Re: APS stepmotor pinout sta

['Mark S. Engbretson' <mark@the-brain.bessrc.aps.anl.gov>]

> 
> by definition the *APS* motor standard is what *we* say it is. 
obviously, if
> there is a standard out there adopted by the industry, then we would be
> intelligent to use it. slosyn appears to have a standard
> which a lot of scientists and engineers know about, but when i called Leo
at
> ACS (vendor of step-paks) i found he wasn't designing his drivers to meet
any
> industry-wide standard, and wasn't much concerned with which way a motor
> moved. 

For what it is worth . . . BESSRC has been getting a lot of pre-wired
motorized devices in which  claim correspond to some 'APS Motor direction
Standard' - i.e. clockwise or some such.

However, the manufacturers in their infinite wisdom have not been taking
the time to insure that whatever direction they choose as clockwise are
actually matching what the limits switchs expect as clockwise - which
implies that we re-wire limit switches about 50% of the time. 

IMHBBO, I could care less what the 'raw' direction a motor actually moves
in . . . after going through gear reduction and limitation on where they
can mount the thing, a default 'direction' isn't going to mean a ******
thing anyway. 

In a perfect world, the default direction would always be in the 'natural' 
coordinate system that a device, say a table normally moves. With the
current tables that we have now, this implies moving 3 axis - 2 up (or
down) and the other down (or up) to keep the surface flat (all moving
clockwise, normally, BTW). Obviuosly, the 'real' solution is to try to run
them all the same direction to perform the same move - no matter what
direct that end up being.

Me