| Along with the development of society and the awareness of safety in production, the state and the government pay more attention to the safety in production and increase the investment in it, especially put the monitoring of poisonous and harmful inflammable and explosive gas the first. In coal mine safety monitoring system, mine gas sensor directly related to the sensitivity and reliability of the monitoring system, plays an important role in monitoring the system. State Production Safety Supervision Administration introduced a series of perfect periodic calibration requirements for the verifying of the mine gas sensor.The use of mine gas sensor calibration system in verifying of the mine gas sensor can automatically and roundly verify the stability of display value, response time, and alarm function of the gas sensors and by correcting the error which detected insure the coal mine safety monitoring system works normally, to further ensure the safety of the production in coal mine.The design combines the mine gas sensor verify principle and infrared signal control theory, direct at the needs of practical application, we design an unmanned adjustment system based on C8051F MCU,this system consists of a piece of C8051F020SCM as control core, bring together with the pneumatic control module, infrared control module, flow control module compose a full control system; use another piece of C8051F020SCM as data acquisition core, finish the collection of mine gas sensor output frequency signal, the amount of output analog signal, breakpoint loading. Infrared control module is the core of the unattended tuning system control, therefore we chiefly research the infrared control principle and infrared signal transmission agreement then develop a reverse engineering of existing infrared remote control signal transmission protocol by means of the microcontroller according to the infrared signaling protocol to send infrared control signal to verify the incorrect mine gas sensor. Flow control module with integrating the back of saturated PI controller to achieve the gas flow controller control deviation of automatic correction. Frequency measurement module is adopted to increase the measurement cycle for improved frequency measurement principle of the measurement cycle, to reach the ore within the gas sensor frequency output range such as precision measurement purposes. In order to achieve the data communication between host computer and the next crew, using the standard Modbus communication protocol and developed serial communication software.The process of this system has to finish the experiment debugging and into the trial run with standard gas, the operation results show that:the control system with high accuracy, real-time data and high, high precision and strong anti-interference ability, good stability. For sensor users and quality control personnel the system solve the toxic and hazardous gas sensor test calibration and provide complete and reliable sensor performance parameters, realize the mine gas sensor unattended adjustments. |
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