Fagor alarm 4001: Parameter LOOPTIME different at the CNC and at the drive

What it means

During ring initialization the CNC compares key synchronization parameters with each drive and found LOOPTIME disagreeing between the two sides. A common cycle time is mandatory for SERCOS phase 4, so the mismatch must be corrected before the bus becomes operational.

Likely causes

• LOOPTIME changed at the CNC without re-parameterizing the drives
• drive replaced with a unit storing a different cycle time
• parameters not saved to flash after a drive service