Woodward MRM4, Manual, Page: 51 / 460

Installation and Connection
The available combinations can be gathered from the ordering code.
Modbus ® RTU / IEC 60870-5-103 via RS485
There are two different versions of the RS485 interface. By means of the
wiring diagram on the top of your device, you have to find out which
version is built in your device (Type1 or Type2).
Make sure that the tightening torque is 0.22-0.45 Nm [2-4 In-lb].
RS485 – Type 1 (see wiring diagram)
Electro-mechanical assignment Type 1 (see wiring diagram)
The Modbus ® / IEC 60870-5-103 connection cable must be shielded. The
shielding has to be fixed at the screw which is marked with the ground
symbol at the rear side of the device.
The communication is Half-duplex
EN MRM4 01/11 Page 51
1
X
10
3
2 3 4 5 6
P N P
*
N
*
+5V
GND
560
Ω
560
Ω
120
Ω
Protective Relay
6 4 5 3 2 1
R1
R2
R1
+5V
GND
R1 = 560
Ω
R2 = 120
Ω
P
N
P
*
N
*
Protective Relay