Comelit Addressable Output Module, 1 Monitored Output, Isolator 41IOM000

Overview

A fire alarm system often has to do more than sound an alarm. It may need to release doors or switch other equipment when a fire is detected, and this module gives the panel one controlled output for that job.

It sits on the loop like any other addressed device, so the output is set up at the panel rather than wired back to it. The commercial fire alarm guide explains how an addressable fire alarm system differs from a conventional one.

How it works

• Loop powered: the module takes its own power from the loop and acts on commands from the control panel.
• Monitored output: a monitored output is one the system checks for wiring faults, rather than simply switching it on and off.
• Built-in isolator: an isolator cuts off a short-circuited section of loop so the rest of the loop keeps working.
• Separate supply for the load: the devices on the 24 V output are fed from a separate power supply, not from the loop.

Where to use it

With an IP21 rating and a working range of -10 to 60 °C, the module belongs in a dry indoor position close to the devices it controls.

Typical loads are sounders and beacons, and door holders that let fire doors close when the alarm operates.

What the figures mean in practice

• 24 V max. 750 mA: the most current the output can deliver. Add up the current of every device on the output and keep the total inside this figure.
• 0.27 mA in stand-by: the module's own draw from the loop at rest. The loop calculation adds it to every other device.
• 3.6 mA with 1 LED on: the draw rises when the LED lights, so allow for it in the loop calculation.
• 15÷32VDC: the loop voltage range it works across. Long loops lose voltage, so check the far end stays inside it.

Installing it

• Before you start: as a rule, take the loop out of service at the panel before connecting new devices.
• Fixing: fix the container to a flat wall where the transparent cover can be seen for inspection.
• Cabling: size conductors to the 0.4 ÷ 2.5 mm terminal range. Fire-resistant cable is the usual choice for fire alarm circuits.
• Commissioning: set the output's cause and effect at the panel, then test that the load switches as planned.

Planning your system

Each output needs its load and a separate 24 V supply, and a fire alarm power supply with battery standby is the usual way to provide it.

Where a load needs volt-free relay contacts instead, a Comelit relay module may suit the job better. Other loop devices sit among the fire panel modules and interfaces.

Check the panel's documentation that it supports this module before ordering, and have changes to a fire alarm system designed and commissioned by a competent person.