Controllogix Controller Workload

Is there a point to where a Controllogix processor receives too many requests for data from external/remote Ethernet devices that it degrades the performance of the processor itself?

jmaty23 said:

Is there a point to where a Controllogix processor receives too many requests for data from external/remote Ethernet devices that it degrades the performance of the processor itself?

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Not quite "degrades the performance of the processor...", the processor will still be running at clock speed.

It will just affect the scan time, which "degrades the performance of the application..." I'm sure that's what you meant, though.

That is assuming, of course, that the "System Overhead Time Slice" is set high enough to handle the incoming data requests, and the resultant sending of same.

In my experience, the communication functions will suffer before the processing of logic is impacted. We’ve been known to set the proportion of time executing logic as low as 15% without impacting processing speed, thereby allowing much more time for comms and other internal housekeeping.

I suggest experimenting with that setting to determine what works best for you.

MasterBlaster said:

In my experience, the communication functions will suffer before the processing of logic is impacted. We’ve been known to set the proportion of time executing logic as low as 15% without impacting processing speed, thereby allowing much more time for comms and other internal housekeeping.

I suggest experimenting with that setting to determine what works best for you.

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Since V16, you can set the SOTS extremely high, to accommodate for comms "splurges", with the check-box set to resume scanning logic as soon as it can. This is the best setting under most circumstances - I have seen and used SOTS 80 to 90% also.