ENMET PGD2Manual.pdf - Manual (Page 21)

ENMET Corporation PGD3-IR
18
10 S
ENSORS
10.1 Infrared Sensors
The PGD3-IR instrument is fitted with miniature infrared sensors for the detection of flammable gases (except hydrogen) and carbon
dioxide. The instrument can house up to 2 infrared sensors. They are ‘EEx d’ certified types and must only be replaced with sensors
labelled with the certification details stated in section 2 of this manual.
The flammable sensors are non-selective that is, they will detect a range of hydrocarbon gases. However, during manufacture of the
PGD3-IR instrument the sensors are calibrated to methane. See Section 6.11 for relative responses for other hydrocarbon gases.
10.1.1 LEL Flammable Sensor Specification
Gases detected Various combustible gases and vapors
Range 0 100% LEL
Resolution 1% LEL
Operating Voltage 3 to 5 Volts dc
Operating Current 80 mA
T
90
Response Time < 30 Seconds
Linearity Linear 0-100% LEL Methane
Long Term Sensitivity 1% LEL / month
Long Term Zero Drift < 3% LEL / year
10.1.2 0-100% Volume Flammable Sensor Specification
Gases detected Methane
Range 0 100% Volume
Resolution 0.05% Volume
Operating Voltage 3 to 5 Volts dc
Operating Current 80 mA
T
90
Response Time < 30 Seconds
Linearity Linear 0 - 100% Volume Methane
Sensitivity Drift < 5% volume methane / month
Range Changing Automatically carried out by the instrument
10.1.3 Carbon Dioxide Sensors
Range 0 5% Volume CO
2
Resolution 1% LEL
Operating Voltage 3 to 5 Volts dc
Operating Current 80 mA
T
90
Response Time < 30 Seconds
Linearity Linear 0 - 5% CO
2
Zero Drift +/ 500ppm / month