General Information

Core Description

The XMTC-6C-11 is a high-stability, micro-processor based thermal conductivity gas transmitter featuring an explosion-proof enclosure and a 2-port sealed reference gas cell package. Fully equipped with an FEP-coated aluminum measuring cell and robust 316 stainless steel wetted parts, this unit works seamlessly inside harsh industrial processing environments to deliver precise, real-time 4 to 20 mA binary gas concentration tracking for critical hydrogen-in-nitrogen mixture loops.

Specific Application

• Generator Hydrogen Cooling Systems: Monitors the purity level and concentration of H2 gas in electric power industry cooling circuits to maintain asset security.
• Metal Furnace Atmosphere Control: Tracks H2 in N2 concentration balances within industrial metal heat-treating atmosphere chambers.
• Hazardous Environment Synthesis: Performs inline binary gas analysis in chemical production zones requiring explosion-proof (Class I Div 1 / Zone 1) certified instruments.

Ordering Information

System Compatibility

Electrical Protocols: Employs an isolated 4 to 20 mA loop-powered analog output alongside digital communication channels running over RS232 or RS485 interfaces.

Sampling Hardware: Mandatorily pairs with a dedicated sample system calibrated to deliver clean gas at a nominal flow rate of 0.5 SCFH (250 cc/min) under standard atmospheric pressure.

Software Interfacing: Fully compatible with standard PC interface configurations designed for digital process value adjustments, calibration triggers, and real-time error logging.

Alternative Models & Functional Differences

XMTC-5C-11 (Weatherproof Configuration): Shares an identical FEP-coated aluminum 2-port design, 316 stainless steel wetted parts, and software features, but utilizes a standard weatherproof enclosure instead of an explosion-proof housing. It is restricted to safe non-hazardous plant sections.

XMTC-2C-11 (4-Port Flowing Reference): Uses an explosion-proof design but upgrades to a 4-port flowing reference gas framework featuring a CPVC cell body. It provides enhanced precision for targeted non-zero based mixtures but demands a continuous supply of external reference gas.

Features

• Ultra-stable glass-coated thermistors
• Single or dual gas push-button calibration
• PC interface package for digital output
• Type IP66/4X construction
• ATEX, IECEx, FM and CSA certified for Zone I and Division 1 hazardous areas

The microprocessor-based XMTC is a compact, rugged, online thermal conductivity transmitter that measures the concentration of binary gas mixtures including hydrogen, carbon dioxide, methane, helium and many others. The analyzer also combines computer enhanced signal measurement with fast-response software, real-time error detection and digital communication via an RS232 or RS485 interface.

Theory of operation

Two ultrastable, precision glass-coated thermistors are used— one in contact with the sample gas and the other in contact with the reference gas (such as air in a sealed chamber). The thermistors are mounted so that they are in close proximity to the stainless steel (or Hastelloy®) walls of the sample chamber. The entire transmitter is temperature-controlled, and the thermistors are heated to an elevated temperature in a constant-current Wheatstone bridge. The thermistors lose heat to the walls of the sample chamber at a rate that is proportional to the thermal conductivity of the gas surrounding them. Thus, each thermistor will reach a different equilibrium temperature. The temperature difference between the two thermistors is detected in the Wheatstone bridge, and the resulting bridge voltage is amplified and converted to a linear 4 to 20 mA output proportional to the concentration of one of the constituents of the binary or pseudo binary gas mixture