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Formula Axis Correction
« on: July 11, 2006, 02:07:45 PM »
Hi,

I am attempting to use formula axis correction to map Y positions to the A axis of my rotary table.  I made:
A = (Y * 360) / (1.125/3.14159).  If I enter y=.1 in the formula dialog and press Test, the result is 10.1859.  However, if I enter g00 y.1 in the MDI panel, the DRO shows 10.1875 at the end of movement. 

1) Why is the DRO showing the wrong value?  It appears that the bigger the value I enter for y in the MDI panel, the greater the error in the DRO at the end.

2) The rapid speed of my A axis appears to be incorrect when formula axis correction is enabled. It appears that the A axis may be picking up the rapid setting from another axis.

3) Using PI in place of 3.14159 in the above formula does not work in the formula axis correction dialog.  The result is always 0.

Suggestions?

Thanks in advance.

David

Offline Graham Waterworth

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Re: Formula Axis Correction
« Reply #1 on: July 11, 2006, 02:42:01 PM »
have you tried PI as 22/7

Graham
Without engineers the world stops
Re: Formula Axis Correction
« Reply #2 on: July 12, 2006, 11:27:47 AM »
Regarding the PI problem.  I think there is a bug or two in the expression evaluation.  I did the following tests:

PI                works (returns 3.14159...)
PI + 2           doesn't work (returns 0)
2 + PI           works
(2 + PI)        works
(2 + PI) * 2   doesn't work (returns 0)
2 * (2 + PI)   doesn't work (returns 0)

Offline ART

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Re: Formula Axis Correction
« Reply #3 on: July 12, 2006, 09:04:48 PM »
Hi:

  Ill schedule this for tests, but Im considering moving formulas to a plugin for better speed of control.
Im not sure whats going on with PI, but its possibel I limited it to 2 decimals or something.. Hmm. Ill see what I
can see..

Art