Highly-Accurate Temperature-Compensated Pneumatic Measurement Using Piezoresistive Pressure Sensor

Abstract

Pneumatic cylinder is known as one of the major transmission power sources in either machinery or automation operation. However, the sensor used in the pneumatic measurement is sensitive to harsh temperature environments. For this reason, a high precision pneumatic measurement using piezoresistive pressure sensor with temperature compensation is proposed in this paper. The pneumatic signal is read and amplified via A/D converter of the microprocessor. The relationship of pneumatic signal maximum level over temperature influence is also built up for a compensation purpose. A human-machine interface (HMI) with the computer is designed for real-time accurate calibration via RS-485. Based on a current loop transmitter, the measured pneumatic signal can be converted into an industrial standard (i.e., 4-20mA output). The experimental results verify that the proposed system can achieve an accurate measurement outcome below 0.5% error in both HMI and output current under a variety of temperature conditions.