F31100 Zero Mark Distance Error fault in siemens drive

F31100 Zero Mark Distance Error fault in siemens drive indicates that the encoder signal error related to the zero mark pulses. 

Cause 
1. Defective encoder.
2. Noisy encoder cable (EMC).
3. Slippage between motor and encoder. 

Remedy 
- Check encoder cable shielding. 
- Tighten encoder coupling. 
- Replace encoder.