System Description; Packaging And Temperature Rating - GE XMTC User Manual

1.4 System Description

The basic XMTC measurement system consists of an XMTC Transmitter mounted in a sample system. The sample
system is mandatory, and can either be provided by GE or constructed according to GE recommendations. The XMTC
is supplied with a standard 10 ft (3 m), 4-wire cable for power and output connections, with lengths up to 4000 ft
(1200 m) available. Optionally available from GE are a 24-VDC power supply to power the XMTC, a remote display
with programming and control capabilities, and several analyzers which can be interfaced with the XMTC.

1.4.1 Packaging and Temperature Rating

The XMTC transmitter is self-contained, consisting of the thermal conductivity sensor and associated electronics. It
requires 24 VDC power (1.2 A maximum at power-up), and provides a 4-20 mA output signal proportional to the
concentration of one of the gases in the binary sample gas mixture.
The XMTC is designed to be installed in a sample system as close as possible to the process sample point. Thus, it is
available in two environmental packages:
•
Weatherproof
•
Explosion-proof (with the addition of flame arrestors to the sample/reference gas inlet and outlet)
Each environmental package is available in a standard 2-port (sealed reference gas) version, or an optional 4-port
(flowing reference gas) version.
The XMTC is supplied with a standard measurement cell operating temperature of 55°C (131°F). An optional 70°C
(158°F) cell operating temperature is available.
Note: The 70°C (158°F) operating temperature should be selected only for high temperature applications, because it
results in reduced sensitivity.
XMTC User's Manual
Chapter 1. Features and Capabilities
3