Optimization of coal mine gas sensor based on simulation and underground electromagnetic measure

In order to prevent from giving false alarms of gas sensors, caused by Electromagnetic Interference (EMI), a original method was presented in which the simulation and radiated emission measure were adopted to accomplish the analysis of immunity about gas sensor. The data was obtained with the R&S spectrum analyzer FSP7 and the Agilent portable oscillograph. With analyzing the influence of alarm and apertures on enclosure shielding properties through simulation and measure, the optimization of explosion-proof enclosure was finished according to the distribution of radiated interference characteristics. After optimizing, the false alarms significantly reduced. However, there were still occasionally false alarms when nearby electrical equipments were turned on and off. Therefore the complex EMI filter was put forward at power ports and the EMI was controlled within the allowable range. The results proved that the problem of false alarms had been resolved successfully. It is concluded that the improved shielding and filtering are highly significant in enhancing the Electromagnetic Compatibility (EMC) of the gas sensor.