AnsweredAssumed Answered

No AF data available in PI Vision

Question asked by John Messinger Champion on Aug 3, 2018
Latest reply on Aug 3, 2018 by John Messinger

So I've come across an interesting problem that I just can't seem to figure out, and looking for some suggestions from here. Basically, adding any symbols to a PI Vision display that reference AF attributes all show 'No Data', and show the following error in the Messages dialog:


The attributes obviously exist, as I can browse the AF element and drag the attributes into the display. Attributes contain either PI Point DR or Formula DR - behaviour is the same for both.



PI Vision 2017 R2 (

PI AF 2017 R2 (both server and AF SDK)

PI Web API 2017 R2 SP1


Current configuration:

All of the above components are installed on the same virtual server.

We are using a CA issued SSL certificate - there are no certificate errors or issues at play that we can see.

Kerberos constrained delegation has been enabled as per the recommended configuration in the PI Vision documentation.

A Domain service account has been created, and the PI Web API and PI Web API Crawler services run under this service account.

An AF Identity and AF Mapping have been configured for the service account, and has been granted required Read permissions to all AF objects.

A PI Identity and PI Mapping have been configured for the service account, and has been granted required Read permissions to all PI Points, as well as the required tables in DBSecurity.

The PI Vision app pools currently run as NetworkService. Changing these to the service account results in an internal server error and no content (displays or data sources) are available. I would like to run the app pools under the service account eventually, but need to identify and resolve the issue just described first. Seems like a permissions thing, but I don't know what it is yet


Other information:

The PI Web API Crawler is doing its thing - the AF databases and PI Data Archive show a good status and are being crawled.

I can see AF data in other tools such as PSE, ProcessBook and PI DataLink - just not in PI Vision. I can also see it if I manually browse directly via the PI Web API.

I have enabled Kerberos logging - no errors are recorded in the event logs.

It's been a long week and it's late on a Friday afternoon, and I could well have missed something obvious. This is what I'm hoping, so please be kind to me if you spot it


Appreciate any suggestions on how to resolve this issue.