This unit monitors: A and B source control voltages, the Automated Environments 24V control voltage, and the fail safe thermostat voltage.

​

This is done by monitoring the position of a relay in an energized state. As long as the relay receives the required power, no alarm is triggered. If the relay loses power, it de-energizes and creates an open circuit.

​

The control program monitors inputs wired to the PMP relays and triggers an alarm when a circuit opens. The 24V signal powering the watchdog circuit is supplied directly by the PMP.