THORLABS ITC4000 Series User manual

Laser Diode Current and
Temperature Controller
ITC4000 Series
Operation Manual
2018

Copyright © 2018 Thorlabs
Version:
Date:
Item No.:
3.9
10-Jul-2018
M0009-510-312

Foreword
Contents 4
1General Information 5
61.1 Safety 81.2 Protection of Laser Diodes 91.3 Ordering Codes and Accessories
2Getting Started 10
102.1 Preparation 112.2 Operating Elements 132.3 First Operation 132.4 System Preferences
3Operating the ITC4000 Series 15
153.1 Connecting Components 153.1.1 Pin Assignment of the Laser Output Jack 163.1.2 Connecting the Laser Diode 163.1.3 Connecting an Optical Sensor as a Feedback Source 163.1.3.1 Connecting a photodiode 173.1.3.2 Connecting a voltage feedback source 173.1.4 Connecting the Laser Voltage Measurement 183.1.5 Connecting Interlock and LD ON Monitoring 183.1.6 Laser Protection "LD Enable" Input 193.1.7 Pin Assignment of the TEC Output Jack 203.1.8 Connecting a TEC Element 213.1.9 Connecting a Temperature Sensor 213.1.9.1 NTC thermistor 223.1.9.2 Current Temperature Sensors AD590 or AD592 223.1.9.3 Voltage Temperature Sensor LM35 223.1.9.4 Voltage Temperature Sensors LM335, LM235 or LM135 223.1.9.5 Platinum RTD Temperature Sensors PT100 or PT1000 233.1.10 Setting up the TEC Voltage Measurement 233.1.11 Connecting Interlock and TEC ON Monitoring 243.1.12 LDC Control Outputs 243.1.13 TEC Control Outputs 253.2 Power-up 263.3 LD Output Configuration 273.4 LD Source Setup 293.5 LD Source Setpoints 303.6 Setting the Power Feedback Source Parameters 303.6.1 Photodiode Input 323.6.2 Thermopile Input

333.7 LD Modulation Settings 353.8 QCW Pulse Settings 373.9 TEC Source Setup 383.10Temperature Sensor Setup 403.11Thermistor Settings 413.12PID Control Loop 453.13PID Auto Tune 473.14Temperature Protection 483.15Display Configuration 503.16Settings Memory 523.17Digital I/O Ports 553.18Systems Preferences 553.19Remote Control 553.20Information
4Computer interface 56
564.1 Using the USB interface 564.2 Instrument driver installation 574.3 Firmware update
5Maintenance and repair 59
595.1 General remarks 595.2 Line voltage settings 595.3 Replacing the mains fuses 615.4 Troubleshooting
6 Appendix 63
636.1 Technical Data 636.1.1 ITC4001 Laser Control 666.1.2 ITC4002QCL Laser Control 696.1.3 ITC4005 Laser Control 726.1.4 ITC4005QCL Laser Control 756.1.5 ITC4020 Laser Control 786.1.6 ITC4000 Series Temperature Control 806.1.7 ITC4000 Series Common Specifications 826.2 Setup and Function of a Temperature Controller 846.3 PID Controller Theory 856.4 Menu Structure Overview 876.5 Factory Settings for Thorlabs ITC4000 controllers 906.6 Error messages 906.6.1 LED status messages 916.6.2 Status indicators 926.6.3 Instrument errors 956.7 Certifications and Compliances 966.8 Warranty

976.9 Exclusion of Reliability and Copyright 986.10Thorlabs "End of Life" Policy (WEEE) 996.11List of acronyms 1006.12Thorlabs Worldwide Contacts

© 2018 Thorlabs
We aim to develop and produce the best solution for your application
in the field of optical measurement technique. To help us to live up to
your expectations and constantly improve our products we need
your ideas and suggestions. Therefore, please let us know about
possible criticism or ideas. We and our international partners are
looking forward to hearing from you.
Thorlabs GmbH
Warning
Sections marked by this symbol explain dangers that might result in
personal injury or death. Always read the associated information
carefully, before performing the indicated procedure.
Please read this advice carefully!
This manual also contains "NOTES" and "HINTS" written in this form.
Attention
Paragraphs preceded by this symbol explain hazards that could
damage the instrument and the connected equipment or may cause
loss of data.
Note
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© 2018 Thorlabs
1 General Information
5
1 General Information
The ITC4000 Series is a high power precision laser diode and temperature controller series
with a USB 2.0 interface for driving laser diodes up to 20A laser current.
Special highlights of the ITC4000 Series Laser Diode and Temperature Controllers are:
· Operate with anode- or cathode-grounded lasers and photodiodes
· Current (photodiode) and voltage (thermopile) feedback inputs
· The laser diodes can be operated in constant current as well as in constant power mode
· CW mode with modulation up to 100kHz
· Internal DDS generator for sine, square, triangle waveforms
· External modulation input
· QCW mode with pulse width down to 100µs
· QCW trigger input and trigger output
· Interlock for automatic switch off by an external emergency switch or by a cable interrup-
tion
· Laser Diode Enable input
· High power TEC with excellent temperature stability and PID Auto-Tune function
· Temperature loop monitoring for laser protection
· A wide variety of protection features safeguard the laser diode and the TEC element from
damage.
· USB interface for remote operation supporting the USBTMC protocol
· SCPI compliant command set
· VXIpnp Instrument Drivers for various programming environments including NI-
LabVIEW™, NI-LabWindows™/CVI and MS-Visual Studio
· Power efficient by active power management
This part of the operation manual contains specific information on how to operate the ITC4000
Series Laser Diode and Temperature Controller. A general description is followed by an explan-
ation of how to operate the unit manually. The instrument provides a USB 2.0 Full Speed inter-
face according to the USB 2.0 specification, the USBTMC specification and the
USBTMC USB488 specification.
Related documents:
· LDC4000 Series Operation Manual available at www.thorlabs.com
· TED4000 Series Operation Manual available at www.thorlabs.com
· Series 4000 Programmers Reference Manual at www.thorlabs.com

© 2018 Thorlabs6
ITC4000 Series
1.1 Safety
Attention
The safety of any system incorporating the equipment is the responsibility of the assem-
bler of the system.
All statements regarding safety of operation and technical data in this instruction manual
will only apply when the unit is operated correctly as it was designed for.
The ITC4000 Series must not be operated in explosion endangered environments!
Do not obstruct the air ventilation slots in the housing!
Do not remove covers!
Do not open the cabinet.There are no parts serviceable by the operator inside!
This precision device is only serviceable if properly packed into the complete original
packaging including the plastic foam sleeves. If necessary, ask for replacement pack-
aging.
Refer servicing to qualified personnel!
Only with written consent from Thorlabs may changes to single components be made or
components not supplied by Thorlabs be used.
Attention
Prior to applying power to the ITC4000 Series, make sure that the protective conductor
of the 3 conductor mains power cord is correctly connected to the protective earth
ground contact of the socket outlet! Improper grounding can cause electric shock result-
ing in damage to your health or even death!
Ensure that the line voltage setting of the fuse holder at the rear panel agrees with your
local supply and that the corresponding fuses are inserted. If not, please change the line
voltage setting (see section Line voltage settings ) and the mains fuses (see section
Replacing the mains fuses ).
To avoid risk of fire, only the appropriate fuses for the corresponding line voltage must
be used.
All modules must only be operated with duly shielded connection cables.
Attention
The following statement applies to the products covered in this manual, unless other-
wise specified herein. The statement for other products will appear in the respective ac-
companying documentation.
Note: This equipment has been tested and found to comply with the limits for a Class B
digital device, pursuant to Part 15 of the FCC Rules and meets all requirements of the
Canadian Interference-Causing Equipment Standard ICES-003 for digital apparatus.
These limits are designed to provide reasonable protection against harmful interference
in a residential installation. This equipment generates, uses, and can radiate radio fre-
quency energy and, if not installed and used in accordance with the instructions, may
cause harmful interference to radio communications. However, there is no guarantee
that interference will not occur in a particular installation. If this equipment does cause
harmful interference to radio or television reception, which can be determined by turning
the equipment off and on, the user is encouraged to try to correct the interference by one
or more of the following measures:
· Reorient or relocate the receiving antenna.
· Increase the separation between the equipment and receiver.
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© 2018 Thorlabs
1 General Information
7
· Connect the equipment into an outlet on a circuit different from that to which the re-
ceiver is connected.
· Consult the dealer or an experienced radio/T.V. technician for help.
Users that change or modify the product described in this manual in a way not expressly
approved by Thorlabs (party responsible for compliance) could void the user’s authority
to operate the equipment.
