TIA V17, CPU 1516-3 PN/DP on a tray sealer. Added a recipe compare FC two weeks ago at the customer's request and since then the CPU stops about twice a day. Buffer, newest first:
"CPU goes to STOP mode. Cause: maximum cycle time exceeded twice in one cycle"
"Time error. Maximum cycle time exceeded. OB 80"
"Time error. Maximum cycle time exceeded. OB 80"
The new FC runs a FOR loop over 4000 recipe entries every scan, in OB1 with the rest of the recipe code. I raised the max cycle time from the default 150 ms to 300 and it still stops, just less often. The customer wants 6000 ms so it never stops, which I'm not doing.
Is the FC really that slow, or is the HMI loading the CPU? They added a second panel around then and I'm out of ideas past that. Is 4000 entries a scan too much for OB1, or am I missing something about the panel?
Online & diagnostics, Cycle time. What does it show for shortest, current and longest? Post the three numbers. And what's in the loop body, a UDT compare or a few Ints?
Leave 6000 alone. That's not a limit, that's a blindfold.