How can you log data flow totals in a AB 1100

[mwhiz 0]

Is there a way log flow totals at midnight in a AB 1100 need daily totals for 365 days. Data logger & FIFO do not allow floating point. We need to display daily readings in Wonderware. Note have Wonderware  set up to do the same but due to com failures it has not worked. 

[Mickey 71]

Depending on the value of your flow data you could use an implied decimal point. By multiplying the floating point value(by 10,100) with a destination of an integer.

 

Then moving the decimal back after it gets to Wonderware.

[PLCMentor.com 60]

Mickey's going old school!  Used to be the way we had to handle floats for some processors.  Glad those days are past, but that is a valid way to use integers.  The problem that I think you will have with the micrologix is a 256 max data table.  I think you can only have 256 elements in each data table.  Maybe mine is old.  If this is a problem then you will need to split your 365 elements into 2 different tables.  I would suggest that you could use indirect addressing to move your values directly into floating point registers.  When your index is greater than 255 then enable a different move that points to a different table.  Something of the format:  F8:[N7:0]  where N7:0 is the index of the element in your F8 file.

[Joe E. 259]

PLCMentor is right. To get greater than 256 elements, you'll need to use more than one file. The PLC5 could have larger files, but the SLC and MicroLogix only go up to 256 elements, even the newer ML1400.

[mwhiz 0]

Thanks everyone. been bench testing & looks like N7:256 is as high as the AB 1100 can count. As well as not being able to use a floating point. I think the best plan is to use a separate counter that resets just after midnight. Also some sites on this project have two flow meters. So if I can count each pulse (1000 gallons each), going to see if I can store 90 days using the data logger or the FIFO. That would be 180 registers. Anyone have input on which one to use? All sites are remote/radio, will only be able to use Wonderware to read values no AB/RSLogix licences available for the desktop.

[Joe E. 259]

Hmmmm....so I created an empty project for a MicroLogix 1100. I wonder how hard it would be to build your own FIFO stack....

How much precision do you need your flow numbers to have? Can you round it to the nearest gallon? Or to the nearest 1000 gallons?

Edited 20 Jan 2021 by Joe E.

[BobLfoot 301]

IF you can get your daily total to fit in one integer then you could create data files N101, N102, N103...N112 and setup as N101:1 = Jan 1 ; N101:31 = Jan 31 ; N102:28 = Feb 28 amd N112:31 = Dec 31.  The S: register for Month and Date could be used to indirect address the N register holding files.

[mwhiz 0]

Thank you, will try this next week. Not sure about the S: register

[BobLfoot 301]

I was thinking of the PLC5 and SLC500 where the RTC is in S: registers the Micro 1100 only has a free running clock in S:4.  YOu'll need to assign a couple of registers for Date and have your SCADA populate them.  Maybe N100:0 for Month and N100:02 for Day  then do N100:0 +100 = N100:1.  Then use N[N100:1]:[N100:2] as where you place that days total.

[mwhiz 0]

Thanks for the update. Will look at it next week have been sent to a different project this week.