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Strobe Light Failure Sensing

Strobe Light Failure Sensing

Strobe Light Failure Sensing

(OP)
I have some warning strobe light installed in a hazardous area and I need a way to sense if the light has failed and report it to the PLC.  If the light has failed the equipment should not run.  Any help would be greatly appreciated.

RE: Strobe Light Failure Sensing

Use a light sensor circuit to give a pulse every time the strobe lights. Use that pulse to hold off triggering of a monostable (a pulse omission detector), or bias off an astable oscillator.

When the strobe fails, the monostable will fire or the oscillator will run.

RE: Strobe Light Failure Sensing

  Simple set use a resettable timer triggered by a photo-cell.  The time delay is set longer than the interval between flashes.  If the flash does not occur within the allowed time the timer times out, sending a signal to the PLC.  Here's a site giving information on the use of this timer for this type of application:

http://www.williamson-labs.com/555-AN170.htm

RE: Strobe Light Failure Sensing


One aside: If the application is something legally required like FAA tower lights, it is unlikely that a locally fabricated means would keep you out of trouble with respect to compliance.  
  

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