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Showing results for tags 'periodic'.
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So I have done quite a bit of googling and i even reached out to our integrator but i am having a nuisance fault of "Watchdog Fault" Caused by periodic task overlap. The task is scheduled to start again before it is finished. I added all of the Programs in this task MAX scan time and it only came out to 102 ms. the task is scheduled for every 100 ms. The watchdog is set at 500 ms. The task is currently running at 146-148 ms and i confirmed this using a TON instruction at the end of the task followed by a reset. What can i do to get this down?? What would be the best practice? Move programs into another task? Make the task continuous? What would happen if i did make it continuous? I tried setting the task to 150 ms and the controller DID NOT like that. I was barely able to get back on line with it to change it back to 100 ms. CPU usage is at 91% and this task accounts for around 50% of that. Thank you all in advance for your help.
OK, I have a program in a Control Logix 5561 controller(ver. 19.52) that every time we go online with it, the communication between the PLC and the PC running RS5000 is so slow you cannot navigate the program efficiently. I am new to this facility but I noticed the programmer used 20 different periodic tasks to organize their program, mostly running at 30ms intervals. several are set to 10ms and some are even set to 3ms. I have gone through and found out that the short interval tasks have been overlapped 10's of millions of times, and the combined total of all scan times is over 160ms. I have a strong feeling this could be causing our comms bog down and possibly other erratic behavior but would like a second opinion. This machine has 2 indexing dials, with work stations that do work between indexes, Pick and Place operations, etc. Is there even a need to be running these with periodic tasks? All thoughts are appreciated. Thank you