SV0302 APC Alarm: Zero Point Not Established fault in Fanuc drive

SV0302 APC Alarm: Zero Point Not Established fault in Fanuc drive

Description

SV0302 is a "State" alarm. It typically appears on a new machine, after a memory wipe, or after replacing a motor. It simply means "I am a Dogless machine (using absolute encoders), but no one has ever told me where 0.000 is." Unlike SV0300 (Reference Request) which asks you to *move* to home, SV0302 means the home parameter doesn't even exist yet. The machine will be locked from auto-operation.

Cause

• New Motor: You replaced a motor. The new encoder has a blank memory.
• Parameter 1815: You toggled bit 4 (APZ) to 0.
• Memory Loss: The SRAM backup battery died, and all parameters were reloaded from a file, but the encoder position data (which changes constantly) cannot be restored from a static file.

Solution

1. Jog to Position: Manually hand-wheel the axis to where the "Home" position should be (align the arrows on the decals).
2. Set Parameter 1815:
   • Go to MDI mode. Enable Parameter Write.
   • Go to Parameter 1815. Find the axis (X, Y, or Z).
   • Set bit 4 (APZ) to 1.
3. Power Cycle: Turn off the control. Wait. Turn on. The current position is now "Memorized" as the grid zero.