Thorlabs GmbH is not responsible for any radio television interference caused by modi-
fications of this equipment or the substitution or attachment of connecting cables and
equipment other than those specified by Thorlabs GmbH. The correction of interference
caused by such unauthorized modification, substitution or attachment will be the re-
sponsibility of the user.
The use of shielded I/O cables is required when connecting this equipment to any and all
optional peripheral or host devices. Failure to do so may violate FCC and ICES rules.
Attention
Mobile telephones, cellular phones or other radio transmitters must not be used within
the range of three meters of this unit since the electromagnetic field intensity may then
exceed the maximum allowed disturbance values according to IEC61326-1.
This product has been tested and found complying with the limits according to IEC
61326-1 for using connection cables shorter than or equal to 3 meters (9.8 feet).
Warning
Laser modules can deliver up to several Watts of (maybe) invisible laser radiation!
When operated incorrectly, this can cause severe damage to your eyes and health!
Be sure to pay strict attention to the safety recommendations of the appropriate laser
safety class! This laser safety class is marked on your external laser source used.
Vous pouvez trouver les traductions françaises des paragraphes ayant trait à la sécurité
d'utilisation de ce produit sur le lien suivant:
https://www.thorlabs.com/_sd.cfm?fileName=16405-D04.pdf&partNumber=ITC4001
En outre, vous pouvez soit scanner le QR code, soit vous référer à la section "Docu-
ments" sur la page web du produit.

© 2018 Thorlabs8
ITC4000 Series
1.2 Protection of Laser Diodes
To protect the user and the connected setup, the ITC4000 Series includes the following protect-
ive features:
Key switch
The key switch will shutoff the laser output. This feature complies with the CDRH (Center for
Devices and Radiological Health) requirements and prevents an unauthorized usage of the
laser driver.
Switch on delay
The ITC4000 controllers are CDRH compliant with the user programmable switch on delay. The
default setting is 3 seconds.
Softstart
The softstart function protects the laser diode against undesired peaks.
Laser current limit (hardware limit)
The maximum laser current can be adjusted by the laser current limit. The threshold can be set
in the LD Source Setup menu (Please refer to section Setting the LD source parameters ).
Interlock
The interlock input provides several protection functions simultaneously:
· Safety lock to prevent unintentional use
· Cable damage monitoring
· An external emergency switch may be connected
· To connect your external automatic protection equipment, e.g. for temperature monitoring
· Laser ON/OFF LED
(Please refer to section Connecting the interlock and LD ON monitoring )
The laser can only be operated with the interlock input being closed.
Open circuit detection for the laser diode
If the connection to the laser is interrupted even for a short time during operation, an immediate
emergency switch off occurs. The open circuit threshold can be set via the "Voltage Protection"
feature (Please refer to section Laser Output Configuration )
Electronic short-circuit switch for the laser diode
With the current module switched off, an electronic switch will short the laser diode so that no
voltage is applied to the laser contacts.
Control LED for laser current ON
When the laser current is switched on, a green LED indicator in the LD ON switch lights up.
Temperature window protection of the laser diode
A laser operation in a specified temperature range can be realized in combination with the tem-
perature protection function of the integrated TEC controller (Refer to sections Temperature
protection and Laser output configuration ). The laser output is switched off, if the temper-
ature leaves the defined temperature window.
Overtemperature protection
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© 2018 Thorlabs
1 General Information
9
The ITC4000 has an automatic overtemperature protection. If the allowed internal operating
temperature should be exceeded, the outputs will be switched off. After a temperature drop of
about 10 °C, the outputs of the ITC4000 can be switched on again.
Defined states after switch-on
When turning on the ITC4000 with the main switch, the laser and TEC outputs remain switched
off.
Line failure monitoring
In case of line failure / line interruption the ITC4000 will restart anew as if it has been turned on.
So the laser output remains switched off.
Mains filtering:
The installed power supply, with carefully dimensioned filters, provides low ripple and noise at
the laser and TEC outputs.
