Pm861.....total load 100% & cyclic load 70...how can we down this one...
We are using pm561......on normal task...250ms....load 100% and cyclic load is 70%...
When I change it from 250 to 400ms total load is 100% and cyclic load is near to 60 to 70%....
It is ok for safe operation??
I want define task individually for all program like 1.all motor---Normal task
2. all analog signal---normal task.... 3.ALL PID ---fast task.... it is posdible without interrupting the process???.
70% is the maximum cyclic load possible to achieve. The remaining 30% is kept for communication.
Arrange execution to obtain less than 70% cyclic load, preferably closer to 60%. Total load should not exceed 90%.
If total load remain at 100% even when reducing cyclic load, it indicates over committment in communication. Too many MMS transactions (Access Variables exchanged with other controllers, process panels, OPC DA traffic with the OPC server, etc).
The Control Builder M>Tools>Remote System>Show MMS Communication dialog will tell what kind of communication takes place.
It is a good practise to not have all code in one block, rather two or more with ample amount of "Task Offset" put in between (to create room for communication and housekeeping). With 0 Task Offset, controller will postpone communication to the remaining 30% reserve. Another way of seeing Task Offset is "splitting these 30%" over the whole period of execution. This is recommended for smooth communication.
Optical module bus will also take its toll (if modulebus IO is used). The bus should be run as slow as possible, 0 mean as fast as possible and is not recommended. A rule of thumb is "the optical module bus should run twice as fast as the fastest task in need of module bus IO", not faster.
The remaining load forming the total load is communication and housekeeping.
Yes you can reduce.
For this first execute task analysis and check any overlapping task.If so then try to execute task without overlapping by providing offset timer.
Second Split program like motor, analog signals, PID .... SO that we can assign each program to different task, also u can create more task along with thses basic task (slow,normal,fast). Depend on process, change cycle time and check.
Recommended is Base load 70% and cyclic load 50% for smooth operation.