Encoder interface cards are used for Flux Vector Control operation with sensor (FVC mode) for asynchronous motors, or for Vector Control operation with speed feedback (FSY mode) for synchronous motors.
For asynchronous motors, in the other control modes (voltage vector control, voltage/frequency ratio), encoder interface cards improve static speed accuracy.
The interface encoder card is inserted in a dedicated slot
It is protected against short circuits and overloads

Different types available:
- With RS 422 compatible differential outputs - VW3A3401, ...402
- With open collector outputs - VW3A3403, ...404
- With push-pull outputs - VW3A3405, ...406, ...407