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Chapter 8: RS-485 Modbus Output
65-2640XL-04 M2A Transmitter Operator’s Manual
Recommended Modbus Wiring
The recommended Modbus wiring for the M2A is illustrated in Figure 9 below. In this
configuration, 5 wires are used for wiring the M2A into a Modbus system. Figure 9 also illustrates
typical alarm device wiring. The ground jumper must be removed in this wiring configuration.
Figure 9: Recommended Modbus Wiring
Adding an M2A to an Existing M2 Modbus Installation with
Recommended Wiring
An M2A can be wired into an existing M2 Modbus system. The shape of the terminal PCB will be
different but the wiring connections are identical and the ground jumper on the M2A must still be
removed.
-
S
+
+
PW
R
/S
IG
PW
R
/S
IG
+
-
S
+
RS
4
8
5
A
B
C
A
B
C
RS
4
8
5
+
-
10-30 VDC
Input
Terminals
Modbus Controller
Remove Ground Jumper
Power Supply
Common
D1
D0
+
C
N
C
NO
AL
A
R
M
1
C
NC
N
O
AL
A
R
M
2
C
N
C
NO
FA
IL
See
Detector
Wiring
C
N
C
NO
AL
A
R
M
1
C
NC
N
O
AL
A
R
M
2
C
N
C
NO
FA
IL
To
Additional
M2As
Remove
Ground
Jumper
TO
X
IC
O
X
Y
+
TO
X
IC
O
X
Y
See
Detector
Wiring
