In most FANUC documentation (especially on lathes with dual tool offsets or specific custom macros), translates to: "Illegal Tool Offset Number."

At that point, it’s safer to call your FANUC service representative than to guess. Don't let Alarm 7127 intimidate you. In 90% of cases, it is simply a typo in the program or a missing offset entry . Keep your offset library clean, double-check your tool call lines, and you’ll be back to cutting chips in no time.

Disclaimer: Machine tool configurations vary by builder (Haas, Doosan, Mazak, etc.). Always consult your specific machine’s maintenance manual before changing parameters.

The machine is trying to execute a T code (Tool number) or a tool offset ( H or D code), but the number you entered is outside the allowed range.