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Author Topic: G73/G83  (Read 26058 times)

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Re: G73/G83
« Reply #30 on: September 17, 2010, 08:05:02 AM »
Seems odd that you can see the DRO change but the axis is not moving.. The Positions on the screen are from the index registers in the SS. The index registers are set by the pulses that go OUT of the SS. So this tells us that the Pulses "should" have been sent from the SS to the axis drive. is there a chance that you  drive faulted due to over acceleration and that we have an accel problem rather then a Drilling problem? I would lower your Z axis acceleration by 50% and see if you still have the problem.

Thanks
Brian
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com

Offline thosj

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Re: G73/G83
« Reply #31 on: September 17, 2010, 08:11:48 AM »
Seems odd that you can see the DRO change but the axis is not moving.. The Positions on the screen are from the index registers in the SS. The index registers are set by the pulses that go OUT of the SS. So this tells us that the Pulses "should" have been sent from the SS to the axis drive. is there a chance that you  drive faulted due to over acceleration and that we have an accel problem rather then a Drilling problem? I would lower your Z axis acceleration by 50% and see if you still have the problem.

Thanks
Brian


I'll certainly try that, and I can look at the G320 led and see if it faults during this peck cycle.

But how would one explain it working on PP and not SS? Do they handle the acceleration differently somehow? Motor tuning is identical between my profiles, PP and SS. I don't get a drive fault any other time moving the Z, but pecking is definately a test!!
« Last Edit: September 17, 2010, 08:13:57 AM by thosj »
Re: G73/G83
« Reply #32 on: September 17, 2010, 08:32:21 AM »
Well... I don't know at this time but with the data that I am getting it looks like the direction we need to be looking..  Welcome to my world :) It will all get sorted out as time goes on.. but you have it so you can make the problem happen and that is a big part in fixing the problem!
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com

Offline thosj

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Re: G73/G83
« Reply #33 on: September 17, 2010, 07:35:06 PM »
Well, I lowered my acceleration by 50% and the problem went away!! As always, Brian, you KNEW!! I guess I should have been watching the Gecko fault LED, but I NEVER THOUGHT of acceleration.

Thanks for that.

Now, how DOES one determine acceleration? I've been running with my accels at 7 for a long time. Suddenly it goes berserk! I set it to 3 for Z and the peck drilling works great. I don't actually notice much difference. Is there a procedure for determining optimum acceleration values? I have Keling servo motors on all three axes, KL34-180-90s, the big bruisers, a 72 volt PS, Gecko 320X/320 drives. CUI AMT-102 encoders at 400 line count. X and Y 24000 Steps per, Z 19200 Steps per. X/Y 100 IPM, could go to 150, Z 40 IPM, could go 50, Z is counterweighted knee on BP clone. Is determining accel a trial and error thing and I just happened to stumble on the break point, or is there a "scientific method"?

Tom

Offline RICH

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Re: G73/G83
« Reply #34 on: September 17, 2010, 08:25:23 PM »
There is a "scientific method" since  there are programs that do all the calcs based on the physicals of the machine. Or you can do the calcs manualy as an engineering exercise. But calculations are only as good as the assumptions used and info in the calcs, and finaly the understanding of what the calc
is telling you.

So practicaly speaking, trial and error ( which dosn't take long to do  anyway ) is a perfectly fine way to do it.

What I have done is after the steps per unit are correct, i then find the max velocity i can get and reduce it to allow for cutting etc, then with that velocity setting i do the same for acceleration.  This way there is headroom in both the velocity and accel settings for the work to be done.
Then some machining tests are done for the worst case of material etc to affirm there should not be a problem for the work that i normaly do.
Which lately seems like not a heck of a lot!  :D


RICH
 

Offline mick

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Re: G73/G83
« Reply #35 on: September 18, 2010, 01:11:12 PM »
Dave,
        my problem with g83 is solved, i'm useing two programs allmost identical appart from z depths, but one of them
        was missing the Q word , if a prog with the Qword in, it will load ok ,without it won't. the mpg error code will show.

        if however the Qword is edited from loaded prog, it will be loaded after editing,but shut msm down, then try to reload
        the mpg error code causes a crash .
 
        this is repeatable every time on my machine,the attachment is the prog that is to blame for my drink problem . ;D

            Mick.
Re: G73/G83
« Reply #36 on: September 18, 2010, 01:35:03 PM »
Mick,
Thanks for letting me know you found the problem.
That wraps up both of the G73/G83 related problems as solved.  :)

I'll forward the info about editing the Q word to Brian. My guess is that he'll add it to the V4 list as he's trying to concentrate on that over V3.

Dave

Author of the MachStdMill Extensions for Mach3
www.CalypsoVentures.com
Re: G73/G83
« Reply #37 on: September 18, 2010, 01:38:41 PM »
Mick,
Thanks for letting me know you found the problem.
That wraps up both of the G73/G83 related problems as solved (at least from an MSM viewpoint).  :)

I'll forward the info about editing the Q word to Brian. My guess is that he'll add it to the V4 list as he's trying to concentrate on that over V3.

Dave


Author of the MachStdMill Extensions for Mach3
www.CalypsoVentures.com