Title :
Measuring and Controlling of Analog Signal Based on High-Speed I/O Port of PLC
Author :
Ma, Hongtao ; Wang, Xiaojun ; Zhou, FenPing
Author_Institution :
Coll. of Inf. Sci. & Eng., Hebei Univ. of Sci. & Technol., Shijiazhuang, China
Abstract :
Frequency signal is gotten from voltage signal by external V/F converter, and then is sent to high-speed counter of PLC. As a host, CPU222 of Siemens S7-200 series PLC is used. Through programming PLC, input voltage is measured by high-speed I/O channels. High-speed digital pulse of variable duty cycle produced by PLCpsilas PWM pulse generator is turned into voltage signal of amplitude-adjustable after external RC low-pass filter circuit filter to achieve controlling of output analog. The method reduces the cost of measurement and control system via replacing expensive analog I/O modules. Peripheral circuit design and PLC program are given. Through analyzing and comparing data, it is found that the system can achieve plusmn 0.1% accuracy.
Keywords :
programmable controllers; I/O port; PLC program; PWM pulse generator; RC low-pass filter circuit filter; analog signal; control system; frequency signal; peripheral circuit design; programmable logic controllers; variable duty cycle; voltage signal; Counting circuits; Digital filters; Frequency conversion; Low pass filters; Programmable control; Pulse circuits; Pulse generation; Pulse width modulation; Space vector pulse width modulation; Voltage measurement; A/D; PLC; high-speed I/O;
Conference_Titel :
Measuring Technology and Mechatronics Automation, 2009. ICMTMA '09. International Conference on
Conference_Location :
Zhangjiajie, Hunan
Print_ISBN :
978-0-7695-3583-8
DOI :
10.1109/ICMTMA.2009.144
