DS0300
APC ALARM: NEED REF RETURN
Fanuc · Series 30i/31i/32i-MODEL B Parameter
What does DS0300 mean?
This alarm indicates that the correspondence between the machine position and the absolute position detector (absolute Pulsecoder or rotary scale with distance-coded reference marks) has been lost. This condition sets bit 4 (APZ) of parameter No. 1815 to 0. A reference position return is required to re-establish the absolute position. The specific cause is further detailed in diagnostic data No. 310#0.
Repair Steps
- 1
Perform a reference position return for the affected axis.
- 2
Check diagnostic data No. 310#0 for a detailed cause code related to the APC alarm.
- 3
After successfully performing the reference return, verify that bit 4 (APZ) of parameter No. 1815 is automatically set back to 1.
Verified technical data. Last updated: March 2026
Source: FANUC Series 30i/31i/32i-MODEL B Parameter