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TagTot calculation going negative after midnight when source data stays positive

Question asked by JeremyMahon on Aug 26, 2016
Latest reply on Aug 29, 2016 by JeremyMahon

Hi all. I recently implemented some PEs that use the TagTot function to give us a daily gas burn total. The gas day goes from 10am-10am, rather than midnight-midnight. A sample of the logic is below:

 

if (Hour('*')<10) then (TagTot('GASFLOW_UOMperHOUR','y+10h','t+10h')*24) else (TagTot('GASFLOW_UOMperHOUR','t+10h','*')*24)

 

Essentially, I am saying that if the hour is prior to 10am, then give me "yesterday's" total from y+10h to t+10h, else give me the running total from t+10h until current time. Makes sense, works as expected...until midnight hits. It jumps way up and then the trend/values start to decline--which is not expected behavior for a "totalizer." The source data remains relatively constant for this unit so it's odd that the totalizer trend would decline. I would expect its slope to go flatter if a unit was coming offline (therefore less gas burn) but this unit runs almost 24/7 (therefore relatively constant gas flow). Any ideas? See trend below (showing yesterday ...

 

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