ZHENG Ze-xiang，JIANG Zhou-shu，HUANG Guo-hui，WANG Jian
（Energy Utilization System and Automation Institute，Hangzhou Dianzi University，Hangzhou 310018，China）
Abstract：Aiming at meeting the precision requirement of temperature measurement in industrial process，a highprecisiontemperaturemeasurementsystembasedonfourwiredplatinumresistancePt100drivenbyaconstantcurrent，was proposed. The measurement errorsand the methods to reduce the errors were analyzed；the designed circuits of constant current source，instrumentation amplifier，anti-aliasing filter sampling holder and A/D sampling，and the principle of parameters was accounted. As four-wired platinum resistance Pt100 used as the temperature sensor，driven by a constantmicro-current to generate measure voltage，the effect of lead resistance was completely eliminated and self-heating was efficientlydecreased. After acquisition signal through instrumentation amplifier，anti-aliasing filter and sampling holder，interfering signals wereeffectively filtered out，interference of themeasurementsystemwasreducedthestabilityreliabilityandaccuracyofmeasurementsystem
were enhanced. The results indicate that，the system is stable and reliable，and the temperature measurement error is less than ±0.03 ℃after calibration.
Key words：temperature measurement；high-precision；platinum resistance；constant-current；anti-jamming