Prosense DPX Series User Manual page 17

DPX Series Gas Control Panel can monitor detectors via RS485 serial connection. It can also
provide power for detectors. V+, V-(GND), A and B ports must be connected via using four-
wire cable. Detector connections supply 27VDC power to detector and read the output
signal of detector from A and B ports. Thus connections should be made correctly to do not
cause any damage on the detectors. Detector power connection should be done with
2
1.5mm cross section cable. The total distance between control panel and detectors should
not exceed 800 meters. Detector connections should be made with 4 core cable wire that 2
for power and 2 for RS485 and pin definitions are as follows:
Port
V+
V-
A
B
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 should be 120 Ohms.
The V+, V- ports and A, B ports are located different sockets in DPX Series Gas Control Panel
main board. These ports are also formed in different sockets on Prosense detectors. The
connections should be done with care to do not mix power and RS485 ports. All detectors
will be connected through one cable via hopping one detector to another till the last
detector on the line. The connection schema is given in Diagram 11:
DP Series Panel
V+
V-
A
B
The connection must have bus structure (daisy-chain) as given in above diagram16. Star
topology should not be used. Also devices cannot be used with mixed connection.
PRS-UM-DP-X-EN-Rev1.0-17.11.2021
Type Usage
output +24VDC to provide power for detector
output -VDC to provide power for detector
input RS485 port A
input RS485 port B
Table 9: Connection pin definitions
B A V- V+
Detector 1
Diagram 15: Panel to detector connections
B A V- V+
Detector 2
V+
V-
A
B
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