Wavelength electronics Qcl500 lab User manual

USER GUIDE

Low-Noise QCL Driver — Laboratory Series1

Firmware versions 1.5 and later operate with the

LabVIEW Virtual Instrument application and the Remote Command Set

ORDERING INFORMATION

PART NO DESCRIPTION

QCL500 LAB 500 mA Low Noise QCL Instrument

QCL1000 LAB 1.0 A Low Noise QCL Instrument

QCL1500 LAB 1.5 A Low Noise QCL Instrument

QCL2000 LAB 2.0 A Low Noise QCL Instrument

NOISESCAN Noise Characterization Scan

55-110014 SMA-BNC Cable

55-110015 USB Cable

WCB310 Shielded SMA-SMA Cable

QCLTL-LO Resistive Test Load for QCL500 or

QCL1000

QCLTL-1500 Resistive Test Load for QCL1500

QCLTL-2000 Resistive Test Load for QCL2000

RCKMT-LABSNGL 19” Single Unit Rack Mount Kit

RCKMT-LABDUAL 19” Double Unit Rack Mount Kit

INTLK REPL KIT

(included with purchase)

Interlock Replacement Kit with BNC

terminator and modied D-SUB

connector to override interlocks

RoHS

Compliant

Applies to Product Revision A,

rmware 1.5 and later

1Covered by U.S. Patents 6,696,887; 6,867,644 and 7,176,755. Licensed from Battelle Memorial Institute

The datasheet for the QCL LAB Series Firmware Version 0.79 (compatible with the QuickConnect Application) is located at:

www.teamwavelength.com/download/datasheets/qcl-lab079.pdf

QCL

TABLE OF CONTENTS

GENERAL OVERVIEW 2

SAFETY 3

QUICK CONNECT GUIDE 4

PIN DESCRIPTIONS 6

ELECTRICAL SPECIFICATIONS 7

OPERATING INSTRUCTIONS

(STAND-ALONE) 9

REMOTE OPERATING INSTRUCTIONS 16

TROUBLESHOOTING 17

ADDITIONAL TECHNICAL NOTES 20

MECHANICAL SPECIFICATIONS 22

CE DECLARATION OF CONFORMITY 23

WARRANTY & CERTIFICATION 24

PAGE

• Output currents of 500 mA, 1 A, 1.5 A, 2 A

• Low noise: <0.4 μA RMS up to 100 kHz

(QCL500, typical)

• Compliance voltage is adjustable, 10 to 20 V

(NOTE: The unit will only deliver the voltage

that the load requires, up to the compliance

voltage limit.)

• Analog modulation up to 2-3 MHz

• Analog modulation input between

-5V and +5V

• Constant Current Mode operation

• Touchscreen with intuitive user interface

• CE compliant, compatible with CDRH laser

regulations

• Feature-rich for research projects

»USB and Ethernet interfaces with software

included

»Auto voltage/current scan function

»Data collection using a computer or USB

ash drive

»Field upgradeable rmware

»Sophisticated error handling

»Save and recall functions for specic set

ups

• Rack mountable: 2 U height and ½ rack width

• Safety features protect your QCL investment

»Adjustable soft-clamp current limit, with

Brick-Wall Never-Exceed circuitry

»Password protection available to lock out a

selectable control set

»Keyswitch, active, and passive interlocks

»Brown-out & overvoltage protection

»Power supply overcurrent protection

»Driver over-temperature protection circuit

»Relay shorts output when current is

disabled

»AC input and patented power supply

ltering

»2 second turn-on delay — adjustable

»1.5 msec current ramp

F E A T U R E S

GENERAL OVERVIEW

THE LOWEST-NOISE DRIVER

AVAILABLE

These low noise QCL instruments have the lowest current

noise density of any commercially available. Powering your

QCL with this patented1driver gives you narrow linewidth,

stable center wavelength, and repeatable scans.

INTUITIVE USER INTERFACE AND

SUPERIOR SOFTWARE CONTROL

With Wavelength’s plug and play instrument, you have the

ability to quickly set the controls using either the instrument or

a remote computer.

PROTECT YOUR QCL INVESTMENT

All the essential control and monitor functions you expect in a

Wavelength laser driver are incorporated into this instrument,

along with protection circuitry to safeguard your QCL from

minor power source faults, over-temperature conditions, and

electrical faults.

The soft-clamping current limit can be set without enabling the

driver output, and uses a brick-wall never-exceed limit circuit

to protect the QCL from potentially damaging overcurrent

situations.

OEM VERSION AVAILABLE

Once you have nalized your work, the QCL circuitry is

available in compact OEM versions.

APPLICATIONS

Due to their unique construction, QCLs operate with high

power in the near-IR through terahertz ranges. These

wavelengths are particularly suited to detection of molecules

signicant to humans.

Applications for the lower noise QCL driver include: remote

detection of explosive materials, medical diagnosis using the

breath, non-invasive glucose testing, emissions monitoring of

the atmosphere or marine environments, and pharmaceutical

process quality control. Additional applications include

anesthesia and hospital air quality monitoring, leak detection,

and remote imaging.

1Covered by U.S. Patents 6,696,887; 6,867,644 and

7,176,755. Licensed from Battelle Memorial Institute

SAFETY

DEFINITIONS

CHASSIS GROUND Symbol

CAUTION: A condition that has the potential to

cause damage to property or instrument.

