Study Of Temperature Measurement System For Measurement Of Large Size Gage Rod

In precision length measurement,the environmental factors will not only cause the length variation of the measured object,but also influence the characteristic of laser's measurement system and other metrical tools. Thereby the measurement result is considerably influenced and it makes the precise measurement no sense. So the temperature measurement is very important.An instrument of temperature measurement with small size, high ability of processing, low cost, high precision and low power is exploitred and a kind of ARM7 embedded microcontroller LPC2214 is the core of measuring system in this design. In order to make sure the high precision,the part of measurement is composed with the Pt1000 platinum resistance temperature sensor and the 24-bit A/D converter. Many external function modules are extended based on the precision measurement such as the SD card, real-time clock, LCD and so on, these parts enrich the system functions , give the users convenience, make the instrument suitable in many occasion where high precision temperature measurement is required.In order to get rid of the non-linearity, a non-linearity compensating method based on software is presented in this paper. Compared with the hardware compensating, the software compensating can not only simplify the design of circuits, reduce the cost, but also enhance the ability of getting rid of stochastic noise, stability, and accuracy, at the same time, the capability of the processor is sufficiently presented. The experimentation showed that the strong power of data processing of ARM can satisfy the need of the real-time processing totally.This paper introduces the system from two facts which are hardware structure and driven program. And then, the principle of the non-linearity compensating method and the process of the software arithmetic are presented in details, at last, this paper proves that the platinum resistance temperature measurement system based on LPC2214 can work steadily for a long time, and the accuracy also satisfies the requirement totally according to the experimentation and calibration.