SV0363 Clock Error (Pulsecoder) fault in Fanuc drive

SV0363 Clock Error (Pulsecoder) fault in Fanuc drive

Description

SV0363 is a hardware health alarm for the Built-in Absolute Pulse Coder. The encoder contains an internal clock oscillator (crystal) that synchronizes the position counting and serial data transmission. If this internal clock frequency drifts or stops due to component failure, the drive detects that the timing of the incoming data packets is erratic and triggers SV0363.

Cause

• Hardware Failure: The crystal oscillator inside the encoder cap has shattered due to mechanical shock or vibration.
• Thermal Drift: Extreme heat has caused the oscillator to drift outside of its frequency tolerance.
• Noise: Extremely high-frequency EMI can sometimes disrupt the clock signal line, though this is rare.

Solution

1. Replace Motor: This is a non-serviceable internal failure of the encoder electronics. The motor (or the separate encoder unit if detachable) must be replaced.
2. Check Vibration: If this happens frequently, investigate the machining process. Is the head vibrating excessively? You may need a more rugged encoder type.
3. Cooling: Ensure the motor cooling fan is working to prevent thermal damage to the electronics.