Field Wiring
20
Figure 11: Addressable Loop Wiring -Class A or Style 6
Loop Operation
When there is a short circuit on the Class A loop with isolators installed, the isolators isolate the shorted fault, the
panel detects it as an open loop and generates an open loop trouble.
When a Class A loop is opened there may be a few missing devices reported by the panel which will be restored
once the panel has established the Class A connection.
Note: When there is an "Open loop trouble" look for both open and shorts on the loop. As a guideline, the
isolators which are activated in response to a short will have their LED ON; look for the short
between the two isolators with their LEDs ON.
CLASS A
WIRING
ION SMOKE
DETECTOR
PHOTO SMOKE
DETECTOR
HEAT DETECTOR
INPUT MODULE
Loop
A
+-+-
B
OUTPUT MODULE
FIRE ALARM MAIN BOARD
To Next Page