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Messages - skunkworks

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21
SmoothStepper USB / Re: Dead ... or alive.
« on: March 11, 2014, 08:46:10 AM »
Can you explain what you mean by 'quick pull out'?

sam

22
CS-Lab / Re: Rigid tapping with IP-A
« on: May 21, 2013, 09:17:30 AM »
Yes - hitting the bottom of a hole is defiantly a pain.  Our spindle mass is huge so acc/decel are long.  (that is one thing A axis servo spindle tapping has over this :) ) Commercial machines that actually do servo spindle tapping call it 'sync tapping'  iirc

I don't have blinders on (too much) I try to be fair as much as I can be ;)  (I still think linuxcnc is the bestest of course. )

You have been 'one' with mach and have made it do thing I never thought it could.  (with help from external motion devices <- I am a bitch - I know...) ;)  I see you always going above and beyond to help people with their setups.   'send me your xml and I will take a look'  We need more experts on both sides to keep pushing the envelope.

Now back to your rigid tapping thread.  You did a great job on a very very technical conversion.  Keep up the great work!

sam



I did not know the plug-in within mach allowed for pid tuning and such - neat.

Yes often the case when trying to score points ;) should really research before you do, that is why I dont criticise EMC as I know very little about it  ;)

Quote
I don't know what you mean by tuning the spindle in linuxcnc.  Yes - if the spindle has its own pid loop for speed control - you would tune it within linuxcnc.  Some do that.  The vfd on our hmc does good enough that I never setup closed loop speed control.  It isn't required for rigid tapping as the axis is slaved to the spindle.  The axis just stays in sync with whatever the spindle does.  (don't know if that is what you where asking..)

Well it was really just because you were saying I had to tune my spindle and it sounded like EMC magically could mind read your VFD so tuning was not required ;D But I see now the main thrust of your argument was tuning in different place from other set-up but that is now known by you to be wrong ;D
 
 Yes tuning is not important for rigid tapping, however precise depth control then becomes trial and error, something I am sure you would soon fall into with use on your particular machine at particular spindle speeds in a particular material etc, ie just try,  measure then increase/decrease in the code to suit.

Quote
I don't know how standard the plc language is in linuxcnc.  I didn't have any trouble wrapping my head around it - having only some exposure in college...  I am about 50/50..  I did the tool change/chain/pallets logic in ladder and the spindle gear shift logic in 'comp'  (a C like language for making realtime components in linuxcnc) I could wrap my had around the 16 gear spindle programmatically vs ladder.  Again - vs the brains/vb - that isn't realtime.  it happens when it happens.  In linuxcnc I know that the ladder is going to scan every 1ms and the realtime logic is going to happen every X ms or us.. 

Here you go again, real time, is it needed for a tool change? I think not. Brains are extremely fast but constrained by Mach3's update of 10Hz for non-critical I/O but if 10Hz is not fast enough for your toolchanger then I would be very surprised. And as far as "it happens when it happens" well no, it happens within the expected time frame.

Mach4's update will be much faster but Brains wont be in Mach4 ;)



Quote
with mesa hardware (5i25 with server daughter board - 6 axis + 48i/o + expandable $239) you can count to 2mhz. 

Ahh come on now Sam, thats only half your war cry, tell me again, I seem to have forgotten, how much does LinuxCNC cost? ;)
2MHz is quite good, especially for hardware at that pricepoint.


Now I do need to say one thing Sam, I do respect what you have done with your machine but more importantly I respect your integrity. I recall some guy listening to John S babbling on how Mach4 wont have threading with the PP etc, so he went to Yahoo and asked Art directly, again trying to get the info he wanted to hear so he could score points.
 Art replied but it was not the info he wanted to hear. The guy  never posted the info from Arts reply on the homeshop  forum as it would not be possible to score points.
  You however reported that info and  my respect for you went up considerably :) You did still manage to get a wee dig in though ;) but that is why I enjoy this banter.
Hood

23
CS-Lab / Re: Rigid tapping with IP-A
« on: May 20, 2013, 09:40:48 AM »
Sure - stepper/servo spindle as an axis - sure.  That has been possible on both platforms for a long time.  (I don't think it is a good way either...)

I did not know the plug-in within mach allowed for pid tuning and such - neat.  I don't know what you mean by tuning the spindle in linuxcnc.  Yes - if the spindle has its own pid loop for speed control - you would tune it within linuxcnc.  Some do that.  The vfd on our hmc does good enough that I never setup closed loop speed control.  It isn't required for rigid tapping as the axis is slaved to the spindle.  The axis just stays in sync with whatever the spindle does.  (don't know if that is what you where asking..)

