| 摘要 |
According to a first aspect of the invention there is provided a method of determining whether a magnetically operated switch which forms part of a safety switch has been welded closed, the method comprising: establishing a first magnetic field in the vicinity of the magnetically operated switch, the magnetic field being arranged to move the magnetically operated switch from a first configuration to a second configuration; and monitoring the state of the magnetically operated switch to determine if the magnetically operated switch has been moved by the first magnetic field, thereby determining if the magnetically operated switch has been welded closed. According to second and third aspects of the present invention there is also provided inventive safety switches.
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