| 摘要 |
PURPOSE:To obtain a simple means which performs switching to a normal measurement signal by calculating the absolute value of the quantity of variation of a measurement signal. CONSTITUTION:Two measurement signals A and B are converted into the quantities HA and HB of variation by calculating the absolute values of difference from their last values. The quantities HA and HB of variation are transmitted to the 1st abnormality decision means 21 and 22 and the abnormality decision means 31 and 32. The means 21 and 22 compares their quantities HA and HB of variation with a predetermined valve HS and output the 1st abnormality decision signal corresponding to their signals A and B on condition shown by inegualities I. Means 31 and 32 compare their quantities HA and HB with the quantities HB and HA of the opposite means and output the 2nd abnormality decision signal for their signals A and B on condition shown by inequalities II (alpha: constant). If the 1st or 2nd abnormality decision signal is generated, signal switching means 51-81 and 52-82 inhibit their measurement signals from being transmitted for postprocessing, but allows the measurement signal of the opposite side to be transmitted. |
