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Author Topic: Jerky motion...yes I've read the other posts :-)  (Read 16862 times)

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Re: Jerky motion...yes I've read the other posts :-)
« Reply #10 on: July 01, 2008, 11:25:58 PM »
Sorry Gerry didn't mean to mis quote you. I didn't know what you meant by settings page, but I just checked now and I see what you mean, I'm a little slow lately.

I'm still a little fuzzy, ok there are 2 CV things on the settings page and there are 2 CV things on the config page as well as another CV check box, so I turn off the ones on the settings page and the 2 on the config page but leave the regular CV enabled? Also what do the settings refer to: CV Distance, CV Feedrate, CV Dist. Tolerance, G100 Adaptive Nurbs CV? I will see if I can find the answer to the definitions too.

I will check my power supply and see but this problem has nothing to do with the change over it was there before.

I did try the CV on with the Sherline but no difference. I've tried all configurations I can think of and it doesn't seem to make any difference. I don't mind living with it as long as it's working and cutting what it's supposed to but like I said before I though it should be fluid as it goes through curves.

Offline Chaoticone

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Re: Jerky motion...yes I've read the other posts :-)
« Reply #12 on: July 01, 2008, 11:32:26 PM »
Cartierusm , Sorry if you have allready said, but what version of Mach are you running? Open Mach, help, about.

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!
Re: Jerky motion...yes I've read the other posts :-)
« Reply #13 on: July 02, 2008, 12:12:00 AM »
Gerry you are the man!! That worked, it's definately smoother, but I'll let you people be the judge of that. Here is a 12mb video of the new settings, same G-Code, same feedrate (I think) 36 IPM. I also went all the way on the acceleration on the Motor Tuning which was 37.5, the highest for my motor's velocity and I wasn't losing any steps just jogging around the table.

http://www.smokeproductions.com/cnc2.avi

I also did a driver test here are the results: Pulse Per Second in 25khz mode 23798, CPU Speed 2661, Apic Timing Constant 5592.

I'm not over 25,000 as someone mentioned should I try to remodey that? I'm not running Quick Time and I don't have any extraneous stuff running, it's a pretty clean computer.

I also did the diagnostic thing with my mouse and it stayed at 23,793. Time In Int. stayed mostly at 4 but occasionaly jumped to 10-11, all while running a G-Code.

P.S. I'm running 2.63, but I just upgraded from 2.45 but I had the same problem before that's why I upgraded.

I appreciate all the help you've given me.
Re: Jerky motion...yes I've read the other posts :-)
« Reply #14 on: July 02, 2008, 08:48:38 PM »
So I just cut a piece and eveything seems to working fine. One of you said to tune the acceleration to the highest I can without losing step, so I did that. Now when the motors move they stop abruptly, which is no big deal if that's OK. I remember reading somewhere to set the acceleration to smooth not abrupt or too slow to spin up. So I just wonder if the abrupt stops are going to cause a lose of accuracy. If it really doesn't matter too much I'm going to slow it down so it's not so abrupt becasue now it's at the maximum.
« Last Edit: July 02, 2008, 09:12:41 PM by Cartierusm »

Offline Chip

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Re: Jerky motion...yes I've read the other posts :-)
« Reply #15 on: July 02, 2008, 11:33:49 PM »
Hi, Cartierusm

In the end it's all a balancing act, Your acceleration value can be above or below your F-speed setting.

If your acceleration value is below your F-speed with short line segments, You may never see your True set F-speed during the job, (slower, smother).

If your acceleration value is above your F-speed, It starts runs stops at the F-speed, (harsher, more Abrupt moves).

Glad It's Working Better, Chip
Re: Jerky motion...yes I've read the other posts :-)
« Reply #16 on: July 03, 2008, 02:52:09 AM »
I reset the acceleration to what I consider a sweet spot. Not so abrupt but no real spin up. I think it works better that way. If any of you would like to I'd appreciate someone videoing their "tuned machine" to run my G-code with the spindle off so I can see the way it moves and the way the motors sound, that would help a lot. It must be steppers though, just seeing someone else's would do me a world of good. Thanks.

Offline Hood

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Re: Jerky motion...yes I've read the other posts :-)
« Reply #17 on: July 03, 2008, 04:02:46 AM »
post your code and I will use i on my mill, wont be today but tomorrow I should manage.

Hood
Re: Jerky motion...yes I've read the other posts :-)
« Reply #18 on: July 03, 2008, 01:29:22 PM »
It's in the first post. Thanks I appreciate it. It's only a 6 minute program but I don't need to see the whole thing.

Offline Hood

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Re: Jerky motion...yes I've read the other posts :-)
« Reply #19 on: July 04, 2008, 05:28:50 AM »
Heres a link to the vid thats it running the file from the first post.
Hood

http://www.youtube.com/watch?v=kYPy320j8nI