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Author Topic: Mach problem or hardware problem?  (Read 13084 times)

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Mach problem or hardware problem?
« on: September 29, 2010, 11:49:41 AM »
I am converting a BF20 to CNC and am having a problem that I cannot figure out.  The problem is that when I tune the motors in Mach 3, I can run any axis individually at 200 IPM and 50 to 100 accel with no problems whatsoever.  If I then just use the arrow keys to jog one axis, then start a 2nd axis going - the first axis (the one already in motion) will start stalling and will continue stalling until I release the button for it.  I can get multiple axes to work simultaneously but only by moving the accel down to 100 or less which seems like a huge jump down.  My hardware is all from Keling, who I asked about the issue, and he tells me it is not a problem with the drivers or steppers and that it must be something with Mach3.  Here is the setup I am running :


C11 Breakout board
KL-7220 Unregulated power supply (72 volts, 20 amps)
KL34H280-45-8A (Nema 34 640 Oz stepper - 3.2 rated amps and an inductance of 8.8)
KL23H2100-30-4BM (2) (Nema 23 495 Oz stepper - 3 rated amps and an inductance of 7.0)
KL-8060 (3) (24 to 80 V Driver)

I am direct driving the BF20 and I have the drivers all set
to 1/8 micro stepping.  The Nema 34 is set to 3.14 amps
and the Nema 23s are set to 2.57 amps.  They are all
set to half-current at idle as well.

I just set the PC up for this application - it has 2 gigs of ram, an AMD 3.0 Ghz CPU, and a GA-M68M-S2P AMD motherboard.  The O/S is XP and the only software I have installed is Mach3.  I would think this could be a power supply (low amperage) problem but with that power supply, I don't see how.  I also don't think it is binding in the ballscrews since each axis seems to run so well on its own.


Any ideas or suggestions you guys may have would be greatly appreciated.

-Kevin

Offline Hood

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Re: Mach problem or hardware problem?
« Reply #1 on: September 29, 2010, 12:17:12 PM »
Can you check the voltage of the power supply when jogging more than one axis and see if its steady and how much of a difference between jogging just one.
Hood
Re: Mach problem or hardware problem?
« Reply #2 on: September 29, 2010, 12:24:45 PM »
I will check that tonight.  Also, I don't know if it makes a difference but the power supply is split into two 10 amp feeds.  I am running one to the Z and the other to both X and Y.

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Re: Mach problem or hardware problem?
« Reply #3 on: September 29, 2010, 01:51:33 PM »
A good test would be to jog X and Z or Y and Z seeing as they are not sharing supplies.
Hood
Re: Mach problem or hardware problem?
« Reply #4 on: September 29, 2010, 02:01:29 PM »
That is actually how I first noticed the problem.  I was moving the Z and tried to start moving the X which caused the Z to stop.

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Re: Mach problem or hardware problem?
« Reply #5 on: September 29, 2010, 02:05:48 PM »
Ok sorry I thought it was just X and Y.
Can you command a move rather than just jogging and see what its like, it would really have to be an equal distance move to test properly. Something like G0X2Y2.
Also if you attach your xml I will have a look through it to see if there any problems there.
Hood
Re: Mach problem or hardware problem?
« Reply #6 on: September 29, 2010, 09:53:43 PM »
I recreated the condition of forcing the stall and noticed no appreciable change in voltage on the PS.  I did a G0X2Y2Z2 several times and it was successful every time.

I also ran the drivertest.exe program twice.  The first time I saw:



the second time I got:



I have attached the XML - I hope some of this can help you figure it out.

thanks again,Kevin

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Re: Mach problem or hardware problem?
« Reply #7 on: September 30, 2010, 03:12:20 AM »
That is not a very good driver test, even although it says excellent, I would say its not and its certainly not one I would be happy with if it was my machine. The second test either shows either that your system is unstable or you had Mach running when you did the test.
Looked at your xml and it is fine from first glance so I think your driver test results are likely the issue. You could try the optimisation steps detailed at the bottom of the downloads page to see if they help.
Hood

Re: Mach problem or hardware problem?
« Reply #8 on: September 30, 2010, 08:23:24 AM »
I will start going through that document tonight to see if it helps.  It is definitely either PC related or configuration related.  I took a (much) older dell PC off of my other CNC mill and hooked it up the G0704 (and re-set the steps per) and it works great at the same velocity.  Not only were there no stalls but the motors sounded as though they were running much smoother.

This is what drivertest looks like on the older PC from my other machine.  It does look a lot better.

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Re: Mach problem or hardware problem?
« Reply #9 on: September 30, 2010, 08:58:13 AM »
Yes, much nicer, glad the problem is found  :)
Hood