Detcon 1600A-N4X - Manual (Page 13)

1600A-N4X
1600A-N4X Instruction Manual Rev. 0.2 Page 9 of 38
Figure 10 Model DA-4 and 4-20mA Gas Sensor Connections
4-20mA
INPUT
COMM
M
S
D
L
S
D
Typical Sensors
Sensor 2
Sensor 1
Sensor 3
Sensor 4
Figure 11 Model DA-4 and 4-20mA Gas Sensors
RS-485 Modbus™ Gas Sensors
Connect the five wires from the Modbus™ gas sensors (Detcon Model 600 and Model 700 Series types) to the
din rail mounted terminals labeled RS-485 “A”, “B”, and “Shld” and VDC “+” and “-”. Note: the controller
power supply is only capable of handling 3Amps accumulative. If the external sensors plus the controller’s
internal modules exceeds this rating, only three wires (RS-485 “A”, “B”, and “Shld”) should be used and a
remote DC power source should be utilized to provide DC power for the remote mounted gas sensors.
NOTE: A 120
: end of line resistor should be installed on the last gas sensor in the serial loop to enhance
communications reliability.