Flow Totalizer in Ladder Logic

Tally_Pants · Jan 25, 2010

I'm running an Allen Bradley CompactLogix L32E plc with Logix5000. I am in need of a method to which fmy Function Block flow totalizers to Ladder, as the version of Logix5000 was purchased without the FB capability (has SFC tho).
The totals must be for today, yesterday and then a 3 day total. any help would be awesome!

Bob O · Jan 25, 2010

Search the site for flow totalizing it has been talked about a lot.
What all signals do you have coming from your sensor?

Welcome to the forum.

Tally_Pants · Jan 25, 2010

the only signal i'm bringing back from the flow meters is an analog with the flow. so i know i have to work with timers. just looking for a good starting point / example to work off of

TConnolly · Jan 25, 2010

Instead of using timers use a dedicated periodic task. Timers are subject to scan time.

Total := Total + (flow_rate_per_second * task_period)

If you are using a floating point number for your flow totalizing then be aware of floating point number resolution limitations, something else that has been discussed in many threads along with totalizing.

Bob O · Jan 25, 2010

Does the unit have a programmable DO for the amount of flow?
Then all you would have to do is increment a counter for total flow.

Tally_Pants · Jan 26, 2010

Ok thanks for the tips! And I'v been looking at a few other threads on the site related to this topic too. Glad to see I'm not the only person who has an issue with this lol

Flow Totalizer in Ladder Logic

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