Siemens SINUMERIK 840D sl Function Manual page 356

K3: Compensation
5.4 Interpolatory compensation
Compensation tables
Because the mentioned dimensional deviations directly affect the accuracy of workpiece
machining, they must be compensated for by the relevant position-dependent compensation
values. The compensation values are derived from measured error curves and entered in the
control in the form of compensation tables during commissioning. A separate table must be
created for each compensation relation.
Entering compensation tables
The size of the compensation table, i.e. the number of interpolation points, must first be
defined in a machine data. After the next POWER ON, the compensation tables are
generated by the NC and preassigned a value of "0".
The compensation values and additional table parameters are entered in the compensation
tables using special system variables. Data can be loaded in two different ways:
● By starting an NC program with the parameter values.
● By transferring the compensation tables from a PC via the serial interface of the PCU.
Note
Compensation tables can only be loaded if:
MD32700 $MA_ENC_COMP_ENABLE (interpolatory compensation) = 0
or
MD32710 $MA_CEC_ENABLE (enable sag compensation) = 0
These compensation values are not lost when the control is switched off because they are
stored in the static user memory. They can be updated if necessary (e.g. following re-
measuring because of machine aging).
356
Note
Compensation tables can be output from the "Services" operating area via the serial
interface on the PCU and loaded back after editing.
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
Extended Functions