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Chapter 8: RS-485 Modbus Output
M2A-XL Transmitter Operator’s Manual
Ground Jumper
The M2A-XL includes a 2-pin ground header (see Figure 10) that is used when the M2A-XL is
used in a Modbus system. Every M2A-XL is supplied with a ground jumper (a jumper block)
installed onto this header. If the M2A-XL isn’t wired into a Modbus system or if it is wired into
one as shown in Figure 33, the ground jumper should be installed. If the M2A-XL is wired in a
Modbus system as shown in Figure 32, the ground jumper should be removed.
Recommended Modbus Wiring
The recommended Modbus wiring for the M2A-XL is illustrated in Figure 32 below. In this
configuration, 5 wires are used for wiring the M2A-XL into a Modbus system. Figure 32 also
illustrates typical alarm device wiring. The ground jumper must be removed in this wiring
configuration.
Figure 32: Recommended Modbus Wiring
Adding an M2A-XL to an Existing M2 Modbus Installation with
Recommended Wiring
An M2A-XL 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-XL
must still be removed.
+
-
10-30 VDC
Remove Ground Jumper
Power Supply
Common
D1
D0
Input
Terminals
Modbus Controller
Remove
Ground
Jumper
C
NC
N
O
AL
AR
M
1
C
NC
N
O
AL
AR
M
2
C
N
C
N
O
FA
IL
-
S
+
A
B
C
R
S
485
PW
R
/SI
G
R
W
G
B
LE
L
-
S
+
A
B
C
R
S
485
PW
R
/SI
G
R
W
G
B
LE
L
See
Detector
Wiring
C
NC
N
O
AL
AR
M
1
C
NC
N
O
AL
AR
M
2
C
N
C
N
O
FA
IL
To
Additional
M2As
See
Detector
Wiring