I have an old SLC 5/02 and I know no way to totalize within the PLC programming because the analog value that I’m working with is in million gallons per day and I need daily totals in gallons.
Is there a way to totalize in the HMI??
take x samples a day and add it to a tag for a daily total
So I need to setup a dataset and also need to divide the MGD sum by 1440 to get GPM?
Can you use a transaction group to log the values? One reading every minute (as you said, divided by 1440) logged to the database. You can then use a query to sum the daily, or populate a table or graph, or whatever you need to do with the data.
Depending on how often you log a value:
60 sec: sum of the values
30 sec: sum of values divided by 2
20 sec: sum of values divided by 3
15 sec: sum of values divided by 4
12 sec: sum of values divided by 5
10 sec: sum of values divided by 6
6 sec: sum of values divided by 10
5 sec: sum of values divided by 12
4 sec: sum of values divided by15
3 sec: sum of values divided by 20
2 sec: sum of values divided by 30
1 sec: sum of values divided by 60
The more often you take a reading, the more accurate the total becomes, but there is more data being saved to the database. It’s up to you on where your tradeoff point is.