I am creating a PI Processbook page that needs to show the current value of a tag, 12hrs, 24hrs, 36hrs etc. ago. I know it's not that hard just haven't done it in a while. If it is easier to do it in AF that would be great.
Simplest method: add an attribute for each time offset: 12h, 24h, 36h, etc....
Then, set the data reference to a PI Point, click 'Settings', select 'Attribute' and the attribute with the source data.
For the retrieval method, set the relative time to the desired offset.
Repeat for each interval.
Another alternative is to set up analysis templates that perform the 'TagVal' evaluation as needed. This means in the analysis tab set up an analysis that evaluates for example TagVal('TARGET_ATTRIBUTE','*-12h'). Then repeat for '*-24h', '*-36h', etc. Map those to your desired AF Attributes, which can be pi tags or not.
Retrieving data ...