Monitoring timing behavior of multi-task programs running on industrial computers

In this article, the problem of measuring and visualizing the response time changes of sequences of partially ordered program tasks in a multi-tasking industrial computer control system is addressed. Response time, defined as the time elapsed from the moment of occurrence of an event in the controlled environment until a reaction of the program to the event, is a crucial parameter which is related with the safe operation of the environment. The proposed measurement technique is based on the use of a hardware-in-the-loop simulation of the controlled environment and the development of two hybrid probes, that are embedded in the multi-tasking system. These probes capture and timestamp the start time and completion time of the sequences of tasks triggered by events generated by the environment. Collected event data and traces are processed and visualized by the use of typical graphics and visualization tools.