Addressable Intelligent Module—AIM-200 Addressable Intelligent Module 21
Isolated-Redundant Circuit
By flanking each communications loop device with a pair of M500XJ fault
isolator modules, each device is protected from short circuit faults that may
occur on other devices. For example, a fault on Zone 2 will not effect
Zones 1 and 3. The isolator modules on either side of Zone 2 will open the
loop. Zone 1 will still operate from power on loop out and Zone 3 will
operate from loop return. Since the system will no longer be able to
communicate with Zone 2, a trouble signal(s) will be generated for that
device.
This circuit is a variation of the redundant circuit, therefore, no T-tapping
or branching is allowed. The ratings and characteristics are the same as for
the redundant circuit.
Figure 13: Isolated-Redundant Communications Loop