Features:
1. Onboard power indicator light and TTL output signal indicator light;
2. It has DO switch signal (TTL) output and AO analog signal output;
3. TTL output effective signal is low level (when the output is low level, the signal light is on and can be directly connected to a microcontroller or relay module)
4. The voltage output in the simulation varies with the concentration, and the higher the concentration, the higher the voltage;
5. Gas output low voltage detected, gas output high voltage not detected