I don't know how standard the plc language is in linuxcnc.  I didn't have any trouble wrapping my head around it - having only some exposure in college...  I am about 50/50..  I did the tool change/chain/pallets logic in ladder and the spindle gear shift logic in 'comp'  (a C like language for making realtime components in linuxcnc) I could wrap my had around the 16 gear spindle programmatically vs ladder.  Again - vs the brains/vb - that isn't realtime.  it happens when it happens.  In linuxcnc I know that the ladder is going to scan every 1ms and the realtime logic is going to happen every X ms or us..  

There is modbus support - but I cannot give you any details as I have never used it.  I mostly see people using it to interface with their vfd's

I hear you with switching.. I don't think I would either.  I like the control that have with linuxcnc.

with mesa hardware (5i25 with server daughter board - 6 axis + 48i/o + expandable $239) you can count to 2mhz.  

Again - awesome conversion.

sam



It has been possible to do rigid tapping for a lot longer than that Sam, as long as you had a servo or stepper on the spindle, no other hardware required. Was it a good way, well not really, you had to use swapaxis() and to be honest I just used the floating holder as it was easier and did a great job.

Regarding tuning in one place, well its all done in Mach, the plugin is in Mach ;)
I presume you have to tune your spindle loop in LinuxCNC?

Now did I need to use the PLC, nope, CSMIO has a load of I/O and lots of expansion capability if required. So why did I use a PLC, well two reasons,
1. I had one sitting doing nothing.
2  I know my way around the direct logic PLCs so its easy. Doing it in Brains and/or VB would take me longer, but it could be done and has been by others.
 
The ladder in my PLC runs to, I think, 17 pages of A4 when  printed out at 60%, lots of I/O on this changer and I wanted lots of interlocks, you can even see one working in one of the vids. The toolchange takes a lot longer to happen simply because I had such a slow accel/decel set for the test and the spindle took so long to drop to 200rpm which is the tool change rpm and the toolchange will not happen until that rpm is seen.

Even if in the future if I decide to go with LinuxCNC (about as likely as you using Mach,  but never say never ;) ) then I would still use the PLC, for the simple reason I would not have to learn the ladder logic in Linux. That is assuming LinuxCNC supports Modbus?

One thing I really like about the CSMIO is the capability of using high res encoders, that means very tight control can be kept.


Hood


24
CS-Lab / Re: Rigid tapping with IP-A
« on: May 19, 2013, 06:11:02 PM »
Is it me?  I saw the video - very nice!  It is always cool to see a converted machine that runs as good or better than the original control.  Nice work. 

Mach has been able to rigid tap for a while with external hardware that supports it..  Kflop and now cs-labs (there might be more).   ( http://www.cnczone.com/forums/benchtop_machines/125999-grizzly_x3_rigid_tapping_1000rpm_video.html ).  'mach' doesn't rigid tap.  The external motion card does.  (as seen by the unconventional gcode to make it work...)  That is the main argument.  Linuxcnc with its realtime control does all the motion and syncing (plus integrated ladder logic).  This makes it so any external hardware (even the printer port) can rigid tap (or do other fancy cool things like gear hobbing...).  While with mach - you have to make sure the motion hardware you buy supports the things you want to do.  (plus you can configure everything in one place. - hood had to tune and setup cs-labs, mach, and his plc.  With linuxcnc - this could all be done in one place.)  And no - you don't have to be a programmer to do it.

Knowing the work that goes into a conversion of that scale - again - very nice work! 

sam


Wow, that's amazing Hood.  Need to show that to those snooty LinuxCNC guys. ;)

LOL one of the loudest exponents of LinuxCNC and Mach bashing has seen it but failed to comment by the looks of it ;D

Hood

25
SmoothStepper USB / Re: SmoothStepper firmware for LinuxCNC?
« on: November 18, 2012, 03:03:01 PM »
There is a few big reason why linuxcnc does it that way (realtime within the computer). 

- interface hardware can be 'dumb'.  (which usually means less expensive.)  - mesa has a $200 pci board set that has 5 hardware step generators, encoder counter, +/- 10 volt ouput, 48 i/o and it is very expandable. 
- any new realtime stuff added to linuxcnc is available to all interface cards.  Example - rigid tapping was added a few years back.  All interface cards (even the printer port if you wanted to) can rigid tap.  With mach - it has to be part of the motion card (like smooth stepper)
- Flexible...  look at the youtube videos.  Gear hobbing, robots, all kinds of cool things are being done with it.  The developers are already looking at what needs to be done in linuxcnc3.  (more realtime kernel support...) 

