I recently had a customer call with a very strange issue: His PanelView Plus was taking over 5 minutes to boot. Calls to tech support and several other troubleshooting steps lead nowhere.
Not knowing what else to do, I asked the client if he could send me his HMI and PLC programs so I could do some testing in house.
He graciously agreed, and what I found was pretty strange – something I had never seen before.
On boot, I was getting a message saying, “Loading symbol from RSLinx Enterprise, please wait.”
This message seemed to coincide with the clients suspicion that the large number of end user aliases in the controller may have been the culprit. And the next message I received (after over 5 minutes) seemed to be confirming that.
It said, “Updating controller symbols has timed out. You may choose to continue updating controller symbols or run the application. Start-up macros and datalogs may not operate correctly…”
Adjusting the processor's (L73) overhead time slice to 50% did provide some improvement. At that setting, I no longer got the timeout message.
However, something really bothered me about the message I was getting… the client only have about 30 tags in his project, so what was RSLinx Enterprise taking over 6 minutes to load?
Surely 30 tags would load in a fraction of a second, so it must be trying to load something else, but what?
Having exhausted all my ideas, and with the system issue successfully duplicated, I once again contacted tech support.
This time the tech I spoke with found an undocumented note about PVPlus slow boot times coinciding with large numbers of devices in the Target Tab in RSLinx Enterprise.
Now you may ask, why would anyone have anything besides the target PLC in the target tab?
Well not everyone is able to commission their HMI's prior to installation. And if you're connected to the plant network when you browse for your PLC in RSLinx Enterprise's local tab, you'll also see ALL the other Rockwell devices on the network too.
An unfortunately, the “copy from local to target” button doesn't just copy the devices that have a “shortcut assigned.”
No, for some unknown reason (well, unknown to me at least) it copies everything from the local tab to the target tab…
With this little tidbit of information, I deleted all the “extra devices” from the target tab, leaving just the PLC assigned to the shortcut.
And presto, the PanelView Plus booted up in a normal amount of time.
Hopefully after a little prodding from myself, Tech Support will write up a public tech note so others who run into this issue won't have to go through as many hoops to find the solution.
Sincerely,
Shawn Tierney
Automation Instructor and Blogger (post views: 7,602 views)
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- Double posted question.Hi Shawn,
I've been helping a customer after a power outage try to get one of his PVP panels working again. The messages are the same as the ones in this article about symbols loading, but the symbols never end up loading on the panel.
Power cycling doesn't appear to change anything. Ethernet communication appears fine. I checked RSLinx Enterprise and only the associated hardware is listed. I even added the PLC (ACD) file to the panel so that RSLinx could access Offline tags.
Any additional ideas that might be helpful?
Thanks,
pico-dc
Good morning ,
My first guess would be the PVPlus loaded an old version of the application - when downloading a new project to a PVPlus, a lot of people forget to set the new application as the default startup app, so on reboot the old project loads.
My second guess is someone changed or "fixed" the communications path using the configuration menu on the PVPlus, and because it was a changed there and not in the PVPlus application/project, the setting was not retained on a power cycte?
It also could be someone changed the tag names (or something else) in the PLC and now it no longer matches what the PVPlus is expecting...
A good step to troubleshoot the issue would be to create a new project with a single display that has a few numeric displays reading values from the PLC - if that works then you know it must be an issue with the old project, and not a hardware issue.
Hope this helps,
Shawn Tierney,
Instructor at www.TheAutomationSchool.comI appreciate the quick response!
There were old versions of the application on the PVPlus. I tried to load those but still got the same error.
It is highly unlikely that tags or communication configurations were changed, but I'll double check that along with setting up a single screen the next time I'm on site.
One other thing that I forgot to mention was that the battery light on the PLC was on. Would that have any impact on whether the symbols load or not?
Thanks Shawn!Good morning ,
So the battery light on the PLC being on means the battery is almost dead or already dead.
This could result in an old program being loaded into the PLC's memory from non-volatile memory (CF card, SD card, etc.)
You might want to connect to the PLC to insure the "Overhead Timeslice" is set to 20% or more to insure the PLC will take enough time to communicate to the HMIs.
You may also want to compare the running PLC program with the program the users think is running in the PLC - they could be different as people often forget to save updated programs to non-volatile memory.
Hope this helps!
Shawn Tierney,
Instructor at www.TheAutomationSchool.com
