Industrial Gas Analyzer

The XGA301 Industrial gas analyzer from Michell Instruments provides a convenient platform to measure oxygen, dew point, CO2 and CH4. The analyzer can be supplied in one of two bench-mounted chassis and with up to three sensors fitted.

Standard features include two fully-programmable alarm circuits (voltage-free contacts), programmable analog outputs, RS232 communications and complete Windows-based data-logging software.

The industrial zirconia oxygen sensor provides fast and accurate oxygen analysis over the range of 1 ppm to 30%* O2 and delivers stable and repeatable readings, with a typical response time of less than 5 seconds for a 90% response to a step change in gas compositions. The zirconia sensor is heated, and temperature-controlled to enable oxygen ions to conduct. An internal pressure sensor compensates for small changes in the gas pressure to maintain accurate and stable readings. An optional, variable speed-pump draws a gas sample at a flow rate set by the user between 0 to 1.2 Nl/min.

The Easidew Sensor is available for dew points down to –100°C in combination with another sensor within the XGA301A2’s chassis.

*Analyzer is not suitable for enriched oxygen.

Product Features

  • Sensor choices from zirconia, galvanic electrochemical, infrared and ceramic impedance technologies
  • Variable speed pump (optional)
  • Zirconia sensor cleaning facility which can be operated at any time during use
  • Intuitive HMI with back-lit display
  • Two fully-programmable alarms
  • 2 x voltage outputs and 2 x 4–20 mA outputs
  • Digital RS232 output
  • Software package includes live graphing and Excel™ compatible data-logging
  • Password protection


Technical Specification

Operating temperature +5 to +35°C
Warm-up time 3 to 4 minutes @ +20°C
Maximum inlet temperature +50°C
Sample flow rate 0 to 1.2 Nl/min, user-selectable with pump
Maximum inlet pressure 1 barg
DisplayXGA301A1/A2:16 x 2 character (9mm) back-lit LCDM
XGA301A3:20 x 4 character (9mm) back-lit LCD
Sample connectionsStandard 4mm ID / 6mm OD nipple — gas fittings on front panel
Optional: Rectus™ or Swagelok® 6mm fittings, rear panel fittings for XGA301A1 only
Dimensions (H x W x D) XGA301A1: 290 x 250 x 250mm (11.4 x 9.8 x 9.8”)
Panel-mount XGA301:4U (177) x 300 x 290mm
XGA301A2/A3: 195 x 355 x 340mm (13.8 x 10.4 x 5.9”).*
Weight XGA301A1: 3.5kg
XGA301A2/A3: 4 to 5.5kg

* Maximum dimensions including needle valve and with the feet extended.

Electrical Specifications
Analog outputs 2x 4-20mA outputs, assignable to any of the fitted sensors
2x alarm relays
2 x 0–10 V (XGA301A1 only)
2 x 0–5 V (XGA301A2/A3 only)
Digital output RS232 ASCII
Power supply 90–260 V AC, 50/60 Hz
Moisture and Pressure Sensors
Sensor Type Water Dew Point** Pressure (2m lead), remote sensor
Accuracy ±2°Cdp of reading <±0.25% of full scale standard, enhanced accuracy of 0.1% and 0.05% available at extra cost
Ranges -65 to +20°Cdp
-100 to +20°Cdp
0-5 barg
0-10 barg

** For full specifications, see the Easidew Transmitter datasheet

Sensor Options and Specification

Sensor Type Zirconia Electrochemical Infrared
Measurand O2 O2 O2
(Low range)
H2 present CO2 CH4
Accuracy ±1% of reading (logarithmic scale) or 0.5ppm whichever is greater. ±1% of full scale at 25°C 1013mbar ±2% of full scale at 25°C 1013mbar ±2% of full scale at 25°C 1013mbar
Inlet Pressure 1barg max 0.7 – 1.4bara 0.7 – 1.4bara
Response Time Approx 5 seconds for a 90% step change (gas flow rate of 1 Nl/ min-1) Approximately 30 seconds (T90) Approximately 30 seconds (T90)
Stablility ±2% of reading per month ±2% of range (over 12 months)
Life Expectancy >17,500 hours Up to 5 years in normal usage (O2 < 1,000ppm for low range sensor) ~10yrs
Output can be user configured 0-10ppm, up to 0-30%