Design Of The Portable Data Acquisition System Of Coal Mine

Modern data measurement, data acquisition system is related to the instrument, which can correctly reflect the measured parameters. Today, the rapid development of coal mining technology, mining safety has been paid more and more attention, many down hole sensor also obtained the fast development and application. With the time growth of instrument application, influence the aging of electronic components and change at application environment, none measuring instrument can be long-term, stable, accurate operation. So the accuracy and stability of periodic detection instrument has become an important work, which can guarantee measure system stable operation and timely discover the warning. This paper describes a portable data acquisition system with excellent performance of chip production, completed the data acquisition work of coal mine.The core of this data acquisition system is DSP chip, which as the signal processor. DSP’s work is digital signal filtering, transformation, decomposition process. Effective components of signal will be sent to a storage device or on-chip FLASH by the cache data serial communication mode. Or transmitted, storied, display and output process by the ARM7control of signal.24bit resolution sigma-delta ADC serve as mine signal acquisition core, which can effectively reduce the error brought by the analog-to-digital conversion, write operation to the IO to control all functions. Extended to multi-channel switching and function with this chip, uses a complex programmable logic device to send the instruction code, complete each channel’s trigger, shutdown, frequency conversion, mode conversion settings of data acquisition system.In the system design process, fully utilizes the modern electronic design technology, draw the schematic diagram of the system by CADENCE software, the electronic component’s simulation model and the network model are used on the work of schematic drawing, analyzes the feasibility of component matching, and take the way of correcting to avoid a lot of mistakes on drawing. System design think about the function of electronic components and economic aspects, then find out the optimal tradeoff complete price. For example, the circuit uses several I2C chip as expansion, which not only expands the control interface but also save the cost of the system. In view of the limited characteristics of the control function of DSP chip, especially make a ARM chip as the core control of whole, its work is send the control command to DSP and analog to digital converter.The environment of coal mine underground is complex, and closed, in the measured signal inclusion interference signal, to meet the application requirements after signal collection, corresponding processing need to make, algorithm is the keys realization of processing function, this paper designed the fast Fourier transformation algorithm, finite impulse response filter and infinite impulse response filter algorithm, used to specific frequency signal and filter out specific signal.In view of the DSP and ARM power consumption, with making the calculation and estimation of current and combined with the characteristics of portable applications, choose the form of power supply system is switching power supply and the linear power supply scheme. In order to solve the problem of greatly interference from switching power supply of the system, made the corresponding planning for PCB routing. In the design of other circuits, also fully considered the electromagnetic compatibility of high-speed circuit and signal integrity problems, and make appropriate adjustments in the choice of components.Hardware development left interface for expanding again, which can use a variety of control mode, also can use a variety of interactive form, to facilitate the completion of portable operation.