| 摘要 |
PURPOSE: A self test type safety relay is provided to further increase the operational reliability of the relay by operating a main relay switch in the relay with synchronization of two micro processor. CONSTITUTION: A self test type safety relay includes an AC/DC converting block(110), a first relay(120), a second relay(130), a detection circuit block(140), a first microprocessor(150), a second microprocessor(160), a display device(170), a first AND gate(180) and a second AND gate(190). The AC/DC converting block(110) supplies the power to the circuits of the relay after an alternative current induced from the coil is converted into a direct current. The first relay(120) is switched by a second magnetic coil and the second relay(130) is connected between the output terminal of the AC/DC converting block(110) and the second magnetic coil. The detection circuit block(140) detects the error of the operation or the circuit design of the relay. The first microprocessor(150) outputs the display corresponding to the operational error and the control signal. The second microprocessor(160) outputs the display corresponding to the checked operational status and the control signal. The display device(170) displays the status of the failure in response to the determination result for the design and the operational states of the first and the second microprocessors(150,160). The first AND gate(180) controls the operation of the second magnet coil. And, the second AND gate(190) controls the switching of the second relay device(120).
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