COLLECTION, EXTRACTION AND DISPLAY OF ERROR EVENT LOGS FROM A PLURALITY OF DEVICES OF A CONTROL SYSTEM

A device and a method for monitoring a networked PLC system, wherein all the abnormalities (events) generated by the devices (100,150) of the system are collected in a central event log (241) on a user terminal (200), then grouped based on generation times (242), classified into main and secondary event logs (243) and the cause of the error is identified and displayed to the user together with various informations on the event logs. Advanced knowledge and a verification time are required to narrow the problem from a large amount of generated event logs to specify the cause. It is necessary to analyze the troubleshooting of the abnormality generated in the network with a combination of pieces of information such as the physical connection, the logical connection, and the generation time relationship. It is necessary for the user to consider various pieces of necessary information in addition to the content of the event log. The visualization is achieved such that both the physical connection and the logical connection can be understood and the detected event (event log) is visually displayed while correlated with the visualized physical connection and logical connection. The control system of the embodiment displays the whole or a part of the state or the generated event log of the control system extending over the plural devices.