Totalizing rate from analog input

rustyP

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Join Date
Apr 2013
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PA
Posts
2
Hello,

I am using an A-B micro830 PLC and analog input plug-in with Connected Components Workbench 3. I have a flow meter sending a 0-5V analog flow reading to the PLC that I need to have calculate current flow rate and total flow rate since user reset. I can read and convert the analog input value to a correct flow rate but I am having trouble figuring out how to integrate the rate to track the total. I think my problem is that I do not know what I should use as the time to integrate the calculated flow value over. I tried putting in a 1 second delay with a TON block right before the analog input value is converted to a flow rate but my total is going up much faster than it should be at the rate I have set so my program must be incorrect somewhere. In debugging it looks like the TON is not actually delaying anything as I can see the total updating more than once every second. Any suggestions?

Thank you!
 
I have a flow meter sending a 0-5V analog flow reading to the PLC that I need to have calculate current flow rate and total flow rate since user reset.

You will totalize flow -- not flow rate.


I can read and convert the analog input value to a correct flow rate but I am having trouble figuring out how to integrate the rate to track the total.

What are your Engineering Units? Assuming Cubic Feet per Hour, if you are sampling every second, then you'll need to divide your Scaled to EU Flow Rate (CFH) by 3600 prior to adding it to your accumulator, since there are 3600 seconds in an hour.
 
Thank you for replying. I guess my problem is that I do not know what the time interval is between sampling periods. What is a good way to capture the amount of time between program cycles in CCW?
 

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