Hi,
Ignition‘s OPC UA client supports to subscription to 3rd party opc-ua server with queues. That’s great to overcome short network issues, but it’s not very clear how queued data are handled in the tag system.
If we receive multiple values from one monitored item/subscription and tag are there any ways to also get all of those values in a script. It looks like that you only get the last value when reading the tag in a gateway tag change script
You can't get them all at once in a script, but e.g. a tag event script or gateway tag change script will be invoked multiple times as it receives the queued values.
My Integration Toolkit's Bulk Script tag action will accumulate all (or many) of the values that arrive together due to its 50ms batching behavior.
Thank you, I will test it again with change scripts. Is there any documented queue limit for a tag or how fast do we need to handle a change so that we will not miss a queued value?
You have a lot of cool thinks in your toolkit. I will check it. Thank you!
Tag event scripts have a queue size of 5 that can only be changed via system property in ignition.conf. There's a parameter you receive in the function that tells you if the queue overflowed. This has nothing to do with the OPC UA monitored item queue.
Gateway tag change scripts have no limit. They're probably a better fit here.