WARNING: A condition that has the potential to

cause bodily harm or death.

GENERAL

• Observe all Cautions and Warnings both in the User

Guide and on the instrument.

• Use the QCL instrument as specied in this guide or the

protection provided by this instrument may be impaired

and the warranty will be voided.

• Use good laser safety practices when using the QCL

instrument.

• Before proceeding, it is critical that you take precautions

to prevent electrostatic discharge (ESD) damage to your

laser.

• Locking the instrument with the keyswitch disables the

output current. The key can only be removed when in the

LOCK position.

POWER CORDS

• This equipment is grounded through the AC power cord

grounding conductor.

• Use only the earth-grounded power cords that are

recommended in this user guide.

• Route power cords and other cables so that they cannot

be damaged.

• Position the QCL instrument in a location that makes it

easy to quickly disconnect the power cord.

• To avoid re hazard, use only the specied power cords

with the correct grounding, voltage, and current ratings.

FUSES

• Disconnect the power to the QCL instrument before

changing the fuses.

• To prevent damage to the QCL instrument when replacing

fuses, locate and correct the problem that caused the fuse

to blow before re-applying power.

• To avoid re hazard, use only the specied fuse with the

correct type number, voltage, and current ratings, and use

only the recommended replacement parts.

CAUTIONS

The QCL instrument has no user-serviceable parts.

Other than the fuses, the QCL instrument is not

designed to be maintained by the user nor does it

contain any parts that can be repaired by the user.

All maintenance and repairs must be performed by

Wavelength or the warranty will be void.

Use a soft cloth to remove dust from the QCL

instrument. Do not expose the QCL instrument to

any liquids, sprays, or solvents. To avoid electrical

shock, unplug the power cord before cleaning the

instrument.

Before connecting to the power source, make sure

the correct cables and voltage for your area are

set. The voltage selection is available on the back

of the instrument. See the Quick Start Guide for

instructions on changing the voltage.

WARNINGS

Position the QCL instrument so that access to the

Main Power On/O󰀨 switch on the back panel is

easily accessed.

Do not use the QCL instrument if there is evidence

of damage from shipping; damaged equipment

can present signicant safety hazards. If you

suspect the QCL instrument is damaged, contact

Wavelength technical support before attempting to

operate the instrument.

To avoid electrical shock, use the recommended

earth-grounded power cables and properly earth-

grounded, 3-prong receptacles only. Failure to

follow this precaution can result in severe injury.

To avoid injury, do not tell the engineers how to

do their jobs. Let them muddle through until they

decide to read the User Guide.

QUICK CONNECT GUIDE

INSTALL FUSE & SELECT VOLTAGE

Figure 1. Fuse Box and Voltage Selector

1. On the back panel, locate the Fuse Box and Voltage

Selector receptacle. (See the Rear Panel diagram on

page 10 for the location.)

2. Insert a small athead screwdriver into the slot (1) at the

top of the receptacle and twist to open faceplate. The red

fuse drawer and fuses are located in the Ship Kit.

3. On the face of the fuse drawer are two voltage choices.

Based on your country, select the proper fuses to install.

VOLTAGE FUSE PART NUMBER

100-120 V 1.25 A, 250 V,

fast blow

Littelfuse 5 x 20 mm,

Part #02351.25HXP

220-240 V 0.63 A, 250 V,

fast blow

Littelfuse 5 x 20 mm,

Part #0217.630MXP

CAUTION: It is imperative that the correct voltage

is used. Serious damage can occur if the incorrect

voltage is selected.

4. Insert the fuses as shown in Figure 2, with a short fuse at

the contact end of the receptacle. Then, turn the drawer

until the correct voltage label is at the top and replace it

in the receptacle. Press rmly to make sure the drawer is

completely seated. It should be ush with the receptacle.

Figure 2. Fuse Installation and Voltage Selector

5. Close the faceplate, again pressing rmly until it is ush.

The correct voltage label is shown through the Voltage

Window (2) on the faceplate.

WIRE A TEST LOAD

Use of a test load is recommended for setup of the QCL

instrument. Use the Wavelength test loads listed on page 1, or

when building your own test load, a 10 Ω resistor with a 50 W

power rating is recommended for the QCL500, QCL1000,

and QCL1500. For the QCL2000, a 50 W 5 Ω resistor is

recommended.

• Install the test load by either connecting to the QCL SMA

port or wiring the load to PIN 5 and PIN 9 on the QCL

D-SUB as shown in Figure 3.

QCL

SMA QCL

1 NOTE: The SMA case is electrically connected to the QCL chassis.

QCL D-SUB

6789

12345

Figure 3. QCL Wiring Diagram

-V

Pin 9 QCL +

or SMA Outer Ring

Pin 5 QCL -

or SMA Center Pin

QCL Driver

Current Sink

QCL

Figure 4. QCL Polarity Diagram

SETUP INTERLOCKS

The Wavelength Interlock Replacement Kit includes a male

D-SUB with the passive interlock pins shorted and a BNC

terminator.

1. For the passive interlock, on the back panel, short PIN 1

and PIN 2 on the QCL D-SUB.

2. For the active interlock, on the back panel, insert a BNC

terminator in the ACTIVE LOCK BNC port.

