Re: Re: Re: GeckoDrives.. Can anyone Help?

From: Jon Elson <jmelson@...>
<s>
So, steppers are totally not interchangeable with servo motors of any
type, and totally different drivers are needed for the two. There are
some servo drives that can accomodate several types of servo motors,
others will drive only one type.
<bigs>

Jon is speaking about the electronic packages needed to drive the
different motors. But there are other considerations where they are
"totally not interchangeable." Velocity control is one additional
difference. For this issue I'd include the step and direction servos with
the steppers.

Velocity control says, go to this position at this rate. Steppers and
step and direction servos, have no equivalent command. The difference might
not be important for hobby uses, but I've seen operators in the shop
need to put a 0.0015 taper on a 10" shaft. Using velocity commands, the
result is a nice smooth cone. Using step and direction, the result is a
set of steps with cylinders between. You might not think that you can see a
difference of 0.0015 but you could see it's reflection by rocking the parts
under a good lamp. You will also see the diference near the quadrants
when milling large circles.

Hope this muddies the waters, but not to much.

Ray