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Author Topic: Progressive Move Error with X and Y  (Read 36164 times)

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Offline Hood

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Re: Progressive Move Error with X and Y
« Reply #60 on: July 28, 2008, 02:19:56 AM »
I had G201's on my first mill but have G202's on the present one, I didnt have the problem with the 201's that you are experiencing but it is funny the Jim Pinder says he is seeing that problem and he has 201's. I wonder what the connection is.
Hood

Offline jimpinder

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Re: Progressive Move Error with X and Y
« Reply #61 on: July 28, 2008, 02:02:56 PM »
I agree with Overloaded that it is a good idea to reference reasonably often - Mach 3 has no feedback, and therefore if an error occurs it will continue to show.

The only thing I can think of is that there is a difference between drivers that require a positiove voltage and those that require a negative voltage. I dont know how they work, but if they fire when they see a positive or negative going voltage, then there will be a difference whether you have selected "active low" or "active high". If you have a pulse figure between 1 and 5 ms then fine, the difference is not going to be great - but is the Sheerline a 50 50 pulse - in which case there would be a timing difference. I don't see a great difference if your steps per unit are high, but if they are low then this could show.

Does anybody know how stepper motors react to microsteps. I know that manufacturers will not guarantee these positions - but say a motor is called to halt at a position the is 3 or 4 microsteps from its full step position - can we guarantee they will hold that psotion until the next time they move. I don't know - but I would like to
Not me driving the engine - I'm better looking.
Re: Progressive Move Error with X and Y
« Reply #62 on: July 28, 2008, 03:09:48 PM »
Jim,
Maybe this will help.
RC
Re: Progressive Move Error with X and Y
« Reply #63 on: August 02, 2008, 04:28:02 PM »
Well, I'm not ready to declare victory yet but today's work seemed promising.  Running my control program, I finally got good results.  Will try and run the gear crossing program later which should be the final test if things are working correctly.  Here's what I did to get to this point:

1. Replaced the dell latitude 8100 laptop with an older HP D530 desktop workstation I bought from geeks.com.
2. Set Motion Mode to Exact Stop as recommended by the team here.
3. Set Sherline 1/2 Pulse Mode as recommended by the team here.
4. Significantly reduced Acceleration in motor tuning.  The ramp up/down is currently over 2 seconds.

I'm in the middle of building a breakout box for the parallel port which is a real PITA so I will resume this effort if things don't go well with the next test.

Thanks again to everyone that has helped me through this project.  It has been greatly appreciated.  Great support team!!

Best Regards.

Carl

Offline Chaoticone

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Re: Progressive Move Error with X and Y
« Reply #64 on: August 02, 2008, 08:43:53 PM »
 :)

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!

Offline Hood

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Re: Progressive Move Error with X and Y
« Reply #65 on: August 03, 2008, 03:40:56 AM »
Fingers crossed.
Hood
Re: Progressive Move Error with X and Y
« Reply #66 on: August 04, 2008, 08:45:07 PM »
Well, it's back to the drawing board.  No luck when I ran the more complex gear crossing program.  Time to get a scope on the inputs and wire direct to the drivers.

Best Regards.

Carl

Offline RICH

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Re: Progressive Move Error with X and Y
« Reply #67 on: August 04, 2008, 11:16:25 PM »
Carl,
Just keep at it, one thing at a time, and don't get frustarted. Still here on the sidelines for you but my cheering won't help any. How about some humor......just 9000+ more reads of this post and the team can make a record.
RICH

Offline jimpinder

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Re: Progressive Move Error with X and Y
« Reply #68 on: August 05, 2008, 04:17:41 AM »
Well - that way we will soon know if it is the machine, or Mach 3 ;D
Not me driving the engine - I'm better looking.

Offline Tweakie.CNC

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Re: Progressive Move Error with X and Y
« Reply #69 on: August 14, 2008, 10:28:37 AM »
Hi Carl,

I have been following this thread with interest, as have many others, and I would like to add my comments regarding progressive errors.

1) Errors are caused by 'gained' or 'lost' steps.
2) Lost steps are usually caused by the stepper's inability to drive the load presented (speed, torque,friction etc.).
3) Gained steps are usually caused by noise spikes occurring on the 0 Volt side of the step pulse train from Mach on the LPT connection.

If you are going to replace your breakout board then try using 74LS14 schmitt's in series with the step inputs (direction inputs will be ok straight through). One schmitt is ok if you change the config, ports & pins, motor outputs, to 'step low active uncheked' else two schmitt's in series (like beer they come in 6 packs).

Good luck.
« Last Edit: August 15, 2008, 12:06:37 PM by Tweakie.CNC »
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.