3. On the front panel, the keyswitch must be on UNLOCK to

enable the current to the QCL.

TURN ON POWER

1. On the back panel, press the power switch to the |. The

front panel power button light pulses slowly.

2. On the front panel, press the Power button. The button

illuminates, the touchscreen activates, and the Control

screen is active.

3. The front panel displays dashes instead of digits until the

unit has nished its power-up sequence (~10 seconds).

SET LIMITS

1. Press to access the Limit Screen.

2. On the Limit screen, press the blue Limit Current value

and rotate the Adjustment knob to change to the desired

value. The instrument will beep when set.

NOTE: The Max Supply Voltage and Cable Resistance values

can be ignored for now.

ADJUST SETPOINT

1. Press to access the Control Screen.

2. Press the Setpoint current value and turn the Adjustment

knob to change it. The instrument will beep when set.

ENABLE CURRENT

Press the ENABLE button. There is a standard 2-second

delay before the button illuminates and the current ows.

SHUTDOWN THE INSTRUMENT

If the Enable button is illuminated, current is still owing to

the test load. Before shutting down, the current needs to be

turned o󰀨.

1. Press the Enable button. The button light will turn o󰀨 and

current to the QCL test load will stop.

2. On the front panel, press the Power button. The

touchscreen will go black but the button light slowly

pulses blue to indicate that the back Power button is still

on. NOTE: Turning o󰀨 only the front Power button puts

the instrument in Standby mode.

3. On the back panel, press the power switch to O.

PIN DESCRIPTIONS

QCL D-SUB

Figure 5. Female 9-Pin D-SUB

Table 1. QCL D-SUB Pin-Out

PIN DESCRIPTION

1, 2 Passive interlock pins (must be shorted to enable

current)

3 Chassis ground

4 Not used

5 * QCL- (negative)

6 Not used

7 Not used

8 Not used

9 * QCL+ (positive)

SHELL Chassis ground

* NOTE: Use Pins 5 and 9 for current to the QCL.

QCL SMA

QCL- (negative)

QCL+ (ground)

Figure 6. SMA Pin-Out

QCL POLARITY

-V

Pin 9 QCL +

or SMA Outer Ring

Pin 5 QCL -

or SMA Center Pin

QCL Driver

Current Sink

QCL

Figure 7. QCL Polarity Diagram

MONITOR D-SUB

Figure 8. Male 9-Pin D-SUB

Table 2. Monitor D-SUB Pin-Out

PIN DESCRIPTION

1 Alignment LED (+5 V) can source 250 mA

2 Alignment LED ground

3 QCL current enabled indicator (+5 V TTL)

high = disabled

low, ground = enabled

4 QCL current enabled indicator ground

5 Not used

6 Analog setpoint monitor

7 Analog monitor ground

8 Analog output current monitor

9 Analog monitor ground

BNC PINS

ACTIVE SIGNAL

GROUND

Figure 9. BNC Pins

TRANSFER FUNCTIONS BY MODEL

External modulation input, setpoint monitor, and analog

current monitor transfer functions:

QCL500 LAB: 0.1 A / V.

QCL1000 LAB: 0.2 A / V.

QCL1500 LAB: 0.3 A / V.

QCL2000 LAB: 0.4 A / V.

The input range is always -5 V to +5 V.

ACTIVE INTERLOCK BNC

Ground the center pin to the outer shell to override the interlock

and allow the current to ow to the QCL. If an external circuit

won’t be used, a 50 Ω or 75 Ω terminator is acceptable.

TRIGGER BNC

See Additional Capabilities on page 16.

ELECTRICAL SPECIFICATIONS

DRIVER OUTPUT CURRENT MIN TYP MAX UNITS NOTES

Output Current 0.5, 1.0, 1.5, or 2.0 A

RMS Noise Current 0.4 1.0 1.3 μA RMS QCL1000 at 500 mA output, 100 kHz test bandwidth

Noise Current Density 1 2 4 nA / √Hz QCL1000 at 500 mA, 10 Ω test load

Stability, short and long term 5 10 15 ppm 25°C ambient

Temperature Coe󰀩cient 5 10 18 ppm / °C

Compliance Voltage Range 10 20 V

Internal Supply Voltage can be adjusted from the front

panel.

NOTE: With this current source, the voltage developed

across the load (laser) is not driven by the controller,

but by Ohm’s Law and the resistance of the load

(laser).

Slow Start Current Ramp (after

Enabled) 1.5 msec To setpoint

Delayed Start 2 sec User adjustable

EXTERNAL MODULATION MIN TYP MAX UNITS NOTES

Modulation Bandwidth 2 3 MHz Sinewave

Rise/Fall Time 250 / 200 nsec To full scale

Slew Rate 30 V / µsec

Depth of Modulation 90 % At 500 kHz

External Modulation Input

Range -5 to +5 V

Input Impedance 1 kΩ

External Modulation Input

Damage Threshold -10 to +10 V BNC Connector

MONITORS AND OUTPUTS VALUE UNIT NOTES

Setpoint Resolution 16 bits 5V = fullscale output

Display Accuracy Measurement

Resolution 24 Bits

Accuracy, Current Output

Monitor vs. Actual Current

(display or analog output)

0.2 % > 5% of full scale

0.5 % < 5% of full scale

Accuracy, Current Setpoint vs.

