RSLogix 5000 Two Totalizer Error

[nibed]

I am using two flow totalizers in my program. One is reseted daily, and one is never reseted (Big Total). The EnableIn and Flow input is the same for both totalizers as is the configuration. I noticed that there is accumulated error between Big Total and manually summed daily totals. Has anybody had this problem. I guess that I could change the program to use only one totalizer but it is strange that the same totalizer with same conditions and inputs sums differently. Tx

 

[Paullys50]

Search the forums for "machine epsilon".

Very long thread about totalization.
http://www.plctalk.net/qanda/showthread.php?t=77686

You're probably experiencing it if you never reset the totalizer and its grown to a very large number.

 

[theutinck]

How far are they out? when you reset the daily totalizer you will lose all the flow that didn't make the totalizer count. If you are totalizing in cubic meter for example, if there was 900 litres in the daily totalizer this would be reset, but the big totalizer would still have it recorded. so you may lose a cubic meter a day but it shouldn't be more than that.

 

[nibed]

1.500.000 m3 in one month ==> Big totalizer
Manualy summed Daily has 8000 m3 error

 

[theutinck]

can you post the code?

 

[nibed]

==> program code for totalizer with reset

==> program code for Bg Total

==> Reset tag is recieved from SCADA and is on riseing edge.

Just want to say that avarage Flow is about 30.000 m3/h. Big Total is currently about 30 000 000 m3 (30 million m3).

 

[(8{)} ( .)]

If you're totalizing to floating-point values you will eventually lose accuracy if you don't reset them in time. Totalize to UDINT with an implied decimal to total up to 429,496,729.5 m3.

Good luck,

Yosi