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Chapter 2: Description
M2A-XL Transmitter Operator’s Manual
Two columns of plug-in style terminal strips are used to make all wiring connections to the M2A-
XL. 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-XL. On the combustible and CO
2
versions of the M2A-
XL, a factory adjust pot just above the programming connector is used to set the detector current.
Figure 10: 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-XL 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-XL 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).
-
S
+
A
B
C
RS
4
8
5
PW
R
/S
IG
R
W
G
B
LE
L
C
NC
N
O
AL
A
R
M
1
C
NC
N
O
AL
A
R
M
2
C
NC
N
O
FA
IL
Modbus Terminal Strip
Ground Jumper
Programming Connector
(Factory Use)
Power/Signal Terminal Strip
Termination Jumper
Ribbon Cable Connector
Detector Current Adjust Pot
(Comb/CO2 Type Only, Factory Adjust)
Detector Terminal Strip
(Comb/CO2 Version Shown)
Relay
Terminal
Strips