Actual Current

0.2 % Internal setpoint

0.2 % External modulation

Accuracy, Analog Setpoint

Monitor1

5 % >10% of full scale

25 % <10% of full scale

1Current Setpoint Monitor is a reference signal only, and may deviate from the actual setpoint by up to 5% when the setpoint is greater

than 10% of full scale.

CONTINUED ON FOLLOWING PAGE

POWER SUPPLY

REQUIREMENTS VALUE NOTES

AC Power Supply and Line

Frequency 100-120 / 220-240 VAC, 2 A, 50-60 Hz Switch selectable: 100-120 V and 220-240 V,

appropriate power cord supplied

Fuse for 220-240 V 0.63 A, 250 V, fast blow 5 × 20 mm, Part #0217.630MXP, Littelfuse

Fuse for 100-120 V 1.25 A, 250 V, fast blow 5 × 20 mm, Part #02351.25HXP, Littelfuse

Power Consumption 9.8 Watts At idle, no output to QCL load

GENERAL SPECIFICATIONS VALUE NOTES

Warm-up Time 1 Hour

Remote Interface USB, Ethernet

Warranty One (1) Year

Safety Tested To

IEC 61000-3-2

IEC 61000-3-3

IEC 61000-4-2

IEC 61000-4-3

IEC 61000-4-4

IEC 61000-4-5

IEC 61000-4-6

IEC 61000-4-8

IEC 61010-1

European Council Directive 2004/108/EC &

European Council Directive 2006/95/EC

ABSOLUTE MAXIMUM

RATINGS VALUE UNIT NOTES

Case Operating Temperature

Range -40 to 50 °C

Humidity 80 % Relative humidity at 30°C (non-condensing)

Weight 12 (~5.4) lbs (kg)

Size 3.47 × 8.86 × 17.72

(89 × 226 × 450)

inches3

(mm3)

OPERATING INSTRUCTIONS (STAND-ALONE)

WHAT’S IN THE BOX

• QCL Instrument

• Power Cable, type appropriate for nal location

• Red fuse tray

• Two 0.63 A fuses and two 1.25 A fuses for fuse box on the

back panel

• USB Flash Drive, includes all necessary software,

instrument documentation, and additional storage space

• Keys for the keyswitch

• Interlock Replacement Kit (interlocks for QCL D-SUB and

Active Interlock BNC)

THEORY OF OPERATION

The QCL Series low noise drivers are designed expressly to

drive quantum cascade lasers, and utilize patented1circuitry

to deliver ultra-low noise current and still maintain a wide

modulation bandwidth.

The QCL drivers are controlled current sources; they deliver

the current commanded by the setpoint. The current source

continually monitors the actual output current, compares it to

the setpoint, and adjusts the current if there is a di󰀨erence

between the two signals.

As current is driven through the load, there is a voltage drop

across the load proportional to the load resistance and current.

As the current increases, the voltage drop may increase to

the point that it reaches the Compliance Voltage limit of the

current source. Once that occurs the current source is no

longer able to increase the current driven to the load even if

you increase the setpoint.

The QCL driver includes features that help protect your laser,

and also make the driver more versatile in a wide array of

applications. These features are explained in detail in the

Operating Instructions.

• The user-adjustable current limit prevents overdriving the

laser even if the external modulation signal is above the

maximum drive current for the laser.

• Over- and under-voltage protection circuits protect the

driver and QCL if the power supply voltages fall outside of

the acceptable operating range.

• Over-temperature protection circuits safely shut down

the output if the internal temperature of the QCL driver

rises to an unsafe level. The fan turns on to manage the

internal temperature.

• Output slow-start ramps the current to setpoint over

1.5 msec.

• A mechanical relay shorts the output connections when

the output is disabled, and when the QCL driver is

powered o󰀨.

1Covered by U.S. Patents 6,696,887; 6,867,644 and

7,176,755. Licensed from Battelle Memorial Institute.

The External Modulation Input can be used for adding to

or subtracting from the internal setpoint on the QCL LAB

Instrument. Inputting positive voltages will result in adding

to the setpoint, while inputting negative voltages will result in

subtracting from the setpoint.

These instructions are for operating the QCL Laboratory

Series instrument. Fuses are provided but not installed. After

installing the fuses in the fuse box, be sure to install the fuse

box so the correct voltage for your country is showing. We

also recommend using a test load until you are familiar with

operation of the instrument.

REQUIRED AND OPTIONAL

EQUIPMENT

FOR SET UP

• Small, narrow headed athead screwdriver (required)

• Test load (optional)

• Wavelength Interlock Replacement Kit with interlock

overrides (optional)

COMPUTER REQUIREMENTS FOR

REMOTE OPERATION ONLY (OPTIONAL)

Operating System: Windows XP SP2 or later

Note: See page 16 for Remote Operation

ESD INFORMATION

Before proceeding, it is critical that you take precautions to

prevent electrostatic discharge (ESD) damage to the load.

ESD damage can result from improper handling of sensitive

electronics, and is easily preventable with simple precautions.

REAR PANEL

ETHERNETUSB

QCL

CHASSIS

GND QCL

MONITORS

SERIAL #

TRIGGEREXT

MOD

ACTIVE

LOCK

FUSE ~250V, 1.25AF (5 x 20mm)

100-120 VAC, 1.25 A, 50-60 Hz

WARNING: Before powering on

device, verify voltage setting is

correct and proper fuses are

installed.