USB's latency doesn't allow for a realtime control loop.  Ethernet seems to be the next interface option for linuxcnc. 

sam

26
General Mach Discussion / Re: Help need fast output for stop spindel
« on: October 02, 2012, 04:10:19 PM »
I think what he is saying is that the axis physically stops to turn off the spindle.....  He wants it to turn off the spindle while passing x90...  (not stoping)

sam

27
Feature Requests / Re: CV bad behaviour need improvement
« on: April 11, 2012, 02:27:56 PM »
Don't forget to play with G64 Px.********* Qx.*********xx with linuxcnc.   It allows you to set path following tollerance to increase speed.

http://linuxcnc.org/docs/2.5/html/gcode/gcode.html#_g64_path_blending_a_id_sec_g64_path_blending_a

Make sure you are updated to the latest release of linuxcnc also (2.5 was just released)

There are a few threads similar to this where mach doesn't seem to obey machine accel/velocity constraints.  Linuxcnc doesn't have as large a 'look ahead' as mach but it does pretty well.

sam


the reason for all headaches was to increase the feed, not to slow it down
my machine limits are 15m/min with acceleration time 0.2 sec
I guess that the problem on my PC become noticalbe a bit early bacause of different settings, more steps per unit, or something else, but soon or later that will become a problem when you wish to improve, it looks like the problem is with the motion algorithm when tryinh to calculate CV movements
unfortunately mach3 work smooth up to 3m/min, with increasing the feed is not so smooth anymore, in some situations do not decelerate, which is unacceptable, actually 3m/min is really good speed for all DIY, even too much for steppers
emc is a bit complicated to setup all features, but I used it for 4-5 days cutting and it looks like the movements are much better, same G code with the only change - feedrate. it is moving smooth up to 15m/min on straight lines only slowing down to 6-7m/min on short-lines-arcs, but still moving so smooth, with the current tool and spindle I can cut with maximum feed of 8.5m/min, and now I can use the full potential, for now I will stick with emc on my mill
so the problem with the mill is solved and Im very happy now, same G code is executed in a quater time than before, and same quality as mach3 on 3m/min
today I tried to run a lathe with mach3 turn, currently I struggle with M6, is not changing the tools, probably I have to read a bit more

28
General Mach Discussion / Re: Motors not running
« on: June 11, 2011, 08:40:12 AM »
Thank you.  That is my experience also.  :) 

sam


    Sam, I didn't mean to imply that Jon was not helpful. My problem was with installing the software using the EMC2 live CD, I searched the forum quite a bit & didn't find any solutions that helped me install the Live CD on the system I was using. I believe there is something about my system in particular that is incompatible with the EMC2 kernel (It's a Samba 854GV with a 2.4Ghz P4 processor, I bought it because it was $42).
    The forum itself seems fine to me, it just didn't solve my issue.
    As for Jon Elson, I think he's one of the most helpful strangers I've ever had the luck to bump into! I contacted him by phone & he suggested that I send him my system & he would find a way to get the software working on my it. That's what I call helpful! By that time though, I had already loaded & become somewhat familiar with the Mach3 system & rather then start over I've decided to stick with it.
    I think I'm going to set my next project up with the EMC2, so it hasn't been a waste. :)

29
General Mach Discussion / Re: Motors not running
« on: June 10, 2011, 04:13:27 PM »
BTW - in this post

http://www.linuxcnc.org/component/option,com_kunena/Itemid,20/func,view/catid,9/id,9734/lang,english/#9735

The guy who replyed (jmelson) is the guy who made the pico board.

it will output step pulses up to 300k.

sam

30
General Mach Discussion / Re: Motors not running
« on: June 10, 2011, 03:56:16 PM »
The pico system hardware works only with emc.  I uses epp protocal to comunicate with the board - not step and direction like a normal 'break out board'

You say the forum was 'the support forum for it is not much help'? did you post any more than these two?  I am sure with a bit of elbow grease the issues could be figured out.
http://www.linuxcnc.org/component/option,com_kunena/Itemid,20/func,view/id,9735/catid,9/
http://www.linuxcnc.org/component/option,com_kunena/Itemid,20/func,view/catid,38/id,9728/lang,english/#9728

JonE (pico systems) will bend over backwards to help.

sam


    Does anyone use the Pico universal stepper controller?
    I originally was going to try & set this machine up with the Linux EMC2 software & that's why I bought this board. But I was unable to get the software to load & the support forum for it is not much help, so I decided instead to go with the Mach3 software on Windows XP.
    I thought I would be able to use this board, but now that I'm looking around the web, every reference to the Pico product line is associated with EMC2, so it looks like I'm going to have to buy another board :(
    Can y'all recommend a stepper controller board that will allow for home & limit switches, e-stop & some SSRs?

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