Re: Gantry Wood Router

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "mij_gib" <mij_gib@y...>
wrote:

> I am designing a wood router using a gantry with a stepper motor on
> each side in the "X" direction. My question is:
>
> Do I need a driver and controller for each one or can they be

hooked

> together?
>
> Some software( MACH2) have a slave feature. Can this feature be

used

> without individual drivers and controllers?
>
> Thank you

MACH 2 treats the slaved axis as a separate axis (A) that has its own
step and direction signals. You need separate control because one of
the main benefits of slaving is the ability to setup a home switch on
each side of your gantry and it will automatically "square" itself in
the even of any racking problems. The first side to hit a home stops
while the other continues until it hits the home.

All of that being said, you do NOT want to try and run two motors off
one motor driver. It puts the motors in parallel and the chances
that two motors will be absolutely identical in all aspects is
slight. Even with both motors tied mechanically to the same shaft
they will cause problems. Across a gantry it would be an even bigger
issue. Most modern motor drives have specific compensation based on
driving a single inductive load. Placing two in parallel upsets the
compensation. Even if you were to use the same step and direction
you still need separate motor drives for each motor (and then you
have to deal with the increased logic drive requirements on the
parallel port)

Driving a dual motor gantry works well and keeps things nice and
square even in heavy and rapid cutting.