CAUTION:

No user serviceable parts. Do

not remove cover.

Covered by U.S. Patents:

6,696,887

6,867,644

7,176,755

FUSE ~250V, 0.63AF (5 x 20mm)

220-240 VAC, 0.63 A, 50-60 Hz

35810

Figure 10. Rear Panel

Table 3. Rear Panel Functions

NAME DESCRIPTION

1 Fan Vent Do not block air ow.

2 Chassis Ground Physical connection to chassis and electrical earth ground.

3 QCL SMA SMA connector, alternate connection to QCL.

4 QCL D-SUB 9-Pin female D-SUB connector.

5 Monitors 9-Pin male D-SUB connector.

6 USB USB port, connection between instrument and a computer.

7 Ethernet Ethernet port, connection between instrument and a computer or network.

8 EXT MOD External Modulation: BNC connector, setpoint signal generator input.

9 Active Lock BNC connector, active interlock, tie center pin to GND to enable output.

10 Trigger BNC connector output, allows instrument to trigger external device for synchronizing

measurement.

11 Fuse Box and Voltage

Selector

Removable fuse drawer allows user to switch between 115 V and 230 V. Fuses need to be

installed prior to operation.

12 Power Switch AC power switch that powers the instrument.

13 Power Plug IEC AC line input.

INSTALL FUSES AND SELECT

PROPER VOLTAGE

Figure 11. Fuse Box and Voltage Selector

1. On the back panel, locate the Fuse Box and Voltage

Selector receptacle. (See the Rear Panel diagram on

page 10 for the location.)

2. Insert a small athead screwdriver into the slot (1) at the

top of the receptacle and twist to open faceplate. The red

fuse drawer and fuses are located in the Ship Kit.

3. On the face of the fuse drawer are two voltage choices.

Based on your country, select the proper fuses to install.

VOLTAGE FUSE PART NUMBER

100-120 V 1.25 A, 250 V,

fast blow

Littelfuse 5 x 20 mm,

Part #02351.25HXP

220-240 V 0.63 A, 250 V,

fast blow

Littelfuse 5 x 20 mm,

Part #0217.630MXP

CAUTION: It is imperative that the correct voltage

is used. Serious damage can occur if the incorrect

voltage is selected.

4. Insert the fuses as shown in Figure 12, with a short fuse

at the contact end of the receptacle. Then, turn the drawer

until the correct voltage label is at the top and replace it

in the receptacle. Press rmly to make sure the drawer is

completely seated. It should be ush with the receptacle.

Figure 12. Fuse Installation and Voltage Selector

5. Close the faceplate, again pressing rmly until it is ush.

The correct voltage label is shown through the Voltage

Window (2) on the faceplate.

CONNECT POWER

Insert the female end of the IEC AC power cord into the Power

receptacle on the back panel and then plug the male end into

the power source.

WIRE A TEST LOAD

Use of a test load is recommended for setup of the QCL

instrument. Use the Wavelength test loads listed on page 1, or

when building your own test load, a 10 Ω resistor with a 50 W

power rating is recommended for the QCL500, QCL1000,

and QCL1500. For the QCL2000, a 50 W 5 Ω resistor is

recommended.

• Install the test load by either connecting to the QCL SMA

port or wiring the load to PIN 5 and PIN 9 on the QCL

D-SUB as shown in Figure 13.

QCL

SMA QCL

1 NOTE: The SMA case is electrically connected to the QCL chassis.

QCL D-SUB

6789

12345

Figure 13. QCL Wiring Diagram

-V

Pin 9 QCL +

or SMA Outer Ring

Pin 5 QCL -

or SMA Center Pin

QCL Driver

Current Sink

Test Load

Figure 14. Test Load Polarity Diagram

SET UP INTERLOCKS

The Wavelength Interlock Replacement Kit includes a male

D-SUB with the passive interlock pins shorted and a BNC

terminator.

1. For the passive interlock, on the back panel, short PIN 1

and PIN 2 on the QCL D-SUB.

2. For the active interlock, on the back panel, insert a BNC

terminator in the ACTIVE LOCK BNC port.

3. On the front panel, the keyswitch must be on UNLOCK to

enable the current to the QCL.

NOTE: To disable operation, turn the keyswitch to the

LOCKED position. The key can only be removed when in the

locked position.

TEXT AND ICON COLOR KEY

TEXT

Text indicates current state.

White, Green Uneditable eld, for information only.

Blue Editable eld, touch to select or toggle eld

(text highlights and changes color), adjust

using either the touchscreen or adjustment

knob. Instrument beeps and text returns to

blue when values are set. Touch again to

cancel selection.

ICONS

Icon color indicates current state.

Blue Screen is active.

Grey Screen is inactive, touch icon to access that screen.

FRONT PANEL

QCL

000

LAB

ENABLE

DATA

POWER

Figure 15. Front Panel

Table 4. Front Panel Functions

NAME DESCRIPTION

1 Power Button Powers the application electronics. Glows blue when application electronics power is on and unit

is operational, slow pulses blue when on Standby and only the back panel power switch is on.

