OPC UA, Read Quality Good, Subscribe Quality Bad


I am setting up a motor drive application and have run into a problem wiht the OPC addressing and subsequent tags.

I imported a modbus address list into the OPC UA device. Many of the addresses have been added with no issues and are showing up in the OPC Quick Client as good quality. Both in the read and subscribe. However, many others are showing up with good quality on the the read but bad quality on the subscribe. Please see the screencaps below:

OPC Read - Copy

I do know these are valid addresses in the VFD I am using and the data from the read example above is accurate. Any thoughts on where to start troubleshooting this?

That usually means you are letting the driver span gaps for optimized reads, but are hitting registers that the device says don’t exist. You probably have to turn off the span gaps feature for the device.

That definately helped. Eliminated about 2/3 of the addresses that were problematic. However, I still have a few more that are exibiting the same behavior.

I’ve experimented with deleting and manualy adding a couple of the addresses still in question and they are now working. Even though the configuraiton was identical. I’m wondering if there were some errors introduced when importing the addresses from a .csv file.

It turns out that yes, that was what was happening. I was using Excel to edit the csv file. Excel was dropping some extra comma delimeters in the file. I discovered them when switching to Notepad++ to finish the edits. I removed the extra delimeters and the remaining wayward points worked as expected.