Research On A New Calibrating System Of Coal Mine Gas Sensors

Gas sensor is one of the most important warranties of coal mine products, and there will be grievous accidents without timely warning from coal mine gas sensor under the situation of excessive harmful gases. Therefore, Our country has regulations about periodic calibrating on the coal mine gas sensor.Based on a series of industry standards for coal mine gas sensors from the State Administration of Work Safety, the calibrating system detects the output signals of coal mine gas sensors in normal operating situations, and automatically calculate coal mine gas sensors'stability of displayed value, basic error, response time and alarming function. It can easily and quickly complete the station of calibrating coal mine gas sensors, and guarantee the security in coal mine production.This paper implements a slave device of the calibrating system on ARM7,and host PC program of the calibrating system on VC++6.0, based on the study of principle in calibrating coal mine gas sensors. And the method and program of computing the core parameters are originally proposed too.The hardware of slave device of the calibrating system is divided into three parts: Power supply, Signal process and Master part. Each part can be also contained of different circuits. Power supply part is divided into Sensor power supply(DC 9V～24V adjustable), Signal acquisition chip power supply (DC9V), Main circuit power supply (DC5V), and The master chip and memory chip power supply (DC3.3V). Signal processing part is contained by the signal Acquisition circuit, the signal Processing circuit, the signal Storage circuit and signal Transmission circuit. Master part had two circuits: both Master chip circuit and Controlled gate circuit. The program of the slave device is programmed under ADS(ARM Developer Suit)that is matched with the main chip S3C44B0X.The host PC program of the calibrating system includes five parts: Communication management, Data storage and link, Human-machine interface, and Conclusions operation. And the part of the conclusions operation program is described deeply in this separate chapter. At present, The calibrating system of coal mine gas sensors is being tested in laboratory. The experimental results show that it has powerful data process capability, good anti-interference and high precision. This paper provides a noval viable method of automatic calibration of the coal mine gas sensors.