Double the pt100 resistance, line 3 and line 4 connection to the influence of the temperature measurement accuracy release date: 2019 - 05 - 23 reading

Pt100 resistance is double, three and four wire terminal 1 influence on accuracy of temperature measurement. Pt100 thermistor of three kinds of connection mode is different in principle. Two-wire system and three line measured by bridge method. Finally set up the relationship between temperature and the analog output value. Four wire no bridge, only persistence current source power supply, voltmeter measurement, measure the resistance value is given. 2. Pt100 resistance of three kinds of connection mode's influence on the measurement precision of cable resistance and contact resistance will produce a great impact on the Pt100 platinum resistance temperature measurement precision, platinum resistance of three lines or four lines connecting method can effectively eliminate the influence. Testing equipment ( Temperature controller, programmable controller input, etc. ) 。 ) Connected to the thermistor has four connection terminals: 1, 1, 5, 5 - 。 Among them, the input and output to provide constant current thermistor, used to monitor the input and output end voltage change of the thermistor temperature changes and sequence detection. Please refer to the below: ( 1) Four wire system from the ends of the thermistor raises four lines. Circuit circuit and voltage measurement circuit in the process of connecting separate connection. High measuring accuracy, need more wires. ( 2) Three wire system is raises three line. Pt100B platinum resistance connection, the current loop and voltage measurement circuits of the benchmark of a wire ( The input and output terminal short circuit testing equipment) 。 A little better accuracy. ( 3) Two-wire system leads to double. Connection Pt100B platinum resistance, current loop and voltage measurement circuit together ( The testing equipment of I and V side short circuit, I and V and short circuit) 。 Accuracy of measurement.