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As a part of R&D project I want to control a solenoid valve proportionally. what are the possible techniques for it, what is the speciality of solenoid which can be controlled proportionally, can I use any solenoid or need solenoid with specific characteristics? also how can I model it on Matlab/simulink... any advise, any link, any material is most welcomed.

many thanks in advance.

You can use any solenoid valve as proportional valve by using the controller in time proportional mode. In time proprtionl mode controller will issue on/off command with respect to deviation between PV and SP.

Hope I have given answer to your question.

Kapil
Kapil_cic@vsnl.net

Dear shah
it is depend loop condition. i,e, if time constant of loop is 1 sec and you want resolution of 100 then solenoid should be operate 100 times in sec, and if time constant of loop is 2 sec and you want resolution of 100 then solenoid should be operate 50 times in sec,
it may be help you.

Regards,
Shailesh C Patel
FDC - Control Systems And Instrumentation

I think you're confusing a solenoid valve and a variable control valve. A Solenoid is on/off digital control. You apply a signal (5/12/24 VDC, 120VAC, 15PSI, or whatever is appropriate) and the valve stokes open (or closed if indirect acting).

If you want proportional control, then you'll need a control valve of some type. But you'll have to be a bit more specific about the application. What are you trying to control? A small air signal, a 12 inch steam line, or a temperature bath of some kind. (Or any of about a thousand other things that might need controlling.) You need to tell us more.

Michael R. Batchelor
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Many thanks for your responses...what I have to control is water for shower or normal tab application my plan is to monitor current for position feed back....the solenoid I can use should be miniature to fit in to tab. Now with PWM can I reduce the size of coil by increasing the PWM frequency also I have seen some solenoid which are termed as propotional solenoid just as one here

http://hydraulics.eaton.com/products/pdfs/V-VLOV-MC001-E3_B.pdf#sea rch='eaton%20proportional%20solenoid'

now I am just wondering that what is the speciality of these because even these have to be controlled with PWM but they call them 'propotional'. Any info regarding this matter, any suggestion about monitoring with current control or any other method if possible to control or anyone working on this type of project .......shahiiee@hotmail.com

Try Pulse Width Modulation. I understand that a PWM driver can be used with a standard binary solenoid, although I have never done it.

Why don't you copy what ASCO has done with their 8202/8203 series - a proportional solenoid valve

http://www.ascovalve.com/products_detail.asp?detail=proportional_da ta

David

I only can tell you an old fashion way to make an on/off control, operates as proportional control:

You need to generate an square wave, this should be frecuency variable fixed by the error, or period constant but the time ON / time OFF adjustable.

I used this time proportioning control w/resitive load.

One way to generate the square w. is

1.- a ramp (triangle) signal generator
2.- pass the signal through the inverting input
3.- put a signal CD AT THE NON INVERING
4.- nOW YOU HAVE A COMPARTOR
5.- the output is square output, on/off.