1.3 Ordering Codes and Accessories
Ordering code
Short description
ITC4001
Laser Diode / Temperature Controller, LD current range 0 .. 1 A, TEC current
0 .. 8A
ITC4002QCL
QCL Laser Diode / Temperature Controller, LD current range 0 .. 2 A, TEC
current 0 .. 15A
ITC4005
Laser Diode / Temperature Controller, LD current range 0 .. 5 A, TEC current
0 .. 15A
ITC4005QCL
QCL Laser Diode / Temperature Controller, LD current range 0 .. 5 A, TEC
current 0 .. 15A
ITC4020
Laser Diode / Temperature Controller, LD current range 0 .. 20 A, TEC current
0 .. 15A
CAB4000
Shielded cable to connect the TEC output of the ITC4000 controller to a
Thorlabs LM14S2, LDM21 or TCLDM9 laser diode mount (male 17W2 mixed
DSUB connector to female 9 pin DSUB connector). The rated TEC current is
5A.
CAB4001
Shielded cable to connect the TEC output of the ITC4000 controller to a
Thorlabs high power TEC mount or laser diode mount (male 17W2 mixed
DSUB connector to male 17W2 mixed DSUB connector). The rated TEC cur-
rent is 20A.
CAB4005
Shielded cable to connect the laser output of the ITC4000 controller to a
Thorlabs LM14S2, LDM21 or TCLDM9 laser diode mount (male 13W3 mixed
DSUB connector to male 9 pin DSUB connector). The rated LD current is 5A.
CAB4006
Shielded cable to connect the laser output of the ITC4000 controller to a
Thorlabs high power laser diode mount (male 13W3 mixed DSUB connector
to male 13W3 mixed DSUB connector). The rated LD current is 20A.
CON4001
Connector kit for the TEC output of the ITC4000 controllers, 20A: mixed
DSUB connector type 17W2 (male) with two 20A high current contacts (male)
CON4005
Connector kit for the laser output of the ITC4000 controllers, 20A: mixed
DSUB connector type 13W3 (male) with three 20A high current contacts
(male)
CAL-ITC4000
Recalibration of an ITC4000 Series controller
Please visit our homepage www.thorlabs.com for further information.

© 2018 Thorlabs10
ITC4000 Series
2 Getting Started
Inspect the shipping container for damage.
If the shipping container appears to be damaged, keep it until you have checked the contents
and you have inspected the ITC4000 controller mechanically and electrically.
Verify that you have received the following items:
· 1 ITC4001, ITC4002QCL, ITC4005, ITC4005QCL or ITC4020
· 1 power cord, connector according to ordering country
· 1 USB cable (A-B)
· 1 ITC4000 Series operation manual
· 1 Series 4000 instrumentation CD (containing manuals, drivers, tools and software)
· With ITC4001, ITC4002QCL, ITC4005 or ITC4005QCL: 1 CAB4000 shielded cable to
connect the TEC controller to a Thorlabs LM14S2, LDM21 or TCLDM9 laser diode mount
(male 17W2 mixed DSUB connector to female 9 pin DSUB connector), rated TEC current
5A
· With ITC4020: 1 CAB4001 shielded cable to connect the TEC controller to a Thorlabs
high power laser diode mount (male 17W2 mixed DSUB connector to male 17W2 mixed
DSUB connector), rated TEC current 20A
· With ITC4001, ITC4002QCL, ITC4005 or ITC4005QCL: 1 CAB4005 shielded cable to
connect the laser diode controller to a Thorlabs LM14S2, LDM21 or TCLDM9 laser diode
mount (male 13W3 mixed DSUB connector to male 9 pin DSUB connector), rated laser
current 5A
· With ITC4020: 1 CAB4006 shielded cable to connect the laser diode controller to a
Thorlabs high power laser diode mount (male 13W3 mixed DSUB connector to male
13W3 mixed DSUB connector), rated laser current 20A
· 1 Connector Kit CON4001 for ITC4000 Series, rated TEC current 20A:
- 1 Mixed DSUB connector type 17W2 (male) with 2 high current contacts (male)
- 1 Mixed DSUB connector type 17W2 (female) with 2 high current contacts (female)
· 1 Connector Kit CON4005 for ITC4000 Series, rated laser current 20A:
- 1 Mixed DSUB connector type 13W3 (male) with 3 high current contacts (male)
- 1 Mixed DSUB connector type 13W3 (female) with 3 high current contacts (female)
2.1 Preparation
Connect the mains connector (R10) of the unit to the line via the provided mains cable (refer to
Operating elements at the rear panel ).
An external optical setup can be connected to ground potential via the connector jack of the
chassis ground (R12).
