| 摘要 |
An electromagnetic lock monitoring system for monitoring the strength of a magnetic field in an electromechanical lock which is created when a steel armature plate is closed against an electromagnet. The system utilizes dual Hall Effect devices positioned in such a way that both ends of the electromagnet and both magnetic fields are monitored, and that the resulting monitoring effectively covers the complete contact surface between the electromagnet and the armature plate. Preferably, the Hall Effect devices are disposed in series at the point of maximum flux density within the center element of an E-shaped electromagnetic core, at opposite ends of the core. If the magnetic flux is below a preset limit, a relay also in series drops out, triggering an alarm which may be sonic, electronic, and/or visual, as is known in the prior art.
|
