Introduction
General Description
The Brasch Environmental Technologies TRNS Generation 2 Gas Transmitter is designed to
function as a gas sensor and signal transmitter. The transmitter consists of a sensor and
digital control circuitry. A linear proportional output circuit is able to provide analog signals to a
customer-supplied building management controller or a variable-frequency drive. An RS-485
circuit is able to provide two-way digital communication using Modbus RTU. A microprocessor
monitors the signal from the sensor and transmits that signal to the output as either an analog
or digital signal.
The sensor used in the transmitter operates on the electrochemical principle. A current is
produced when the target gas reacts chemically with an electrode inside the sensor. This
small current is changed to a voltage by the transmitter’s circuitry, amplified, and converted to
the proper output signal. This signal is proportional to the target gas concentration present at
the sensor.
The transmitter’s circuitry consists of a printed circuit board mounted inside a polycarbonate
housing. The housing has a NEMA 3R rating. Vents are located on the bottom and side of the
housing to allow the sensor access to ambient air.
IOM02
Rev 1.0 – December 22, 2020
4
