OPC UA scan class issue with Ignition 7.6

Hello all,

I am using Ignition 7.6 to read values from OPC UA server. I use scan class with direct mode and slow rate 10000ms. Tags are read every 5000ms not 10000ms, when I try to set any value less than 5000ms tags are read according to that time.

I was wondering is there some sort of limitation for Ignition 7.6 version, so that maximum OPC UA sample time cannot exceed 5000ms or maybe there are other settings to check other than scan class?


I vaguely recall encountering that limit, yes. Are you on the very last v7.6 ? Try that if not.

Ignition’s OPC server or 3rd party? Which driver?

I remember this being a problem with our sim drivers for a long time but not others unless you are also accessing those tags at 5000ms in another faster scan class or something.

I’m on Ignition 7.6.7, thanks!

3rd party OPC server, B&R PLC to be exact.

I don’t think 7.6 has any kind of client-side diagnostics to verify the subscription rates, so you’ll have to connect a 3rd party client like UaExpert and use its diagnostics view or get a Wireshark capture of Ignition’s client connecting and creating subscriptions to verify, but I think it may just be the server is not honoring the requested sampling rate from the Ignition client.