Calibration System for Thermocouple Application Based on Technology of Virtual Instrument and Neural Network

Sensors of thermocouple is used in measure temperature system widely. However, the relation between thermocouple voltage E and temperature T, which is also called character of thermocouple, is non-linear. In automatic calibration system for thermocouple, means to realize transfer between thermocouple and temperature are method of tables and establish mathematical model of thermocouple character E~t. The paper combined technology of virtual instrument with neural network to found model on thermocouple character of E~t and the gradient descend algorithm with a momentum factor is used to adjust the parameters of RBF neural network. Then use it to measure thermocouple on-line. The paper introduces new methods about calibration system for thermocouple based on technology of virtual instrument. And it shows the hardware and software. Compare to conventional methods, it improves transfer precision, and applicable in practice.