[Emc-users] Helical interpolation not quite round, WTF?

[Igor Chudov]

I have a routine that lets me mill a deep circle in several passes,
typically to cutout circles from plates.

Something strange is going on and the resulting shape is not exactly round.
It can be best described as a circle with humps.

The routine is below. It is basically a while loop, milling progressively
deeper until Z reaches the required depth. Every loop consists of two half
circles milled helically, with the end mill going down along a spiral.

Any idea why the shape may not end up being circular?

Thanks

Routine attached.

(Copyright - Igor Chudov, released under GNU Public License V3)

O sub (circular groove, good for milling through holes too)
  # = #1 (X center)
  # = #2 (Y center)
  #  = #3 (safe height)
  #  = #4 (depth of milling)
  # = #5 (outside radius)
  #  = #6 (end mill diameter)
  #  = #7 (feed rate)
  #  = #8 (z step, per circle, optional)

  O if [ # NE 0 ]
F#
  O endif

  O if [ # EQ 0 ]
# = [#/3]
  O endif

  # = #
  # = [# - #/2]

  G0 Z#
  G4 P0
  G0 X[# + #] Y#

  O while [ 1 ]

O if [ # - # LT #]
  # = [# - #]
O endif

G2 X[# - #] Y# Z[# - #/2] R#
G2 X[# + #] Y# Z[# - #] R#

# = [# - #]

O if [ # LE # ]
  O break
O endif

  O endwhile

  G2 X[# - #] Y# R#
  G2 X[# + #] Y# R#

  G0 Z#

O endsub

M2
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Re: [Emc-users] Helical interpolation not quite round, WTF?

[andy pugh]

On 25 September 2012 19:20, Igor Chudov  wrote:
> I have a routine that lets me mill a deep circle in several passes,
> typically to cutout circles from plates.

You ought to be able to do this with one line of G-code?

G2 I[http://www.ifixit.com/Manifesto

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Re: [Emc-users] Helical interpolation not quite round, WTF?

[dave]

On Tue, 2012-09-25 at 13:20 -0500, Igor Chudov wrote:
> I have a routine that lets me mill a deep circle in several passes,
> typically to cutout circles from plates.
> 
> Something strange is going on and the resulting shape is not exactly round.
> It can be best described as a circle with humps.
> 
> The routine is below. It is basically a while loop, milling progressively
> deeper until Z reaches the required depth. Every loop consists of two half
> circles milled helically, with the end mill going down along a spiral.
> 
> Any idea why the shape may not end up being circular?
> 
> Thanks
> 
> Routine attached.
> 
> (Copyright - Igor Chudov, released under GNU Public License V3)
> 
> O sub (circular groove, good for milling through holes too)
>   # = #1 (X center)
>   # = #2 (Y center)
>   #  = #3 (safe height)
>   #  = #4 (depth of milling)
>   # = #5 (outside radius)
>   #  = #6 (end mill diameter)
>   #  = #7 (feed rate)
>   #  = #8 (z step, per circle, optional)
> 
>   O if [ # NE 0 ]
> F#
>   O endif
> 
>   O if [ # EQ 0 ]
> # = [#/3]
>   O endif
> 
>   # = #
>   # = [# - #/2]
> 
>   G0 Z#
>   G4 P0
>   G0 X[# + #] Y#
> 
>   O while [ 1 ]
> 
> O if [ # - # LT #]
>   # = [# - #]
> O endif
> 
> G2 X[# - #] Y# Z[# - #/2] R#
> G2 X[# + #] Y# Z[# - #] R#
> 
> # = [# - #]
> 
> O if [ # LE # ]
>   O break
> O endif
> 
>   O endwhile
> 
>   G2 X[# - #] Y# R#
>   G2 X[# + #] Y# R#
> 
>   G0 Z#
> 
> O endsub
> 
> M2
Hi Igor,
Just off the top of my head I suspect that your program is fine; but the
machine is well used and has measurable backlash. In a perfect machine
you get real axis reversal ( X | Y ) every 90 degrees. If your
ballscrews (lead screw) have backlash then you have to catch up with
that before the axis actually changes direction. 
Since the slope is small around the inflection points not much happens
until you take up the slack and then you see the actual reversal. Might
be as much as 10 degrees off the ideal. Multiple passes may make it look
better but will not necessarily improve the precision. Backlash comp
does not fix this; only throwing $$$ at the machine. :-(

I hope it turns out to be something fixable without the injection of
many $. 

