On 05/08/2020 04:04 PM, Dan Henderson wrote:
Thanks Jon and Chris!
Jon do you have a code example of the Hal filter that is needed?
# set up 4th DAC generator as a spindle speed control
newsig spindle-speed float
newsig spindle-DAC-cmd float
newsig spindle-DAC-filt float
newsig spindle-DAC-abs float
linkps motion.spindle-speed-out => spindle-speed
linksp spindle-speed => mult2.1.in0
setp mult2.1.in1 0.002457
linkps mult2.1.out => spindle-DAC-cmd
linksp spindle-DAC-cmd => lowpass.0.in
linkps lowpass.0.out => spindle-DAC-filt
setp lowpass.0.gain 0.005
linksp spindle-DAC-filt => abs.0.in
linksp spindle-DAC-abs => abs.0.out
linksp spindle-DAC-abs => ppmc.0.DAC.03.value
This is for my PPMC analog boards, but ppmc.0.DAC.03.value
is the speed value sent to the drive.
lowpass.0.gain is set to 0.005, the name of the pin is a bit
odd, as gain is actually what sets the time constant of the
filter. You will have to loadrt lowpass and then addf
lowpass to the servo_thread
mult2 sets up the speed factor so that the S word gives the
right speed.
Jon
On Fri, May 8, 2020 at 3:58 PM Chris Albertson <albertson.ch...@gmail.com>
wrote:
You have to compare the signals on BOTH sides of the interface to see what
is happening. The build-in halscope can only see what has crossed the
interface. Compare this to what is on the parallel port pins and also what
is on the encoder side of the opto-isolators.
If a new digital oscilloscope is out of budget then look at one of these:
ebay.com/itm/USB-SALEAE-24M-8CH-Logic-Analyzer...
<
https://www.ebay.com/itm/USB-SALEAE-24M-8CH-Logic-Analyzer-24M-8-Channel-with-Buffer-Support-1-1-16/173828458153?hash=item2878fbc6a9:g:tDUAAOSwJiddkJ1E
It is an 8-channel logic analyzer that is fast enough fo anything you will
ever do with a machine tool of motion control. It has no trouble sampling
Mhz class square waves. (The above is a Chinese clone of the actual
Saleae unit.)
Get the software for it here. You can try the software without buying the
hardware but obviously can't collect data.
https://www.saleae.com/downloads/
The oscilloscope is best because it shows the actual analog waveform but
the analyzer has more channels and has very complex triggers and can
de-code serial busses
On Thu, May 7, 2020 at 3:45 PM Gene Heskett <ghesk...@shentel.net> wrote:
On Thursday 07 May 2020 17:39:32 Dan Henderson wrote:
Why certainly Gene (see attached). I actually have it working a little
better now. My spindle-at-speed LED will start going bonkers around
1200 rpm. I'm guessing this is when the counter "throws up it's hands
and says - I quit!" lol. The spindle will operate all the way to
around 4700 rpm but anything above this and the MC-2100 shuts it down
-- must be some kind of voltage limiter kicking in then.
The one time I tried to use one of them was a failure, it seemed to have
a mind of its own. I made a power supply and bought one of the pico
systems pwm-servo's. Bulletproof but be sure and tell Jon you are going
to drive a PMDC spindle motor with it so he'll add more toroids so it
runs cooler when working continuously.
That said, your config is as well laid out as any I've looked at, and I
don't see anything wrong at all. But I can also see how the parport and
its missing of the encoders signals could be all of the higher speed
problems. The 4700 limit might be the pwmgen going to 100% duty, losing
the 0% recharge pulse. You can check that with halscope. I run more
voltage than the mc2100 can muster, so I can spin a treadmill motor up
to where I worry about the cast iron fan/pulley exploding but set limits
somewhat below that, probably around 7 grand max. Even though its geared
3/1 before it gets near the spindle drive, its still too fast to cut
steel.
If you can set the encoder even lower you might get to a couple thousand
revs before the tach gets funkity.
18:40 here, I'd better go see what my missus wants for dinner.
On Thu, May 7, 2020 at 2:29 PM Gene Heskett <ghesk...@shentel.net>
wrote:
On Thursday 07 May 2020 13:19:23 Dan Henderson wrote:
I believe this is open loop. Isn’t PID only used in closed loop
control?
Its (the PID is) a waste of processor time if open loop. I don't use
one of those in any spindle run by a vfd, the vfd is generally stiff
enough control by itself. If I thread on that machine, it will have
a spindle encoder, but its only job is to glue the axis motion being
driven to cut the thread, to the spindle rotation, in the case of a
g33.1, going both in and out of the hole. If you aren't useing a PID
for the spindle, that leaves motion I think.
I think its time we saw your .hal file. Can you insert it into a
mail?
On Thu, May 7, 2020 at 11:03 AM Gene Heskett
<ghesk...@shentel.net>
wrote:
On Thursday 07 May 2020 11:27:57 Jon Elson wrote:
On 05/06/2020 09:20 PM, Dan Henderson wrote:
I’ve confirmed the fluctuation occurs when spindle-at-speed
is configured. When I remove this feature, the spindle rpm
appears to stabilize. It’s almost like it gets caught in a
loop trying to chase its tail.
This is VERY common in servo systems, and is due to delay in
response of the object being controlled.
You need to slow down the response of the PID to ignore the
delay. This may be possible by adding
D to it.
Jon
But my msg was that a near module generated spindle.N.at-speed
was never to be injected into any signal path leading back to a
PID. That near's output s/b only to that input to motion, and
possibly to an indicator led in the gui so the operator can be
advised if its acting funkity. Flickering could be worn brushes
in a brushed PMDC motor for instance.
What you are describing as delays can often be fixed by the
proper re-ordering of the addf's involved for the oscillating
axis. That aspect of configuring LinuxCNC hasn't been mentioned
recently or I wouldn't even have included that paragraph in my
reply.
And from Dan's description above, I think this is an entirely
different critter from a timeing delay.
Cheers Jon & stay well, 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 <http://geneslinuxbox.net:6309/gene>
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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 <http://geneslinuxbox.net:6309/gene>
_______________________________________________
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 <http://geneslinuxbox.net:6309/gene>
_______________________________________________
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--
Chris Albertson
Redondo Beach, California
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