The existing hardware circuits can only measure a single point temperature in a small range owing to the influence of extremely little output voltage and the poor linear degrees of thermocouple on testing temperature, and it is difficult to meet the demand of practical use because of its low measurement precision. This system realized accurate measurement of multipoint temperature in a large range using optimization design to overcome the above-mentioned defects. It uses low maladjustment and high precision operation amplifier ADOP07 to constitute the inphase and shunt-wound difference amplification circuit to carry out non-electric measurement of thermocouple It also uses the CD4051 chip to compose the switch circuit at different time in order to realize the measurement of multi-thermocouple, and the ICAD538 is used to implement square operation in order to make linear compensation of temperature, finally sends the measurement value to single-chip computer through A/D converter to process data which is controlled by the application of modern fuzzy controlling theory so as to reach the aim of precise measurement and control. The experiments show the system can realize accurate measurement of multipoint temperature in a wide from 20 to 400°C, and the experimental results are satisfying.
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