DC1040CR-302000-E Honeywell Input module

There are three isolator devices used to protect critical elements of the SLC from faults on other SLC branches or segments.

• Fault Isolator Module I300

• Six Fault Isolator Module ISO-6

• Isolator Detector Base B224BI

A Fault Isolator Module on both sides of a device, or the combination of Isolator Base and Isolator Module is required to comply with

NFPA Class X requirements.

4.1.1 Isolating an SLC Branch

The module continuously monitors the circuit connected to terminals 3(–) and 4(+). Upon power-up, an integral relay is latched on. The 

module periodically pulses the coil of this relay. A short circuit on the SLC resets the relay. The module detects the short and disconnects 

the faulted SLC branch or segment by opening the positive side of the SLC (terminal 4). This isolates the faulty branch from the remainder of the loop preventing a communication problem with all other addressable devices on the remaining branches (labeled “Continuation of the SLC” in the figure below). During a fault condition, the control panel registers a trouble condition for each addressable device 

which is isolated on the SLC segment or branch. Once the fault is removed, the module automatically reapplies power to the SLC branch 

or segment.

4.1.2 Wiring an Isolator Module

The figure below shows typical wiring of an I300 Isolator Module: 

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CAUTION: MAXIMUM ADDRESSABLE DEVICES

• If relay or sounder bases are not used, a maximum of 25 addressable devices can be connected between Isolator Modules and/or

Bases. When relay or sounder bases are used, the maximum number of addressable devices that can be connected between Isolators

is reduced to seven. Isolator modules will not function properly when these limits are exceeded.

• When more than 100 Isolator Modules are connected to an SLC loop, the address capacity of the loop is reduced by two (2) addresses

for every isolator device in excess of 100.