Fanuc alarm SV0456: ILLEGAL CURRENT LOOP
αi/βi Servo (SV0xxx) · Fanuc 0i-D
What it means
A current loop period (high-speed HRV level) was requested that the hardware cannot execute: the amplifier/pulse module in use isn't qualified for the selected HRV level, or system constraints for high-speed HRV aren't satisfied. Lower the HRV/current-loop setting in the relevant parameters, or fit amplifier hardware supporting the requested level.
Likely causes
- HRV control level parameter exceeds amplifier capability
- Older pulse module incompatible with selected current loop
- System-level constraint violated (axis grouping, option absence)
Need the part urgently?
Send us alarm SV0456 with your machine details — typical RFQ turnaround is 24–48h.