Re: [Emc-users] Another Python question

[ken.strauss]

Thanks for the instantaneous response! Now I need to figure out how to retrofit 
to 2.7...

-Original Message-
From: andy pugh  
Sent: December 18, 2020 7:01 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Another Python question

On Fri, 18 Dec 2020 at 23:55,  wrote:

> Where can I download the python helpful functions enhancements in 2.8 
> documented at 
> http://linuxcnc.org/docs/2.8/html/hal/halmodule.html#_helpful_functions? I am 
> primarily interested in how get_value is implemented.

I think that they are a part of halmodule.cc

https://github.com/LinuxCNC/linuxcnc/blob/43ac9730f4d6be679bd28292d88fdfcdb8204907/src/hal/halmodule.cc

So they are not implemented in Python, but are available to Python if you 
import hal

--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is designed for 
the especial use of mechanical geniuses, daredevils and lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Another Python question

[andy pugh]

On Fri, 18 Dec 2020 at 23:55,  wrote:

> Where can I download the python helpful functions enhancements in 2.8 
> documented at 
> http://linuxcnc.org/docs/2.8/html/hal/halmodule.html#_helpful_functions? I am 
> primarily interested in how get_value is implemented.

I think that they are a part of halmodule.cc

https://github.com/LinuxCNC/linuxcnc/blob/43ac9730f4d6be679bd28292d88fdfcdb8204907/src/hal/halmodule.cc

So they are not implemented in Python, but are available to Python if
you import hal

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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[Emc-users] Another Python question

[ken.strauss]

I'm obviously not sufficiently github knowledgeable. 

Where can I download the python helpful functions enhancements in 2.8 
documented at 
http://linuxcnc.org/docs/2.8/html/hal/halmodule.html#_helpful_functions? I am 
primarily interested in how get_value is implemented.




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Re: [Emc-users] More on the BS-1

[Todd Zuercher]

Considering your piece was never intended to be automated, only hand positioned 
and locked in place.  Precision of the worm drive components probably weren't a 
priority.

Todd Zuercher
P. Graham Dunn Inc.
630 Henry Street 
Dalton, Ohio 44618
Phone:  (330)828-2105ext. 2031

-Original Message-
From: Gene Heskett  
Sent: Friday, December 18, 2020 2:06 PM
To: emc-users@lists.sourceforge.net
Subject: Re: [Emc-users] More on the BS-1

[EXTERNAL EMAIL] Be sure links are safe.

On Friday 18 December 2020 13:16:00 Chris Albertson wrote:

> I do have a case where a "home" is needed on a rotary axis.  It is a 
> robot cart that uses a motor in place of a steering wheel to control 
> the angle of the two front wheels.  The wheels also turn but they are 
> not homed, we assume the wheels are at zero at power-up.  The steering
> homes to "center".I use two switches on the steering home so I
> know which direction to move,  Center is when both switches are open.
>
> I bring this up because you said you did not want to wait for a 359.9
> degree rotation.   With two switches you can always know on which half
> of the circle you are on. and never turn more than 180 degrees.  (the 
> microswitch rides on a ridge that covers 1/2 the circumference)

I thought of that, then discovered just how much trouble it was to make the 
notch in the spindle flange and said screw it. With the current config, if it 
has not been moved, only moves it 5 degrees to find that edge of the notch, and 
back to zero which is usually about +.003 on the dro.

That is very impressive, until you grab the chuck and discover about 1 degree 
of backlash at that parking point. I haven't totally blocked access to the 
adjustment lock screw but before I loosen that, I'll make a couple chisel cuts 
so I can tap it a thou at a time, and make sure theres no endplay in the worm. 
This piece of crap doesn't even have a ball bearing ball to cushion that 
adjustment screw, so there WILL be a high wear rate there. I've no clue what a 
REAL BS-1 is worth, but I'm beginning to rethink buying this Chinese junk.

> On Fri, Dec 18, 2020 at 5:27 AM Gene Heskett 
wrote:
> > On Friday 18 December 2020 05:23:45 andy pugh wrote:
> > > On Fri, 18 Dec 2020 at 08:16, Gene Heskett 
> >
> > wrote:
> > > > > Also for a rotary table I wonder if you could use a push
> > > > > button on a control pannel.   You define home to be whatever
> > > > > you want.   For example if you need to make 20 cuts to cut a
> > > > > gear, do you care where the firth tooth is on the black?
> > > >
> > > > Generally no, Chris, but there will be times, like when a gear 
> > > > already has the keyway cut. :)
> > >
> > > I have not bothered with home switches on my rotary, it just homes 
> > > where it is. (zero search velocity) as part of the home sequence.
> > >
> > > If there is already a keyway or feature on the shaft then I am not 
> > > sure that homing really helps, unless it is a job that was left in 
> > > overnight.
> > > (And in that case I would return to zero before shutting it down).
> > >
> > > Aligning to an existing keyway or flat is a touch-off process, not 
> > > homing.
> >
> > That was my impression too, Andy, but I can drive it till the 
> > encoders rawcount is maybe a dozen counts from zero, touch it off to 
> > zero, and restart LinuxCNC and its back to -44 thousand counts on 
> > the restart. So call me puzzled. Even nuking position.txt doesn't 
> > prevent it long term. I parked it on the switch but didn't touch off 
> > to 0.000 before the last shutdown and this is position.txt now:
> >
> > 0.00010004874109802
> > 0.0004978340956
> > 6.2490801172967
> > -33.1094999843385
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> >
> > Thanks Andy
> >
> > 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)
> > If we desire respect for the law, we must first make the law 
> > respectable. - Louis D. Brandeis Genes Web page 
> > 
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users


