Good afternoon,
I am new to PI, as is the company I work for. I am attempting to get totalizers set up in the best way possible. I originally started with PEs, but I couldn't explain the difference between TagTot and TagAvg. My users are concerned that these functions will not consider plant downtime. I then discovered Totalizers, and thought this would be my best solution.
I am trying to capture the Total production over the last 24 hours, and archive a value every minute. Basically the user could look up any minute and find the total production of the previous 24 hours. The tag measures an instantaneous production rate in units of Tonnes per Hour (TPH).
For my PE, I used:
TagTot('G17_GDST_BWGBW6_TPH', '*-24hours', '*')*24
and
TagAvg('G17_GDST_BWGBW6_TPH', '*-24hours', '*')*24
Which yields results which appear correct, but the calculations return slightly different results. My first question is:
1. What is the difference between these two calculations? How is the archive data being treated differently?
Then when I set up a totalizer, I would have thought to use "sample every 24 hours, results every 1 minute with a conversion factor of 24 to convert TPH to Tonnes". I have tried changing the sample and results settings but cannot get the right configuration.
2. What is the totalizer doing? Or am I trying to do this the wrong way?
3. When I use the totalizer I am getting occasional 'Bad Total' readings, although the source tag is perfectly fine. Why could this be the case?
Any help is appreciated!
Thanks,
Steve.