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Chapter 2: Description
65-2646RKS-SW M2A Transmitter Operator’s Manual
Two columns of plug-in style terminal strips are used to make all wiring connections to the M2A.
The column on the left consists of the power/signal, detector, and Modbus terminal strips. The
column on the right consists of the relay terminal strips. A 20 position connector at the bottom of
the terminal PCB is used to connect the terminal PCB to the control PCB with a ribbon cable. A 5
position connector on the left side of the terminal PCB is used by factory or field service
personnel to program the M2A.
Figure 4: Terminal PCB Component Location
Power/Signal Terminal Strip
The power/signal terminal strip is a three position plug-in style terminal strip located at the top of
the left terminal column. It is used to connect 24 VDC power to the M2A and to connect the 4 - 20
mA output signal to a device.
The signal output, the S terminal, does not have to be connected for the M2A to function. The S
terminal is used if you want to connect the 4 - 20 mA output signal to another device such as a gas
monitoring controller, chart recorder, or programmable controller (PLC).
Detector Terminal Strip
The detector terminal strip is a four position plug-in style terminal strip and is the middle terminal
strip in the left terminal column. The two terminals labeled “TOXIC” are used to connect the
detector to the M2A.
NOTE:
The detector is factory-wired to the M2A. See “Wiring the M2A Transmitter” on
page 17. for all wiring procedures related to M2A.
Modbus Terminal Strip
The Modbus terminal strip is a three position plug-in style terminal strip and is the bottom
terminal strip in the left terminal column. It allows connection of the M2A into a Modbus
network.
C
N
C
N
O
AL
A
R
M
1
C
NC
N
O
AL
A
R
M
2
C
N
C
N
O
FAI
L
Modbus Terminal Strip
Ground Jumper
Programming Connector
(Factory Use)
Termination Jumper
Relay
Terminal
Strips
R
S
485
A
B
C
-
S
+
PW
R
/S
IG
+
Ribbon Cable Connector
Power/Signal Terminal Strip
Detector Terminal Strip
T
O
X
IC
O
X
Y
+
