to the LDX-3232. There are connections provided for laser cathode and anode,
photodiode cathode and anode, chassis ground and interlock. The pinout diagram for this
connector is shown in Figure 2.5.
Figure 2.5 Back Panel LD Connector
Interlock Connections
In order for the laser output to be enabled a short circuit must exist between the Interlock Pins
(Pins 1 and 2) of the connector. The short can be a direct short across the pins or a switch to
prevent laser operation until the switch is closed. If a short does not exist between these two
pins, the INTERLOCK LED will illuminate on the front panel and the laser output will be
disabled.
Note: The BNC Interlock Connection from the BNC connector on the rear panel will also
make the INTERLOCK LED illuminate. Please see the notes in chapter 5 on use of the
BNC interlock connection to learn more about its operation.
The interlock terminals on the LASER connector, pins 1 and 2, must be kept isolated
from all other connections including earth ground.
Photodiode Connections
Many laser diode modules contain an internal photodiode that monitors the back- facet emission
of the laser. Usually, this photodiode is internally connected to either the laser anode or
cathode.
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The photodiode and laser connections to the LDX-3232 are electrically isolated from ground and
each other. If a 4 pin connection is made (no common connections), no additional jumpers are
required. Figures 2.1 - 2.4 show the recommended connections and shielding for 3-pin lasers
(where the common connection is internal to the device). A 4-pin laser should be connected with
the same shielding as shown in Figure 2.1, but the common connection (between the
photodiode and the laser) is optional.
Setting the PD Bias
The LDX-3232 provides an adjustable reverse bias of 0-5 VDC for the photodiode. To set the
photodiode bias to 5 V reverse bias, turn the back panel PD BIAS ADJUST fully clockwise. To
set the photodiode bias to 0 V reverse bias, turn the back panel PD BIAS ADJUST fully counterclockwise.
Grounding Considerations
The LASER outputs of the LDX-3232 High Compliance Current Source are isolated from
chassis ground, allowing either output terminal to be grounded at the user's option. Figures 2.1 -
2.4 show the proper earth-ground shielding for laser diode/photodiode connections.
Front Panel Operation
Figure 2.6 LDX-3232 Front Panel
This section describes fundamentals of operation for the LDX-3232 in the two operating modes:
Constant Current (I) and Constant Power (P).
The Display
The digital display is used to show control parameters such as laser drive current (mA), laser
current limit (mA), laser forward voltage (V), voltage limit (V), monitor photodiode current (µA),
and laser optical power (mW) in both set point and measurement modes. It will also display
error codes that relate to LASER operation. Error indicators underneath the display indicate
control errors and are explained in the section titled “ERROR INDICATORS”. All laser control
parameters are displayed on this digital display with the appropriate annunciator illuminated.
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