Research On Test Instrument In Freeway Soft Base Sedimentation

With the rapid development of the freeway construction in China, the technique of examination and monitoring to its constructional function is regarded more and more by scientists and engineers. Because there is a great difference in temperature between winter and summer in the northern region of our country, and still with the pass of soft land, to set up the freeway in this circumstance is still a practical puzzle that we have to solve. In order to solve these problems, the engineers should be supplied sufficient and continuous data for decision-making. It also helps to make the freeway that has consumed us many funds in perfect status. So the precise, examination of the major parameter of freeway is an important task.This thesis will introduce a new freeway sedimentation test instrument that based on digital signal process and field-bus. It can increase the automatic degree to sedimentation test as well as improve its test accuracy by on-line error compensation. And have the ability of field-bus communication and data storage, so the information can be communicated for long-distance or stored for long-term. With the SIMATIC S200 series PLC as a core and mated with the field-bus communication module and related components, I bring forward a complete design of hardware, and design some related procedure of the PLC and monitor computer.Because that the sensor has the problem of non-linear and temperature drift, some compensatory method should be taken to improve the accuracy of measure. In this design, the compensation is processed by software. To the non-linear error and temperature drifting error of displacement measure, I adopt the method of multi- variable linear simulation. Then turn the high-rank equation to low-rank equation by the method of dividing and store end-point data in the EPROM to increase the speed of process.To the problem that the sensor is easy to be disturbed or go down in the atrocious circumstance, I put forward a series hardware and software measures to improve the ability to anti-disturbance and reliability of the instrument. I also adopt a new simple on-line self-diagnose calculating method that can judge the common fault of the instrument basically but effectively.The field-bus technique is the third revolution of automatic measure and control in industry. It is a combination of advanced technique of computer, communication and control. It can realize the true disperse control and open type system, which have perfect mutual manipulate ability. Although the technique is still in the phase of development, its prospect is great. Network intelligence test technique that follows behind the development of field-bus technique certainly has the extensive future of practicability.