Creating a Totalizer?

[Guest Jeff]

Hello Gentelmen, I was wondering if anyone knows how to program a single analog input that is scaled 0-2000 scfh in a slc 5/04 to make it into a totalized value. I would like to take what ever the flow reading is and totalize it. I have never had to do this before and don't know if there is a way to make rslogic 500 work in this manner. Thank You Jeff

[Chris Elston 78]

Like you mean an AVERAGE? Check this PDF out.

[Guest Jeff]

Well an average would work but i'm not sure how accurate it would be. I have a analog gas flow reading that is scaled in my panelview with engineering units that are 0-2000 scfh (not scfm). The flow reading is not stable and can fluctuate anywhere within this range. The gas is flowing 24/7 and I would like to totalize the flow to show and accurate total amount basically counting the scfh with the ability to press a reset button on the panelview to reset the counter to zero. Thank You for your help.

[Guest]

Jeff, I think I know what you’re asking for ... and even if this isn’t exactly what you need, maybe it will get you thinking in the right direction ... the basic idea shown below is to first set up a timer done bit to serve as a “trigger” which will fire “on” once per minute ... then once per minute, divide the SCFH (standard cubic feet per hour) reading (example: 1500) from the analog input (example: I:1.0) by 60 minutes per hour and place the results in a temporary location (example: F8:0) ... now F8:0 contains a reading in SCFM (standard cubic feet per minute) (example: 25.0) ... next take any previous “totalized” value stored in F8:1 (example: 100.0) and add the current value of F8:0 to it ... now F8:1 contains the “totalized” value of gas used since the last time we “reset” F8:1 back to zero (example: 125.0) ... the units associated with F8:1 are SCF (standard cubic feet) ... the screen shot shown below shows the results of running for 5 minutes at a rate of 1500 SCFH ... in other words, a “totalized” reading of 125 standard cubic feet of gas has been stored in F8:1 ... if the SCFH input reading in your system fluctuates very erratically, then you might consider using a trigger timer set to fire once each second ... and then adjust the divisor to obtain a conversion into SCFS (standard cubic feet per second) in F8:0 ... hope this helps ... Ron