Chapter 2: Installation and configuration
LaserSense 100 Aspirating Smoke Detector Installers Handbook
25
Connecting the detector to a SenseNET/RS-
485 detector network
Up to 127 detectors may be linked in a single SenseNET bus, supporting a total
length of wire between adjacent detectors of up to 1.2 km (3/4 mile). Use a 120
ohm screened twisted pair such as Belden 9841 24 AWG for all loop
connections. The RS-485 A and B wires should be taken through a ferrite
(supplied) with a single loop.
Figure 15 below shows an example of two detectors linked into a 127-detector
bus with a command module and a number of LaserSense HSSD-2 detectors. It
will be noted that whereas the LaserSense HSSD-2 detectors have two
input/output buses (1A/1B and 2A/2B), this detector has only a single such bus
(A/B). Therefore, each bus terminal has an input and an output wire, compared
with a single wire in each terminal in the LaserSense HSSD-2.
Figure 15: Connecting the detector to a SenseNET network
(1) Command module
(2) Detector 1 (LaserSense HSSD-2)
(3) Detector 2 (LaserSense 25, LaserSense 100)
(4) Detector 3 (LaserSense 25, LaserSense 100)
(5) Detector 127 (LaserSense HSSD-2)
It is easy to join the input and output wires for each bus and screen connection
together and to solder or crimp a single wire or connecting ferrule to each wire
pair so that they are easier to fit into the screw terminals. If this is performed, it is
recommended that bare wire joints be insulated to prevent possible shorting of
the data bus, which will cause a drop-out of data on the SenseNET bus.
In the example shown in Figure 15 above, there could be a total length of RS-485
cable of up to 1.2 km (3/4 mile) between the command module and detector 2,
since these are all on a single bus. However, detector 2 is a LaserSense HSSD-2
which has a second communications bus (RS-485 bus 2) and an RS-485
repeater. This allows a further total of 1.2 km (3/4 mile) of cable until the next
LaserSense HSSD-2 in the RS-485 loop.
Summary of Contents for LaserSense 100
Page 1: ...LaserSense 100 Aspirating Smoke Detector Installers Handbook P N 10 3512 505 LS10 04 02MAR17...
Page 46: ...Chapter 4 Troubleshooting 38 LaserSense 100 Aspirating Smoke Detector Installers Handbook...
Page 52: ...Chapter 5 Maintenance 44 LaserSense 100 Aspirating Smoke Detector Installers Handbook...
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