| 摘要 |
The invention relates to an access protection device for a physical area which can be switched on and off in a controlled manner, comprising a fixed part, at least one movable part for closing an access opening in the fixed part and, for each movable part, a tumbler device having a magnetic circuit, which comprises a magnetizable yoke located on the movable part and an electromagnet which can be closed by means of the yoke, it being possible to regulate the locking force of said electromagnet by means of a current regulator, a first and a second desired value being predetermined for the current regulator, and it being possible to periodically carry out a controlled jump from the first to the second desired value, it being possible to measure the time from the beginning of the controlled jump to the time at which the second desired value is reached.
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