PLC를 이용한 엔코더의 펄스수방식과 펄스폭방식 모터속도 비교

Comparison of Pulse Count and Pulse Width Methods for Detecting Motor Velocity through Encoders Using PLC System

This paper compares two methods for detecting the velocity of DC(direct current) motor using encoders. The first method(method(I)) detects the velocity by measuring the angular displacement during a fixed time, and the second method(method(II)) detects the velocity by determining the time taken for a fixed angular displacement. The experimental set-up for comparing the accuracy of detection of the two methods comprised two PLCs(programable logic controllers), a touch screen and a PC. The velocity was deduced from the pulse count by PLC1, and pulse width time by PLC2. A TCP/IP(transmission control protocol/internet protocol) communication was implemented using a communication socket for transferring the data from each PLC to the PC. The data from the PLCs was fed to the with the help of LabVIEW. With the help of this experimental set-up, the shape of velocity as determined by the two detection methods was displayed graphically on the PC screen. At the same time, the data from each PLC was stored and analyzed in the PC. According to the experimental results, the velocity as determined by method(I) was found to be more accurate than that detected by method(II).