Real-time Storage Emptying Time/Date Calculation

[Sam P.]

Using only the real time data from a storage vessel's weight transmitter/load cell, is there a way to create some sort of calculator that estimates the date/time it will be empty in real time? The calculation would need to update in real time and use a capsule of the last 15-30 min of load cell data to calculate a linear rate. 

I've tried using the new forcastLinear() function, but am having a hard time translating that data into an emptying time estimation. I am also unsure if it will update its forecast in real time, as I do not currently have real time data to test it out on. It appears to be simply pulling the historical data of the load cell and copying it.

Any help is much appreciated.

[Shamus Cunningham]

Sam, 

You can pretty easily forecast the value from now till you empty setpoint and then display the result as a Capsule on the screen as well as a Time/Duration in a Scorecard/Table and have all the results update in real-time 

For my example I am going to use some example data but this should look very similar for your use case 

Step 1 - Create a Forecasted Value - This function may not work on exactly as you expect on historical data depending on your datasource 

$signal.forecastLinear(1.5h,5d)
//Train in the last 1.5 hours of data
//Project 5 days into the future

Step 2 - Create a condition that captures the time between now() and when you fall below your "empty" threshold. This step will only work for online data as it is using the past() operator

$LowerLimit = 0%

$AboveLowerLimit = $fv > $LowerLimit

$AboveLowerLimit - past()

Step 3 - Create a Scorecard to Quantify the time between now and full and display it in a table. This uses the "Condition" mode in the Tables view and a Condition scorecard type

 

Content Verified DEC2023

[Sam P.]

Thank you Shamus for your quick response!

As you may have foretold, I am getting an error when I try to execute the formula using the past() function.

 

Is this something that would iron itself out once the data becomes dynamic again? Or is it possible this is due to the type of data I am using?

Here is a snip of my $ft1 function over several days. Currently that function is configured (15min, 4d).

[Teddy]

Sam,

What version of Seeq are you running?  The past() function is not avaible until version R51.0.0+.  

Regards,
Teddy

[Shamus Cunningham]

You can also re-create the same effect at the past() operator in offline situations or in older versions by modifying the formula to remove the period of time that there is data in the original source signal 

$LowerLimit = 0%

$AboveLowerLimit = $forecast > $LowerLimit

$AboveLowerLimit - isvalid($original)

 

[Sam P.]

Thanks Shamus, this work around did not produce any errors in the version of Seeq my work uses (50.2.3).

The only problem now is that it seems that it is not actually providing any empty times.

[Shamus Cunningham]

Can you see the forecast signal ever crossing your empty threshold.

You can visually mark your lower limit on the trend by creating a Scalar value in formula