Discussion:
[Emc-users] tach/generator/encoder
jeremy youngs
2017-06-06 14:31:45 UTC
Permalink
Good day folks. Im waiting for ebay to drop this at my door
https://www.google.com/url?sa=t&source=web&rct=j&url=http://spectechind.com/Documents/KB/KBMG-212D-manual.pdf&ved=0ahUKEwjM6aSAtqnUAhUG3IMKHcT_CUgQFggqMAA&usg=AFQjCNGFBaUXQadurcokpyECREPoUQtv-A&sig2=Pi3K5iam1Y-9UdVNt5mrew
. It calls for a tach/generator my google foo shows them to be very cost
prohibitive. I have so far only setup stepper system. I am using this as a
spindle drive on my mill 90 v treadmill motor. I want to be able to rigid
tap. My question is can I just use an encoder and have Linux cnc control
the position ? I think so but before I order an encoder I would like to
know . Thanks
Jeremy
Gentlemen,
Debian Wheezy
latest linuxcnc release - installed today - but the last release did the
same thing
Axis interface
Kasuga 3 axis mill
when starting (run from here) on line 310 I get the error "length of cutter
compensation entry move is not greater than the tool radius"
This only happens when I 'run from here'.
When running through the program the machine runs this code just fine. I
cannot run through the program as I must change tools in the holder - set
the tool length - and - start by picking 'run from here' (right click on
the mouse).
status window shows G40 prior to initiating 'run from here'
after initiating 'run from here' the error shows and the status window
shows G41
mdi g40 resets the status window
reinitiation of 'run from here' shows the error and sets the status window
to G41
Editing the G41 and G40 out of the program allows 'run from here' to start
the machine and run the tool.
snippet of code from the program
N288X.1684Y-.6104
N289G01Z.105F100.0
N290G41X.0024F4.0
N291Y-1.428
N292G40
N293X.1024
N294G00Z1.115
N295M05
N296M09
N297G91G28Z.0
N298(MSG)
N299(MSG TOOL T4.0000 IS)
N300(MSG DIA 0.5000)
N301(MSG CRAD 0.0000)
N302(MSG FLTLEN 0.2500)
N303(MSG STKOUT 0.5000)
N304(MSG)
N305(MSG 1/2 SPOT DRILL.)
N306(MSG)
N307(MSG SPOT DRILL HOLE)
N308(MSG)
N309(MSG)
N310G91G49G28Z.0
N311T04M06
N312G64P.001
N313G90G00G43
N314S1400M08
N315X1.375Y-3.0M03
N316Z1.115
N317X-.3Y-.1
N318G81X-.2Y-.2Z.075R.275F2.0
N319G80M05
N320M09
N321G91G28Z.0
thanks
Stuart
--
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If you are not the addressee then my consent is not given for you to read
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reading, and cease and desist from saving or opening my private
correspondence.
Thank you for honoring my wish.
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Jon Elson
2017-06-06 16:57:37 UTC
Permalink
Post by jeremy youngs
Good day folks. Im waiting for ebay to drop this at my door
https://www.google.com/url?sa=t&source=web&rct=j&url=http://spectechind.com/Documents/KB/KBMG-212D-manual.pdf&ved=0ahUKEwjM6aSAtqnUAhUG3IMKHcT_CUgQFggqMAA&usg=AFQjCNGFBaUXQadurcokpyECREPoUQtv-A&sig2=Pi3K5iam1Y-9UdVNt5mrew
. It calls for a tach/generator my google foo shows them to be very cost
prohibitive. I have so far only setup stepper system. I am using this as a
spindle drive on my mill 90 v treadmill motor. I want to be able to rigid
tap. My question is can I just use an encoder and have Linux cnc control
the position ? I think so but before I order an encoder I would like to
know .
Big problem with KB drives is they are NOT isolated from the
power mains. So, your source of the speed command must be
isolated. Tach generators are really just DC brush motors
wound to be free of voltage ripple. Maxon makes some nice
small motors that make excellent tachs. You can often find
them surplus for under $10.

Jon
jeremy youngs
2017-06-06 17:36:49 UTC
Permalink
Isolated, as in opto isolator on the bob ? Thank you
Post by jeremy youngs
Good day folks. Im waiting for ebay to drop this at my door
https://www.google.com/url?sa=t&source=web&rct=j&url=http://
spectechind.com/Documents/KB/KBMG-212D-manual.pdf&ved=0ahUKE
wjM6aSAtqnUAhUG3IMKHcT_CUgQFggqMAA&usg=AFQjCNGFBaUXQadurcokp
yECREPoUQtv-A&sig2=Pi3K5iam1Y-9UdVNt5mrew
. It calls for a tach/generator my google foo shows them to be very cost
prohibitive. I have so far only setup stepper system. I am using this as a
spindle drive on my mill 90 v treadmill motor. I want to be able to rigid
tap. My question is can I just use an encoder and have Linux cnc control
the position ? I think so but before I order an encoder I would like to
know .
Big problem with KB drives is they are NOT isolated from the power mains.
So, your source of the speed command must be isolated. Tach generators are
really just DC brush motors wound to be free of voltage ripple. Maxon
makes some nice small motors that make excellent tachs. You can often find
them surplus for under $10.
Jon
------------------------------------------------------------
------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Emc-users mailing list
https://lists.sourceforge.net/lists/listinfo/emc-users
Jon Elson
2017-06-07 01:49:30 UTC
Permalink
Post by jeremy youngs
Isolated, as in opto isolator on the bob ? Thank you
The speed command is an analog voltage, so a simple
optoisolator won't work. There are isolated spindle speed
controllers that use a PWM scheme on an optoisolator and
then convert to voltage on the isolated side.

Jon
jeremy youngs
2017-06-07 02:39:16 UTC
Permalink
So pwm to analog 10v is necessary
Post by jeremy youngs
Isolated, as in opto isolator on the bob ? Thank you
The speed command is an analog voltage, so a simple optoisolator won't
work. There are isolated spindle speed controllers that use a PWM scheme
on an optoisolator and then convert to voltage on the isolated side.
Jon
------------------------------------------------------------
------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
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Gene Heskett
2017-06-07 03:22:04 UTC
Permalink
Post by jeremy youngs
So pwm to analog 10v is necessary
Yes, and the velocity output from an encoder module to tell this
controller how fast the spindle is turning. Its the feedback signal to
the PID module. The actual lock step that drives the z axis is
determined from the position output of this same encoder module.

There is a spindle speed limit when doing the coarser threads, in the
form of the z axis MAXVEL. But I'm not sure it squawks if you exceed it,
so don't exceed it.
Post by jeremy youngs
Post by jeremy youngs
Isolated, as in opto isolator on the bob ? Thank you
The speed command is an analog voltage, so a simple optoisolator won't
work. There are isolated spindle speed controllers that use a PWM
scheme on an optoisolator and then convert to voltage on the
isolated side.
Jon
------------------------------------------------------------
------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Emc-users mailing list
https://lists.sourceforge.net/lists/listinfo/emc-users
----------------------------------------------------------------------
-------- Check out the vibrant tech community on one of the world's
most engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Emc-users mailing list
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)
Genes Web page <http://geneslinuxbox.net:6309/gene>
Gene Heskett
2017-06-06 21:23:46 UTC
Permalink
Post by jeremy youngs
Good day folks. Im waiting for ebay to drop this at my door
https://www.google.com/url?sa=t&source=web&rct=j&url=http://spectechin
d.com/Documents/KB/KBMG-212D-manual.pdf&ved=0ahUKEwjM6aSAtqnUAhUG3IMKHc
T_CUgQFggqMAA&usg=AFQjCNGFBaUXQadurcokpyECREPoUQtv-A&sig2=Pi3K5iam1Y-9U
dVNt5mrew . It calls for a tach/generator my google foo shows them to
be very cost prohibitive. I have so far only setup stepper system. I
am using this as a spindle drive on my mill 90 v treadmill motor. I
want to be able to rigid tap. My question is can I just use an encoder
and have Linux cnc control the position ? I think so but before I
order an encoder I would like to know . Thanks
Jeremy
As long as that controller is passably real time, which with an scr
controller might be a problem since itr can't react any faster than the
lines power frequency, I don't see why not. I have one with an
opto-interruptor setup thats effectively a 268 counts per spindle rev,
driving by a PID control setup, reacts fast enough to rattle the gears
between a brushed 1 hp motor and the spindle of a Grizzly G0704, so the
speed is fairly well controlled. But that has very little to do with
rigid tapping as the 268 steps per revolution is what the (normally Z)
axis follows quite accurately.

I've a similar setup on The Little Monster, a 7x14 mini-lathe, similar
horsepower but moving a 5" chuck, which has buckets of mass to reverse,
so the turnaround time at the bottom of the hole can be considerable,
particularly in terms of overshoot, so I have to drill the hole at least
4 tap turns deeper, else the tap hits the bottom of the hole, followed
by the sickening crunch of yet another broken tap.

I have a hall effect encoder ( 240 steps/rev) on an 11x36 sheldon I am
just now bringing to life, and again, that nearly 8" chuck, and the
turnaround ballistics of the vfd driving the 1 hp, 3 phase motor will
also make me keep track of how much deeper I need to drill the hole to
keep from hitting the bottom of it as its slowing, having reached the
depth you gave the G33.1 in the call. I've developed some hal code that
will tell me how much overshoot I have, but on that 3/4 ton machine, I
don't expect to be able to tap at anything over 250 revs. Those are the
gotcha's, but if the tap doesn't break, the rigidly tapped hole will be
tapped nicely.

What I'm trying to say is that a common A/B/X quadrature output encoder
(it must have an indeX once per rev) even with much larger slices of
rotation per step than what I am using, can and has done rigid tapping
for several folks here. The quadrature gives linuxcnc the direction
information on the next pulse output as it hits zero speed and starts
the reversal.
Post by jeremy youngs
Gentlemen,
Debian Wheezy
latest linuxcnc release - installed today - but the last release did
the same thing
Axis interface
Kasuga 3 axis mill
when starting (run from here) on line 310 I get the error "length of
cutter compensation entry move is not greater than the tool radius"
This only happens when I 'run from here'.
When running through the program the machine runs this code just
fine. I cannot run through the program as I must change tools in the
holder - set the tool length - and - start by picking 'run from
here' (right click on the mouse).
status window shows G40 prior to initiating 'run from here'
after initiating 'run from here' the error shows and the status
window shows G41
mdi g40 resets the status window
reinitiation of 'run from here' shows the error and sets the status
window to G41
Editing the G41 and G40 out of the program allows 'run from here' to
start the machine and run the tool.
snippet of code from the program
N288X.1684Y-.6104
N289G01Z.105F100.0
N290G41X.0024F4.0
N291Y-1.428
N292G40
N293X.1024
N294G00Z1.115
N295M05
N296M09
N297G91G28Z.0
N298(MSG)
N299(MSG TOOL T4.0000 IS)
N300(MSG DIA 0.5000)
N301(MSG CRAD 0.0000)
N302(MSG FLTLEN 0.2500)
N303(MSG STKOUT 0.5000)
N304(MSG)
N305(MSG 1/2 SPOT DRILL.)
N306(MSG)
N307(MSG SPOT DRILL HOLE)
N308(MSG)
N309(MSG)
N310G91G49G28Z.0
N311T04M06
N312G64P.001
N313G90G00G43
N314S1400M08
N315X1.375Y-3.0M03
N316Z1.115
N317X-.3Y-.1
N318G81X-.2Y-.2Z.075R.275F2.0
N319G80M05
N320M09
N321G91G28Z.0
thanks
Stuart
--
Addressee is the intended audience.
If you are not the addressee then my consent is not given for you to
read this email furthermore it is my wish you would close this
without saving or reading, and cease and desist from saving or
opening my private correspondence.
Thank you for honoring my wish.
------------------------------------------------------------
------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Emc-users mailing list
https://lists.sourceforge.net/lists/listinfo/emc-users
----------------------------------------------------------------------
-------- Check out the vibrant tech community on one of the world's
most engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Emc-users mailing list
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)
Genes Web page <http://geneslinuxbox.net:6309/gene>
jeremy youngs
2017-06-06 22:12:28 UTC
Permalink
Thank you guys
Post by Gene Heskett
Post by jeremy youngs
Good day folks. Im waiting for ebay to drop this at my door
https://www.google.com/url?sa=t&source=web&rct=j&url=http://spectechin
d.com/Documents/KB/KBMG-212D-manual.pdf&ved=0ahUKEwjM6aSAtqnUAhUG3IMKHc
T_CUgQFggqMAA&usg=AFQjCNGFBaUXQadurcokpyECREPoUQtv-A&sig2=Pi3K5iam1Y-9U
dVNt5mrew . It calls for a tach/generator my google foo shows them to
be very cost prohibitive. I have so far only setup stepper system. I
am using this as a spindle drive on my mill 90 v treadmill motor. I
want to be able to rigid tap. My question is can I just use an encoder
and have Linux cnc control the position ? I think so but before I
order an encoder I would like to know . Thanks
Jeremy
As long as that controller is passably real time, which with an scr
controller might be a problem since itr can't react any faster than the
lines power frequency, I don't see why not. I have one with an
opto-interruptor setup thats effectively a 268 counts per spindle rev,
driving by a PID control setup, reacts fast enough to rattle the gears
between a brushed 1 hp motor and the spindle of a Grizzly G0704, so the
speed is fairly well controlled. But that has very little to do with
rigid tapping as the 268 steps per revolution is what the (normally Z)
axis follows quite accurately.
I've a similar setup on The Little Monster, a 7x14 mini-lathe, similar
horsepower but moving a 5" chuck, which has buckets of mass to reverse,
so the turnaround time at the bottom of the hole can be considerable,
particularly in terms of overshoot, so I have to drill the hole at least
4 tap turns deeper, else the tap hits the bottom of the hole, followed
by the sickening crunch of yet another broken tap.
I have a hall effect encoder ( 240 steps/rev) on an 11x36 sheldon I am
just now bringing to life, and again, that nearly 8" chuck, and the
turnaround ballistics of the vfd driving the 1 hp, 3 phase motor will
also make me keep track of how much deeper I need to drill the hole to
keep from hitting the bottom of it as its slowing, having reached the
depth you gave the G33.1 in the call. I've developed some hal code that
will tell me how much overshoot I have, but on that 3/4 ton machine, I
don't expect to be able to tap at anything over 250 revs. Those are the
gotcha's, but if the tap doesn't break, the rigidly tapped hole will be
tapped nicely.
What I'm trying to say is that a common A/B/X quadrature output encoder
(it must have an indeX once per rev) even with much larger slices of
rotation per step than what I am using, can and has done rigid tapping
for several folks here. The quadrature gives linuxcnc the direction
information on the next pulse output as it hits zero speed and starts
the reversal.
Post by jeremy youngs
Gentlemen,
Debian Wheezy
latest linuxcnc release - installed today - but the last release did
the same thing
Axis interface
Kasuga 3 axis mill
when starting (run from here) on line 310 I get the error "length of
cutter compensation entry move is not greater than the tool radius"
This only happens when I 'run from here'.
When running through the program the machine runs this code just
fine. I cannot run through the program as I must change tools in the
holder - set the tool length - and - start by picking 'run from
here' (right click on the mouse).
status window shows G40 prior to initiating 'run from here'
after initiating 'run from here' the error shows and the status
window shows G41
mdi g40 resets the status window
reinitiation of 'run from here' shows the error and sets the status
window to G41
Editing the G41 and G40 out of the program allows 'run from here' to
start the machine and run the tool.
snippet of code from the program
N288X.1684Y-.6104
N289G01Z.105F100.0
N290G41X.0024F4.0
N291Y-1.428
N292G40
N293X.1024
N294G00Z1.115
N295M05
N296M09
N297G91G28Z.0
N298(MSG)
N299(MSG TOOL T4.0000 IS)
N300(MSG DIA 0.5000)
N301(MSG CRAD 0.0000)
N302(MSG FLTLEN 0.2500)
N303(MSG STKOUT 0.5000)
N304(MSG)
N305(MSG 1/2 SPOT DRILL.)
N306(MSG)
N307(MSG SPOT DRILL HOLE)
N308(MSG)
N309(MSG)
N310G91G49G28Z.0
N311T04M06
N312G64P.001
N313G90G00G43
N314S1400M08
N315X1.375Y-3.0M03
N316Z1.115
N317X-.3Y-.1
N318G81X-.2Y-.2Z.075R.275F2.0
N319G80M05
N320M09
N321G91G28Z.0
thanks
Stuart
--
Addressee is the intended audience.
If you are not the addressee then my consent is not given for you to
read this email furthermore it is my wish you would close this
without saving or reading, and cease and desist from saving or
opening my private correspondence.
Thank you for honoring my wish.
------------------------------------------------------------
------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Emc-users mailing list
https://lists.sourceforge.net/lists/listinfo/emc-users
----------------------------------------------------------------------
-------- Check out the vibrant tech community on one of the world's
most engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Emc-users mailing list
https://lists.sourceforge.net/lists/listinfo/emc-users
Cheers, Gene Heskett
--
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
------------------------------------------------------------
------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Emc-users mailing list
https://lists.sourceforge.net/lists/listinfo/emc-users
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