2 Adjustment Knob Turn to adjust the numeric values. Instrument beeps when values are set.

3 Enable Button Allows instrument to deliver current to the QCL. Glows blue when current is enabled.

4 Keylock Switch UNLOCK allows laser output current to ow, LOCK disables laser output current. NOTE: The

key can be removed only in LOCK position.

5 Data Port USB ash drive, used to update the rmware or save data. This is not used for remote USB

control of the instrument.

TURN ON QCL INSTRUMENT

1. Press the Power switch on the back panel to |. The front

panel power button light slowly pulses.

2. Press the Power button on the front panel, the button

illuminates, touchscreen is activated, and the Control

screen is active.

NOTE: Turning o󰀨 front Power button powers down the

application electronics and puts the unit into standby

mode. Turning o󰀨 rear Power switch powers down all

electronics and settings return to factory default.

3. The front panel displays dashes instead of digits until the

unit has nished its power-up sequence (~10 seconds).

SET LIMITS

1. Press to access the Limit Screen.

2. Press Limit Current, Maximum Supply Voltage, and/or

Cable Resistance values and rotate the Adjustment knob

to change each value. The instrument will beep when set.

Figure 16. Limit Screen

NOTES:

• The Limit Current should not exceed the damage current

threshold of your QCL.

• The Maximum Internal Supply Voltage can be lowered

to minimize internal instrument temperature or to act as a

compliance voltage clamp on the QCL output current. See

Additional Technical Notes on page 20 for optimization

instructions.

• The Cable Resistance range is 0 – 4 Ω.

QCL Voltage displays the voltage at the QCL DSUB or

SMA terminals. To account for voltage loss across the

cable to the QCL, you can enter a non-zero value for

Cable Resistance.

The QCL Voltage will now display as:

Voltage Displayed = Voltage@Pins - (Cable Resistance x Operating Current)

• The minimum limit current is about 8% of full scale.

ADJUST THE SETPOINT

1. Press to access the Control Screen.

2. Press the Setpoint value and turn the Adjustment knob

until the desired operating current is displayed.

Figure 17. Control Screen

NOTE: The Control screen is on by default when the

instrument is turned on. The Mode is Constant Current by

default and cannot be changed.

DISPLAY EXISTING CURRENT AND

VOLTAGE VALUES

Press to access the Monitor Screen.

Values on this screen cannot be changed and are for

information only.

Figure 18. Monitor Screen

ENABLE THE QCL INSTRUMENT

Press the Enable button on the front panel. The button will

glow blue only when current is delivered to the load. There is

a standard 2-second delay before the button illuminates and

current ows.

VI SCAN

1. On the Control screen, press to access the VI

scan screen.

2. Press the Current Start value to select the current at

which to start the scan. Turn the Adjustment knob to

change it.

Figure 19. Scan Screen

3. Press the Current Stop value to select the current at

which to stop the scan.

4. Press the Step Size value to select the current interval at

which to take a measurement. The maximum interval is

10% of full scale. Minimum step is 1% of full scale.

5. Press the Time Interval value to select the amount of time

to allow the current to settle. For the best data accuracy,

use a Time Interval of 2 seconds or more. The minimum

time interval is 0.1 seconds.

6. Insert the USB ash drive in the USB slot on the front

panel.

7. Press the green Run button to start the scan. When

nished, data is saved to the USB ash drive with

the lename viscanxx.txt, where xx starts at 00 and

increments.

8. To stop mid-scan, press the red Stop button to abort the

scan. Any data collected during the aborted scan is saved

to the USB ash drive.

NOTES:

• The step interval time is approximate. In the scan les,

time intervals are slightly more than the step interval

indicated on the instrument. Each interval builds on the

previous one.

• Should the Step Size interval not nish at the Stop Current,

the reading is still taken and recorded. For example,

if the Start Current is 250 mA and the Stop Current is

1.04 A with a Current Step of 250 mA, a reading is taken

at 1000 mA (1 A) and 1040 mA (1. 04 A) but not at 1250

mA (1.25 A).

• After a VI scan is completed, the output is disabled and

the setpoint is zeroed.

SAVE OR RECALL SETTINGS

Press to access the Save/Recall Screen.

Under Save Settings to, press the blue text

to toggle through the Prole options, select

one, and then press the Save icon.

The following variables are saved:

OPERATION SETTINGS VI SCAN SETTINGS

Setpoint VI Start Current

Current Limit VI Stop Current

Max Supply Voltage VI Step Size

Cable Resistance VI Time Interval

Display Brightness

Beeper Status

Figure 20. Save / Recall Screen

Under Recall Settings from, press the

blue text to toggle through the saved Prole

options, and then press the Recall icon to

recall the saved settings. Select Factory to

restore the settings to the factory defaults.

SETTINGS SCREEN

Press to access the Settings Screen

Move the slider bar on the touchscreen to change the display

brightness. Press the blue text to toggle the Beeper on-o󰀨

setting.

Figure 21. Settings Screen

LOCK OR UNLOCK SETTINGS

(OPTIONAL)

Settings are not locked.

This is the default. Critical values set with the

Adjustment knob can be locked. Press to lock

the settings.

Settings are locked.

Press to unlock the settings.

Settings are locked and password protected.

Locked settings that are password protected

can only be locked and unlocked using a remote

computer.

