42
Alarm Inputs - Safe areas
Inputs from sources which cannot meet the segregation requirements e.g. inputs from relays
in safe area equipment, or inputs that do not meet the simple apparatus requirements must
be isolated using an appropriate IS interface. The approved device for this purpose is the
DAE149 or DAD149 Intrinsically Safe Relay. Typical connections for normally closed alarm
contacts are shown in Figure 12.3 and for normally open alarm contacts in Figure 12.4 below
Alarm ways with normally closed contacts mounted in the safe area
(Figure 12.3)
12
11
10
9
8
7
6
5
4
3
2
1
LN1000/AC
ALARM CARD
UPPER
WINDOW
HAZARDOUS AREA
SAFE AREA
LOWER
WINDOW
IS RELAY
2
1
4
3
DAE
149
IS RELAY
2
1
4
3
DAE
149
+
-
N/C ALARM
CONTACT
N/C ALARM
CONTACT
ALARMCONTACT
SUPPLY
10-250V AC/DC