【摘要】 基于可编程序控制器(PLC)的水轮机调速器,受PLC内部高速计数器最高计数频率的限制,频率测量大多通过PLC外部单元来实现。通过对调速器工作原理及传递函数的分析,根据调速器动态特性、静态特性对频率测量的实时性和精度要求不同的特点,应用西门子公司S7-200PLC CPU 226基本单元中内置的高速计数器以及相应的外围电路,实现了水轮发电机组频率的测量。在满足技术要求的前提下,提高了调速器整机可靠性,降低了成本。更多还原

【Abstract】 Owing to the limited frequency of the internal high-speed counter of PLC, the peripheral unit of PLC is used for PLC-based frequency measurement of hydraulic turbine governors. On the basis of analysis of the working principle and transfer function of the governor, according to the different requirements of dynamic quality and static quality for response time and accuracy of frequency measurement, and by use of the high-speed counter in the SIMENS S7-200 PLC CPU 226 basic unit and peripheral circuit, frequency measurement of hydraulic turbine governors is realized. Consequently, the technical requirement is met, the reliability is enhanced, and the cost is reduced.更多还原