LEAD WIRE RESISTANCE COMPENSATION FOR TWO-WIRE RESISTIVE TEMPERATURE TRANSDUCERS
Keywords:
thermoresistive converter, communication lines, resistance coefficient weakening relative error.Abstract
Method of lead wire resistance compensation for two-wire resistive temperature transducers based on the commutation inversion of measuring current with analogue signal averaging on the lead-wire inputs is suggested. The structural and principle scheme of a two-wire resistive temperature transducer has been elaborated. The analysis of incomplete compensation of lead wire resistance influence caused by inequality of reference currents is conducted. The coefficient of lead wire resistance influence mitigation at the relative error of reference currents 0,01 makes 40 dB, and rises with relative error decrease. The influence of transient processes in lead wires at the moment of reference currents commutation on the accuracy of temperature conversion has been regarded. The research of the designed scheme of a resistive temperature transducer is realized by the method of computer modelling in the Electronics Workbench software medium. It has been ascertained that the fall of an error caused by transient processes is possible with misbalance of reference current values. At the difference of reference currents 0,03 мА , the absolute error of lead wire resistance influence does not exceed 0,05°С at the lead wires resistance value 5 Ом, and 0,5°С at the lead wires resistance 30 Ом.
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References
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