48
Alarm Outputs
Each alarm channel has two outputs; Group Trip A (GTA) and Group Trip B (GTB). Each
gives an open collector type output and may be configured for polarity and function as listed
in the Technical Specification. They may be used individually or grouped together to take
alarm signals to other equipment or initiate control action. The example below shows four
alarm channels from two cards connected together to a single group alarm relay situated in
the safe area. The second Group (GTB) may be used individually or grouped in the same
way as group A
Group Trip output connections (Figure 13.4)
12
11
10
9
8
7
6
5
4
3
2
1
LN1000/AC
ALARM CARD
HAZARDOUS AREA
SAFE AREA
IS RELAY
2
DAA
149
N/O CONTACTS
1
4
3
12
11
10
9
8
7
6
5
4
3
2
1
CLOSE ON ALARM
GROUP ALARM RELAY
ENERGISED ON ANY ALARM
IN THE GROUP
GTB1
GTB2
GTA2
+
-
GTA1