Position transmitter having a normal mode and a power saving mode operation for the acquisition of the position of a rotatable shaft

Position transmitter for the acquisition of the position of a shaft (4) which is rotatable about an axis of rotation (3), comprising:

• a first optical sensor arrangement (12) for the acquisition of a single-turn position of the shaft, and
• a second optical sensor arrangement (13) for the acquisition, in particular for gearless acquisition, of a multi-turn position of the shaft.
• a first evaluation unit (14) for evaluating the single-turn position;
• a second evaluation unit (15) for evaluating the multi-turn position;
• and
• a control/evaluation unit (16), for processing the single-turn position and the multi-turn position, wherein the position transmitter has at least two operating modes comprising:
• a normal mode, the position transmitter operating in the normal mode when applying an external voltage supply from an external power supply and;
• a power-saving mode, the position transmitter operating in the power-saving mode when the external power supply is switched off or fails, wherein in the normal mode the multi-turn position is determined by both the first optical sensor arrangement and the second optical sensor arrangement and a comparison of the two determined positions is carried out.