any gas detectors are now available to replace detection sensors, but this does not mean that a detector can be replaced at any time. Whenever the sensor is replaced, the instrument must be calibrated in addition to the necessary sensor aging. The corresponding standard gas shall be used for calibration.

The calibration methods of combustible gas alarm and toxic gas alarm are consistent. Firstly, a zero gas (generally clean air or standard gas without measured gas) and a certain concentration of standard gas are used to calibrate the instrument, and the calibration curve is obtained and stored in the instrument. During the measurement, the instrument will be measured gas into electrical signals, after calculation, converted into the actual concentration value. Therefore, it is essential to calibrate the instrument at any time and to calibrate the instrument regularly.

It is suggested that all kinds of instruments before using the gas detector, the standard gas used in the instrument should be tested in response to ensure that the instrument really plays a protective role. If such an instrument is used as a safety alarm in an open place, such as an open workshop, the portable diffused gas detector can be used, because it can continuously, real-time and accurately display the concentration of toxic and harmful gases on site. The fixed detector is generally a two-body type. The detection head composed of sensor and transformer is installed in the detection site as a whole. The secondary instrument composed of circuit, power supply and display alarm device is installed in a safety place as a whole to facilitate monitoring. The detection principle of gas detector is the same as that mentioned above, but in the process and technology, it is more suitable for the continuous, long-term stability and other characteristics required by fixed detection.

In general, each sensor corresponds to a specific detection gas, but any gas detector is unlikely to be absolutely specific. Therefore, when selecting a gas sensor, the detection interference of other gases to the sensor should be understood as much as possible to ensure its accurate detection of specific gases.