THORLABS ITC4000 Series, Руководство по эксплуатации, Страница: 20 / 105

© 2018 Thorlabs 18
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)!
26