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)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] More on the BS-1

[Gene Heskett]

On Friday 18 December 2020 13:16:00 Chris Albertson wrote:

> I do have a case where a "home" is needed on a rotary axis.  It is a
> robot cart that uses a motor in place of a steering wheel to control
> the angle of the two front wheels.  The wheels also turn but they are
> not homed, we assume the wheels are at zero at power-up.  The steering
> homes to "center".I use two switches on the steering home so I
> know which direction to move,  Center is when both switches are open.
>
> I bring this up because you said you did not want to wait for a 359.9
> degree rotation.   With two switches you can always know on which half
> of the circle you are on. and never turn more than 180 degrees.  (the
> microswitch rides on a ridge that covers 1/2 the circumference)

I thought of that, then discovered just how much trouble it was to make 
the notch in the spindle flange and said screw it. With the current 
config, if it has not been moved, only moves it 5 degrees to find that 
edge of the notch, and back to zero which is usually about +.003 on the 
dro.

That is very impressive, until you grab the chuck and discover about 1 
degree of backlash at that parking point. I haven't totally blocked 
access to the adjustment lock screw but before I loosen that, I'll make 
a couple chisel cuts so I can tap it a thou at a time, and make sure 
theres no endplay in the worm. This piece of crap doesn't even have a 
ball bearing ball to cushion that adjustment screw, so there WILL be a 
high wear rate there. I've no clue what a REAL BS-1 is worth, but I'm 
beginning to rethink buying this Chinese junk.

> On Fri, Dec 18, 2020 at 5:27 AM Gene Heskett  
wrote:
> > On Friday 18 December 2020 05:23:45 andy pugh wrote:
> > > On Fri, 18 Dec 2020 at 08:16, Gene Heskett 
> >
> > wrote:
> > > > > Also for a rotary table I wonder if you could use a push
> > > > > button on a control pannel.   You define home to be whatever
> > > > > you want.   For example if you need to make 20 cuts to cut a
> > > > > gear, do you care where the firth tooth is on the black?
> > > >
> > > > Generally no, Chris, but there will be times, like when a gear
> > > > already has the keyway cut. :)
> > >
> > > I have not bothered with home switches on my rotary, it just homes
> > > where it is. (zero search velocity) as part of the home sequence.
> > >
> > > If there is already a keyway or feature on the shaft then I am not
> > > sure that homing really helps, unless it is a job that was left in
> > > overnight.
> > > (And in that case I would return to zero before shutting it down).
> > >
> > > Aligning to an existing keyway or flat is a touch-off process, not
> > > homing.
> >
> > That was my impression too, Andy, but I can drive it till the
> > encoders rawcount is maybe a dozen counts from zero, touch it off to
> > zero, and restart LinuxCNC and its back to -44 thousand counts on
> > the restart. So call me puzzled. Even nuking position.txt doesn't
> > prevent it long term. I parked it on the switch but didn't touch off
> > to 0.000 before the last shutdown and this is position.txt now:
> >
> > 0.00010004874109802
> > 0.0004978340956
> > 6.2490801172967
> > -33.1094999843385
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> > 0.0
> >
> > Thanks Andy
> >
> > 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)
> > If we desire respect for the law, we must first make the law
> > respectable. - Louis D. Brandeis
> > Genes Web page 
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users


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)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] More on the BS-1

[Chris Albertson]

I do have a case where a "home" is needed on a rotary axis.  It is a robot
cart that uses a motor in place of a steering wheel to control the angle of
the two front wheels.  The wheels also turn but they are not homed, we
assume the wheels are at zero at power-up.  The steering homes to
"center".I use two switches on the steering home so I know which
direction to move,  Center is when both switches are open.

