User Manual

FIREli nk - 25 – Installation Manual Page 29 of 40

9-5-0-344/ISS4/OCT10

5.2 Connecti n g a FIRElink-25 to a SenseNET/RS485 Detector

Network

Up to 127 detectors may be link ed i n a si ngle S enseNET bus, support ing a total length of wire between

adjacent detec tors of up to 1.2km.

In t he abov e example, two FI REli nk - 25 detectors are linked i nto a 127- detector bus wit h a Command

Module and a number of other FIREli nk detector s. It will be noted that wher eas the FIRElink-400 unit s

hav e two input / output buses (1A / 1B and 2A / 2B), the FI REli nk -25 has onl y a singl e such bus (A / B)

and ther efore each bus terminal has an input and an output wire, compar ed with a single wir e in each

terminal in the FIRElink-400.

For this reason, it may be easi er to join the input and output wires for each bus and scr een c onnecti ons

together and to solder or crim p a si ngle wir e or connect ing fer r ule to each wi r e pair so that they are easier

to fit into the screw termi nals. If this is done it is rec ommended that bare wire joints be i nsul ated to

prevent possibl e short ing of the data bus, which will cause a dr op- out of data on the SenseNET bus.

In the above example, ther e c ould be a tot al length of RS485 cable of up to 1.2km between the

Command Module and Detector 3, sinc e these are all on a si ngle bus. However , Det ec tor 3 is a

FIREli nk - 400 whic h has a second communi c ations bus (RS485 bus 2) and an RS485 repeat er. This

allows a further total of 1.2km of cable until the nex t FIRElink - 400 in the RS485 loop.

In t he abov e example, if det ectors 4-126 (not sho wn) were all of the FIREli nk - 25 type then the total length

of wir ing between detect or s 3 and 127 would be limited to 1.2km. However, each additional FIRElink - 400

detec tor wi r ed up usi ng both RS485 buses woul d allow an additional 1.2km of c abling to be added to the

RS485 l oop.

5.3 Connecting a FIRElink-25 to an addressable Fire Panel

An Addr essable Programmable Interface Card (FIRElink-A P IC) may be used to dec ode detector

informati on and to relay this to a Fi r e P anel.

The FI RE link-APIC is fi tt ed to the four mounti ng studs on the FI REl ink-25 PCB using the supplied screws

as shown below: