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/