现场PLC扫描周期对控制系统影响的研究及对策

Study and Measure of the Influence on the Scan Time of PLC to the Controlling System

现场PLC的循环扫描方式的扫描周期往往会对控制系统产生重要影响,只有深入了解、分析其对控制系统的影响,才能达到满意的控制要求.文章首先介绍了PLC的工作原理,然后从PLC工作方式角度,讨论了PLC扫描周期对系统可靠性、系统逻辑功能、系统故障诊断能力、系统I/O响应快速性等方面的影响,并结合实际提出了消除影响的措施.

The working way of PLC is able to produce important influence on the controlling system precision sometimes at the time of using PLC to control industry. Understand and analyse the influence on the scan time to it, could reach the satisfied control result. This paper from the point of PLC operating principle discusses the influence on the reliability, the fault diagnosis and I/O response speediness, provides the measure of eliminating the influence.