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© 2018 Thorlabs
2 Getting Started
11
2.2 Operating Elements
Front Panel
F1
Key switch (Locked/Unlocked)
F2
Line switch (On/Off)
F3
LC display
F4
Softkeys for menu navigation
F5
ESC
Escape key
F6
TEC ON
On/Off button for TEC output with TEC ON LED (green) and
ERROR LED (red)
F7
LD ON
On/Off button for LD output with LD ON LED (green) and ERROR
LED (red)
F8
Adjustment knob to change set values, push to enter

© 2018 Thorlabs12
ITC4000 Series
Rear Panel
R1
LD ENABLE IN
Laser Enable input (high to enable laser ON), TTL 5 V max.
R2
QCW PULSE IN
Input for external trigger signal, TTL 5 V max.
R3
TRIGGER OUT
QCW pulse tracking output, TTL 5 V
R4
OPT SENSOR IN
Input for optical sensor, 0 ... +10 V max.
R5
MODULATION IN
Input for external modulation signal, -10 ... +10 V max.
R6
ANALOG CTL OUT
Output for laser current monitoring, 0 ... +10 V
R7
Serial No.
Serial number of the unit
R8
Cooling fan
R9
LASER OUTPUT
Laser diode output and optical sensor input (13W3 mixed
DSUB jack)
R10
LINE IN
Mains connector and fuse holder
R11
USB connector
R12
4 mm banana jack for chassis ground
R13
DIGITAL I/O
MiniDin-6 jack for 4x digital I/O, I/O supply voltage (internal
+12V) and GND
R14
DEVIATION OUT
Actual temperature deviation output, -5 ... +5 V
R15
TEMP OK OUT
Temperature OK output (high if inside temperature window),
TTL 5 V
R16
TEC OUTPUT
TEC element output and temperature sensor input (17W2
mixed DSUB jack)

© 2018 Thorlabs
2 Getting Started
13
2.3 First Operation
Warning
Prior to switching on your ITC4000, please read the safety instructions in section
Safety carefully.
Turn on the unit by means of the line switch (F2 -see section Operating Elements )
After switching on the unit, the backlight of the display (F3) must get visible and the backlight
behind the adjustment knob (F8) must light up.
If nothing is shown on the display, please check the line voltage (see section Line Voltage Set-
tings ) and the mains fuses (see section Replacing the mains fuses ).
The ITC4000 Series is immediately ready to use after turning on. The rated accuracy is
reached, however, after a warming-up time of approx. 30 minutes.
After switching on the unit, the graphics display will show the device status, followed by the
measurement screen.
By using the softkeys (F4) you can select the menu items, the set values and the measurement
values to be displayed. You can change the set values by pressing the Modify button or the ad-
justment knob and then turning the adjustment knob (F8). Push this knob or the Done key to
enter the adjusted value. If several menu items are displayed, you can select them also by turn-
ing and then pressing the adjustment knob.
If changing a parameter isn’t permitted in the actual operating mode, or you arrive at the end of
a parameter number range, entering is declined and a short beep is audible.
From any menu level, you can navigate to the next higher menu level using the ESC key (F5).
The highest level is the measurement screen.
To leave the measurement screen and to enter the menu, press the Menu key or the ESC key.
2.4 System Preferences
The System Preferences menu allows to select different settings concerning your ITC4000 sys-
tem configuration, including Message Handling, Display Brightness, Display Contrast, Sound
Signals, and Update Capability. To get into the System Preferences menu, press the ESC
(F5) button and turn the adjustment knob or press Up / Down until System Preferences is
highlighted. Press Enter or the adjustment knob to confirm.
Turn the adjustment knob or press Up / Down and select your desired menu item by pressing
the Modify key or the adjustment knob. Make your necessary changes and confirm with the
Enter key or by pressing the adjustment knob again.
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ITC4000 Series
Message Auto-Hide:
Message and error conditions which force the Laser output to switch off may disappear after a
short time. So it may be preferable to keep the error messages displayed. You can choose the
following settings:
Enabled (auto-hide): Error pop-up messages disappear after 10 seconds, you can close
them instantly by pressing the ESC button (F5).
Disabled: Messages are displayed until they will be confirmed by pressing the ESC button.
Display Brightness, Display Contrast:
Both display parameters can be changed from 0% to 100%. The brightness value also determ-
ines the illumination brightness of the adjustment knob.
Note
Please take care not to reduce the contrast value to a level making it impossible to read the dis-
play.
