Hi all, trying to figure out a jam counter on the wrapper. 1756-L71, Studio 5000 V32. I'm online, put Jam_Count in the Watch window and it sits at 0. The operator screen on the PanelView shows Jam Count going up every time there's a jam, right in front of me, 14, 15, 16. Same tag name, I checked the spelling three times.
I closed and reopened the Watch window, went offline and back online, and looked for forces, there aren't any. I'm on placement and nobody's documented this plant, so I'm guessing the PanelView reads from somewhere else and the tag I'm looking at is just old.
Is there a way to tell where the PanelView is actually reading from, or could someone explain what I'm missing?
In the Watch window, what does the Scope column say next to Jam_Count? And in the PanelView project, the tag on that numeric display, does the reference start with the shortcut and then a program name, like {Wrapper}Program:MainProgram.Jam_Count?
Scope says MainProgram. The PanelView reference is {Wrapper}Jam_Count, no Program bit. I searched the tag database and there's two Jam_Count tags. One under MainProgram, one at controller scope. I think I've been watching the wrong one, haven't I?
Two tags, same name, different scope. Controller one is the live one.
Yes, on this L71. Without Program in the reference the PanelView reads the controller scoped tag, so that's the one the logic writes. The MainProgram one is a leftover nothing writes to. Watch window, scope dropdown, pick the controller. Cross Reference will show which one has writes, then delete the dead one. Writeup on the scope thing here: https://plctr.com/how-to-use-rockwell-plc-watch-window/
Switched the Watch window scope to the controller, Jam_Count went 16, 17 with the screen. Cross Reference on the MainProgram one shows zero writes, one read from a rung that's been disabled forever. Deleted it this morning after the supervisor said yes.
So two tags called Jam_Count, one program scope and one controller scope, and I'd been watching the dead one all along. Controller scope in the watch window, dead one deleted.
Now I'm wondering how many more of these are in here. Started a list.
Thanks hannah and rsdave.
The list will be long. Every plant has one.