This situation is only possible if after a system power-up or a reset, the PLC does not indicate any gear with GEAR1 through GEAR4 for the spindle. Then, the spindle has no active gear and if it is not used before programming G63, the CNC will not generate a gear automatically, either.

Before starting a G63 tapping, the spindle must have a gear activated. If the spindle has an automatic gear changer (parameter AUTOGEAR), the CNC generates the gear when programming a speed; otherwise, the gear (M41-M44) must be programmed with the speed.