Hi ,

My problem exits in calculated data

In Excel i want the total m³ a tank was decreased.

Between two timestamps .

Problem is that the volume fluctuates.

Someone ideas?

Thanks

erwin

Hi ,

My problem exits in calculated data

In Excel i want the total m³ a tank was decreased.

Between two timestamps .

Problem is that the volume fluctuates.

Someone ideas?

Thanks

erwin

You will have to use a combination of an expression and PI Calculated Data (Expression)

Step1:

Use the following expression and just add you tank level

if PrevVal('LEVEL','*')>TagVal('LEVEL') then Range('LEVEL',PrevEvent('LEVEL','*'),'*') else 0

Step2:

In DataLink use the Calculated Data combined with Expression (notice the picture below I selected Expression and NOT Data Item), and make sure you set the "Advanced" options correct as seen below.

Hi erwin,

If you have two specific points in time:

You can use the PI DataLink 'Archive Value' function to retrieve each value and let Excel subtract the two to find the difference.

This would be the simplest solution. If you're looking to use a PI Expression, you can use the expression TagVal() - TagVal().

If you are trying the find the maximum difference within a given time frame, you would use TagMax() - TagMin() expression for the time range.

You can find all the available PI Expression functions in the the PI Server Applications User Guide.

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