Connecting Interlock And Status Led - THORLABS ITC8 Series Operation Manual

18 Connecting components
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1.6.3 Connecting interlock and status LED

Pin 1 and pin 5 of the connector jack serve as safety connectors to determine
whether the current output for the laser diode may be switched on. A short-circuit or
at least a low resistance (R<430 Ω) must be maintained between the two pins.
With the contacts open or resistance too high the current module cannot be switched
on. Should the interlock contact open during operation the output will be switched off
immediately.
Status display
It is also possible to use a LED with a 0.5 kΩ resistor in parallel between the two
pins. The LED will light up if the current output is switched on.
Here are the two possibilities for the pin assignment:
<430 Ω
about 0.5 kΩ
NOTE
Using a resistor above 430 Ω- without LED (or if the LED is incorrectly
poled) may lead to malfunction as the status of the interlock is then
undefined.
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