Operation
Normal Operation
The sensor is considered in normal operation after startup procedure is complete
and the sensor does not display “FLT” (Fault) or “ALr” (alarm).
Gas Reading Display
The sensor displays the gas concentration in ppm (parts per million) or in % volume.
See table I for your sensor target gas, detection range and the unit of display.
Signal Output 4-20mA
The 4-20mA signal output is directly proportional to the detection range of the
sensor. The output signal generated is proportional to the gas concentration
displayed on the LED display of the unit.
Use the formula below to compute the mA output for any given gas concentration
or vice versa.
Formula to convert gas reading to mA:
( 16 x gas_reading ) + 4 = Analog output (mA)
Detection Range
Formula to convert mA to gas reading:
( mA Output - 4 ) x Detection Range = gas_reading
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(Note: Detection Range is the full scale range of the sensor)
PT295 Series Toxic Sensor Rev 5.1
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