3.3.1.2. Sensor calibration and remote programming
When fabricated the sensor is typically programmed by the manufacturing company. The sensor’s technical specification provides the calibration values which should be programmed into the memory of micro processing unit of sensor node by a user. However, during its operation the sensor parameters degrade which necessitates periodical calibration approximately every year.
To calibrate the sensor, its output response voltage for a detected and known gas concentration has to be measured and recorded in the memory of the sensor node. The remote calibration of the sensors starts with the sensor node ‘wake up’ and its setting in calibration mode. While in this mode, the user can remotely set up the thresholds for gas detection and set other important parameters, e.g. measurement time, device ID.