F31117 fault in Siemens V70 Drive indicates an Inversion error on signals A/B/R. This means the differential (inverted) tracks from a square-wave encoder are missing or mismatched with the primary tracks.
Cause: For a square-wave encoder (bipolar, double ended) signals A*, B* and R* are not inverted with respect to signals A, B and R.
Remedy:
- Check the encoder/cable.
- Does the encoder supply signals and the associated inverted signals?
