Re: Angular axes

[Ray Henry <rehenry-at-up.net>]

John

It seems to me that one of the problems may be the great difference in the 
number of steps between a unit on the linear axis and the number of steps in 
a rotary axis.  If you keep the quantity of steps per unit nearly the same, 
then you can drive the axes at the same speeds.

So long as you define a unit as 1 and make the INPUT_SCALE the number of 
pulses to complete a full revolution you will have the programming problem 
that you are experiencing.  In order to make a command of a90 be a 90 degree 
move, you must set INPUT_SCALE to the number of steps to complete a 1 degree 
move rather than a 360 degree move.

I do remember something about the six axis implementation being incomplete 
when the new interpreter was integrated into the rest of the EMC.  Your study 
and reports of the problems that you are having will help.  Thanks 

Ray 



On Wednesday 03 July 2002 21:45, you wrote:
> Hi Chris.
>
> I have determined this evening that it does not seem to make any difference
> whether the axis is configured as LINEAR or ANGULAR it just plain does not
> work at any reasonable speed with the INPUT_SCALE and OUTPUT_SCALE set to
> any thing less than 1000 steps per unit.  It also appears to totally ignore
> the UNITS parameter on the fourth axis.  You are correct in that if the
> fourth axis is configured identically to the other axis it will work at
> reasonable speeds but you cannot tell it to move say 90 degrees other than
> by decimal numbers such as g0 a0.25 will get you a 1/4 revolution move.
> This is not how I want to use my rotary table.  Oh well, I am sure it will
> get fixed sooner or later.  Maybe I will have to brush up on my C skills
> and fix it may self, which is NOT what I want to do.  I want to build
> engines, not fix software.
>
> John Guenther
> Sterling, Virginia
>
> > -----Original Message-----
> > From: emc-at-nist.gov [emc-at-nist.gov]On Behalf Of Chris Wagner
> > Sent: Wednesday, July 03, 2002 11:29
> > To: Multiple recipients of list
> > Subject: Angular axes
> >
> >
> >
> > Greetings,
> >
> > There has been list traffic about various problems with angular axes,
> > so I thought I would try some tests.  I will eventually (very long term)
> > want to use a rotary table.
> >
> > I found a problem similar to J Guenther - very slow motion.  I played
> > around with my .ini and found that the problem occurs anytime there is
> > an angular axis (any of X R, X Y R, X Y Z R, X Y Z R P W).  The slow
> > motion also effects the linear axes - they also creep along.  I would
> > expect that adding a fourth axis would not effect the behavior of the
> > previous three, but it does.
> >
> > As far as .ini understanding or parsing issues go, I did get a setup
> > that would run all the axes fast, by simply copying my three existing
> > linear axes sections (the [AXIS_0] etc) to three new sections, changed
> > the new [AXIS_x] tags to sequential numbers, used AXES=6, COORDINATES=X
> > Y Z R P W in the [TASK] section.  I did _not_ set the three new axis
> > type to angular (or make other changes).  The front ends (Tkemc, yemc)
> > then show all 6 axes (XYZRPW), and all axes will clock at high speed.
> > Moves work with e.g., G1X10Y20Z30A20B30C50 ...  (also works with XYZR)
> >
> > Of course It would be hard to set steps/revolution or degree since the
> > axis section is setup for linear units...
> >
> > Tentative conclusions:
> > 1) Problem is in setup/understanding of ANGULAR .ini configuration.
> >
> > 2) Something is wrong with the emc parsing of the ANGULAR ini.
> >
> > --
> > Recreational Calculus - Just For Fun!
> >
> > Chris Wagner
> > clwagner-at-eecs.wsu.edu