ML1400 Gallons

[mhowasso 5]

Hi All... Im using a MicroLogix 1400 / RSLogix 500 I know Im making this harder than it appears, but Im trying to get convert my level (inches) into gallons in a round tank. I know the formula for such is: Pi (3.1416) x Radius Squared x Depth / 231 = Gallons Given Values: F8:222 = Depth in Inches (0 - 30.0) F8:224 = Diameter in Inches (53.0) F8:225 = Radius in Inches (26.5) F8:226 = Radius Squared in Inches (702.25) F8:228 = Gallons Using CPT instructions, this just gives me bit and word errors. Could someone straighten me out here..?? What am I doing wrong..?? Is there an easier way..?? Thanks Edited 27 Oct 2012 by mhowasso

[b_carlton 61]

It would be easier if you posted a screen capture of the CPT command. One guess, though, is to remember that the 'divide' symbol is the vertical 'pipe' '|' not the familiar slash '/'. The slash is the seperator for a bit so that may be the source of some of your errors.

[Michael Lloyd 85]

In the ML series I use the above formula to calculate gallons per foot of level in a spreadsheet and then use that in a simple multiply block. I scale the AI in feet. FT x Factor = gallons (all values are floating point). Actually I do that for barrels because that is the industry standard unit but the principle is the same. If you scale in inches just figure out how many gallons in 1 inch and use that. If you scale in percent then % x Height in in. max x factor. I have a couple of AOI's that I wrote for CLX. One is for a vertical cylindrical tank with flat top and bottom. The other is for a horizontal cylindrical tank with 2:1 elliptical heads. The second AOI wasn't "complicated" but it required a little extra work since the volume decreases as level rises above 50% and increase as the level rises from 0% t0 50%. Both AOI's spit out barrels, gallons, and pounds (might only do pounds with the vertical tank, I don't remember, but that's an easy calc). Edited 27 Oct 2012 by Michael Lloyd

[mhowasso 5]

Thank You Very Much..!!! Sometimes I can not see the forrest for the tree's..!!!

[Michael Lloyd 85]

I know the feeling I failed to mention how many times I've done ALL of the calculation in the PLC before "discovering" that I didn't really need to do that. It's a little different story in the CLX because if I am using something with that kind of power the odds are, in my business, I'm dealing with a lot more tanks. The AOI makes the tag structure "standardized" so the HMI works is a lot faster, time is money... I made the CLX AOI's so I didn't have to calc the factor. I just put in diameter and height for the vertical tanks and seam to seam length and diameter for the horizontal bullet tanks and it does everything for me. I did the same thing with the liquid orifice calc and the gas flow through an orifice calc.