GE Security ZP3, Инструкция по установке и обслуживанию

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ZP3 Fire Control Panel Installation, Commissioning and Maintenance Manual
REV 11 (ISS 08/03/2010) Page 53
Z-Loop parameters
The Z-loop connects the ZP analogue addressable devices to the fire control panel. It is a 2-wire loop
that supplies power to the connected devices, and carries communication between each device and
the panel. Loops must be wired in correctly sized cable, and must be continuously screened.
Screening
Refer to Table 8 below. Cables must be shielded and shields must be continuous i.e. connected
through at each device. For class-A return loop wiring, both ends of the shield must be connected
to their earth terminals at the panel. For class-B single-direction wiring, the screen must be
connected to its earth terminal at the panel end, and left disconnected at the far end.
Shielded cable may be 2-core or multi-core. If multi-core cables are used, only Z-loop wiring or
the fire system DC wiring must be run inside the same screen. Third-party cabling, for example
public address and intercom systems, must not be run inside the same screen.
Z-loops should, where possible, be separated from high-voltage cabling. They must not run
adjacent to high-voltage cable for any substantial distance. Separation should be at least 100 mm.
Table 8: Screen connection wiring best practice
The ZP line loop screen connection must
be kept as short as possible to ensure the
best results for noise immunity, which is a
CE requirement.
The adjacent illustration shows two
screen connections. Option B (the
preferred method), has a shorter screen
connection even though this results in
longer plus and minus terminal wires.
SCREEN
Option A
SCREEN
Option B
4456-01
Alternate screen connection
See adjacent illustration. For optimum
connection, if thick mineral insulated
cabling is being used, we recommend
using EMC glands as an alternate method
for the screen connection.
Strip away the outer covering of the cable
to expose the metal sheath. Connect the
metal sheath directly to the ZP3 panel box
via the EMC conductive gland.
Cable sizing
Cable sizing depends upon the length of the Z-loop, and the number and type of devices
connected. Input devices, such as fire sensors, callpoints, and interface units, use very little
current, and allow the maximum loop length. Adding loop-powered output devices, such as
sounders, to the loop requires heavier cable and reduces the allowable loop length. See
Appendix
A: ZP Wiring guide on page 99 for more details.