Design and fabrication of digital PID controller with Wireless Modbus communication function

• Main Authors: Cheng-Yo Chen, 陳重佑
• Other Authors: Kai-Jan Lin
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/11649018343462838864

碩士 === 南台科技大學 === 機械工程系 === 99 === In this research, we constructed a digital PID controller with PID parameters auto tuning mode and develop master-slave controller modbus protocol communication via radio frequency wireless carrier. The input of the controller can be Resistance Temperature Detectors (RTD), Thermalciuple (TC), voltage input (0-10V), current input (4-20mA); the output control devices are relays and/or solid-state relays. The modes for temperature control are PID, P, PI, PD, FUZZY, adaptive control algorithm. The transfer rate of our developed wireless RF transmission can be up to 2400 bps, and the correct data transfer ratio is 99.7% in wireless communication at a distance of 10m. Digital micro-processer is an 8-bit micro-controller of 8051 structure. We use C compiler to develop all algorithm. The experimental on temperature control on a water tank is fulfilled at the temperature range between 32 ℃ to 60 ℃, and the steady-state error maintained at level ± 0.1 ℃. The behavior for cool start test of the controller is better than normal PID control mode in not-so-high overshoot (transient state) and more stable steady state.