Commissioning - Siemens SINUMERIK 840D sl Function Manual

K3: Compensation
5.4 Interpolatory compensation
Complex compensation
Since it is possible to use the position of an axis as the input quantity (base axis) for several
tables, to derive the total compensation value of an axis from several compensation
relationships (tables) and to multiply tables, it is also possible to implement sophisticated and
complex beam sag and angularity error compensation systems.
This function also makes it possible to deal with different error sources efficiently. For
example, it is possible to combine a table with a modulo function for a periodic recurring
error component with a second table without a modulo function for an aperiodic error
component for the same axis.
Leadscrew errors can also be compensated with this function by parameterizing an identical
axis for the base and compensation axes. However, in contrast to the MSEC, measuring-
system switchovers are not automatically registered in this case.
Preconditions/activation
The "sag compensation" function does not become active until the following conditions are
fulfilled:
● The option "Sag compensation, multidimensional" is enabled.
● The function has been activated for the relevant machine axis (compensation axis):
● The compensation values are stored in the static user memory and are active (after
● Evaluation of the relevant compensation table has been enabled:
● The current measuring system of the base and compensation axes has been referenced:
As soon as these conditions have been fulfilled the setpoint position of the compensation
axis is altered in all modes with reference to the setpoint position of the base axis and the
corresponding compensation value and is then immediately traversed by the machine axis.
If the reference is then lost, e.g. because the encoder frequency has been exceeded (DB31,
... DBX60.4 or 60.5 = 0), compensation processing is deactivated.
5.4.3.2

Commissioning

Number of compensation interpolation points (MD18342)
The number of required interpolation points in the compensation table must be defined for
every compensation relationship and the memory space required is reserved using the
following machine data:
MD18342 $MN_MM_CEC_MAX_POINTS[<t>] (maximum number of interpolation points for
sag compensation)
368
MD32710 $MA_CEC_ENABLE[<AXi>] = 1
POWER ON).
SD41300 $SN_CEC_TABLE _ENABLE[<t>] = 1
DB31, ... DBX60.4 or 60.5 =1 (referenced/synchronized 1 or 2)
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
Extended Functions