What are the values that you are getting for Attribute2? I just want to make sure it's not the easy solution .
Can you execute the analysis in "Preview" and see what the table of numbers look like? Do the numbers make sense?
You can also right-click on attribute 1 and attribute 2 to bring up the Time Series Data dialog box and check to see if the data make sense.
Let us know what you find.
Funny thing. The dummy configuration presented is slightly different from the original. Just as a last attempt, I changed the configuration to the one I showed here. It seems that it is working fine now.
The original configuration uses DR formula to do the multiplication. Than the average uses the formula result as input.
Attribute1: Value from PI point
Attribute2: Value from a Table
DR Formula: Attribute3 = Attribute1 * Attribute2
Analysis: Tagavg('Attribute3','*-5m','*') Scheduling: every 5 minutes
Attribute4: Output from Analysis saved in PI Point
So now the question is: what does Tagavg do if the input is a DR formula? I have several other configurations done this way.
Speculating possible reasons...
The DR formula is
Default value = 0
I realised that the last value in a Processbook graph shows the default value (why? I don't know! Not always, but it is fairly common to see that). If the Tagavg includes the default value, in this case zero, it will always average a lower value.
Is this correct?
The Table Lookup gets a constant to make unit convertion.
Here what I got after some testing.
Formula DR with DefaultAllowed=1
The average function Tagavg() consider the default value in the calculation. In my case, zero, causing a bias to a lower value. Since my average is for 20 or so value, I usually get 4-5% bias.
The average works fine. But the result does not match exactly the average done in Excel Datalink. So it is a new kind of problem...