Dave


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Re: [Emc-users] Helical interpolation not quite round, WTF?

[N. Christopher Perry]

Igor,

I don't have an answer for you, other than to check on how you've defined you 
trajectory planning accuracy outside of this routine.

Why are you using two half circles?  You could just send the cutter back to the 
starting xy location in a single G2 instruction.

N. Christopher Perry

On Sep 25, 2012, at 14:20, Igor Chudov  wrote:

> I have a routine that lets me mill a deep circle in several passes,
> typically to cutout circles from plates.
> 
> Something strange is going on and the resulting shape is not exactly round.
> It can be best described as a circle with humps.
> 
> The routine is below. It is basically a while loop, milling progressively
> deeper until Z reaches the required depth. Every loop consists of two half
> circles milled helically, with the end mill going down along a spiral.
> 
> Any idea why the shape may not end up being circular?
> 
> Thanks
> 
> Routine attached.
> 
> (Copyright - Igor Chudov, released under GNU Public License V3)
> 
> O sub (circular groove, good for milling through holes too)
>  # = #1 (X center)
>  # = #2 (Y center)
>  #  = #3 (safe height)
>  #  = #4 (depth of milling)
>  # = #5 (outside radius)
>  #  = #6 (end mill diameter)
>  #  = #7 (feed rate)
>  #  = #8 (z step, per circle, optional)
> 
>  O if [ # NE 0 ]
>F#
>  O endif
> 
>  O if [ # EQ 0 ]
># = [#/3]
>  O endif
> 
>  # = #
>  # = [# - #/2]
> 
>  G0 Z#
>  G4 P0
>  G0 X[# + #] Y#
> 
>  O while [ 1 ]
> 
>O if [ # - # LT #]
>  # = [# - #]
>O endif
> 
>G2 X[# - #] Y# Z[# - #/2] R#
>G2 X[# + #] Y# Z[# - #] R#
> 
># = [# - #]
> 
>O if [ # LE # ]
>  O break
>O endif
> 
>  O endwhile
> 
>  G2 X[# - #] Y# R#
>  G2 X[# + #] Y# R#
> 
>  G0 Z#
> 
> O endsub
> 
> M2
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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Igor Chudov]

Andy, thanks, what is P? Number of passes?

The problem is that the lumps do not look like caused by backlash.

There is one place where there is a lump, caused by all passes except the
first one. I am very puzzled.

i


On Tue, Sep 25, 2012 at 1:40 PM, andy pugh  wrote:

> On 25 September 2012 19:20, Igor Chudov  wrote:
> > I have a routine that lets me mill a deep circle in several passes,
> > typically to cutout circles from plates.
>
> You ought to be able to do this with one line of G-code?
>
> G2 I[
> Lumps at the 4 quadrants would normally be due to backlash problems.
>
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> If you can't fix it, you don't own it.
> http://www.ifixit.com/Manifesto
>
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Re: [Emc-users] Helical interpolation not quite round, WTF?

[andy pugh]

On 25 September 2012 20:01, Igor Chudov  wrote:
> Andy, thanks, what is P? Number of passes?

Yes.

> The problem is that the lumps do not look like caused by backlash.

Odd, then.

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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Stephen Dubovsky]

How big are the "humps"?  How many are there?

Are you in exact stop mode?  If motion stops at the beginning/end of
each semicircle then you will get a little hump from springback during
the pause.  Lead-in & out are typ used when cutting IDs to prevent
that.

Stephen

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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Igor Chudov]

On Tue, Sep 25, 2012 at 2:13 PM, Stephen Dubovsky wrote:

> How big are the "humps"?  How many are there?
>
>
There is one big hump on an about 4 inch circle. This hump is about 1mm
tall and 20mm wide.

It appears consistently on all passes, except the first one.

There is also a much smaller hump in another quadrant, visible, but
smaller.

I am not` in exact stop mode.

i


> Are you in exact stop mode?  If motion stops at the beginning/end of
> each semicircle then you will get a little hump from springback during
> the pause.  Lead-in & out are typ used when cutting IDs to prevent
> that.
>
> Stephen
>
>
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Re: [Emc-users] Helical interpolation not quite round, WTF?

[dave]

On Tue, 2012-09-25 at 15:13 -0400, Stephen Dubovsky wrote:
> How big are the "humps"?  How many are there?
> 
> Are you in exact stop mode?  If motion stops at the beginning/end of
> each semicircle then you will get a little hump from springback during
> the pause.  Lead-in & out are typ used when cutting IDs to prevent
> that.
> 
> Stephen
> 
Ah! Both good questions I should have been smart enough to ask. Since my
mill is not as stiff as would be ideal I tend to take small Z
increments/360 degrees and work my way down taking at least an extra
pass or two at the max depth as spring passes. 

To extend Stephen's question: where are the humps, exactly at 0, 90, 180
& 270 or offset some. Are they deep enough to not be backlash anomalies?

Dave
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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Igor Chudov]

Humps are

1) Northwest corner, biggest hump, 1mm tall by 20mm wide
2) Northeast corner, 0.5mm by 15mm wide

On Tue, Sep 25, 2012 at 3:08 PM, dave  wrote:

> On Tue, 2012-09-25 at 15:13 -0400, Stephen Dubovsky wrote:
> > How big are the "humps"?  How many are there?
> >
> > Are you in exact stop mode?  If motion stops at the beginning/end of
> > each semicircle then you will get a little hump from springback during
> > the pause.  Lead-in & out are typ used when cutting IDs to prevent
> > that.
> >
> > Stephen
> >
> Ah! Both good questions I should have been smart enough to ask. Since my
> mill is not as stiff as would be ideal I tend to take small Z
> increments/360 degrees and work my way down taking at least an extra
> pass or two at the max depth as spring passes.
>
> To extend Stephen's question: where are the humps, exactly at 0, 90, 180
> & 270 or offset some. Are they deep enough to not be backlash anomalies?
>
> Dave
> >
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>
>
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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Ben Potter]

It's pretty unlikely, but with the first pass being free of humps I'd be
tempted to look at tool deflection. If your first pass is milling in from
fresh air it'll take a lighter cut, the heavier (and more consistent) cut on
each subsequent pass could then be deflecting slightly. 

If this is the case, and you don't find a better solution - you can always
do the cut in two passes, cut it 1-3 mm undersize then do a quick finish
pass to cleanup. Not ideal, but I tend to have to do this with smaller
diameter cutters on my non-rigid router.

Your sub looks OK, but I'd also be tempted to use G2 I J Z P directly to
rule out any... odd motion planning.

Ben

-Original Message-
From: Igor Chudov [mailto:ichu...@gmail.com] 
Sent: 25 September 2012 21:31
To: dengv...@charter.net; Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] Helical interpolation not quite round, WTF?

Humps are

1) Northwest corner, biggest hump, 1mm tall by 20mm wide
2) Northeast corner, 0.5mm by 15mm wide

On Tue, Sep 25, 2012 at 3:08 PM, dave  wrote:

> On Tue, 2012-09-25 at 15:13 -0400, Stephen Dubovsky wrote:
> > How big are the "humps"?  How many are there?
> >
> > Are you in exact stop mode?  If motion stops at the beginning/end of 
> > each semicircle then you will get a little hump from springback 
> > during the pause.  Lead-in & out are typ used when cutting IDs to 
> > prevent that.
> >
> > Stephen
> >
> Ah! Both good questions I should have been smart enough to ask. Since 
> my mill is not as stiff as would be ideal I tend to take small Z
> increments/360 degrees and work my way down taking at least an extra 
> pass or two at the max depth as spring passes.
>
> To extend Stephen's question: where are the humps, exactly at 0, 90, 
> 180 & 270 or offset some. Are they deep enough to not be backlash
anomalies?
>
> Dave
> >
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>
>
>
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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Terry Christophersen]

Sometimes milling in the opposite direction will help.Rough one direction then
put in a finish pass in the other.
Looking at your code I see you have a G2.Unless this is plastic or something 
really gummy you should be using G3 for ID work.Or you are using left handed 
mills.
Climb milling is the way to do most everything.

Terry




- Original Message -
From: dave 
To: Enhanced Machine Controller (EMC) 
Cc: 
Sent: Tuesday, September 25, 2012 3:08 PM
Subject: Re: [Emc-users] Helical interpolation not quite round, WTF?

On Tue, 2012-09-25 at 15:13 -0400, Stephen Dubovsky wrote:
> How big are the "humps"?  How many are there?
> 
> Are you in exact stop mode?  If motion stops at the beginning/end of
> each semicircle then you will get a little hump from springback during
> the pause.  Lead-in & out are typ used when cutting IDs to prevent
> that.
> 
> Stephen
> 
Ah! Both good questions I should have been smart enough to ask. Since my
mill is not as stiff as would be ideal I tend to take small Z
increments/360 degrees and work my way down taking at least an extra
pass or two at the max depth as spring passes. 

To extend Stephen's question: where are the humps, exactly at 0, 90, 180
& 270 or offset some. Are they deep enough to not be backlash anomalies?

Dave
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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Jon Elson]

Igor Chudov wrote:
> Andy, thanks, what is P? Number of passes?
>
> The problem is that the lumps do not look like caused by backlash.
>
> There is one place where there is a lump, caused by all passes except the
> first one. I am very puzzled.
>   
Can you blow up the Axis plot window and see the lump?  You can also 
plot velocity
in Halscope and look for non-sinusoidal bumps there.

You might try makebore.c or makering.c from my web
page http://pico-systems.com/gcode.html
and see if you get different results.  makering.c makes a slightly undersize
circular pass in 4 quadrants X the number of depth steps, then spirals out
and makes 4 more quadrants
at the finish diameter.  It definitely does not give bumps with a 2.4.x
LinuxCNC on an older Linux kernel.  I have not done any precision work
with 2.5 (my production system runs a bit behind on updates).

Jon

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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Jon Elson]

Igor Chudov wrote:
> Humps are
>
> 1) Northwest corner, biggest hump, 1mm tall by 20mm wide
> 2) Northeast corner, 0.5mm by 15mm wide
>   
This has to be a program error.  And, you should be able to EASILY see 
this on
the Axis 3D display.  Load the program, and then use the mouse buttons to
tilt the display until you are looking flat at the XY plane.  Zoom in 
and pan
around the circle.  The deviation on successive depth passes should show up
very easily if it is a mm deep into the wall of the hole.

If it shows up on the preview, that gets backlash and the entire motion 
system
off the hook.

Jon

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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Gene Heskett]

On Tuesday 25 September 2012 23:23:36 Igor Chudov did opine:

> I have a routine that lets me mill a deep circle in several passes,
> typically to cutout circles from plates.
> 
> Something strange is going on and the resulting shape is not exactly
> round. It can be best described as a circle with humps.
> 
> The routine is below. It is basically a while loop, milling
> progressively deeper until Z reaches the required depth. Every loop
> consists of two half circles milled helically, with the end mill going
> down along a spiral.
> 
> Any idea why the shape may not end up being circular?
> 
> Thanks
> 
> Routine attached.
> 
> (Copyright - Igor Chudov, released under GNU Public License V3)
> 
> O sub (circular groove, good for milling through holes
> too) # = #1 (X center)
>   # = #2 (Y center)
>   #  = #3 (safe height)
>   #  = #4 (depth of milling)
>   # = #5 (outside radius)
>   #  = #6 (end mill diameter)
>   #  = #7 (feed rate)
>   #  = #8 (z step, per circle, optional)
> 
>   O if [ # NE 0 ]
> F#
>   O endif
> 
>   O if [ # EQ 0 ]
> # = [#/3]
>   O endif
> 
>   # = #
>   # = [# - #/2]
> 
>   G0 Z#
>   G4 P0
>   G0 X[# + #] Y#
> 
>   O while [ 1 ]
> 
> O if [ # - # LT #]
>   # = [# - #]
> O endif
> 
> G2 X[# - #] Y# Z[# - #/2] R#
> G2 X[# + #] Y# Z[# - #] R#
> 
> # = [# - #]
> 
> O if [ # LE # ]
>   O break
> O endif
> 
>   O endwhile
> 
>   G2 X[# - #] Y# R#
>   G2 X[# + #] Y# R#
> 
>   G0 Z#
> 
> O endsub
> 
> M2

The first thing I'd check would be uncompensated backlash.  Then it would 
go to damaged screws, like a highly used area wobbled out.  Third would be 
scaling error on one axis, but thats fairly easy to check.

Cheers, Gene
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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Igor Chudov]

I am beginning to suspect that perhaps the screws that are used to tram the
head are not tight. I will check.

Igor

On Tue, Sep 25, 2012 at 10:28 PM, Gene Heskett  wrote:

> On Tuesday 25 September 2012 23:23:36 Igor Chudov did opine:
>
> > I have a routine that lets me mill a deep circle in several passes,
> > typically to cutout circles from plates.
> >
> > Something strange is going on and the resulting shape is not exactly
> > round. It can be best described as a circle with humps.
> >
> > The routine is below. It is basically a while loop, milling
> > progressively deeper until Z reaches the required depth. Every loop
> > consists of two half circles milled helically, with the end mill going
> > down along a spiral.
> >
> > Any idea why the shape may not end up being circular?
> >
> > Thanks
> >
> > Routine attached.
> >
> > (Copyright - Igor Chudov, released under GNU Public License V3)
> >
> > O sub (circular groove, good for milling through holes
> > too) # = #1 (X center)
> >   # = #2 (Y center)
> >   #  = #3 (safe height)
> >   #  = #4 (depth of milling)
> >   # = #5 (outside radius)
> >   #  = #6 (end mill diameter)
> >   #  = #7 (feed rate)
> >   #  = #8 (z step, per circle, optional)
> >
> >   O if [ # NE 0 ]
> > F#
> >   O endif
> >
> >   O if [ # EQ 0 ]
> > # = [#/3]
> >   O endif
> >
> >   # = #
> >   # = [# - #/2]
> >
> >   G0 Z#
> >   G4 P0
> >   G0 X[# + #] Y#
> >
> >   O while [ 1 ]
> >
> > O if [ # - # LT #]
> >   # = [# - #]
> > O endif
> >
> > G2 X[# - #] Y# Z[# - #/2] R#
> > G2 X[# + #] Y# Z[# - #] R#
> >
> > # = [# - #]
> >
> > O if [ # LE # ]
> >   O break
> > O endif
> >
> >   O endwhile
> >
> >   G2 X[# - #] Y# R#
> >   G2 X[# + #] Y# R#
> >
> >   G0 Z#
> >
> > O endsub
> >
> > M2
>
> The first thing I'd check would be uncompensated backlash.  Then it would
> go to damaged screws, like a highly used area wobbled out.  Third would be
> scaling error on one axis, but thats fairly easy to check.
>
> Cheers, Gene
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> My web page:  is up!
> A penny saved has not been spent.
>
>
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> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Jon Elson]

Igor Chudov wrote:
> I am beginning to suspect that perhaps the screws that are used to tram the
> head are not tight. I will check.
>   
Oh, well, that is an entirely different matter.  You should be able to 
put a bar in the
spindle and try to rock it.

Jon

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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Igor Chudov]

I am highly embarrassed, but I will confess anyway, the problem was that
the bolts holding the head, worked loose.

I tightened them and milled out perfect circles with beautiful finish.

Thanks, guys!

i


On Wed, Sep 26, 2012 at 9:16 PM, Jon Elson  wrote:

> Igor Chudov wrote:
> > I am beginning to suspect that perhaps the screws that are used to tram
> the
> > head are not tight. I will check.
> >
> Oh, well, that is an entirely different matter.  You should be able to
> put a bar in the
> spindle and try to rock it.
>
> Jon
>
>
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Re: [Emc-users] Helical interpolation not quite round, WTF?

[John Stewart]

Igor;

> I am highly embarrassed, but I will confess anyway, the problem was that
> the bolts holding the head, worked loose.
> 
> I tightened them and milled out perfect circles with beautiful finish.

Sometimes the simplest, easiest solutions are the hardest ones to find.

I just spent a good few hours trying to figure out why some complex computer 
code would not run, and I felt like an idiot when I noticed that the character 
"A" in a name should have been "a". 

(ok, techies, run-time linking with an Android-ndk library is case sensitive…)

John Alexander Stewart







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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Dave Caroline]

I favorite thing that happened to a few of us at a previous job fixing
electronic kits (amplifiers tuners etc)
one sits there scope probe in hand probing everywhere on the board and
someone wanders by and says
I would work better if you switch it on!

I have been on both sides of that one :)

Dave Caroline

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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Dave]

Having done customer support in the past on PLC related equipment, you 
quickly learn that when someone calls you with a problem where they 
can't communicate with it, it is no longer operational etc;
The first question you always ask, is there a power on light on the 
front of the controller, and what color is it?  That way they look to 
make sure it is actually on.   The power on indicator lights were always 
green, but they don't know that.  :-)

Dave



On 9/27/2012 9:41 AM, Dave Caroline wrote:
> I favorite thing that happened to a few of us at a previous job fixing
> electronic kits (amplifiers tuners etc)
> one sits there scope probe in hand probing everywhere on the board and
> someone wanders by and says
> I would work better if you switch it on!
>
> I have been on both sides of that one :)
>
> Dave Caroline
>
>


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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Jon Elson]

Igor Chudov wrote:
> I am highly embarrassed, but I will confess anyway, the problem was that
> the bolts holding the head, worked loose.
>
> I tightened them and milled out perfect circles with beautiful finish.
>   
Well, the only surprise is that the machine worked at all, I'd think 
with the head loose
it would start rocking and wobbling on any cut.  Glad you found the problem.

Jon

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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Jason Burton]

On Sep 26, 2012 9:55 PM, "Igor Chudov"  wrote:
>
> I am highly embarrassed, but I will confess anyway, the problem was that
> the bolts holding the head, worked loose.
>
> I tightened them and milled out perfect circles with beautiful finish.
>
> Thanks, guys!
>
> i
>
>

When I first tested my home built rotary phase converter nothing on earth
would start the idler.

My calculation of starting cap bank size should have been good. Nothing.

Bought another set of caps to wire in parallel the next morning. The moment
I went to install them the facepalm moment came.

In my fatigue the night before, I had run the point to point wiring without
insulation stripping to make sure everything would reach. As the build
finished later that night, I tightened the terminal strip screws on
insulated wires!

Stripped them all and it worked fine. One of those moments...
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Re: [Emc-users] Helical interpolation not quite round, WTF?

[John Stewart]

Jason;

IMHO, so far you win the prize! ;-)

Another JohnS.

On 2012-09-28, at 1:10 PM, Jason Burton wrote:
> 
> In my fatigue the night before, I had run the point to point wiring without
> insulation stripping to make sure everything would reach. As the build
> finished later that night, I tightened the terminal strip screws on
> insulated wires!
> 
> Stripped them all and it worked fine. One of those moments...

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Re: [Emc-users] Helical interpolation not quite round, WTF?

[cogoman]

On 09/27/2012 09:41 AM, Dave Caroline wrote:
> I would work better if you switch it on!
There is someone at work who has done it to me so often that the first 
thing I say to her is "Did you plug it in? Did you turn it on?"

   One day she came to me and said something like "The computer's stuck 
in DOS.  Fix it!"

   Did you plug it in? Did you turn it on? I asked.

   "Yes I plugged it in and turned it on!" She confidently affirmed.

   I went to check it out.  She hadn't read the screen which cryptically 
said that there was no video signal.

