MONITORING DEVICE FOR SEQUENTIAL FUNCTION CHART TYPE PROGRAMMABLE CONTROLLER

摘要

PROBLEM TO BE SOLVED: To speedily specify a cause at the time of abnormality occurrence in a sequential function chart(SFC) type programmable logic controller(PLC). SOLUTION: The reference value of active time in any arbitrary step is stored, the active time in the arbitrary step in a program is measured and by having the measured active time exceeds the reference value, abnormality is detected. Also, it is stored whether respective steps are executed, and the program is displayed in the state of distinguishing abnormality detected steps, executed steps and not yet executed steps.