Re: stepper motor in servo loop question

Elliot,

What do you gain over just replacing the servo motors/drives in
the "old...equipment"? Prices are lower. Reliability is higher.
Tuning is easier. Why do this?

Price, maybe???
This method requires that the analog output section of the control be
working. You trade the cost of the servo drive for the cost of the
stepper drive(plus whatever VCO related circuitry you use). The
motors will similarly balance out,IMO.

In the end, you have lower performance at possibly a HIGHER cost...
For reasons Mariss has eloquently explained, the stepper will never
reach the performance of the servo.

Could it be done? prob'ly. But should it be done? Not IMO.

You may want to talk to Otto at MaxNC, as his CL "servo" system uses
steppers with encoders....

Hope this helps,

Ballendo

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Elliot Burke" <elliot@h...>
wrote:

> In the vast group memory of CCED, does any one remember if this has

been

> tried?
> Could a VCO be connected between low level analog output from a

servo and a

> stepper motor driver to allow use of a stepper motor in a servo

loop? Some

> sort of additional circuit would detect polarity and set the

direction

> signal appropriately.
>
>
>
> It seems so obvious, it must have been done. If it works it could

help

> revive an old piece of equipment with, you guessed it, steppers and
> encoders.
>
>
>
> regards-
> Elliot B.