Applicable Systems
Series 0i
Series 16/18/21
Alpha
Beta
Symptoms
The Z axis APC detected a parity error.
Possible Causes
- APC battery voltage low
- APC communication cable disconnected or damaged
- APC pulse coder internal fault
- Electromagnetic interference
Troubleshooting Steps
- Step 1: Check the APC battery voltage for the affected axis
Battery voltage is within specification (above 3.6V) - Step 2: Inspect the APC communication cable connections
All connections are secure and cables are undamaged - Step 3: If battery is low, replace the APC battery
New battery installed, voltage normal - Step 4: Perform manual reference point return for the affected axis
Axis returns to reference point successfully
How to Reset
To reset APC alarm 334: 1) Replace the APC battery if voltage is low. 2) Reconnect any loose cables. 3) Power cycle the CNC. 4) Perform manual reference point return for the affected axis. Caution: Always replace batteries with power on to prevent position data loss.
Frequently Asked Questions
- Q: What does 334 mean on Fanuc FANUC 0/0i/30i Series?
The Z axis APC detected a parity error.
- Q: How do I fix 334 on Fanuc?
Follow the troubleshooting steps: Check the APC battery voltage for the affected axis
Source: FANUC CNC System Alarm Manual (doc.eleok.com)
Category: CNC