Re: [CAD_CAM_EDM_DRO] Re: stepper vs. servo

On Wednesday 11 February 2004 12:26 am, Jon Elson wrote:

> Many people use Gecko 320/340 drives and Rutex drives which take step and
> directions signals from a computer and drive a servo motor from those
> commands. When Ballendo writes "non-step servo" he is referring to servo
> systems which do not use step/direction signals. The most well-known would
> be the old-style analog velocity servo, where the CNC control sends a
> voltage from -10 V to +10 V to the servo amp, which produces a motor
> velocity proportional to the command voltage. Zero volts means hold still.

Ah, okay. I appreciate the clarification.

> Stepper motors with encoders can be used in many ways. Some of which
> may be servo-like, and others may not be at all. For instance, in some
> cases the stepper motor can be turned off to allow an operator to move
> something manually, with the encoder keeping track of position. In other
> cases the encoder may be to detect stalls and loss of steps, but still not
> for closing a positioning loop.

The only thing I can think of that these motors would have come out of, just
based on the size of them, is old daisywheel printers that got scrapped. I
have one that I'm pretty sure is out of that, there's a bushing on one side
of the motor that looks like it'd fit a daisywheel, and a "flag" (plastic)
on the other side which would appear to work with an optointerrupter, so
that the thing could find a "home" position in terms of the rotation of the
daisywheel. I'm not sure what I'm going to do with that one, but if I keep
hanging out in these groups maybe I'll get some ideas... :-)