65-2658RK-CH4-4 M2A Transmitter Operator’s Manual
11
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 16 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.
Termination Jumper
A two pin header with a termination jumper installed is located below the Modbus terminal strip. Leave this
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
NC
NO
AL
A
R
M 1
C
NC
NO
AL
AR
M
2
C
NC
NO
FA
IL
-
S
+
A
B
C
R
S
485
PW
R
/S
IG
R
W
G
B
LE
L
