Panelview Forget Value on power down

[marvedjensen]

hi guys i am pretty new to pv and i have this problem

The PV forgets the set value on power down and this will be a problem for the operator when the value tag is blank the value is set to zero

https://youtube.com/shorts/kjKUqdmomgo

how to get it to remember selected value on power up/down

 

[parky]

Not done much in panelview but a few things come to mind. Battery in panelview (unlikely)
The tags in the PLC are not retentive i.e. they loose the value when the power is dropped (again unlikely) as if these are read/written to the plc then would expect them to be 0, The other thing are these write only, so powering down the panel the panelview may tags may not display the values, it looks like the values are there for example if the first digit was a 5 when you power down then when powered up you increment it it goes from 5 to 6 that means that the data is there but for some reason it is not refreshed the data on the screen, If the tags are in the plc & not just on the PV (i.e. manipulated by a script) then check they are read/write, this would force the PV to read the values perhaps.

 

[marvedjensen]

Not done much in panelview but a few things come to mind. Battery in panelview (unlikely)
The tags in the PLC are not retentive i.e. they loose the value when the power is dropped (again unlikely) as if these are read/written to the plc then would expect them to be 0, The other thing are these write only, so powering down the panel the panelview may tags may not display the values, it looks like the values are there for example if the first digit was a 5 when you power down then when powered up you increment it it goes from 5 to 6 that means that the data is there but for some reason it is not refreshed the data on the screen, If the tags are in the plc & not just on the PV (i.e. manipulated by a script) then check they are read/write, this would force the PV to read the values perhaps.

its panelview 800 model 2711r-t4t its programmed in (ccw) connected components workbench
and the tags its mate in the pv external tags. the plc is reading them but when we drop power its goes blank on pv like in the video and the plc program reads 0 from the tag

 

[parky]

Not done that model of PV, however, some HMI's can have the tag as read only, write only or both, cannot remember off hand the ones I have seen with that ability so it might be worth checking that those fields are read/write, also again with CCW never used it & assuming you have a micro800 processor (again not used it) are the tags retentive. i.e. keep the values when powered down.
Try just dropping the power off the panelview & leaving the PLC on & disconnect the coms, if the values are still in the plc then it is definitely something on the PV, then connect the coms, after a short time they should appear if the tag is read/write.

 

[joseph_e2]

I also haven't used that model before, but I remember there being a setting in the old Panelview standards to "write on powerup". There may be a similar setting for the 800.
I like parky's suggested test too, to make sure it's really the PV800 doing it.

 

[parky]

It really seems it's not reading the values from the plc, so if there is no values the spin button object I suspect is either pretty poorly written i.e. needs a kick up the you know what or it's corrupted, or it's not reading the values back from the plc if the latter try forcing a value in the plc & see if it changes.
I do remember once having something similar on VB an edit field I put on the window when first run would be blank even though the opc server was reading the values from the PLC, if you clicked on the box the values came up I re-loaded VB & it worked.
One other thing once powered & it's blank try pressing one of the up/down keys if it then displays for example before you switched off 5, then when you press the up/down if the value is either +- 1 i.e. 6 or 4 then the PV is reading the values from the plc (assuming that it is only the PV turned off) then it must be the PV As I said before, try just switching off the PV not the PLC & disconnect the coms then if you switch off the plc & back on if the values are still in the plc but if you connect the coms they go to 0 then it is almost certain it's the PV.
One other thing, on some HMI's the spin button control has settings so it can be set to limits for example the minimum input is say 1 & the max is 7 then normally if you try to take it above 7 or below 1 it will not change however, if the value in the plc is forced to above or below these limits it may blank the digit display.

 

[KuulKuum]

ID: QA36878 | Access Levels: Everyone
PanelView 800: Numeric Increment/Decrement button last value

https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/1032460/loc/en_US#__highlight

Question: Can the Numeric Increment/Decrement button be configured to return to last selected value on power cycle?
Answer: No. The object writes on manual value selection at runtime. Therefore, it defaults to zero (0) on power cycle or reset so unexpected machine movement does not occur on power up.

If possible, you could modify the screen by adding read tags of the PLC values as separate "numeric display" from the Toolbox>Display selection.

You also might have to change how you are implementing the numeric increment/decrement by utilizing a "Confirm" entry for proper operation.

 

[parky]

Interesting... Why would a say position field be the cause of machine movement, although it is possible, I have written many systems that will read the values from the PLC, it is up to the programmer to make his code safe.
Just imagine you are using this for settings of position, it defaults to 0 so if your drive what ever it is will go back to 0 position do you really want it to without some intervention of an operator, personally I would program it to not move until initiated by the operator and only as a recovery not determined by a silly HMI that it thinks it knows best, I think that in many circumstances putting a setting to 0 could be just as dangerous, I believe it is yet another oh.. we have a problem, find an excuse. This is the first time I have seen an HMI deliberately set settings on entry fields to 0.

 

[KuulKuum]

I believe it is yet another oh.. we have a problem, find an excuse.

Well, this is Rockwell Automation we are talking about...
The pull your hair out issues I've been involved with had several RA experts finally throw their hands up and give up. It's a good thing this forum exists because you can often get the solutions here...
:site:

 

[joseph_e2]

Wouldn't unexpected motion be MORE likely by defaulting to 0 instead of reading what's in the PLC? I'm confused...

I agree with parky that they uncovered a bug and it was easier to document it than fix it.

 

[marvedjensen]

some news

problem solved

First on hmi numeric increment/decrement send value to plc tag
that plc tag is set to retained under plc global tags so when we power cycle the value is remembered in plc
but the hmi is blank and forgets
to get the hmi to show the retained value after power cycle
we send the tag to hmi trough numeric display to show the value on hmi
we make the numeric display to read the retained plc tag