What does the following picture mean for an Allen Bradley SLC device
Shall I worry? How can I improve?
Ignition 8.3.8 (b2026071409)
Thanks in advance, regards
It means the plc cant keep up with the comms load to Ignition/the rest of the network.
You should be seeing laggy tags, missing trend data etc for any connected to this plc as a result.
What SLC are you connected to? Can you upgrade?
Yes. Any overload above a few percent indicates a real problem--your tags aren't being scanned at the configured pace.
Check your PLC's status file for these settings, first:
Be aware that if throttled with those settings, unthrottling will impact PLC scan time.
Otherwise, there's not much you can do other than reduce the number of tags monitored.
Hi @pturmel , thanks for your hints. I cannot touch the PLC - old thing. I've just tried increasing the tag group rate to 10.000 and overloading is gone - tags are temperature values and the customer is happy with a larger scan rate too.
You could consider two scan groups, one for slow information that rarely changes (alarm set points, ranges, etc) and then one faster group for your realtime data. That way you can have better updates but lessen the load on the PLC/Network