In PI Vision 2020 you can create on-the-fly calculations so you can analyze a process in real
time. I'm Jeff Resnick with OSIsoft Learning and today we'll take a look at PI Vision Calculations.
You'll notice that our left-hand pane in PI Vision has an added tab for Calculations.
Here we can build out quick calculations to get added insight from our displays.
This includes summary calculations like minimum, maximum and average, basic arithmetic operators
and PI Vision Calculations also supports using performance equation functions.
You can use a calculation on any PI Vision symbol or configuration that supports a data item.
Currently the calculations feature supports PI Points.
Let's go take a look at an example and I'll get a few of my PI Points to work with.
On this display I'm looking at the overall function of a production line in my plant.
I have some OEE, overall equipment effectiveness, metrics on the left and it looks like the actual
calculation for OEE is failing. I could troubleshoot the analysis and figure out the
root cause but I really want to know the result now. And I can see all the information that I
need is available and working, so I’m going to make a calculation on the calculation tab.
I’ll click on the plus sign to create a new calculation.
I’ll give it a name of OEE and OEE is defined as quality times availability
times performance and then quantified as a percentage. I’ll look at my PI Points by only
searching through my Data Archive and if I search for Fulton line 5 then I’ll find my PI Points.
I can drag and drop them onto the Calculation Editor.
By default the editor will add the PI Point values together but I’ll switch it to multiplication and
then we'll divide by 10,000 to get the right amount of decimal places for my percentage.
There are some advanced options as well. We can have a custom time interval to sample over.
We can also make a resulting plot appear as stepped for discrete calculations.
Or if you're doing a total we have a conversion factor to add in.
I'll keep the calculation simple for now and we'll click save.
Now we see the calculation OEE is listed and there are two dashes to the right of it indicating it's
not currently shown in the display. To see its values we can drag it out like any other
data item in PI Vision and I'll make another radial gauge to keep with the display theme.
Now we can see that we get a check mark because the OEE calculation is listed on this display.
By default the radial gauge range will use database units which calculations don't have,
so I’ll have to put in a custom range
and I’ll make the style match the other symbols by changing the angle. To finish it off I’ll use
a text box to add the percentage unit and now I have a working OEE calculation on my display. If
I were interested in mapping the values over time I could use a trend symbol to show my calculation
and I can add in a few more columns so I can see the min, max, and average appear in the trend too.
For one more step if I was interested in the results at a particular hour
I’ll give my calculation a time interval and you can see how the trend updates.
I’ll change the time range and show you the calculation updates.
And as a secret between you and me I have a working calculation that uses a PI Analysis.
So let's double check that we have the correct result. Looks good to me. There you have it:
a calculation on the fly that can help me gain insight from my data in real time.
Expression Functions Reference
Note: PI Vision Calculations have been introduced to enable the migration of PI ProcessBook display
which are using PI Calculation data sets and are mostly limited to match this functionality. Most
notably, this means that only PI Points from one Data Archive can be used within a single
Calculation. AF attributes are not supported. Given these limitations in the upcoming exercise,
we will explore PI Vision Calculations primarily for working with migrated ProcessBook displays.