Messages

881

General Mach Discussion / Re: Problems threading on the lathe

« on: October 10, 2009, 11:16:13 AM »

Hi Rich:

  Just to be sure we're on the same plugin , I publish it here.

My results show the RPM is much more stable under the advanced threader plugin. It shows a normal RPM of 393-395RPM fluctuating constantly,
the advanced threading shows 393.50 to 393.6 RPM and very steady. This fluctuation could accoutn for a highe rpitch error at low RPM, and lower error at high
RPM due to the fluctuation being a smaller % of the total RPM, and your testing seems to point directly at that possability. If this can be confirmed, I will simply
change the single point threading to measure the RPM based on time, not # of interrupts.

  Here is a photo of my advance3d threading run, both Timing and Index inputs are enabled and both are set to pin 15 ( my index signal).

 I ran a test thread in the air and all runs fine, so I suspect you can thread quite well even with one slot per rev which is what will display under such a setup.

 Im of the opinion that it isnt necessary to have a slotted wheel, though it may make things more accurate as instead of being one rotaiton behind, the corrector
will be one slot behind.

Let me know how it goes..

Thx
Art
 

882

General Mach Discussion / Re: Problems threading on the lathe

« on: October 09, 2009, 08:06:47 PM »

Sorry about that Rich.

Ill check why and reissue the plugin after I test it on my lathe for RPM operation. I probably need to make a small
change to allow for single pulse intput..

Art

883

Tempest Trajectory Planner / Re: Tempest Planning - Preliminary information and testing

« on: October 09, 2009, 08:05:04 PM »

Hi Randy:

  Yes, its likely the driver has changed. Here's a post of the driver required if you wish to test Tempest.
Just rename your mach3.sys in the mach3 folder to .old , then copy this one in. Remove the driver from the control panel
device manager, and then run drivertest.exe and it will install this one.  Name th eold one back to .sys after deleting this one,
and repeat the proceedure to go back to you current Tormach version.

  Take note, this is only required to test Tempest if your using a version older than 1.26 or so, or a special build like Tormachs.


Good luck, Id love to hear how it runs on the Tormach.
Art

884

General Mach Discussion / Re: Problems threading on the lathe

« on: October 09, 2009, 02:02:39 PM »

Rich:

  Yup, thats the one. If you set the index and timing to the index pin, youll still be able to use it with only an index pulse..no wheel required.

Art

885

General Mach Discussion / Re: Problems threading on the lathe

« on: October 08, 2009, 02:59:08 PM »

Hi Rich:

  Wow, thats pretty clear. SO the lines are pretty good, the pitchis decreasing by .8% or so ..


>>I rebooted after the threading  test and got the same same exact kernel as above. Those are different than  what was shown in the other tests.
The other driver showed 25455 and Chip's  screen reported 23654.

  Not important. What happens is that as the kernal starts up, it measures the number of interrupts per second, and vary's a few internal variables that
control the operating system, when it figures its close enough, it locks them in so they dont fluctuate. Mach3 takes into account what the number is when
planning, so the differing kernal numbers should have no effect, and they dont seem to.

   So we're left with a variation, .8% at 115RPM, lower as we go up.. Ill crunch some more numbers tonight to see if I can see where that may be at,
though Im off the mind that its the RPM reading thats off, .8% of 115 woudl only be a bit less than 1RPM, so thats likely where the error is. The error
seems less at higher RPM's, but that may make a twisted sense of logic happy in the driver..

   We're thrust next on trying to make the RPM more accurate to see if that helps. The smoothstepper counts the RPM internally on a firmware clock,
and the tests you have done don't. Id like ot know though if a set RPM reads differently in the advanced threading plugin as opposed to the standard rpm ,
the advanced plugin tells you both I think, the ratio between them may be interesting ....

Thx
Art

886

General Mach Discussion / Re: Problems threading on the lathe

« on: October 08, 2009, 09:06:08 AM »

Hi Hood:

  Well, it proves the feedrate and such are all being computed properly. Thats a help. Any error must lie in th edriver.


Rich, heres a driver that has no correction, its turned off, otherwise all is the same.

To load it, you need to simply remove the driver using control panel, then copy this into your mach3 folder, and run drivertest.exe.

If you get the message "Driver is loaded , Reboot", ( you dont have to reboot), then install worked. If you dont, you didnt remove the old
one properly. ( Id back up your old one just renamig it mach3.sys.old

Good luck
Art
 

887

General Mach Discussion / Re: Problems threading on the lathe

« on: October 07, 2009, 10:14:11 AM »

Rich:

  Dont think we need to go that deep. The numbers appear to be telling  astory.. Im just trying to decipher what it is.

The fact teh accuracy increases as rev speed increases seems to show that the long time of correction between rev's is allowing an error
to creep in, the lower the time between rev's the less the error.

   Ill generate a driver with no correction to see.

Art

888

General Mach Discussion / Re: Problems threading on the lathe

« on: October 06, 2009, 10:02:27 PM »

Rich:

  Interesting. The error decreases as speed increases..  I would have thought the reverse would have been true.
Since any perterbation of the timing in any of the variables would be a larger percentage of the time of one revolution
as we go faster, I would have thought any constant affecting us would then increase the error as we go faster.

  It would seem then that whatever the error is..is isnt a constant. It must be progressively getting smaller as the
interrupt timing gets smaller.  I woudl think calcuated feedrate cannot then be the problem as its decimal granularity is the same
for all speeds. I have to give this some thought as to why the non-intuituve nature of that result. It may be that any correction
being done is being doen for shorter periods as we go faster.. so any error in correction would then affect the result less and less.
Also, as the correction algorithm runs, its numbers woudl be smaller so interrupt skipping woudl occur less frequently..

 I think I may have to send you a driver with speed correction turned off entirely to see what the effect of that would be, I think
Im getting an idea of where the problem may lie, it may be a granularity of spindle rpm measurment causing a correctiion to be applied
that is really not necesaary..

Ill crunch some numbers and let you know what I think.

Art

889

Video P*r*o*b*i*n*g / Re: New 3d Video Probe

« on: October 06, 2009, 05:31:57 PM »

Steve:

  Sorry for the sad news. Tom was a great pioneer in the video probinbg area. I had a few conversations with him on it, and his passion
was always evident. I didnt know him well, but he seemed a great guy to deal with. I was aware of his health problems which made
his dedication even more amazing than his knowledge on the subject.
   I always have this project on my back burner, and I will dedicate any future releases in that area to Tom.

 My condolances to his family and all that knew him.

Regards
Art

890

General Mach Discussion / Re: Problems threading on the lathe

« on: October 05, 2009, 11:14:20 PM »

Rich:

  John S is at a show, but he'll be joining us soon on this.

For the multislot, you can use an encoder input, ( on ecoder #3 as I recall) OR a timing input, as well as index input . If using encoder I
think its possible to just use the encoder. I need to look at that module now and get back up to snuff on how that worked. Last threads cut on it were
looking good to me, but had variances similar to your initial tests. The two work very differently, so similarities in results will help point us to the real culprit and what
( if anything ) can be done to make it all better.

 I do recall the new module was much better at rpm measurment..

Art