65-2646RKS-SW M2A Transmitter Operator’s Manual
Chapter 2: Description
•
11
Internal Description
This section describes the internal components of the M2A. The internal components of the M2A
include the terminal PCB which provides for all the wiring connections to the M2A and the
control PCB which displays the gas reading and has the control buttons.
Figure 3: M2A Internal Components
Terminal PCB
The terminal PCB is encapsulated in epoxy for protection against moisture and physical damage.
It is mounted into the rear of the junction box with three standoffs and rests on a thin layer of
foam. A banana jack is screwed into each of the standoffs and used for mounting the control PCB.
The terminal PCB converts the electrical output from the detector to a signal which can be
displayed by the OLED display, a 4 - 20 mA signal (that is proportional to the detection range),
and an RS-485 Modbus output signal. The 4 - 20 mA signal may be used by a recording device,
gas monitor controller, or programmable controller. The Modbus output may be used to connect
the M2A to a Modbus network. The terminal PCB also controls three relays, one fail and two gas
alarm relays.
NO
Control PCB
M2A Junction Box
Terminal PCB
3/4 NPT Conduit
Opening for Wire Entry
M2A T RANSMITT ER
RKI INSTRUMENT S
3/4 NPT Conduit Opening, Plugged
