twido volume calculation HELP!!!

Hi I am new to twido and am looking for some help on where to start with a project i have on. I am looking for a way to input a formula in to twido to calculate volume of a horizontal cylinder tank. The tank will perfectly level and I know the formula but am un sure how to enter it into twido. I am guessing this would be done with a operation block or several operation blocks.
The formula for the volume is as follows
vol=lengthx[(r2acos((r-d)/r) - ((r-d) X (Sqroot(2rd)-d squared)]
where r=radius of container
d=depth of liquid
and all measurements are in the same units.
I will be getting a signal from a ultrasonic level transmitter. Just need some ideas as to how this would be input into the twido.
Hopefully someone can help out.

You can do use hte acos, sqrt and sqr instructions in operation blocks.
To make it easier just break down the formula into small parts, each in its own operation block. In the help file just type in cos or sqrt to get an example.
Btw you will have to make your answers floating point, so use %mf instead of %mw

Chris,

Double-check your formulas for Volume. According to a former college math professor (my dear wife), there are two formulas that must be used, due to the geometry of your tank.

If depth of liquid is less than or equal to Tank Radius, use this one:

V = Length X r^2[Arccosine((r-d)/r)]

If depth of liquid is greater than Tank Radius, use this one:

V = Length X r^2[Arccosine((d-r)/r)]

I think it has to do with the places where a negative Arccosine is undefined.

ok thanks for that great to get advice and so fast as well. Can anyone give me an example of how I would insert a rung with a analog input from %I1.0 (analog extension module) to a operation block. I was trying to insert operation with %mw2500:=%I1.0 and vice verser I just trying to take the analog value and insert into a memory word so I can then start using the formula. I not sure about what I should be inputting the analog signal into. ie what sort of block, maybe a comparision??????
Thanks heaps guys.

Chris,

I would like to help, but I am not expert on Twido. Wait for someone else.

This is another one of those problems where I like to use Excell to develop an empirical equation and then I can solve with four function math. A number cubed is NxNxN - easy. So a polynomial series is just a series of multiplies and adds. Much less painful than advanced math. You will need real numbers, though! See the attached spreadsheet.

Regarding the analogue you will use %IWx.x
x.x depending on where the analogue channel is situated