Sound Signals:
Here you can disable or enable the audibility of the error beeps and the menu navigation click
response.
Temperature Unit:
The preferred temperature unit can be selected: °C (Celsius), °F (Fahrenheit), and K (Kelvin).
The conversion between the units will be calculated automatically.
Line Frequency:
According to the mains properties, the line filter frequency can be set to 50 Hz or 60 Hz to sup-
press unwanted readout aliasing effects. The "Auto" function detects the line frequency auto-
matically (default setting).
Update Capability:
Firmware updates can be performed by the user via the USB interface.
Three options are available:
Enabled: Firmware can be updated at any time.
Enabled once: Firmware can be updated once, afterwards this setting changes to disabled.
Disabled: Firmware update is inhibited (default setting).
For more information please refer to section Firmware Update .
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3 Operating the ITC4000 Series
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3 Operating the ITC4000 Series
3.1 Connecting Components
3.1.1 Pin Assignment of the Laser Output Jack
Pin assignment of the 13W3 DSUB laser output jack (rear panel view)
Pin
Connection
Interlock and Status Indicator:
5
Output for interlock and status indicator "LASER ON/OFF" (+)
6
Ground pin for interlock and status indicator "LASER ON/OFF" (-)
Monitor Input / Power Feedback Source:
1
(Thermo) voltage sensor input (+)
2
(Thermo) voltage sensor ground (-)
7
Photo current sensor input
8
Photo current sensor ground
Laser Voltage Measurement:
4
Laser diode anode (+)
10
Laser diode cathode (-)
Laser Diode:
A1
Laser diode ground
A2
Laser diode cathode (with polarity AG) (-)
A3
Laser diode anode (with polarity CG) (+)
3, 9
Not connected
Attention
The maximum laser output current for the ITC4020 is 20A. Use only the specified con-
nector type: 13W3 mixed DSUB plug with high power contacts A1, A2, and A3 rated for at
least 20A current. For wiring of A1, A2, and A3 use only wires rated for at least 20A cur-
rent.
If Thorlabs laser diode mounts like TCLDM9, LDM21, or LM14S2 are used, the easiest way to
connect them using a shielded cable CAB4005 (rated Laser current is 5A).
For use of other equipment's, a shielded cable with two 13W3 mixed DSUB plugs, CAB4006,
(20A Laser current rating) is also available.
If using a custom-made cable, we recommend to use a shielded cable for the sensor inputs
with twisted pairs. Use a separate shielded cable for the Laser current and Laser voltage meas-

© 2018 Thorlabs16
ITC4000 Series
urement lines. The Laser current lines should be as short as possible and as close together as
possible (e.g. twisted) to minimize inductance.
3.1.2 Connecting the Laser Diode
For CG polarity connect the laser diode with anode to A3 and with cathode to A1 (ground). For
AG polarity, connect the laser diode with cathode to A2 and with anode to A1 (ground). Please
refer to section Pin assignment of the laser output jack .
Attention
Take care to select the proper polarity for the connected laser diode. A wrong polarity
may damage the laser diode.
We recommend using separate shielded lines drilled in pairs (twisted pair) for laser diode cur-
rent and laser voltage measurement, as well as for the sensor inputs.
Some laser modules have a common ground pin for laser and photodiode. Figure 6 shows four
wiring configurations for these modules.
Connecting combined laser diode and photodiode modules
3.1.3 Connecting an Optical Sensor as a Feedback Source
The ITC4000 Laser Diode Controllers support optical current sensors (e.g. photodiodes) and
optical voltage sensors (e.g. thermopiles) for monitoring the laser power output. Both sensor
types can be used as a feedback source for a constant power loop to stabilize the laser output
power.
3.1.3.1 Connecting a photodiode
The photodiode input circuit design is a trans-impedance amplifier with virtual ground (input im-
pedance ~0 W ).
The photodiode can be connected to the 13W3 DSUB jack "LASER OUTPUT" (R9) pins 7 and
8 or to the BNC jack "OPT SENSOR IN" (R4) at the rear panel of the ITC4000 (please refer to
section Operating elements at the rear panel ).
For more information about connecting modules with common laser and photodiode ground
please refer to section Connecting the Laser Diode
The photodiode input parameters like input route, polarity, current range, BIAS state, BIAS
voltage and response can be set via Setting the Photodiode Input Parameters .
We recommend using shielded “twisted pair“ wiring for the monitor diode current measurement.
