DMTech FP9000A - 2.3. Connecting Devices

Instruction manual
Fire Alarm Panel FP9000A
DMTech LTD, 16 N.Haytov Street, Pleven Tel.: 0889992660 e-mail:office@dmtech-ltd.com page - 12 - of 20
ISO 9001:2015 Certified Company
2.3. Connecting devices
2.3.1. Connecting devices to a loop
A terminal strip and an example for connecting devices to the loop are shown in Fig. 8. Up to 250 devices can
be connected to the loop. It is recommendable that the first and the last device, and each 25th device in the loop
have a built-in short circuit isolator. The cross-section and the Ohm resistance of the cable used for connecting
the devices to the loop shall be carefully assessed, the loop length varies.
For convenience, a calculator has been developed for calculating the loop length and the cable cross section
according to specified number and type of devices.
++
- -
LOOP-1-1 LOOP-1-2ERT
++
- -
LOOP-1-1 LOOP-1-2
ERT
Fig. 8 Example of devices connected in a loop
2.3.2. Connecting devices to a conventional line
+
-
L
1
L
1
R
4.7k
EOL
1 ... n < 32
Fig. 9. Example of devices connected to conventional line