
Re: How to calculate mass changes(dynamics)
John Messinger Apr 26, 2018 11:15 AM (in response to siz07)Hi Ildar,
AF Expression Analysis would be the way that I would choose to perform these calculations. If you have many reservoirs, then AF allows you to define the Analysis as part of the asset template, and of course an AF Analysis can write its results back to a PI Point.
John

Re: How to calculate mass changes(dynamics)
igreguri Apr 26, 2018 8:07 PM (in response to siz07)Hi Iidar,
In my case I using FlovTOV value (m3/h) from tank radar.
If you want to calculate only just emptying create totalyzer and then in option
Sampling → Whenever the source data with the following expression put condition:
'FlowTOV Tag' < 0
Then in Results...
You can do this in AF Analysis, but I described my case.
Later I multiply that amount in m3 with density for mass.
Regards,
Igor

Re: How to calculate mass changes(dynamics)
siz07 Apr 26, 2018 12:01 PM (in response to igreguri)We only have mass and level in the tank...

Re: How to calculate mass changes(dynamics)
igreguri Apr 26, 2018 12:36 PM (in response to siz07)3 of 3 people found this helpfulMaybe something like this in Analysis... difference from midnight to now (for draining).
I have used level but same situation is with mass if emptying, because newer level is lower than the previous one.

Re: How to calculate mass changes(dynamics)
siz07 May 4, 2018 5:03 AM (in response to igreguri)I created next analysis:
Then I checked archive in PI of the output tag and tag of mass and compared values. Some values in archive was absent:
On right side  is archvie of mass tag, on left h is dynamic and output tag, middle  difference.
By this calculations I lose actual data. Compressing in tags are disabled.

Re: How to calculate mass changes(dynamics)
John Messinger May 4, 2018 8:18 AM (in response to siz07)1 of 1 people found this helpfulAs I look at this question again, and the latest approach you have taken, it seems that this is very similar to another post at calculating volume from tank level where it was required to calculate the volume withdrawn from a tank each day. I believe you could probably adapt this approach to calculate your mass change each day.
John





Re: How to calculate mass changes(dynamics)
gmichaudverreault May 1, 2018 12:57 PM (in response to siz07)1 of 1 people found this helpfulAs others have mentioned, AF Analytics would be the best suited tool here, IMO.
You can also refer to KB00868  PI Analytics: Which tool is best for the job
Gabriel

Re: How to calculate mass changes(dynamics)
siz07 May 23, 2018 10:59 AM (in response to siz07)Dear friends.
We had to calculate this programmatically. AF analytics sometime do not calculate values, and we had to recalculate each other day.