Monitoring device for closure arrangement such as door

摘要

The device monitors a closure part with a controller which operates a drive depending on a control signal. The monitor has an alarm device which responds to an unauthorised movement of the closure part. An unauthorized movement of the closure part is detected when the sensor monitoring the closure part detects a movement of the closure part, when the controller is not operating the drive. The movement of the closure part is detected when the sensor signal deviates from the sensor signal corresponding to a closed condition of the closure part.