Re: [CAD_CAM_EDM_DRO] Basic stepper control question

In a message dated 30-Jun-01 15:18:28 Central Daylight Time,
datac@... writes:

> > I came up with this theory while playing with a 200 step per rev motor,
> and noting that you only feel 50 little "clicks" per rev when you spin it
> by hand. If you shut off the current, wouldn't you expect the motor to
> drop back to the nearest "click" position, moving you 1-2 steps away from
> where you really want to be?
>

Tom: I have been operating home-brew stepper-controlled lathes for years,
now, and exactly as you surmise, there is only a 25% chance that the desired
"click" when DC is restored will be ON the mark! I have 100-division
handwheels on my lead-screws, all directly-driven by steppers on the ends
opposite the handwheels, and each division takes two "clicks". If I should,
say, want a particular lead-screw to "start" on the "zero line", and manually
SET it there, then, flip on the DC, it ALWAYS jumps off at least TWO "clicks"
one way or the other.

Mariss mentioned that in a discussion of his G210 drive, but I forget the
detail, now. Maybe he will come up with grande wisdom?

Jan Rowland
Old Ugly Troll


[Non-text portions of this message have been removed]