The instrument is calibrated and tested before it leaves the factory. No calibration is required at field, but if certification of accuracy is required, then the following two methods are described below:
Gas Cylinder of known PPM
This method is used at the factory where sample gas mixture of high pressure with known PPM and balance with nitrogen can be used. Calibration can be done by switching on the instrument and sensor connected with alarm. (Both sensor and alarm are powered from the instrument so no external power is required).
Take the gas cylinder of known PPM(which is available for calibration with us) and put a needle valve and sensor in series. Remove the guard from the sensor, put the sensor in calibration chamber and close it properly (Avoid Leakage). Now instrument will read zero at display. Open the needle valve at cylinder, the reading will increase at display rated at cylinder PPM. Keep on the valve for few seconds to stabilise the reading then close the needle valve.
The reading will decrease again and come back to zero. If in case the reading has drifted at display, then turn the pot-4 to read as per PPM of cylinder. The calibration is over.
Glass ampoules of fixed PPM
This method is being used by field customers with low-pressure glass ampoules of known PPM, which is available along with calibration chamber. In using this method, Calibration can be done same as gas cylinder method. Take the glass ampoules of gas and fix up inside the calibration chamber near the screw for puncturing. Now switch on the instrument and connect the sensor. It will display zero reading. Now remove the guard from the sensor and put sensor inside of calibration chamber and close tight to prevent leaks. Puncture the glass ampoule by turning the screw. Gas will diffuse inside chamber and instrument will read display of the same PPM of ampoules if drift then turn the Pot-4 to read as corresponding display. Calibration is over.
We strongly recommend that an experienced service engineer or an expert in the field should carry out the calibration. Once the Pot-4 setting and correspondingly, calibration is disturbed, the detector will not function properly.