Design of High Precision Pneumatic Transducer Using Piezoresistive Pressure Sensor

A high precision pneumatic transducer using piezoresistive pressure sensor is proposed in this paper. The pneumatic pressure signal can be read and amplified by the microprocessor via A/D converter. A human-machine interface (HMI) with the computer is also designed for real-time accurate calibration via RS485. Based on a current loop transmitter, the processed pressure signal outputted from the microprocessor can be converted into an industrial standard, i.e. 4-20mA output. The experimental results show that the proposed system can achieve an accurate measurement outcome in output loop current with very low error below 0.5%.