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65-2661RK-03-04 M2A Transmitter Operator’s Manual
Figure 3: 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. All four terminals 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 12 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.
Relay Terminal Strips
The right column of terminal strips consists of, from top to bottom, the fail, alarm 1, and
alarm 2 relay terminal strips. They are three-position plug-in style terminal strips. The
relay terminal strips are used to connect devices such as lights and horns that are
controlled by the relay contacts. The relay contacts are rated at 115 VAC, 5 amps. The relay
contacts may also be used to control higher rated relays.
Relay
Terminal
Strips
Ribbon Cable Connector
Termination Jumper
Detector Terminal Strip
Power/Signal Terminal Strip
Detector Current Adjust Pot
Programming Connector
(Factory Use)
Ground Jumper
Modbus Terminal Strip
C
N
C
N
O
AL
AR
M
1
C
NC
N
O
AL
A
R
M
2
C
N
C
N
O
FA
IL
-
S
+
A
B
C
R
S
485
PW
R
/S
IG
R
W
G
B
LE
L
