She scrolled through the parameter pages. . That was the one. The reference counter capacity. It told the CNC how many pulses from the position coder equaled one full revolution of the spindle for C-axis positioning. If it was off by even one count, the axis would think the world had twisted under its feet.
So why the alarm?
A severe impact can jump the encoder or move the physical axis, making the stored value in 1860 inaccurate. Related Alarms fanuc parameter 1860
If you tell me the you're seeing or if you just replaced a battery , I can give you the exact step-by-step procedure to reset your home position. Series 16i/18i/21i/20i-A Maintenance Manual, GFZ-63005EN/02 She scrolled through the parameter pages
A: The spindle will not orient at all – it may drift or refuse to complete M19. Never set to zero intentionally. The reference counter capacity