SV0462 FSSB: Send Error (Slave) fault in Fanuc drive

SV0462 FSSB: Send Error (Slave) fault in Fanuc drive

Description

SV0462 is a Fanuc Serial Servo Bus (FSSB) communication fault. Specifically, "Send Error" means the Servo Amplifier (Slave) tried to send data back to the CNC (Master), but the transmission failed. This implies the drives are receiving commands okay, but the "Return Path" of the optical ring is broken or noisy. The CNC waits for a response from the drive (e.g., current position), and when it times out, it triggers SV0462.

Cause

• Optical Cable Damage: The fiber optic cable connecting the "Out" of the drive to the "In" of the CNC (or next drive) is damaged.
• Drive Control Board: The optical transmitter on the servo amplifier is failing (dim LED).
• Noise: High-frequency noise is corrupting the light pulses.

Solution

1. Trace the Ring: The FSSB is a ring. CNC -> Drive 1 -> Drive 2 -> CNC. If Drive 2 has the error, the problem is usually the cable coming *out* of Drive 2 going back to the CNC.
2. Swap Cables: Swap the optical cable with a known good one.
3. Replace Drive Control Card: If the cable is good, the optical port on the drive is likely burnt out.