Gentlemen,
   I have the lead screw compensation working - finally.
   It seems as if the compensation is applied differently depending on
which side of the nominal value the machine is on.

   I have comp in my machine as follows:

in the X axis comp file I have

-0.5 -0.502 -0.4972
0.0 0.000 0.0043
0.5 0.5005 0.5052

all the rest of the numbers from -61.5 to 61.5 have the triplets equal
- no compensation

I am working around the point X zero

there is about .0042/.0046 backlash in the X axis ballscrew. I have
been told by a longtime maintenance man that a ballscrew this size
will be built to have .003/.004 backlash. I don't like it but that is
another story. Maybe my experience of rebuilding a ballscrew of this
size was not the dismal failure I thought it was.

set the machine to jog the X axis .0001 or .001
position the X axis to -.0002 or more negative
using the + or - buttons in AXIS or a handwheel - jog the axis
positive or negative one unit of motion
the axis motion is smooth and accurate - very nice

set the machine to jog the X axis .0001 or .001
position the X axis to -.0001 or more positive
per above - jog the axis in the negative direction one unit and then
one unit positive

the compensation is immediate and harsh - the table is moved (bounced)
farther than the unit - jogging the axis farther positive reveals the
ballscrew catches up with the table and the compensation is accurate.
On axis reversal you can feel the 'hit' of the compensation.

per above - jog the axis in the positive direction one or more units
and then one unit negative - the table is moved smooth and accurate to
the indicated position - no 'hit' or impulse is felt during axis
reversal in the negative direction.

when the X axis is -.0001 or more positive - oscillating the jog one
unit will reveal a 'hit' for every jog (axis reversal) positive and
smooth motion for every jog (axis reversal) negative.

the compensation magnitude seems to be accurate for all motion
directions and positions

the compensation seems to implement the tuning for all negative jog motions

the compensation seems to be immediate and harsh (not per the tuning
of the axis) for positive jog motions on the positive side of the
nominal compensation location

further testing reveals the exact same results when using MDI

I will add another triplet on each side (-1.000 and 1.000) and check
the motion at -.500 and .500
thanks
Stuart

again - Chris (and everyone) - thanks for the correction yesterday

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