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7 . 1 3 C a b l i n g I n f o r m a t i o n
7.13.1 Planning the Cable Routes
Care should be taken to avoid running alarm cables in the same trunking as, or otherwise close to, cables
carrying signals that may cause interference – e.g. telephone cables, etc.
Similarly, where practical, avoid routing cables close to equipment capable of generating interference – e.g.
fluorescent lighting, welding equipment, etc.
Never run alarm cables in the same trunking as mains cables.
7.13.2 Screened Cable
When screened cable is used, the screen should be terminated at the control panel (or RIX module) only.
For best results, connect to the metalwork immediately at the point of cable entry into the housing, with a
'pigtail' not exceeding 5cm.
Terminals are provided in all PCX housings for this purpose.
Cables should not be looped inside the housings, or routed across or underneath printed circuit boards.
Ensure that screen connections are continuous through all intermediate detectors, junction boxes, etc.
7.13.3 Wiring Specifications
NOTE: The following specifications must be observed when installing PCX alarm systems.
General Principals
1
Routing:
No alarm system cable should be run with other cables carrying AC or digital signals.
2
Insulation:
Should be protected by the use of grommets, etc. where appropriate.
3
Specifications:
The following specifications for cable types and distances are important for reliable
operation.
RS-485 Wiring
1
Cores:
4-core minimum. Use of 6-core and doubling up of power supply core is
beneficial to minimise voltage drops, but never double communications
connections.
2
Cable Type:
As much as it is good practice to use screened cable, the PCX RS485 bus will
operate with standard alarm cable up to 300m. After 300m a 485 repeater device
will be required to be fitted when wiring keypads, prox readers, RIXs and ROXs.
The PCX system requires standard 7/0.2 unscreened alarm cable when wiring
keypads, prox readers, RIXs and ROXs.
Screened cable should be used if the system has been installed in hostile
environments where there maybe high levels of Radio Frequencies or mains
interference, e.g. heavy plant welding.
Example: Twisted pair, e.g. Belden 9744 (unscreened) or 9502 (screened).
3
Wiring Format:
Parallel, 'daisy-chained'.
4
Cable Length:
Overall network max. 1Km.
5
Termination:
Extreme end points fitted with 470Ω resistors between A (D3) and B (D4).
End of Line Input Wiring
1
Cores:
2
Cable Type:
3
Wiring Format:
4
Cable Length:
RINS871-3
4-core.
Standard alarm cable, screened in poor environments.
Detectors individually wired, using EOL resistors mounted at detector.
Max. 1Km per detector.
P C X S M S A N D P C X 2 5 6 S Y S T E M M A N U A L
Page: 29
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