Operation - MSA Chillgard RT Instruction Manual

close and "normally closed" contacts open to signal an alarm condition.
These relays DO NOT change state when power is removed.

Operation

Proper operation of the alarm relays requires maintaining successful
communication between the Relay Module and the controlling Chillgard
RT Refrigerant Monitor since all alarm relay operations are based on
cumulative information received from the Refrigerant Monitor.
Alarm level information for each point of the multi-point sequencer is
received from the controlling Chillgard RT Refrigerant Monitor. This
information is used to set the CAUTION, WARNING, and ALARM relays
corresponding to each sequencer point.
• In non-latching configurations, relay(s) will reset when information
from the controlling Refrigerant Monitor indicates that the alarm
condition(s) for the specific point has abated.
• In latching configurations, relay(s) remain set (latched) when the
condition abates, and do not reset until the Relay Module reset
switch is pressed.
Reset Switch
The reset switches of the Chillgard RT Relay Module and controlling
Chillgard RT Refrigerant Monitor act independently. Pressing the reset
switch on the Refrigerant Monitor does not affect the Relay Module
alarm relays, and pressing the reset switch on the Relay Module does
not affect the Refrigerant Monitor alarm relays.
• In non-latching configurations, the Relay Module reset switch does
not affect the state of the alarm relays.
• In latching configurations, the reset switch resets the alarm relay
only if the alarm condition has abated.
Trouble Relay
While a trouble condition in the Chillgard RT Refrigerant Monitor
activates the trouble relay in the Chillgard RT Relay Module, a trouble
condition in the Relay Module does not activate the trouble relay in the
controlling Chillgard RT Refrigerant Monitor.
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