Siemens 611u drive fault A508 encoder fault

[sammmy_s]

We havea 100kw AC motor with HEIDENHAIN encoders ERM 280speed encoder.

The motor works ok up to 500 rpm under closed loop control.

Anything above 500 it trips on A508 encoder fault.

The encoder reader head and the disc are they a matching pair?

Thanks for any advice.

 

[sammmy_s]

HEIDENHAIN encoders ERM 280 speed encoder.

Is it an alignment problem or cable?

Please advise.