Cartoner line, CompactLogix 1769-L33ER with a PanelView Plus 7 on the embedded port through the line switch. Monday an integrator hooked a new Ignition 8.1 gateway onto the same controller for the OEE project, and since then the PanelView lags. Press a button, 3 to 4 s before the indicator changes. Numeric displays update in jumps. Before Monday it was under 200 ms.
Ignition itself is fine, the OEE screens update quickly. The integrator has gone home and isn't answering his phone.
I rebooted the PanelView twice and went over the switch, no errors on any port, no duplicate IP. The PLC scan time has gone from 4 ms to 6 ms.
The only thing that changed is the gateway. Is there anything on the PanelView or in the L33ER that'll show me what the gateway is actually asking for, before I go asking for it to be pulled?
How many tags did the integrator subscribe, and in what tag group?
Gateway says 6,800 tags on that device and they all sit in one tag group set to 100 ms and I think he just browsed the whole controller and dragged the lot in, we have maybe 60 tags the OEE screens actually use.
Not the switch. 6,800 tags every 100 ms is 68,000 tag values a second off that embedded port. The driver packs them into far fewer packets than that, but it's still the SCADA and the PanelView sharing one port on a L33ER, and the PanelView's requests queue behind the gateway's. Poll rate matters more here than which controller it is.
Fix in the gateway. Make a tag group at 2 s, move everything into it. Make a second group at 100 ms or 250 ms and put only the 60 tags the screens need in there. Then delete the 6,000 tags nobody reads. Watch the embedded port's web page, packets per second, before and after.
Someone did a decent article on how SCADA polling lands on the PLC: https://plctr.com/introduction-to-scada-systems-and-their-integration-with-plc/
Add to that: set the screen-only tags to leased so they only poll fast while a client has them open.
Moved everything into a 2 s group and put the 60 OEE tags in a 250 ms group. PanelView's better, about 800 ms a button now. Not the 200 ms it was. Packets per second on the port went from 4,100 to 1,900. Haven't deleted the unused tags yet.
The 6,000 unused tags are still polling at 2 s, that's 3,000 reads a second for nothing. Delete them. Export the tag folder, prune it in a spreadsheet, import it back, or just delete the folders you don't use.
Deleted 6,400 tags, 400 left, 60 of those at 250 ms leased. PanelView's back to about 200 ms a button, scan time back to 4 ms, port at 600 packets a second.
The whole thing was the integrator browsing the entire controller into one 100 ms tag group and burying the embedded port. A slow group for everything, a fast group for the 60 tags the OEE screens actually read, and the rest deleted, and the panel is back where it was on Friday.
IT still want to swap the switch and I'm not sure I could prove that wouldn't have helped a bit as well. Leaving that one.
Thanks scott_m, redgum.
Let IT swap the switch. Costs nothing, keeps them off the gateway.