Small Signal Voltage-frequency Conversion Processing Method for SF6 Sensor

This paper provides a SF6 gas sensor signal processing method, including the following steps: SF6 gas sensor output small signal through the frequency converter voltage signal into frequency signal, in order to achieve SF6 gas sensor small signal frequency. The frequency signal of small signal is amplified, and the amplified frequency signal is input to the analog comparator. The duty ratio of PWM (Pulse Width Modulation) is adjusted by MCU. The duty ratio is input to the input end of analog comparator, and then the output end of analog comparator is connected to the input end of MCU. The MCU judges whether the analog comparator is flipped (the flip of analog comparator means that the input value of analog comparator is 0, When the output value of analog comparator is 1, it is flipped, if the output value is still 0, it is not flipped). And if the analog comparator flips, record the PWM frequency value at the flip time of the analog comparator. According to the mapping relationship between PWM frequency value and SF6 gas sensor output voltage of small signal, by searching SF6 gas sensor manual and calibration, restore the original SF6 gas sensor small signal voltage value. Small signals are digitally filtered to eliminate the interference of ambient temperature, environment and electromagnetic field when small signals of SF6 gas sensor are output. And compare SF6 gas sensor manual, reduce SF6 gas concentration.