Re: [Emc-users] Acceleration Confusion

[Gene Heskett]

On Thursday 31 August 2017 07:05:44 theman whosoldtheworld wrote:

> seems really a confusion ... but not from XHC and acceleration, but
> from velocity and acceleration . In fact, but it may be that I
> lost something in the meantime, I do not remember it is possible to
> change axses acceleration on Lcnc, but only speed. I think in the new
> versions 2.8 there should be a "pin selector in hal file" to use a
> ramp of acceleration rather than another, but here too they should
> also make this strange memory clear to me  but that you can vary
> the acceleration with an MPG it sounds to me very strange. Speed
> ​​instead . sounds better.
>
> bkt
>
In the dials I added for independent x-z control, no attempt was made to 
control the accel's used, in fact without some further hal trickery I 
don't know if its possible.  So each movement is fed into the jog input 
as a motion times selected scale unit, eg 1 click can be up to .2" in my 
original configuration, but that was way too easy to "wind up", leaving 
the axis moving at maximum speed some unknown distance with the 
potential for crashing into things, so I have now restricted it to 50 
thou per click, still enough to encounter the wind up, catch up 
scenario. 20 thou as a maximum jog increment may wind up being my 
choice. Minimum is .0001" which will get there but is slow. Very handy 
for dialing in that last 3 thou to size.  The jog inputs to motion do 
not have a velocity pin, but this is an instance where one might find it 
usable if it was available.

As is, once it exceeds the step size of the motors full step, its also 
obviously noisy. Z in particular as the keyboard & mouse table is on top 
of the z motor mount, which was designed to use the same 3 bolt holes in 
the bed that formerly held the QCGB driving the screw. Vibration 
coupling is excellent. :)

That motor is serious overkill at 1600 oz/in, but its what I had left 
after I took it off the G0704, and moves Z on the lathe 3x faster than 
it could on the G0704, and its geared down 30 teeth to 42 on the 5 tpi 
screw. So where it was stalling at 30"/min on the G0704, it can move at 
nearly 150 ipm if the accels are gentle enough.  But its steps are so 
violent (I should play with the drivers current, it doesn't need the 
brute force of a 1600 there) I'm going to have to scrounge up a bigger 
piece of 3/4" and put a skirt around the front and ends to keep the 
mouse from vibrating off while its running a long program.

And a splash guard on the rear to keep flying oil from the rear spindle 
bearing from spraying all over the keyboard by raising a barrier up and 
over the bearing.

> 2017-08-30 18:16 GMT+02:00 王若溪 :
> > I have an XHC-HB04 18-button wireless MPG on my mill. It's amazing
> > that it works on LinuxCNC. But I found something confusing about
> > acceleration:
> >
> >1. The acceleration in [XHC_HB04_CONFIG]mpg_accels seems to have
> > an effect on both jogging and program running. Isn't it supposed to
> > affect MPG
> >jogging only?
> >2. Probably not related to XHC_HB04. Jog acceleration when using
> >Shift+Arrow keys seems to be higher than G0 acceleration. I
> > thought they should be identical. I'm using Axis GUI,
> > [AXIS_#]MAX_ACCELERATION = 250, [AXIS_#]STEPGEN_MAXACCEL = 937.5

mm's obviously.

> > Maybe there is some internal mechanism that I don't know, hope
> > someone could cast some light on it.

Thats my light, batteries could be weak though. :)

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page 

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Re: [Emc-users] Acceleration Confusion

[theman whosoldtheworld]

seems really a confusion ... but not from XHC and acceleration, but from
velocity and acceleration . In fact, but it may be that I lost
something in the meantime, I do not remember it is possible to change axses
acceleration on Lcnc, but only speed. I think in the new versions 2.8 there
should be a "pin selector in hal file" to use a ramp of acceleration rather
than another, but here too they should also make this strange memory clear
to me  but that you can vary the acceleration with an MPG it sounds to
me very strange. Speed ​​instead . sounds better.

bkt

2017-08-30 18:16 GMT+02:00 王若溪 :

> I have an XHC-HB04 18-button wireless MPG on my mill. It's amazing that it
> works on LinuxCNC. But I found something confusing about acceleration:
>
>1. The acceleration in [XHC_HB04_CONFIG]mpg_accels seems to have an
>effect on both jogging and program running. Isn't it supposed to affect
> MPG
>jogging only?
>2. Probably not related to XHC_HB04. Jog acceleration when using
>Shift+Arrow keys seems to be higher than G0 acceleration. I thought they
>should be identical. I'm using Axis GUI, [AXIS_#]MAX_ACCELERATION = 250,
>[AXIS_#]STEPGEN_MAXACCEL = 937.5
>
> Maybe there is some internal mechanism that I don't know, hope someone
> could cast some light on it.
> 
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[Emc-users] Acceleration Confusion

[王若溪]

I have an XHC-HB04 18-button wireless MPG on my mill. It's amazing that it
works on LinuxCNC. But I found something confusing about acceleration:

   1. The acceleration in [XHC_HB04_CONFIG]mpg_accels seems to have an
   effect on both jogging and program running. Isn't it supposed to affect MPG
   jogging only?
   2. Probably not related to XHC_HB04. Jog acceleration when using
   Shift+Arrow keys seems to be higher than G0 acceleration. I thought they
   should be identical. I'm using Axis GUI, [AXIS_#]MAX_ACCELERATION = 250,
   [AXIS_#]STEPGEN_MAXACCEL = 937.5

Maybe there is some internal mechanism that I don't know, hope someone
could cast some light on it.
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