EXTERNAL MODULATION

(EXT MOD) BNC

This is the external modulation input. The voltage input on

this BNC sums with the DC value on the screen. The input

impedance is 1 kΩ. To calculate the external modulation

signal voltage, see the next section for the transfer function,

and use the following equation:

VEXT_MOD = ISETPOINT / Transfer Function

If the external modulation input causes the driver to reach the

current limit, the output signal will be clamped at the limit level

but will not switch o󰀨.

The bandwidth of the Current Monitor is lower than the

bandwidth of the output. To monitor the actual output

waveform at high frequencies, connect an oscilloscope across

the output pin on the MONITOR D-SUB, Pin 8 (positive), and

Pin 9 (ground) while using the resistor test load.

CAUTION: Connect the oscilloscope across the

test load only — never connect the oscilloscope

across a quantum cascade laser.

EXTERNAL MODULATION BNC

TRANSFER FUNCTIONS

The external modulation transfer function depends on the

QCL instrument model and is as follows:

QCL500 LAB: 0.1 A / V.

QCL1000 LAB: 0.2 A / V.

QCL1500 LAB: 0.3 A / V.

QCL2000 LAB: 0.4 A / V.

The input range is always -5 V to +5 V.

ADDITIONAL CAPABILITIES

ANALOG CURRENT MONITOR

This signal is the sum of the DC setpoint as shown on the

screen and the external modulation input.

To monitor the analog current level:

1. Connect the Analog output Current Monitor (PIN 8) on the

MONITOR D-SUB to an oscilloscope.

2. Connect an Analog Monitor Ground (PIN 7 or PIN 9) to

oscilloscope ground.

SETPOINT CURRENT MONITOR

This is a reference only and can be o󰀨 by as much as 5%

when setpoint is >10% of full scale.

To monitor the setpoint current:

1. Measure the voltage on the Analog Setpoint Monitor

(PIN 6).

2. Ground for that measurement is the Analog Monitor

Ground (PIN 7 or PIN 9).

The setpoint monitor and analog current monitor transfer

functions depend on the QCL instrument model and are all

as follows:

QCL500 LAB: 0.1 A / V.

QCL1000 LAB: 0.2 A / V.

QCL1500 LAB: 0.3 A / V.

QCL2000 LAB: 0.4 A / V.

The input range is always 0 – 5 V.

ALIGNMENT LED DRIVE

+5 V, up to 250 mA sourced.

To drive an alignment LED, on the MONITOR D-SUB

1. Connect an LED to the Alignment LED +5V (PIN 1).

2. Ground the LED at the Alignment LED Ground (PIN 2).

ENABLE STATUS INDICATOR

This is a +5 V TTL indicator. If current to the QCL output

is enabled, the voltage between PIN 3 and PIN 4 on the

MONITORS D-SUB will be low. It will be high if current is

disabled.

USE THE TRIGGER SIGNAL

A trigger signal is provided so that external measurement

equipment can be synchronized with laser current. Exactly

10 msec after a remote change in setpoint, a 20 µsec positive

going pulse appears on the Trigger BNC plug.

To use the Trigger, connect a BNC cable to the TRIGGER

BNC output.

INSTALL THE QCL LABVIEW

INTERFACE APPLICATION

Complete installation instructions can be found in the LAB

Series Virtual Instrument Operating Guide.

The instructions explain how to download the .EXE le. If you

would like a copy of the .VI le, contact Technical Support.

USE REMOTE COMMANDS AND

NATIONAL INSTRUMENTS DAQ

CARD

Complete documentation of the remote commands supported

by the QCL LAB instrument can be found in the Remote

Command Set.

CUSTOM VIRTUAL INSTRUMENTS

Wavelength also o󰀨ers custom Virtual Instrument applications

tailored to your specic needs. Contact Technical Support for

more information.

REMOTE OPERATING

INSTRUCTIONS

The following instructions are for QCL LAB Series

instruments running rmware Version 1.5 and

later. These use the LabVIEW Virtual Instrument

application or the Remote Command Set.

TROUBLESHOOTING

Table 5. Troubleshooting

PROBLEM POTENTIAL CAUSES SOLUTIONS

Front panel Power button does not turn on

The button has been pushed on and

o󰀨 within 3 seconds.

The front panel Power button has a 3 second

delay between when it is turned o󰀨 and on in

rapid succession. This is a safety mechanism

to ensure there is no damage to either the

QCL instrument or the attached load.

The rear panel switch is o󰀨. Turn the rear panel switch to the on or |

position.

The Enable button does not turn on

The button has been turned on and o󰀨

within 2 seconds.

The button cannot be pressed faster than

every 2 seconds.

The QCL D-SUB interlock or Active

Interlock connections are open, or the

keyswitch is in the LOCKED position

• Make sure PIN 1 and PIN 2 on the QCL

D-SUB are shorted.

• The “Active Lock” BNC connector may

be open. Install a BNC shorting plug.

• Rotate the key to the UNLOCKED

position.

The instrument experienced an

internal fault.

(See Error Messages on page 19.)

The instrument will remain disabled until

manually powered o󰀨 and then on using the

rear panel power switch.

The instrument heatsink temperature

has exceeded 70ºC.

Allow the instrument to cool down and then

press the front panel power button.

The front panel Power button is not

on.

Press the Power button on the front panel to

enable the display.

The instrument is on but the front panel

display is blank

The instrument experienced an

internal fault.

(See Error Messages on page 19.)

