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Author Topic: Slaved stepper not moving the same amount???  (Read 6053 times)

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Slaved stepper not moving the same amount???
« on: July 23, 2014, 02:26:52 PM »
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
Re: Slaved stepper not moving the same amount???
« Reply #1 on: July 23, 2014, 04:00:19 PM »
I have attached the xml file if that is of any assistance.

Best Regards,

Preston

Offline Hood

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Re: Slaved stepper not moving the same amount???
« Reply #2 on: July 25, 2014, 05:50:50 PM »
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
Re: Slaved stepper not moving the same amount???
« Reply #3 on: August 01, 2014, 06:08:51 PM »
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

Offline Hood

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Re: Slaved stepper not moving the same amount???
« Reply #4 on: August 01, 2014, 06:27:59 PM »
Change the pin numbers in Mach for the master and slave or you could physically change the wires on the breakout.
Hood
Re: Slaved stepper not moving the same amount???
« Reply #5 on: August 02, 2014, 03:28:45 PM »
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

Offline Hood

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Re: Slaved stepper not moving the same amount???
« Reply #6 on: August 02, 2014, 03:49:50 PM »
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
Re: Slaved stepper not moving the same amount???
« Reply #7 on: August 02, 2014, 04:41:42 PM »
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

Offline Hood

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Re: Slaved stepper not moving the same amount???
« Reply #8 on: August 02, 2014, 05:04:21 PM »
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
Re: Slaved stepper not moving the same amount???
« Reply #9 on: August 02, 2014, 06:14:59 PM »
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