The Study Of Intelligent Gas Sensor Calibration System Based On DSP

In China the proportion of coal is70%of primary energy using, coal mining has become the important production activities. But in China geological structure of coal mine is complex, majority are high-gas coal mine. In order to ensure the safety of personnel and production, the government provides that each coal mine must be installed monitoring and control system. As tentacles of the system, sensors perceive of the actual situation of the mines through the acquisition of real-time data. The accuracy of sensors directly affects reliability of the system, so the coal mine safety regulations formulate the sensor calibration cycle. Catalytic combustion gas sensors are widely used in coal mine, because every7days the sensor must check once, and sensors are widely distributed, calibration workload is huge. Currently there are two categories gas sensor calibrator:manual calibrator and large desktop calibrator, there are some defects of them, such as low work efficiency, low accuracy. For these reasons, the subject of intelligent calibrator system which can automatically check8gas sensors at same time.TMS320LF2407is used for master chip of calibration system, the chip has a powerful data processing capabilities. The sensor output signal is frequency, the signal through the isolation amplifier link entry DSP; flowmeter output current signal, the signal through the filtering, isolation, amplification circuit input ADC conversion module; analog signal drive actuating mechanism who control gas flow, SPI module output digital signal, the signal through D/A and isolation circuit entry the actuating mechanism; the signal which control the relay through optical isolation and the driver circuit output; the digital signal which output from I/O pin adjust sensor zero, the amplified signal sends through the infrared emitting diode; man-machine interface touch screen through the SCI module to communicate with the DSP, the printer print the test table by the DSP I/O driver.This subject include software designing, first introduced the main program of the intelligent calibration system, then described the various subroutine, including the A/D sampling procedure, zero-point adjustment procedures, verification procedures, printing programs, and serial communication program, and anti-jamming design of hardware and software. Used ordinary PID, Smith Predictor and Fuzzy-Smith to control the flow of standard gas, comparison of three methods, finally choose Fuzzy-Smith predictor, and simulation in MTALAB, achieved the desired control objectives.The design of the subject gas sensors intelligent calibration system can automatically adjust the eight gas sensors, speed data processing, high precision, without manual adjusting the zero point, saving time and labor, applicable coal mines environment, with a certain degree of market prospects.