On Fri, 2 Oct 2009 08:25:32 -0500, you wrote:
>On Fri, Oct 02, 2009 at 12:18:50PM +0100, Steve Blackmore wrote:
>
>> " One occurrence that is interesting - when the rotation in the same
>> direction reaches 360.0 (a full circle), it continues to increase. It
>> does not become zero degrees again."
>
>I think your book is describing the same behavior EMC has always had.
>My opinion is that's the only sane way for rotaries that can't turn
>forever, like a tilting head.
Ehh?
It's sane for any rotary, particularly those that CAN rotate forever.
>Lots of users have pointed out (rightly in my opinion) that this
>behavior is awkward for rotaries that turn forever, because the
>position winds up forever.
What if it does wind up forever - you can always re zero it if you wish
as Ian Wright has shown.
Also as Andy pointed out, you can do an optional short move to zero in
some controllers, invent a code for it if considered essential.
>Once an axis says "12345.67" you have no
>idea from looking at the number which way it points. You have no
>idea what number to program in either G90 or G91 mode to get it to 90
>degrees from there without an unwanted 30-ish turn unwind.
Yes you do? 12435.67 gets it +90 degrees (cw) from 12345.67 or 12255.67
gets it -90 degrees (ccw) from there.
>Stuart's machine is like this, where C turns forever (but not B) and I
>think the solution he proposes is an at-least-somewhat-sane way of
>dealing with it.
>
>Are you objecting to this second scheme being added at all? If so,
>why? Is there another way, that's better in your opinion, that a
>different control handles an unlimited-turning rotary that solves the
>windup problem?
I'm objecting strongly to there being no such thing as 360 or bigger, as
Stuart suggested
Quote
Gentlemen,
I have previously requested the rotary axis usage as follows:
1: the rotary position stays within 0 and 359.999
you never see 360 (or more) in the program nor on the position
screen
Steve Blackmore
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