Fagor alarm 3751: Drive Feedback not valid

What it means

At CNC power-up or reset the position feedback of an axis could not be calculated correctly because the drive did not initialize properly. The CNC receives an unusable position value, so the axis is flagged instead of closing the loop on bad data.

Likely causes

• drive failed to initialize its feedback interface at boot
• feedback cabling or parameterization inconsistent between drive and CNC
• drive firmware/software version mismatch with the feedback type

Replacement parts

We supply the following units for this alarm — tested, warranty-backed:

• AXD (DDS) servo drive module

  drive · Common cause

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• EC-P-D feedback cable SUB D15 HD

  cable · Common cause

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