EXTERNAL  ALARM  FAULT  INPUT:

External Alarm

The External Alarm input is an optional fault input.  It is not necessary to use it for normal operation.  It can be hooked up to anything from a rear door to a coffee maker, but……

Typically The External Alarm input is used for a Low Elevation alarm input.

Some antennas are equipped  with a Low Elevation alarm output.  This is a dry relay contact output that can be used to signal the outside world that the antenna has an elevation where the amplifiers should not be transmitting. 

Besides monitoring this Low Elevation alarm, it can also be used to produce a summary RF inhibit on both amplifiers when an external alarm is present.

This is user defined.  The External alarm input is shipped as a normally closed relay input to the controller.  When this input “opens” both amplifiers are inhibited.   To defeat this function, simply place the dip switch S4 (located on the main PCB) -switch 3 in the Off position.

On the main PCB inside the controller is a 3 position dip switch (S4).  This dip switch may be used to alter the external alarm input.

S4-switch 1

          On = inhibit in the event of an external alarm

          Off = do not inhibit in the event of an external alarm

S4-switch 3

          On = external alarm fault input is normally closed

          Off = external alarm fault input is normally open

(not associated with external alarm is S4-switch 2.  This dip switch is used to tell the main program if 1 or 2 waveguide switches (output switches) are in the system

Refer to the Rear Chassis Interface