| 摘要 |
PURPOSE:To reset a relay automatically when automatic condition is restored within a certain time by providing an automatic stand-by relay which stores an automatic mode for the certain time when the automatic condition is not satisfied. CONSTITUTION:When a system A is a main system, a contact 4 is made to make automatic condition (A)5 effective and when a system B is the main system, automatic condition (B)5' becomes effective. When a controller performs switching between the systems A and B, contacts 4 and 4' are both broken for a time T1. This T1 is about 5 milliseconds and shorter than the operation time T2 (about 10 milliseconds) of a relay 1, so the automatic state is maintained. When the automatic condition is not satisfied, the relay 1 turns off the time T2 later and a manual mode is entered. Consequently, this circuit is provided with the automatic stand-by relay 6 which operates after the time limit resetting of a time T2 (about 500 milliseconds) additionally. If a fault diagnosis is put in operation in the period of the time T3 and the controller switches from the main system to a stand-by system, the relay 1 is reset again automatically. |
