基于虚拟仪器技术实现PLC控制系统的状态监测和故障诊断

Condition Monitoring and Fault Diagnosis for PLC Control System Based on Virtual Instrumental Technology

在PLC控制系统的故障中,以传感器和执行器故障居多,一般还具备隐蔽性和突发性较强的特点,单纯依靠简单的测试工具和人工检查等传统手段难以及时发现和解决。研究并实现了在LabVIEW6 1编程环境下计算机与PLC的串行通信,利用虚拟仪器技术构建了基于RS485/232总线的PLC控制系统的状态监测和故障诊断平台,通过对系统操作状态、传感器和执行器状态、生产工艺流程状态的监测,实现对整个控制系统的状态监测和故障诊断。在工业现场的成功应用验证了该系统优于传统手段的结论,并且具有有效性和广阔的发展前景。

Malfunctions caused by sensors and executives make up of the majority in PLC control system, which are often characterized by concealment and suddenness, so that it is probably hard to check them out by traditional methods, such as general measurements and manual works. In this paper, serial communication between PC and PLC is studied and realized on the platform of LabVIEW61, and the condition monitoring and fault diagnosis platform for PLC control system is designed based on RS485/232 bus and virtual instrumental technology. The whole PLC control system is monitored and diagnosed by means of being separated into three parts, including manipulation of the system, conditions of sensors and executives, information of manufacture and technology. The successful utilization of the platform in industrial environment indicates its brilliant future and validity beyond traditional methods.