9752 Installation Guide
3. Installation
497098 Issue 3
Page 23
Connecting Detector Circuits to the Main PCB
The connectors for the detector circuits, or zones, are on the left-hand edge of
the main PCB in the control unit. The table below summarises the number
and type of zones that can connect to the main PCB of the control unit. Use
Command 21 to specify which of these wiring types you are using. You
cannot specify different wiring types for different zones.
If you require more zones, fit one or more expanders as explained on page
25). There can be up to 24 zones on expanders.
Control Unit
Wiring Type
Zones
8
four-wire CCL with common tamper
8
two-wire FSL
CCL Connections
Figure 15 shows how to connect four-wire CCL zones.
1
2
Zone 1
Zone 2
Global Anti-tamper
Zone 3
Zone 4
Zone 5
Zone 6
Zone 7
Zone 8
Tamper loop
Zone 1
Zone 2
Alarm contacts
Alarm contacts
Figure 15. CCL Connections (common tamper)
FSL Connections
Each FSL zone is a "Fully Supervised Loop" using a two-wire closed loop. As
shown in Figure 16, the loop uses resistors of different values to differentiate
between "Circuit" and "Tamper" signals: a 2K2 resistor fitted in series at the
end of the wired loop (EOL) and a 4K7 resistor fitted across the alarm contact.
With the loop in a normal state and the alarm contacts closed (shorting out the
4K7 resistor), the total resistance of the loop is 2K2. When the alarm contacts
open (removing the short from the 4K7 resistor), the resistance of the loop
increases to 6K9 and so the control unit detects an alarm condition. If a
tamper device opens, the loop resistance becomes infinite (open circuit) and
so the control unit detects a tamper signal.
