Connecting Devices To The Network - Securacom SEC8 Installation Manual

Connecting Devices to the Network

Before connecting devices to the control panel network, isolate
ALL power from the control panel (AC Mains & Battery). Do not
continue if there is still power present on the control panel.
Connecting devices with power still present on the
control panel may damage the device or control panel
and invalidate any warranty.
Remote keypads and zone expanders are all connected to the
same network terminals located at the bottom left hand corner of
the control panel and may be connected serially (daisy chain), in
parallel (star) or any combination of the two.
Control Panel
Network
Cable Type and Distances
For improved immunity to electrical noise, the use of screened 4
core cable is recommended. The screen should be twisted
together and wired into the (–) terminal at the control panel only.
The maximum recommended distance for devices when using
standard 7/0.2 alarm cable is:
250m for each branch when using the star (parallel)
configuration
When using a daisy chain (series) configuration the
maximum distance will depend on the number of devices
connected on the chain. The more devices that are
connected, the shorter the distance to the last device (this is
due to voltage drop in the cable)
Whichever method of wiring configuration is used, ensure that the
voltage between the '+' and '–' terminals at each device is no
lower than 10.0V when the system is running on the standby
battery.
Control Panel
Network
P0031-LI-01.00
Remote Keypad
Address = 1
12V 0V
500 metres
Remote Keypad Remote Keypad
Address = 1 Address = 2
0V R D
12V 12V
Network Connections
The network is made up of four terminals incorporating power and
data. To ensure correct operation, all four terminals on the device
must be connected to the corresponding terminals on the control
panel, or previous device. The table below shows each terminal
and its description:
+ +12V Supply
- 0V Supply
R Data Return
D Data I/O
500 metres
Remote Keypad
Address = 2
R D 12V 0V R D
Overcoming Voltage Drop
There are several ways to overcome voltage drop:
Use thicker lower resistance cable. Standard 7/0.2 alarm
cable has a resistance of 8Ω per 100m
Double up on the power connections – this will require using
a 6 or 8-core cable rather than a 4-core cable
Install a power supply to power the device locally, remember
to common the two negative connections
Installing a Power Supply
When a power supply is installed, the 0V connections on the
power supply must be connected through to 0V on the control
panel and the +12V connection between the control panel and
the device must be disconnected (see figure below).
1km
Remote Keypad
Address = 3
0V R D 0V R
12V
Remote Keypad
Address = 3
12V 0V R D
D
Disconnect +12V
from control panel
Remote Keypad
Address = 4
12V 0V R D
Remote Keypad
Address = 4
0V R D
12V
12V 0V
Power Supply
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