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Re: Re: Rotating potentiometers??????

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Posted By<" ">jay maechtlen on April 17, 2002 at 19:38:48:

In Reply to: Re: Rotating potentiometers?????? posted byRandy Kimball on April 14, 2002 at 09:32:21:

: : Hi I am struggling to find a solution to a design problem that I have and thought I might ask at a few places like this. I am trying to replace a potentiometer with something that rotates yet still works like a pot. Or to put it another way, some thing that can give me variable resistance with variable rotation speed. I would be thankful for any ideas,
: : Kevin.

: Are you looking for variable radial position OR variable speed,these are completely two different things?
: A pot will not give you rotation speed unless you are talking a portion of a circle in, say twenty turns or less.
: What you may need is an encoder. An encoder will allow you to count turns and small portions of a turn and use electroncs to calculate speed and position accurately. Here you would convert the number of pluses sent to distance/time. Then use a digital to analog converter to provide a varaible voltage.
: There are digital to analog converts that will convert speed of pulses to voltage. They are used for example in some speed feed backs and analog looking gauges.
: -randy-

a tachogenerator may used to provide a voltage precisely proportional to RPM.
That's kind of old technology, though - modern CNCs just track the encoder pulses and compute velocity...

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Subject: Re: Re: Re: Rotating potentiometers??????

Comments:: : : Hi I am struggling to find a solution to a design problem that I have and thought I might ask at a few places like this. I am trying to replace a potentiometer with something that rotates yet still works like a pot. Or to put it another way, some thing that can give me variable resistance with variable rotation speed. I would be thankful for any ideas, : : : Kevin. : : Are you looking for variable radial position OR variable speed,these are completely two different things? : : A pot will not give you rotation speed unless you are talking a portion of a circle in, say twenty turns or less. : : What you may need is an encoder. An encoder will allow you to count turns and small portions of a turn and use electroncs to calculate speed and position accurately. Here you would convert the number of pluses sent to distance/time. Then use a digital to analog converter to provide a varaible voltage. : : There are digital to analog converts that will convert speed of pulses to voltage. They are used for example in some speed feed backs and analog looking gauges. : : -randy- : a tachogenerator may used to provide a voltage precisely proportional to RPM. : That's kind of old technology, though - modern CNCs just track the encoder pulses and compute velocity...

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