Carbon monoxide transmitter for detecting CO concentration in air

HML and HML-N carbon monoxide transmitters are designed for measuring carbon monoxide in underground parking garages and parking halls. The measuring cell is an environmentally friendly electro-chemical cell with a long life, good long term stability, and high accuracy. As the sensor is heated, the transmitter is working also in temperatures > -30°C. The output of 0…10 V or 4…20 mA is available on the ranges of 0…100 or 0…300 ppm CO concentration for controlling ventilation.


The recommended transmitter calibration interval is one year. HMV exchange kit can be used to ensure the correct transmitter function. A new calibration report is delivered with the exchange kit.

Technical details

Supply power: 24 VAC/DC (22…28 V), 2 VA
Measuring range: 0...100 ppm or 0...300 ppm*
Accuracy (at 25°C): ±10 ppm < 70 ppm values
±15 % of value for > 70 ppm values
Output signal: 0…10 VDC < 1 mA* or
4…20 mA < 500 Ω
Time constant (t63%): 1.5 min
Warm-up time: 6 min
Operating temperature: -30…40 °C
Protection standard: IP54, cable gland downwards
Dimensions (w x h x d): 100 x 113 x 46 mm
Sensor life time: < 7 years (40 % rH, 20 °C)
* factory settings

Other Indoor air quality: