User Manual

3 7 65-2649RK-HC-04 M2A Transmitter Operator’s Manual
Recommended Modbu s Wiring
The recommended Modbus wiring for the M 2 A is illustrated in Figure 8 b el ow. In this
configuration, 5 wires are used for wiring the M2A into a Modbus system. Figure 8 also
illustrates typical alarm device wiring. The ground jumper must be removed in this wiring
configuration.
Figure 8: Recommended Modbus Wi ring
Adding an M2A to an Existing M2 Modbus Installation with Recommended Wiring
An M2A can be wir ed into an existing M2 Modbus system. The shape of the terminal PCB
will be different but the wiring connectio ns are identical and the ground jumper on the
M2A must still be removed.
Alternate Modbus Wiring For Existing Installations
Although the wiring shown in Figure 8 is recommended, it is possible to wire the M2A
into a Modbus system with only 4 wir e s in situations where a pre-existing system is be ing
replaced and wiring is already in place. Th is should only be done if wiring for a system
that is being replaced is already i nsta lled and it is no t practical to run anoth e r w ire. See
Figure 9 below for this wiring configuration. In this configurati on, the wire between the
“C” terminal on the M2A and the Common terminal on the Modbus controller is omitted.
Instead, the Common terminal on the Modbus controller is connected to the “-” of the 24
VDC power supply. The ground jumper must be installed in this wiring configuration.
Figure 9: Alternate Modbus Wiring
Power Su pply
Remove Ground Jumper
10-30 VDC
-
+
Modbus Controller
Input
Termin als
D0
D1
Comm on
To
Additional
M2As
C NC NO
ALAR M 1
C NC NO
ALARM 2
C NC NO
FAIL
See
Detect or
Wiring
- S +
A B C
RS 485 PW R/SIG
R W G B
LEL
- S +
A B C
RS 485 PW R/SIG
R W G B
LEL C NC NO
ALAR M 1
C NC NO
ALARM 2
C NC NO
FAIL
See
Detect or
Wiring
+
-
10-30 VDC
Power Supply
Input
Terminals
Modbus Controller
D1
Common
D0
C N C N O
ALAR M 1
C N C NO
ALAR M 2
C N C N O
FAIL
- S +
A B C
RS 485 PW R/SIG
R W G B
LEL
- S +
A B C
RS 485 PW R/SIG
R W G B
LEL
See
Detector
Wiring
C N C N O
ALAR M 1
C N C NO
ALAR M 2
C N C N O
FAIL
To
Additional
M2As
See
Detect or
Wiring