Crowcon T4 - Sensors

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2.6 Sensors
T4 is available with the following sensor options:
• Oxygen Sensor
• Carbon Monoxide Sensor (Electro-chemical)
• Hydrogen Sulphide Sensor (Electro-chemical)
• Flammable gases sensor (Pellistor)
T4 also offers a Hydrogen immune carbon monoxide sensor if required.
T4 ammable gas sensor is congured and calibrated at the factory to detect methane.
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T4 ammable sensor must only be calibrated with methane.
However T4 can be congured to detect other ammable gases. The ammable gas to be detected
and the correction factor can be changed in T4 via the PC Application, Portables Pro 2.0.
The table below shows the ammable gases T4 (Type 2) can be congured to detect.
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Correction factors must only be used if the ammable sensor has been calibrated with methane.
Flammable Gas Correction Factor Response Time T90
Hydrogen 0.72 < 10 seconds
Methane 1.00 < 20 seconds
Propane 1.83 < 30 seconds
Butane 1.83 < 30 seconds
Pentane 2.22 < 30 seconds
2.6.1 Oxygen sensor
This sensor is in the form of an electro-galvanic fuel cell which is an electrical device used to measure the
concentration of oxygen gas in the ambient air. Set as default with both higher and lower alarm levels.
2.6.2 Electro-chemical sensors
Electrochemical gas sensors measure the volume of a target gas by oxidising or reducing the target
gas at an electrode and measuring the resulting current.
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