Siemens SINUMERIK 840D sl Function Manual page 374

K3: Compensation
5.4 Interpolatory compensation
On large machines, sagging of the foundation can cause inclination of the whole machine.
For the boring mill shown in the diagram, for example, it is determined that compensation of
the X1 axis is dependent both on the position of the X1 axis itself (since this determines
angle of inclination β) and on the height of the boring mill (i.e. the position of the Z1 axis).
To implement compensation, the compensation values of the X1 and Z1 axes must be
multiplied according to the following equation:
ΔX1 = Z1 * sinβ(X1) ≈ Z1 * β(X1)
Figure 5-8
Compensation table 1 (table index = 0) describes the reaction of axis X1 on axis X1 (sine of
the position-dependent tilting angle β(X1)).
Compensation table 2 (table index = 1) describes the reaction of axis Z1 on axis X1 (linear).
In table 1, the multiplication of table 1 (index = 0) with table 2 is to be selected:
$AN_CEC_MULT_BY_TABLE[0] = 2
Input of compensation values in a grid structure
The compensation values of the Z axis sag on flat bed machines are often measured in
practice at various points as a function of the X and Y coordinates. Under these
preconditions, it is useful to enter the measured compensation values according to a grid-
type distribution. The interpolation points with the relevant compensation values are
positioned at the intersections of the grid (X-Y plane). Compensation values between these
interpolation points are interpolated linearly by the control.
374
Table multiplication
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
Extended Functions