level control in a spherical tank

[Rahini]

Hi,

I hav to  control level in spherical tank.how to find  transfer function for this system,bcoz i hav to simulate the system using transfer function.simulation using PID and fuzzy is required.should i find transfer function only through open loop test bcoz wen i tried using that,i didnt get exact output ie the system didnt settle at all. if u hav any idea regarding this,pls help me.....

[mikeporter]

You would do it the same way you would with a tank of any shape. The only difference is that you are dealing with the volume of a sphere rather than a cylinder or rectangle. Hence the amount of fluid required to raise the level by X is non-linear in that it varies with how much stuff is already in the tank - which is a function of the volume of a sphere (actually the volume of a partial sphere).

Mike...

[chromepet]

Hi,

    I'm new to lab view..Pl suggest me a proper mathematical expression or equations for controlling level in a spherical tank and help me in its implementation in labview...

[GerdW]

Hi,

even when you're new to LabVIEW it should be no problem to grab a math book of your choice to look for the correct formula for calculation of tank volume... When you found that formula and still have problems in making that into LabVIEW please ask again!

[gopi05]

i did mathematical modelling for level  in spherical tank and got the open loop response.. but the non linear response has no delay time in it..  what should be the fault ?