Siemens SINUMERIK 840D sl Function Manual page 338

Compensations (K3)
5.1 Brief Description
Interpolatory compensation
The "Interpolatory compensation" function allows position-related dimensional deviations (for
example, by leadscrew errors, measuring system errors or sag) to be corrected.
The compensation values are measured during commissioning and stored in a table as a
position-related value. During operation the axis is compensated between interpolation
points during linear interpolation.
Friction compensation
The "friction compensation" function is particularly effective in achieving a significant
improvement in contour accuracy in circular contour machining operations. If the direction of
rotation of an axis changes, contour errors occur when the velocity equals zero (quadrant
transition point) because of the changing friction conditions. "Friction compensation" (also
called "Quadrant error compensation") compensates for this error reliably the first time the
contour is machined.
A neural network integrated in the SINUMERIK 840D adapts the optimum parameters in a
self-learning process to compensate for friction, backlash or torsion. The system allows for
simple, automatic re-optimization at any time.
The friction compensation function can be commissioned most easily by means of a
circularity test. The circular contour is followed and the actual position deviations from the
programmed radius (most especially at the quadrant transition points) are measured and
then displayed graphically. The circularity test is a "commissioning tool" function.
Activation
The compensations are active in all operating modes of the control as soon as the input data
are available. Any compensations that require the position actual value are not activated until
the axis reaches the reference point.
Position display
The normal actual-value and setpoint position displays ignore the compensation values and
show the position values of an ideal machine. The compensation values are output in the
"Service axes" display in the "Diagnosis" operating area.
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Function Manual, 01/2008, 6FC5397-1BP10-3BA0
Extended Functions