I bring this up because you said you did not want to wait for a 359.9
degree rotation.   With two switches you can always know on which half of
the circle you are on. and never turn more than 180 degrees.  (the
microswitch rides on a ridge that covers 1/2 the circumference)


On Fri, Dec 18, 2020 at 5:27 AM Gene Heskett  wrote:

> On Friday 18 December 2020 05:23:45 andy pugh wrote:
>
> > On Fri, 18 Dec 2020 at 08:16, Gene Heskett 
> wrote:
> > > > Also for a rotary table I wonder if you could use a push button on
> > > > a control pannel.   You define home to be whatever you want.   For
> > > > example if you need to make 20 cuts to cut a gear, do you care
> > > > where the firth tooth is on the black?
> > >
> > > Generally no, Chris, but there will be times, like when a gear
> > > already has the keyway cut. :)
> >
> > I have not bothered with home switches on my rotary, it just homes
> > where it is. (zero search velocity) as part of the home sequence.
> >
> > If there is already a keyway or feature on the shaft then I am not
> > sure that homing really helps, unless it is a job that was left in
> > overnight.
> > (And in that case I would return to zero before shutting it down).
> >
> > Aligning to an existing keyway or flat is a touch-off process, not
> > homing.
>
> That was my impression too, Andy, but I can drive it till the encoders
> rawcount is maybe a dozen counts from zero, touch it off to zero, and
> restart LinuxCNC and its back to -44 thousand counts on the restart. So
> call me puzzled. Even nuking position.txt doesn't prevent it long term.
> I parked it on the switch but didn't touch off to 0.000 before the last
> shutdown and this is position.txt now:
>
> 0.00010004874109802
> 0.0004978340956
> 6.2490801172967
> -33.1094999843385
> 0.0
> 0.0
> 0.0
> 0.0
> 0.0
> 0.0
> 0.0
> 0.0
> 0.0
> 0.0
> 0.0
> 0.0
>
> Thanks Andy
>
> 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)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] More on the BS-1

[Gene Heskett]

On Friday 18 December 2020 05:23:45 andy pugh wrote:

> On Fri, 18 Dec 2020 at 08:16, Gene Heskett  
wrote:
> > > Also for a rotary table I wonder if you could use a push button on
> > > a control pannel.   You define home to be whatever you want.   For
> > > example if you need to make 20 cuts to cut a gear, do you care
> > > where the firth tooth is on the black?
> >
> > Generally no, Chris, but there will be times, like when a gear
> > already has the keyway cut. :)
>
> I have not bothered with home switches on my rotary, it just homes
> where it is. (zero search velocity) as part of the home sequence.
>
> If there is already a keyway or feature on the shaft then I am not
> sure that homing really helps, unless it is a job that was left in
> overnight.
> (And in that case I would return to zero before shutting it down).
>
> Aligning to an existing keyway or flat is a touch-off process, not
> homing.

That was my impression too, Andy, but I can drive it till the encoders 
rawcount is maybe a dozen counts from zero, touch it off to zero, and 
restart LinuxCNC and its back to -44 thousand counts on the restart. So 
call me puzzled. Even nuking position.txt doesn't prevent it long term. 
I parked it on the switch but didn't touch off to 0.000 before the last 
shutdown and this is position.txt now:

0.00010004874109802
0.0004978340956
6.2490801172967
-33.1094999843385
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0

Thanks Andy

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)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] More on the BS-1

[andy pugh]

On Fri, 18 Dec 2020 at 08:16, Gene Heskett  wrote:

> > Also for a rotary table I wonder if you could use a push button on a
> > control pannel.   You define home to be whatever you want.   For
> > example if you need to make 20 cuts to cut a gear, do you care where
> > the firth tooth is on the black?
>
> Generally no, Chris, but there will be times, like when a gear already
> has the keyway cut. :)

I have not bothered with home switches on my rotary, it just homes
where it is. (zero search velocity) as part of the home sequence.

If there is already a keyway or feature on the shaft then I am not
sure that homing really helps, unless it is a job that was left in
overnight.
(And in that case I would return to zero before shutting it down).

Aligning to an existing keyway or flat is a touch-off process, not homing.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] More on the BS-1

[Gene Heskett]

On Friday 18 December 2020 02:56:53 Chris Albertson wrote:

> This is not LCNC specif, but just motion control...
>
> Many times the secret is to do the homing twice.  Once at full speed
> and as you note it overshoots.   Then backup up until you bump the
> switch again then finally move as you say as 0.1 degrees per second. 
> You don't need to actually stop at the home, just note the encoder
> count as you pass as the switch trips
>
> Look at you 3D printer for inspiration.  I think it goes fst to get a
> rough-homethen hits it slow a few times to take an average.

My ender 3 only hits it twice, second time quite slow.

> Also for a rotary table I wonder if you could use a push button on a
> control pannel.   You define home to be whatever you want.   For
> example if you need to make 20 cuts to cut a gear, do you care where
> the firth tooth is on the black?

Generally no, Chris, but there will be times, like when a gear already 
has the keyway cut. :)


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)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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