Wiring An Alarms Option Card - GE DigitalFlow GS868 Startup Manual

Chapter 1. Installation

1.6.6 Wiring an Alarms Option Card

The Model GS868 flowmeter can accommodate up to 4 alarms option cards. Each alarms option card includes three
Form C relays (designated as A, B and C).
The alarm relays on the option card are available in two types:
•
general purpose
•
hermetically sealed for Class I, Division 2 hazardous areas.
The maximum electrical ratings for the relays are listed in Chapter 4, Specifications. Each of the three alarm relays can
be wired either as 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 6
below for the operation of a NO alarm relay in both conventional and fail-safe mode.
Connect the two wires required for each alarm relay in accordance with the pin number assignments shown in
Figure 10 on page 20.
14
Conventional,
not triggered
NO
C
NC
Alarm
Monitoring
Device
Conventional,
triggered
NO
C
NC
Alarm
Monitoring
Device
Figure 6: Conventional and Fail-Safe Operation
Fail-Safe,
not triggered
NO
C
NC
Alarm
Monitoring
Device
Fail-Safe,
triggered or power failure
NO
C
NC
Alarm
Monitoring
Device
DigitalFlow™ GS868 Startup Guide