Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: PrestonE on July 23, 2014, 02:26:52 PM
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Hello Everyone,
It has been quite some time since I used everyone's kind help,
but I am in need of that now.
I moved and when I re-setup my CNC router and hooked everything
back up using a different computer...as the old one died, there is a
problem.
I copied all of the parameters before taking the router apart and used
those same parameters with the Dell GX-620 computer.
I have the Y axis slaved to the A axis as there are 2 steppers that drive
the gantry from opposite sides.
The motor tuning is exactly the same, but when I engage the stepper
gears into the rack and move it...one stepper is moving more than
the other.
I disengaged the steppers from the rack and put a piece of tape pointing
down on both gears. Then I command the stepper to move 5 revolutions on
the right side stepper...it does that, but the stepper on the left side is out
of phase about 90 degrees from down.
I have checked that all the wiring is tight.
We are using Gecko G202's and nothing hardware wise other than the
computer has changes.
Before the move, we had likely several thousand hours of nicely maching
aluminum parts very accurately...
Any ideas where I should look next, as I am totally confused.
Very Best Regards,
Preston
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I have attached the xml file if that is of any assistance.
Best Regards,
Preston
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Try swapping motors and do your tests, if it changes to the other motor then your motor is suspect. If it stays the try changing the drive, if that doesnt change things then try swapping pins.
Hood
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Thanks Hood, Well finally got the time to do some testing...
Swapping the motors side for side the same motor still lags.
Swapping the motors on the Gecko 202's and the same motor lags.
Not quite sure what you meant by if that doesn't change things, change pins.
What pins would I be changing.
Very Best Regards,
Preston
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Change the pin numbers in Mach for the master and slave or you could physically change the wires on the breakout.
Hood
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Thanks Hood,
The current pins are Y is Step Pin 3 and Dir Pin 7
A axis Step Pin is 5 and Dir Pin is 9
If I were to change the Y to the A pin numbers
and vise verse for the A, would that do what your
asking or do I need to change to totally different pins?
Very Best Regards,
Preston
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Yes, just changing the pin assignment in Mach will be fine for this test.
If the problem still happens with the same motor then it is likely there is an issue with the breakout board or possibly the drive if you have not tried swapping them.
If the problem shifts to the other motor then it seems likely there is a problem with the output from Mach as Mach will now be seeing that motor as the slave.
Hood
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Ok Hood,
Swapping pins and we still have the same motor lagging behind.
By drive...do you mean the Gecko 202's???
I swapped those between motors and the same motor still lagged.
I do have another Breakout Board, but would like to eliminate swapping
it until everything else possible is checked.
Thanks So much for the very Valuable Help!!!
Preston
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If you have swapped the pin assignment in Mach and still the same side is out then I would say it has to be a hardware issue.
Reason being is you have effectively swapped which motor is the slave as far as Mach is concerned, so if it was a software issue then it should have swapped sides.
If you have spare outputs on the BOB you could swap the slave to them to see if anything changes, you would of course have to tell Mach the new pin numbers for the slave.
Hood
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Ok, I changed the plugs from the Breakout Board and switched the Y for the A axis and the
same motor still lags behind the same amount as always.
Would this not indicate that something is wrong with that Stepper Motor?
The stepper is a Oriental Motor Co PK299-01AA.
Best Regards.
Preston
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Ok not 100% sure what you are meaning regards "same motor", if you are meaning you changed the plugs around and it stayed with the slave side then its not motor or drive. If you are meaning that it swapped over to the master side then it is a problem with motor or drive.
Hood
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Ok, I have the Y axis motors labeled YR and YL
No matter what is do, the YR stepper is always behind the YL
I can switch Gecko 202's, leads,pins in Mach3, ect and always the actual YR motor always is behind the YL...
For instance, after 5 revolutions of the YL...the YR is about 90 degrees behind the YL
No matter what is change in Pins, Geckos, outputs from the Breakout Board...
The actual YR motor trails the YL ....
Thus, I cannot see how it could be anything other than the YR stepper being bad...
Does this make since???
Thanks Hood!!!
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Ok if its always staying with the same physical motor, ie following the motor as you swap things around, then yes it would seem to be the motor.
Hood
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Thanks for all the help SO MUCH Hood!!!!!!
I could not have done this with you...
I will be ordering a new stepper, but this one has 4 leads and the new one of the same model
that Oriential sells now has 6 wires...will it be compatible with the other 4 wire, or do I need
to buy 2 new ones???
Very Best Regards,
Preston
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You will just have to connect the motor in series to be the same as the one you have now, so should be no need for two motors.
Hood
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I will be ordering a new stepper, but this one has 4 leads and the new one of the same model
that Oriential sells now has 6 wires...will it be compatible with the other 4 wire, or do I need
to buy 2 new ones???
Hi Preston,
I don't know if this helps...
Tweakie.
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Ok, to test this all out before ordering a new stepper like the old one...
I have several new smaller steppers that are the same.
Could I hook 2 of them up and check to see that these 2 operate normally and
one does not loose 90 degrees after 5 revolutions?
That should confirm if the other stepper is really bad, correct???
Best Regards,
Preston
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You should be able to do that as long as you make sure you have limited the current on the Gecko to suit those smaller steppers, assuming they require less than the current ones.
Hood
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Ok, the small steppers use less voltage than the Gecko 202's are rated for...
But, the router has 2 other of these same Oriental Motors of exactly the same size...duh...too close to the problem!
I swapped one of these motors for the one acting up and it does the same thing...looses about 45 degrees after
5 revolutions...so the other motor, looks to be good.
What now???
Could it be a bad connection in one of the plugs?
Best Regards,
Preston
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Hi Preston,
I see in your xml that the pulse width for both motors are set at 0 in motor tuning. Maybe increase both to 5 just to see if it makes any difference.
If you said earlier, I apologize, but do you know which motor is actually moving the correct distance ? The leader, or the lagger ?
Russ
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Russ, I'm not sure...
How would one determine this?
Best Regards,
Preston
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There will be 200 steps per motor rev and the Geckos are 10 microsteps so 2000 steps per rev. If you command a distance equal to 2000 steps then you will see which is lagging.
Hood
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Ok, it's been a busy few weeks...but back to the problem...
Not quite sure how to command a move of 2000 steps, but moved with
the DRO 0.500 inches, 1.000 inches and back to 0.000 with differing
configurations of YL stepper driving Left side of gantry, YR stepper driving
right side of gantry and X stepper driving right side of gantry.
In repeating going from 0.000 to 0.500 to 1.000 and back to 0.000
with the differing configurations I cannot get a repeatable error cycle.
All configurations vary from -0.002 to -0.032 inches and are not repeatable
in the amount of the error.
I did turn the jog rate down to 1.5% to be able to accurately set the amount
of the movements.
What on earth would that indicate? Bad control board??? I do have another
that I could swap this one with.
Best Regards
Preston
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Ok, since no one offered any further ideas...
I changed the breakout board for a spare that I had.
Now when I move eitherstepper motor via the DRO a certain distance and back
it returns to the same location with either stepper motor...
The left and right motors are within 0.020 of each other in a move of 1 inch and
when returning to 0.000 measure on the dial indicator 0.000 repeatably.
Thus, I believe that something was wrong with the other Breakout board...
Not sure what, but it was not repeatable at all.
Hopefully further testing will show more progress.
Best Regards,
Preston