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Author Topic: Home Off Error X Axis  (Read 3206 times)

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Offline c30232

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Re: Home Off Error X Axis
« Reply #10 on: January 02, 2015, 08:25:57 AM »
I see an issue or at least from here.  Both home-offs were set to 2.180.  The 2.171 is the result of the software setting itself after homing.  The xml you have is from after the "auto" reset. The difference has been as much as 7.00"

Would please set A to 0.070 and see what occurs.  In either case both .070 and 2.180 produce a re-write to the home screen when run on two different computers.  The current error of 8 thou doesn't create a problem, but the fact that the software is creating settings worries me.

Thanks for your help!!     

Offline Hood

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Re: Home Off Error X Axis
« Reply #11 on: January 02, 2015, 09:01:04 AM »
Ok I set to 0.07 and it set the value to 0.0661.
Now that was strange but I decided to try and see why it was doing such a thing. I opened the screenset in Screen4 and made the A DRO show 16 decimals. The value when homed is showing as  0.0660770833184247.
Ok so next I looked at your A axis steps per unit and they work out as 0.0094395833312035 degrees per step.
So if you divide your DRO value by the resolution (degree per step) then it comes out to 7, or almost. I suspect if I expanded the DRO  to show more decimals it would be exactly 7 times your min step.

So what seems to be happening is Mach is saying to itself it can not possibly move to  0.070 degrees as the steps per unit wont allow it. Now of course Mach is not actually moving to that position, it is just setting the value of the Home position, it however means that it can not physically move to G53A0 if it accepts the 0.070 value you entered and thus is setting it to the nearest your steps per degree allow.


Hood

Offline c30232

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Re: Home Off Error X Axis
« Reply #12 on: January 02, 2015, 10:08:01 AM »
Well done!  Thank you!!  That explains everything.  The issue surfaced when we installed new drives.  The steps were well off, but our first move was to the home switch, hence the larger error.  As we dialed in the steps the number settled at about  7 times by doing the head math on the fly with larger offsets, but it wasn't exactly so we 7. 

Thank you again.  When the machine is back up I will confirm your findings and let you know.  I an confident you are correct.   

Offline c30232

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Re: Home Off Error X Axis
« Reply #13 on: January 10, 2015, 01:47:31 PM »
Your conclusion proves spot on!  The newly installed drives have more settings than the Cat Detector Van has aerials.  This is our first programmable drive.  What an improvement.  We installed them with the default settings and thus the issue.  On axis has a 20:1 screw and the other is nearly direct drive. Thus one axis worked out of the box and the other did not. When the drive resolution is changed the error changes proportionally.  Both offsets are now zero-zero-zero.  Thanks again!!!        

Offline Hood

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Re: Home Off Error X Axis
« Reply #14 on: January 11, 2015, 05:16:14 AM »
Good you got things solved :)