[simpits-tech] stepper motors

[John P. Miguez]

I will say, you guys do know your stuff.  That is a very comprehensive and
detailed answer.  Thanks for taking the time to write it out.  Between you
and Martin, I have an education on stepper motors and servos.  Thanks again
to both of you.

John
----- Original Message -----
From: "Marv De Beque" <mdebeque@woh.rr.com>
To: <simpits-tech@simpits.org>
Sent: Sunday, February 02, 2003 3:14 PM
Subject: Re: [simpits-tech] stepper motors


> Hey, I can answer that.
>
> A stepper is a motor that moves in a specified direction one step at a
time.
> You can specify the number of steps to be taken by repeating the step
> command.  Actually, that is a bit misleading.  There are different types
of
> stepper motors, but basically, a quadrature signal (two square waves at 90
> degrees out of phase from each other) are applied to the motor.  Each
cycle
> of the waveform moves the motor one step.  If you reverse the phase
> relationship at startup, the motor will run in the opposite direction.
> There is usually no limit as to how far the motor can be turned.  That is,
> it can rotate indefinitely in any direction.
>
> A servo usually has a limit of 180 degrees.  It is controlled by a
periodic
> pulse.  The width of the pulse is proportional to the position of the
motor.
> If you stop the pulses and park the servo, the position is maintained.
>
> Servos use a potentiometer to measure the shaft position of the servo.
> Circuitry in the servo compares the pulse width of the input signal to the
> resistance of the pot.  The circuitry will then move the motor to that
> position and stop.
>
> Servos can be modified to rotate continuously, but you loose the ability
to
> determine the shaft position.
>
> I use servos for gauges where the needle moves less than 360 degrees.  I
use
> step up gears to double the shaft rotation to do that.
>
> Marv
>
>
> On 2/2/03 3:27 PM, "John P. Miguez" <jmiguez@bellsouth.net> wrote:
>
> > Also, what is the difference between a servo and a stepper motor?
> >
> > John
> >
> > ----- Original Message -----
> > From: "Ido Dekkers" <idekkers@clicksoftware.com>
> > To: <simpits-tech@simpits.org>
> > Sent: Sunday, February 02, 2003 7:35 AM
> > Subject: [simpits-tech] stepper motors
> >
> >
> >>
> >>
> >>
> >>
> >> What is the difference between bipolar and unipolar motors ?
> >> Which of them does the stepper phidget support ?
> >>
> >> Thanks
> >>
> >> Ido
> >>
> >>
> >
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> > Thanks!
>
>