15
PRS-UM-DP32-EN-Rev.02-05.2019
Diagram 14: RS485 communication
Each detector connected to same S-DP32 panel should have unique address. Detectors
having same address would not be recognised by control panel. S-DP32 panel can
communicate up to 32 detectors. In case less than 32 detectors connected, control panel
would not show non-existent detectors. Unused detectors should be deactivated on channel
settings menu steps.
The
last
detector at the RS485 serial line should have the end of line resistor to enable the
total communication line. Otherwise control panel may not communicate to all, some or
none of the detectors. The end of line resistor controlled by end of line pins located on
address module of Prosense detectors and can be enabled via putting the jumper on end of
line pins.
Detector connections supply 24VDC power to detector and read the output signal from
RS485 serial ports. Thus connections should be made correctly to do not cause any damage
on the detectors. Cable diameter should be selected correctly via taking care about voltage
drop due to cable internal resistance. Thus the cable diameter should be increased while
distance increase between the panel and detectors. The applications show that connection
made with 1.5mm
2
cross section cable works fine in general.
Prosense RS485 Serial Communication Module for Prosense Detectors
Prosense produce a communication module to enable RS485 Modbus serial
communication. The board has 4 ports thus the detector connection should be made by 4
wire that 2 for power and 2 for RS485. The total length of the connection line should not
exceed 800 meters.
The wiring for detectors utilized with RS485 board should be done by using connection
cable EIA RS485 2 core wires with section 0.22 / 0.35 mm2 and shielded. Nominal capacity
between the wires should be < 50pF/m and nominal impedance 120 Ohms.
Detectors will be wired in daisy chain (bus) mode. We recommend not using star mode
connection due to negative impact of interference. Each detector should have unique
address number in the chain. The detectors with same address would not be recognised by
control panel. The address of detector can be adjusted via using DIP-Switch set on the
board or using the detector menu depending of the detector model:
