In-situ gas analyzers
GM901
CO measurement for emission monitoring and process control
Your Benefits
- Nearly uncompromised measurement results thanks to direct in-situ measurement
- Quick and easy installation and commissioning
- Simple, user-friendly operation
- Economical because it is low maintenance

Overview
CO measurement for emission monitoring and process control
The GM901 gas analyzer is available as a cross-duct or probe type. As a result, it is suited to a broad range of applications – even for difficult measuring tasks such as high dust loads, overpressure, critical flow profiles, or high measuring gas concentrations.
At a glance
- Representative measurement along the duct diameter
- Operation via control unit
- Short response times
- Verifiable with gas-filled cell; gas-testable probe with test gas
Accessories
Spare parts
Applications
Service & Support
Technical overview
- GM901 cross-duct system
GM901 cross-duct system
Description Cross-duct version Measured values CO Measurement principles Gas filter correlation Measuring ranges CO 0 ... 500 ppm / 0 ... 20,000 ppm Relative to 1 m measuring path Response time (t90) 5 s ... 360 s Accuracy ± 5 %
Of measuring range full scaleAmbient temperature –20 °C ... +55 °C Conformities TUEV type-examination Electrical safety CE Mounting Mounting flange, DN125, PN6
Mounting flange, ANSI, 5″
Test functions Manual span check with gas-filled cell
- GM901 Measuring probe system
GM901 Measuring probe system
Description Measuring probe version Measured values CO Measurement principles Gas filter correlation Measuring ranges CO 0 ... 500 ppm / 0 ... 20,000 ppm Depending on active measuring distance and gas temperature Response time (t90) 5 s ... 360 s Accuracy ± 5 %
Of measuring range full scaleAmbient temperature –20 °C ... +55 °C Conformities U.S. EPA conform
Only gas-testable measuring probe (GPP)Electrical safety CE Mounting Single mounting point on the duct
Mounting flange, DN125, PN6
Mounting flange, ANSI, 5″
Test functions Manual span check with gas-filled cell
- Sender/receiver unit
Sender/receiver unit
Description Analyzer unit in measuring probe version Electrical safety CE Enclosure rating IP65 / NEMA 4 Dimensions (W x H x D) 254 mm x 338 mm x 304 mm (for details see dimensional drawings) Weight 6 kg Power supply Voltage 24 V DC Voltage Supply via control unit
- Sender unit
Sender unit
Description Sender unit of the cross-duct measuring system Measuring distance Cross-duct version 0.5 m ... 8 m Process temperature ≤ +250 °C With extended calibration ≤ +430 °C Process pressure ≤ 30 hPa
Depending on purge air supplyProcess gas humidity Non-condensing Electrical safety CE Enclosure rating IP65 / NEMA 4 Dimensions (W x H x D) 150 mm x 169 mm x 241 mm (for details see dimensional drawings) Weight 3 kg
Including purge air fixturePower supply Voltage 24 V DC Voltage Supply via control unit
- Receiver unit
Receiver unit
Description Receiver unit of the cross-duct measuring system Measuring distance Cross-duct version 0.5 m ... 8 m Process temperature ≤ +250 °C With extended calibration ≤ +430 °C Process pressure ≤ 30 hPa
Depending on purge air supplyProcess gas humidity Non-condensing Electrical safety CE Enclosure rating IP65 / NEMA 4 Dimensions (W x H x D) 150 mm x 169 mm x 405 mm (for details see dimensional drawings) Weight 3 kg
Including purge air fixturePower supply Voltage 24 V DC Voltage Supply via control unit
- Open measuring probe (GMP)
Open measuring probe (GMP)
Description Measuring probe in open design with integrated purge air control system Measuring distance See dimensional drawings Accuracy Pressure sensor 1 % Temperature sensor 1 % Process temperature ≤ +250 °C With extended calibration ≤ +430 °C Process pressure –60 hPa ... 30 hPa
Depending on purge air supplyProcess gas humidity Non-condensing Dust load ≤ 3 g/m³
Based on a 1 m measuring distance, depending on applicationElectrical safety CE Enclosure rating IP66 Dimensions (W x H x D) See dimensional drawings Material in contact with media Stainless steel 1.4571, stainless steel 1.4539 Power supply Voltage 24 V DC Voltage Supply via control unit Auxiliary gas connections Purge air Hose nozzle 40 mm Integrated components Flow monitor for purge air monitoring
PT1000 temperature sensor
Pressure sensor
- Gas-testable measuring probe (GPP)
Gas-testable measuring probe (GPP)
