1 of 1 people found this helpful
You can try out bilinear interpolation using the AF Table Lookup Data Reference. You will need to create an AF Table with 3 columns as your reference.
Thermal Load, Efficiency (or Performance?),Condenser Pressure
Then you can feed in the Thermal Load and Efficiency in the Table Lookup DR to get your Pressure.
Please see this link for an example
Thanks for the answer. AF must stand for the "PI Analysis Framework", which I'm not familiar with. I was wondering whether I could utilize Performance Equation only to make the bilinear interpolation. Regards, ZYY
2 of 2 people found this helpful
Actually it stands for "PI Asset Framework"
I would really encourage you to start adopting AF to do things the "right way" and not accumulate technical debt.
Many of our newer products are all based on AF. AF provides context to data which is quite important in my opinion. As you know, PE scheduler is deprecated too.
For a new installation of the PI Data Archive, the default installation does not include PI AF Link Subsystem, PI Alarm Subsystem, PI Performance Equation Scheduler, PI Recalculation Subsystem and PI Batch Subsystem.
So i wouldn't encourage to continue using it.
I read through the AF Overview, wow...., it is really an excellent new technology.
I get back to my "PI System Management Tools" - "PI Version" with the finding that all the PI version is 3.4.380.70, while all my menual refers AF to "Analysis Framework" after looking up all the Help documents I have.
Is the "Asset Framework" involved in my PI installation?
It is a separate install kit during the old versions (not the integrated install kit like now). You can also install the newest version which is AF 2018 (to have the bilinear interpolation Table Lookup Data Reference) if you have access to it. The release notes for the newest version AF 2018 states that
The PI AF Client supports access to PI Data Archive version 3.4.380 or later.
If possible, I will also advise you to upgrade your PI Data Archive as 3.4.380 is quite old that I can't find it in the roadmap. This is to minimize compatibility issues with the AF Server.