Design of Pt100 Temperature Measuring System Based on System-on-Chip for C8051F410

In order to reduce development costs, improve system stability and reliability, we designed high precise temperature measuring system with system-on-chip of C8051F410 as control core, using three wire constant current sources to drive Pt100 temperature sensor. The Operational principle and design basis of current source, signal conditioning and modulus convert circuits are analyzed, and also given circuit structure and circuit parameters. Experimental results show that absolute error is less than 0.15°C and accuracy level is 0.02 that can achieve real-time measure with high precisions in -50°C ~ 500°C range.