Description Measuring probe with gas permeable filter element for adjustment with test gas Measuring distance See dimensional drawings Accuracy Pressure sensor 1 % Temperature sensor 1 % Process temperature ≤ +220 °C Process pressure –120 hPa ... 200 hPa Process gas humidity Non-condensing Dust load ≤ 30 g/m³ Electrical safety CE Enclosure rating IP65 Dimensions (W x H x D) See dimensional drawings Material in contact with media Stainless steel 1.4571, stainless steel 1.4539, ceramics, PTFE Power supply Voltage 115 V AC, ± 10 % 230 V AC, ± 10 % Frequency 50 Hz / 60 Hz Power consumption ≤ 150 VA Auxiliary gas connections Test gas Clamp connection 1/4″ Integrated components PT1000 temperature sensor
Pressure sensor
Heating of optical surfaces
- GM901 control unit
GM901 control unit
Description The control unit serves as the human machine interface and is responsible for data processing and output as well as control and monitoring functions. Electrical safety CE Enclosure rating IP65 Analog outputs 1 output:
0/4 ... 20 mA, 500 ΩAnalog inputs 1 input:
0 ... 20 mA, 100 Ω
For gas temperatureDigital outputs 2 relay contacts:
48 V AC, 1 A, 60 VA / 48 V DC, 1 A, 30 WDigital inputs 1 input:
24 VSerial ✔ Type of fieldbus integration RS-232 Function Proprietary service interface CAN bus ✔ Function Internal system bus Indication LC display Status LEDs: "Operation", "Service", "Warning" and "Malfunction" Input Arrow keys
Functional keys
Operation Menu-driven operation via LC-display and membrane keyboard Model Steel sheet enclosure Dimensions (W x H x D) 210 mm x 381.4 mm x 108 mm (for details see dimensional drawings) Weight 4.3 kg Power supply Voltage 115 V AC, ± 10 % 230 V AC, ± 10 % Frequency 50 Hz / 60 Hz Power consumption ≤ 50 VA
- GM901 control unit, with extended connectivity
GM901 control unit, with extended connectivity
Description The control unit serves as the human machine interface and is responsible for data processing and output as well as control and monitoring functions. Electrical safety CE Enclosure rating IP65 Analog outputs 3 outputs:
0/4 ... 20 mA, 500 Ω
Electrically isolatedAnalog inputs 1 input:
0 ... 20 mA, 100 Ω
For gas temperatureDigital outputs 3 relay contacts:
48 V AC, 1 A, 60 VA / 48 V DC, 1 A, 30 WDigital inputs 3 inputs:
24 VSerial ✔ Type of fieldbus integration RS-232 Function Proprietary service interface PROFIBUS DP ✔ Remark Option Type of fieldbus integration RS-485 CAN bus ✔ Function Internal system bus Indication LC display Status LEDs: "Operation", "Service", "Warning" and "Malfunction" Input Arrow keys
Functional keys
Operation Menu-driven operation via LC-display and membrane keyboard Model Steel sheet enclosure Dimensions (W x H x D) 210 mm x 381.4 mm x 108 mm (for details see dimensional drawings) Weight 4.3 kg Power supply Voltage 115 V AC, ± 10 % 230 V AC, ± 10 % Frequency 50 Hz / 60 Hz Power consumption ≤ 50 VA
- Connection unit
Connection unit
Description For extending the internal CAN bus connection with a cable provided by the customer Electrical safety CE Enclosure rating IP65 / NEMA 4 Dimensions (W x H x D) 175 mm x 110.5 mm x 57 mm (for details see dimensional drawings) Weight 3 kg Power supply Voltage 115 V AC, ± 10 % 230 V AC, ± 10 % Frequency 50 Hz / 60 Hz Power consumption 60 VA Integrated components On-board 24 V power supply for the sender/receiver unit
- SLV4-2 purge air unit, 2BH1300, 3-ph
SLV4-2 purge air unit, 2BH1300, 3-ph
Description Unit to provide dust-free air for flushing of optical surfaces Gas flow rate 38 m³/h ... 63 m³/h
At 30 hPa counter pressure, depending on low pressure inside the filterAmbient temperature –40 °C ... +55 °C Electrical safety CE Enclosure rating IP54 Dimensions (W x H x D) 550 mm x 550 mm x 258 mm (for details see dimensional drawings) Weight 18 kg Power supply Three-phase current Δ: 200 ... 240 V AC, 50 Hz, 2,6 A, 400 VA Y: 345 ... 415 V AC, 50 Hz, 1,5 A, 400 VA Δ: 200 ... 275 V AC, 60 Hz, 2,6 A, 500 VA Y: 380 ... 480 V AC, 60 Hz, 1,5 A, 500 VA Δ: 270 ... 330 V AC, 50 Hz, 2,0 A, 400 VA Y: 465 ... 570 V AC, 50 Hz, 1,16 A, 400 VA Δ: 290 ... 360 V AC, 60 Hz, 2,1 A, 500 VA Y: 500 ... 600 V AC, 60 Hz, 1,26 A, 500 VA Δ: 230 V AC, 50 Hz, 2,7 A, 370 VA Δ: 115 V AC, 60 Hz, 3,0 A, 450 VA Δ: 220 ... 270 V AC, 50 Hz, 2,5 A, 400 VA Y: 380 ... 465 V AC, 50 Hz, 1,45 A, 400 VA Δ: 240 ... 290 V AC, 60 Hz, 2,6 A, 500 VA Y: 415 ... 500 V AC, 60 Hz, 1,55 A, 500 VA Auxiliary gas connections Purge air 40 mm Test functions Pressure switch (switching point –35 hPa) Integrated components 2-step air filter, type Europiclon, dust capacity 200 g