Switch the back panel power button o󰀨 and

then on again, and turn the front panel power

button on.

The internal temperature has reached

an unsafe level.

Allow the instrument to cool down and then

switch the back panel power button o󰀨 and

then on again, and turn the front panel power

button on.

The front panel Power button is

pulsing on and o󰀨 in standby mode.

Press the Power button on the front panel to

enable the display.

The date and time on my VI scan le are

wrong

The QCL instrument does not have a realtime

clock. When a VI scan le is created, the date

and time stamp are randomly chosen.

The VI scan les are not in the order that

they were created

Some les may have been deleted o󰀨

of the USB ash drive.

When les are deleted o󰀨 of the USB ash

drive and new les are saved to it, the new

les are given sequentially the names of the

deleted les.

Unable to create new VI scans

The interlocks may not be satised.

Turn the keyswitch to UNLOCKED, or

install the ACTIVE LOCK BNC and passive

interlocks.

There are too many les on the USB

ash drive. Delete les from the USB ash drive.

I can’t nd my VI scan les VI scan les are named sequentially.

If les have been deleted from the ash drive,

any new les added are named sequentially

and have the names of the deleted les.

The fan keeps coming on The internal temperature is being

regulated.

To reduce internal heat generation, choose a

lower supply voltage. The instrument will shut

down if the internal temperature gets too hot.

PROBLEM POTENTIAL CAUSES SOLUTIONS

Noise current is higher than expected.

There may be ground loops in the

system; some system components

may be higher noise than expected;

cabling and shielding may be

inadequate.

Refer to Wavelength Electronics Application

Note AN-LD08: Manage Grounding to

Minimize Noise with the QCL Drivers:

www.teamwavelength.com/download/

applicationtechnotes/an-ld08.pdf

Also reference AN-LD09: Troubleshooting

Low Noise Systems:

www.teamwavelength.com/download/

applicationtechnotes/an-ld09.pdf

The output switched o󰀨 unexpectedly

The instrument detected an internal

error.

(See Error Messages on page 19.)

Switch the back panel power button o󰀨 and

then on again, and turn the front panel power

button on.

The internal temperature has

exceeded 70ºC.

Allow the instrument to cool down and then

press the front panel power button.

20 kHz noise is in the output current QCL driver is operating in current limit.

If safe for the quantum cascade laser,

increase the output current limit setting.

When actively operating in current limit, the

safety circuits add noise to the output.

If I run my QCL at about 5% of maximum

output current, the transfer function

becomes non-linear and I see distortion in

my output current waveform.

QCL driver resolution is too low.

Select a QCL driver with a much lower

maximum output current. For example,

to run 50 mA, request a QCL125 (125 mA

maximum output).

My instrument doesn’t show up in the list.

(Remote Only)

Your instrument may not be turned on. Power up the instrument and click Refresh

on the Choose Instrument window.

Your instrument may not be plugged in

to the computer.

Check that either a USB or Ethernet cable is

tightly connected to the instrument and to the

computer.

Your instrument may be on a di󰀨erent

sub-net.

Add the sub-net to the Choose Instrument

window and then click Refresh.

Actual current does not match the setpoint.

The setpoint exceeds the limit current

setting.

If the limit current can be increased without

damage to the QCL, increase the limit

current setting.

The QCL is compliance voltage

limited.

Increase the Max Supply Voltage slightly to

see if actual current increases. Follow the

instructions on page 20 to optimally set

the Max Supply Voltage.

Table 6. Error Messages

To clear error text, x the cause then press any icon or the Enable button.

ERROR POTENTIAL CAUSES SOLUTION

The USB ash drive is missing or not

accessible. Please make sure that a USB

ash drive is inserted into the front panel.

To run a local VI scan, a USB ash drive

must be in place.

Insert a USB ash drive in the data port on

the front panel.

The USB ash drive was removed. The

scan has been aborted.

To run a local VI scan, a USB ash drive

must be in place.

Insert a USB ash drive in the data port on

the front panel.

Output current is disabled. The keyswitch

is in the locked position.

The keyswitch is horizontal or in the locked

position.

Turn the keyswitch to the vertical or

unlocked position.

Output current disabled. Pins 1 & 2 on the

QCL D-SUB are not tied. The passive interlock is not shorted. Short Pin 1 and Pin 2 on the QCL D-SUB.

Output current disabled. The Active

Interlock is not shorted. The active interlock is not grounded. Ground the center pin of the Active Lock

BNC.

The internal temperature limit of the

instrument has been exceeded. Output

current has been disabled to protect the

laser.

The ambient air temperature is too high for

the instrument.

Reduce the ambient air temperature to

50ºC or less.

The VI scan was canceled by the user. The Stop button was pressed during the

scan.

Scan was canceled because output

current is disabled.

The Enable button was pressed during a

scan, cutting current to the load.

An open circuit was detected at the

load. Please verify the load and load

connections.

The instrument cannot drive current

through the load.

Make sure the QCL SMA or Pins 5 & 9 of

the QCL D-SUB are connected.

A short circuit was detected at the load

terminals. Please verify the load and load

connections.

The instrument is detecting that there is no

resistance where the load should be.

Make sure the QCL SMA or Pins 5 & 9 of

the QCL D-SUB are connected.

An internal error occurred while reading

data from hardware. Please contact the

factory for further assistance.