# determining dither frequency and amplitude for a solenoid valve?

Discussion in 'General Electronics Chat' started by navidelec, Jan 22, 2015.

1. ### navidelec Thread Starter New Member

Jul 12, 2014
29
0
In the above figure from Hydraforce.com the frequency and amplitude for a solenoid valve is 70-350 Hz , regarding the valve mechanical response it is too high for the valve response to this range of frequency dither,
I wonder if you tell me what is the procedure to determine the valve mechanical response to the dither,
the relation between the amplitude of the dither to the frequency of it,
and what is the procedure to determine the amplitude and frequency of the dither for a special valve?

http://www.hydraforce.com/electro/E...ec_Mobile_Equip/3-440-1_Elec_Mobile_Equip.htm

• ###### Hi-Freq_PWM_2.gif
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Jan 15, 2015
969
235
My best guess is dither amplitude and frequency will be a function of the valve body or the specific valve. It's been maybe 30 years ago I got involved (more like sucked into) several hydraulic shaker tables and other fun filled hydraulic things using mostly Moog Valves and Moog servo controllers. You may want to give some of these documents a glance as to dither. For a special valve, as you mention you may want to contact the valve manufacturer for detailed info.

Ron

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3. ### navidelec Thread Starter New Member

Jul 12, 2014
29
0
Dear friend

in the one of the moog documents I saw this: The dither frequency depends on the electrical characteristics of the valve.
I want to find the valve cut-off frequency by finding the L and R with LRC meter and by the equation of f=R/(2*pi*L) the cut-off freq. is been define.
and after finding the cut-off freq. for example 160 Hz, then use a dither frequency near and less than this cut-off frequency about 150 Hz.
Is this correct, according to the moog document that it mentioned the dither is depends on electrical characteristics.
I wonder if you help me on this.

Last edited: Jan 23, 2015

Jan 15, 2015
969
235
Getting the dither right requires more than just knowing the frequency response of the coil. I suggest you start with giving this a read. Finding the valve cut off frequency is a good start. Also this may help a little. Again, I generally just look at the manufacturers data sheet or contact the manufacturer.

Ron

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5. ### timgow New Member

Aug 12, 2015
10
0
Thank you Navidelec for asking the question.

The link to 'may help a little' is broken, do you have the document title or a current link?
Tim

Jan 15, 2015
969
235
That was awhile ago and yes, the link no longer works. I don't remember where it went unfortunately. A Google of Dither Frequency brings up quite a few hits. Used dither years ago on hydraulic vibration tables.

Ron

7. ### timgow New Member

Aug 12, 2015
10
0
Ron, thank you for the quick reply.
I'm using pressure difference across an orifice plate as gas flow rate feedback to a proportional valve. I'm going to try using an H-bridge driver + microprocessor.
Tim

8. ### alfacliff Well-Known Member

Dec 13, 2013
2,449
428
dither is the ripple from the pwm, the valve does not produce dither, or need it for operation. it is ripple, and should be higher than the response time of the valve.