Three -way resistance temperature detecting system that heats of multichannel based on two constant current sources

The utility model provides a three -way resistance temperature detecting system that heats of multichannel based on two constant current sources, its structure includes: N way thermal resistance is connected to the ADC of integrated two constant current source I1 and I2, gain able to programme through multichannel difference multiplexer, ADC is connected to the control unit, constant current source I1, I2 process multichannel difference multiplexer assemble the thermal resistance lead wire L3 that flows through together, reference voltage sampling resistor rref to the power ground of flowing through at last respectively through two lead wire L1, the L2 of thermal resistance again, produce the electrical potential difference on thermal resistance RTD, process ADC is enlarged to be converted data signal to and transmits and give the control unit, by the temperature that draws the measurand after the the control unit receipt through the operation. It is based on the two constant current source uniformity of integrated are good, circuit design is simple, the cost is lower, the reliability is high, measurement accuracy is high.