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3 Operating the ITC4000 Series
17
Attention
Input voltage / current must not exceed 10V / 20mA!
3.1.3.2 Connecting a voltage feedback source
An optical voltage sensor (like thermopile) can be connected to the 13W3 DSUB jack "LASER
OUTPUT" (R9) or to the BNC jack "OPT. SENSOR IN" (R4) at the rear panel (please refer to
section Operating elements at the rear panel ). Sensor amplifiers or power meters with
voltage output can be connected here as well.
Attention
Prior to connecting an optical voltage sensor to the BNC jack "OPT. SENSOR IN", make sure
that the thermopile sensor input route is set to rear panel BNC (refer to Setting the Thermopile
Parameters ).
The voltage sensor input parameters like input route, voltage range and response can be set
via Setting the Thermopile Parameters .
We recommend using shielded “twisted pair“ wiring for the thermopile voltage measurement.
Attention
Input voltage must not exceed 10V!
3.1.4 Connecting the Laser Voltage Measurement
The ITC4000 controllers offer laser voltage measurements with standard accuracy or enhanced
accuracy. Without additional wiring, the laser voltage is measured at the "LASER OUTPUT"
jack (R9) at the rear panel of the unit (two terminal measurement). This leads to a measure-
ment error due to the voltage drop along the "current" lines to the laser diode, so a slightly in-
creased voltage will be displayed.
For an enhanced laser voltage measurement, two additional lines must be connected as close
as possible to the laser diode pins (four terminal measurement). Connect the laser diode anode
to pin 4 and the laser diode cathode to pin 10 of the "LASER OUTPUT" jack (R9) at the rear
panel of the unit.
Attention
If the laser voltage measurement contacts (pin 4 and pin 10 of the "LASER OUTPUT" jack) are
not used, they must be left unconnected to any other potential, otherwise the overvoltage pro-
tection may not work properly.
We recommend using separate shielded “twisted pair“ wiring for the Laser voltage measure-
ment to minimize noise in the current- or voltage feedback measurement.
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ITC4000 Series
3.1.5 Connecting Interlock and LD ON Monitoring
The interlock function is realized using two pins that must be connected to each other as a pre-
condition for switching on the laser. These are pin 5 and pin 6 of the 13W3 DSUB "LASER
OUTPUT" jack (R9) at the rear panel of the unit.
Connecting the laser Interlock with and without monitoring LED
Pin 5 and pin 6 must be connected externally by a wire (total resistance <430 W ). If this connec-
tion is opened while the laser is switched on, there will be an acoustic signal and the laser will
be switched off immediately. If the two pins are not connected, the laser cannot be switched on.
Furthermore the red LED in the "LD-ON" key (F7) on the front panel of the ITC4000 and a
corresponding error message on the display will indicate that the interlock is open.
A LED can be connected in parallel to a resistor (<430 W ) between pin 5 and pin 6. This LED
lights up when the laser current is switched on (Laser ON indicator).
It is possible to connect several switches in series to the interlock pins, setting up a closed loop
that can be opened by each switch. Thus different protective functions can be accomplished
simultaneously via the interlock.
Examples of various protective interlock functions:
· An external emergency key (opener) is connected to the two pins of the interlock or in
series to other interlock switches.
· If the laser is to be operated in a closed setup (lab) a switch can be installed in a suitable
position interrupting when the setup (lab-door) is opened.
· If the interlock line is led in parallel to the laser current line a cable damage monitoring
can be realized.
3.1.6 Laser Protection "LD Enable" Input
The ITC4000 has a "LD Enable" input for additional laser safety. Using this input, the laser di-
ode can be switched off by an external TTL signal. Please connect this external "safety signal"
to the BNC input jack "LD ENABLE IN" (R1) at the rear of the unit. The external signal should
be low, in case of an error, to switch off the laser output.
The input is high active with an internal pull-up resistor, therefore, if no cable is connected, the
input is at high level and the laser output is enabled.
In the Laser Output Configuration you can change the LD Enable functionality (please refer to
section Laser Output Configuration for more information).
For example, if the ITC4000 is used together with an additional temperature controller
(TED4015 or TED350), you can use the BNC jack "LD ENABLE IN" (R1) as a temperature win-
dow input, to switch off the laser current, if the temperature leaves a predefined window.
Attention
The LD ENABLE Input voltage must not exceed TTL level (5V)!
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