30305238 Issue 1.02
Features
Digital communication with fire alarm control
panel (FACP) ensures immunity to
electromagnetic interference and reliable
operation.
Optoisolated output signal, resistant to
industrial frequency interference.
Description
P-9903 Loop Relay Module is 24VDC powered. The
input and output of loop signal are insulated to
ensure transmission of detector signal which
enhances interference-resistant ability of the system
and prolongs the loop distance.
P-9903 is mainly used in applications where strong
electromagnetic interference exists or where the
loop needs to be extended to longer than 1000m.
The relay module consists of a transmitter circuit,
a receiver circuit, and an isolated power supply.
Optocoupler isolation technology is used between
the transmitter and receiver circuit.
Connection & Wiring
1. Terminals are shown in Fig. 1.
Z1IN Z2IN 24VIN 24VIN Z1o Z2o
Fig. 1
Z1IN, Z2IN: loop input terminals,
polarity-insensitive, connecting with loop
output terminals of the FACP. The distance to
the FACP shouldn’t be longer than 1000m.
24VIN, 24VIN: 24VDC power input terminal,
polarity-insensitive. It shares the ground with
output loop of the relay, requiring the voltage
between 18VDC and 27VDC.
Z1o, Z2o: Isolated loop output terminal,
polarity-insensitive. It can connect with 1～242
loop devices.
2. Recommended wiring: 1.5 mm2or above fire
cable for the polarity-insensitive signal loop and
24VDC power supply, subject to local codes.
P-9903
Loop Relay Module
56mm
85mm
50mm
128mm
116mm
M4 Screw
Fig. 2
Installation
Mounting dimension is shown in Fig. 2. If the relay is
used to resist interference, it should be installed
outside the area suffering from the interference. For
example, it can be installed inside the FACP. If it’s
used to lengthen communication distance, it should
be installed where the distance to the FACP is not
longer than 1000m. It should be indoor-installed
using M4 screws.
Application
Typical application is shown in Fig. 3.
+24V
GND
P-9903
LOOP
24VIN 24VIN
Loop Device Loop Device
Z1IN Z2IN
Z1o Z2o
Cable Length ≤1000m
Fig. 3
Troubleshooting
1. Possible reasons and fixing methods if there is
no output voltage:
There may be fault with the power, please
clear the fault.
The output loop may be shorted, please fix the
shorted point.
Internal power may be damaged, please return
it to the manufacturer for repair.
2. If there is an error with the transmission of loop
signal,
