| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect the vibration degree by providing an accelerator sensor for detecting the acceleration of a vibration, measuring level discriminating means for discriminating the vibration level, vibration time measuring means for measuring the vibration time, earthquake identifying means for identifying an earthquake, etc. SOLUTION: The outputs of accelerator sensors S1, S2 have levels corresponding to accelerations αx, αy, and polarities corresponding to accelerating directions, and are given to absolute value circuits 37, 38 through buffers 35, 36 to calculate their absolute values |αx|, |αy|. An arithmetic circuit 39, in response to the outputs of the circuits 37, 38, obtains their acceleration values, multiplies them by about 1/√2 to obtain an acceleration component α3 composed by the vector composition method. The outputs of the circuits 37-39 are given to a max. value select circuit 41 which derives a max. value output on a line 42 with a time lapsed. The outputs of AND gates 48, 49 and the output of a level discriminator circuit 45 are inputted to a processor circuit 56, and if an earthquake is identified, a drive circuit 57 closes a stop valve 58 to ensure the safety. |
