OK RELAY

The purpose of this relay is to provide a means to annunciate a problem that is detected with any

transducer system connected to the rack. The OK Relay is connected to the OK Circuit of every 

monitor in the rack. The OK Circuit continuously checks the condition of the transducer(s)

associated with that monitor. If the circuit detects a transducer problem, the OK LED on the front

of the affected monitor goes off and a relay drive signal is sent to the OK Relay in the System Monitor.

The OK Relay is located on the System Monitor PIM, is normally energized, and is a single-pole,

double-throw (SPDT) relay. Since it is normally energized, the relay also can be used to

annunciate when mains power to the rack is lost or interrupted. Either a system power-up inhibit

signal from the System Monitor or a not OK signal from any monitor in the rack will cause the OK

Relay to change state.