To set the Device ID as the reference for the alarmA $DEVICE_DOWN alarm occurs when a device stops talking to a PLC.There are three components that make up a unique alarm
Procedure
The Alarm ID which in this case is $DEVICE_DOWN;
The Resource ID, which in this case it takes it from the device's resource and
A Reference ID.
As a result, each device will have a unique alarm, regardless of its resource. The Alarm ID is static for all $DEVICE DOWN alarms; the resource changes based on the device; now the Reference ID is the Device ID.