Closure device for a convertible roof construction

The invention relates to a closure device (10) for a convertible roof structure (12) with at least one closure element (14) which can assume an open position and a closed position, wherein the closure device (14) at least temporarily, a sensor device (16, 18, is assigned to 20) which can detect the open position and the closed position. According to the invention it is provided that the sensor device (16, 18, 20) comprises only one sensor (16) which generates a first signal when the open position is reached and generates a second signal when the closed position is achieved , Furthermore, the invention relates to a roof structure for a convertible, and a method for monitoring a closure device for a convertible roof structure.