Calibration
Refer to Table at the end of this section for the recommended calibration gas for the
target sensor. Also see section on Spare Parts for part numbers for other calibration
accessories.
Following items are needed for the sensor calibration:
• Calibration adapter with tubing
• Magnet tool to activate the magnetic sensor on the transmitter board assembly.
• Calibration gas bottle with flow regulator. The flow of the calibration gas
should be between 0.5 to 1.5 LPM (liters per minute)
See Figure 8
Caution
Do not calibrate the sensor without using calibration adapter. Failure to use
proper adapter may result in faulty calibration and invalid span adjustment
by the microprocessor.
Model PT295 sensor can be auto calibrated without removing the enclosure cover
and declassifying the zone. A magnet tool is used to activate the internal switch to
initiate the calibration. Once the calibration is initiated the alarm relay will be
deactivated and the 4-20mA analog signal will be held at approximately 2mA to
avoid any false alarm.
Figure 7. Magnetic switch position to activate Calibrate Mode
PT295 Series Toxic Sensor Rev 5.1
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