   Text, not a wallpaper, looked like DOS to her.  The old AT style 
computer had just been replaced with an ATX style computer at the same 
station.  I went back and told her I just turned it on (and told her 
where to do it herself).  She HAD turned on the power strip associated 
with that system.



   I used to program GenRad in circuit testers, and the language allowed 
you to use any base for a number you wanted.

b'10110111'   o'267'   and   x'b7'

all represented the same number.  The gotcha for me was that if you left 
the base designation out, it took the number to represent a pin on the 
device you were testing.

If I said addr=2  instead of addr=d'2'  the software would 
dutifully look to see what value was on pin 2, and apply that value to 
the address bus (inserting as many preceeding zeros as necessary).

   That one bit me regularly, and all too often.

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Re: [Emc-users] Helical interpolation not quite round, WTF?

[cogoman]

On 09/27/2012 11:19 AM, Dave wrote:
> The first question you always ask, is there a power on light on the
> front of the controller, and what color is it?  That way they look to
> make sure it is actually on.   The power on indicator lights were always
> green, but they don't know that.
What a gracious way of leading them to the solution.

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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Kent A. Reed]

On 9/28/2012 9:13 PM, cogoman wrote:
> On 09/27/2012 09:41 AM, Dave Caroline wrote:
>> I would work better if you switch it on!
> There is someone at work who has done it to me so often that the first
> thing I say to her is "Did you plug it in? Did you turn it on?"
>
> One day she came to me and said something like "The computer's stuck
> in DOS.  Fix it!"
>
> Did you plug it in? Did you turn it on? I asked.
>
> "Yes I plugged it in and turned it on!" She confidently affirmed.
>
> I went to check it out.  She hadn't read the screen which cryptically
> said that there was no video signal.
>
> Text, not a wallpaper, looked like DOS to her.  The old AT style
> computer had just been replaced with an ATX style computer at the same
> station.  I went back and told her I just turned it on (and told her
> where to do it herself).  She HAD turned on the power strip associated
> with that system.

I'm sure we all have funny stories along these lines concerning other 
users just as I suspect we tend to suppress such stories about ourselves:-)

Just last night I added a 2nd SATA drive (so I could run Yocto; see 
emc-developers) only to have my system fail to recognize it. The drive 
was all cabled up. It took several moments to realize I'd connected the 
drive to a SATA power-adapter cable but neglected to connect the other 
end of the adapter to a spare power connector. Seems I was too busy at 
the time getting the drive fastened in its slot. Sigh.

>
>
> I used to program GenRad in circuit testers, and the language allowed
> you to use any base for a number you wanted.
>
> b'10110111'   o'267'   and   x'b7'
>
> all represented the same number.  The gotcha for me was that if you left
> the base designation out, it took the number to represent a pin on the
> device you were testing.
>
> If I said addr=2  instead of addr=d'2'  the software would
> dutifully look to see what value was on pin 2, and apply that value to
> the address bus (inserting as many preceeding zeros as necessary).
>
> That one bit me regularly, and all too often.

This, on the other hand, is a good example of a truly egregious 
human-computer interface problem. The GenRad folks should have been made 
to suffer, preferably in one of Dante's inner circles of hell. Stop me 
before I start spouting about notable disasters---some fatal---that 
involved such stupidities.

Regards,
Kent


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Re: [Emc-users] Helical interpolation not quite round, WTF?

[Jason Burton]

Hi John,

Thanks. I just wanted Igor to know he's in sympathetic company. :)

Best,
Jason

On Sep 28, 2012 12:15 PM, "John Stewart"  wrote:
>
> Jason;
>
> IMHO, so far you win the prize! ;-)
>
> Another JohnS.
>
> On 2012-09-28, at 1:10 PM, Jason Burton wrote:
> >
> > In my fatigue the night before, I had run the point to point wiring
without
> > insulation stripping to make sure everything would reach. As the build
> > finished later that night, I tightened the terminal strip screws on
> > insulated wires!
> >
> > Stripped them all and it worked fine. One of those moments...
>
>
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