ID 20521Programmed shift mode unknown for this axis. Description Within the axis exchange command, an unknown offset mode in the system is programmed for the axis. For further information see [PROG// Section: Axis exchange commands] Response Class 2 Abort NC program processing. Solution Class 3 Check and modify the axis exchange command. Program a permissible shift mode. Parameter %1: Logical axis number [-] Number of the invalid axis Error type 1, Error message from NC program.