GE DigitalFlow XGM868i - Page 23

DigitalFlow™ XGM868i Startup Guide 15
Chapter 1. Installation
1.7.5b Wiring an Alarms Option Card
Each alarms option card includes two or four general-purpose Form C relays (designated as A, B, C and D).
The maximum electrical ratings for the relays are listed in Chapter 4, Specifications. Each of the alarm relays can be
wired as either Normally Open (NO) or Normally Closed (NC).
In setting up an alarm relay, it may be wired for either conventional or fail-safe operation. In fail-safe mode, the alarm
relay is constantly energized, except when it is triggered or a power failure or other interruption occurs. See Figure 4
for the operation of a NO alarm relay in both conventional and fail-safe mode.
Before making any connections, complete the steps in Preparing for Wiring on page 14. Connect each alarm relay in
accordance with the wiring instructions shown on the label inside the rear cover (see Figure 3 on page 6 and Figure 11
on page 26).
Figure 4: Conventional and Fail-Safe Operation
C
NO
NC NC
C
NO
NC NC
C
NO
C
NO
Monitoring
Alarm
Device
Monitoring
Alarm
Device
Monitoring
Alarm
Device
Monitoring
Alarm
Device
not triggered
Conventional,
not triggered
Fail-Safe,
triggered
Conventional,
triggered or power failure
Fail-Safe,