基于可编程逻辑控制器的多冗余高精度测频系统

基于台达DVP-EH系列可编程逻辑控制器（PLC）中PWD输入脉宽检测指令和DCNT高速计数指令开发出PLC测频系统。PLC测频系统提供了3路测频通道,3路频率信号同时输入的情况下,采用不同处理方法输出正确的频率信号,再经过区间比较、计数延迟的方法判断出频率信号的状态,给出了综合判断后的机组频率。

Multi-redundancy and High-precision Frequency Measure System Based on Programmable Logic Controller

Based on PWD input pulse width detecting instruction and DCNT high-speed counting instruction of programmable logic controller （PLC） of Delta DVP-EH series, a PLC frequency measure system is developed. It provides three frequency measure channels, so it has an ability to deal with simultaneous input of three-channel frequency signals and to adopt different treatment methods for output correct frequency signal. By comparison of range and delayed counting, frequency signal states are judged, and an integrated unit frequency after operation of PLC is given.