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Electronic Theatre Controls Inc

Sensor Overtemp Operation

Sensor dimmer overtemp error messages are generated when a dimmer's internal sensors indicate that it is running too hot.  This message is then sent to the CEM, and "OVERTEMP XXX" is displayed.  On the MPE, the beacon will flash, and you can run tests to see what the error is.


  • FALSE OVERTEMP ERRORS ARE NEVER A PROBLEM WITH THE CEM (CLASSIC, +, OR 3)!!!  It is impossible for the overtemp circuit in the CEM to send a false error as it requires a specific digital signal to read an error.  The failure mode of the overtemp circuit is such that it will not read overtemps at all because it is impossible for it to send the proper digital signal.
  • Overtemp is NOT an AF function.  Overtemp errors are generated independent of the AF cards in the rack.
  • Overtemp messages only appear after the dimmers are brought up above level zero.  We use the power cube control line to sample for an OT signal on the OT bus.  You can bring the dimmers up to 20% and then wait and see if messages appear.
  • Modules reporting overtemp that are truly overtemp are hot enough to the touch that you may require high temp gloves.
  • Overtemp is a bussed signal.  That means that if a module is falsely reporting an OT error, it quite often will cause OT messages for adjacent modules to appear.  In this case, pull out the suspect modules, clear the error by holding clear for 10 sec., and then insert one at a time and see if the messages come back.  When they do, you have found the bad power cube.  Again, make sure you bring the dimmers to a level above zero.  See Overtemp Errors for Series of Dimmers on a Sensor CEM


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