Portable gas detectors have a fixed detection range for various types of toxic and harmful gas detectors. Only when the measurement is completed within its measurement range can the instrument perform the measurement accurately. If the measurement is performed outside the measurement range for a long time, it may cause permanent damage to the sensor. For example, the LEL detector, if accidentally used in an environment exceeding 100% LEL, may completely burn the sensor. And toxic gas detectors will also cause damage if they are used for a long time at higher concentrations. Therefore, if the fixed instrument sends out an over-limit signal during use, the measurement circuit should be closed immediately to ensure the safety of the sensor
