# Coordinate system offset, rotation centre

Some measuring technicians do not include the error parameters of rotary axes in the machine coordinate system but in the system for the rotation centre of the axis (for example, in the tool table).

If the rotation centre of the C axis lies at [0, 0, -550], for example, the method of measuring the machine with [X, Y, Z] commands may result in the output of compensation values that would actually be expected with [X, Y, Z ± 550].

This problem can be solved by implementing a coordinate system offset on the axis side. The parameters IDX, IDY, IDZ can be used for this; see Section “Workpiece axes“.

## Attention

In the event that the C axis was compensated in a different coordinate system than the Cartesian axes, it is imperative to configure two compensations. Otherwise, the machine cannot be compensated at the exact position.