Multi-turn limiting device and method of limiting the movement of a motor driven element

A multi-turn limiting device for limiting movement of an element driven by a motor, the limiting device comprising:

• a memory configured to store a value corresponding to a limit position of the element;
• an angular position sensor configured to provide a sensor signal corresponding to an angular position of the element;
• an output for providing a switching signal to the motor, and
• a controller connected to the sensor for receiving the sensor signal and to the memory for retrieving the value and to the output for providing the switching signal,
• wherein the controller is configured to provide the switching signal by comparing the sensor signal with the value corresponding to the limit position;
• wherein the multi-turn limiting device further comprises:
• a movable member, the movable member being mechanically couplable to the element via a transmission having a non-unitary first transmission ratio;
• and
• a further angular position sensor configured to provide a further sensor signal corresponding to the angular position of the movable member, and
• wherein the controller is further connected to the further sensor for receiving the further sensor signal, and wherein the controller is configured to:
• provide the at least one switching signal further depending on the further sensor signal;
• and
• provide a position signal to the output separate from the at least one switching signal, wherein the position signal corresponds to the position of the element over a multi-turn range;
• and
• wherein the limiting device further comprises a housing, at least the controller, the angular position sensor, the movable member, and the further angular position sensor are housed in the housing, the output being provided to the exterior of the housing.