| 摘要 |
PURPOSE:To discriminate the abnormality of either one of two sensors by detecting abnormality, in a double system sensor comprising two sensors, by taking the sum and difference of the outputs of the two sensors and detecting the polarities of the change amounts of the sum and difference. CONSTITUTION:Two sensors A, B are provided to a plant 1 and biases C, -C are added to the outputs thereof while outputs SA+C, SB-C are inputted to an average processing part 2 and outputted as a sensor signal S=(SA+SB)/2. Further, said outputs are inputted to a difference signal detection part 4 and the difference D=(SA-SB)+2C thereof is calculated. Next, the change amount DELTAD of the difference D is compared with a prescribed value eta to detect abnormality. The change amount DELTAS of output S and the output DELTAD are inputted to an abnormality discrimination part 6 and the abnormality of either one of sensors is detected from the positive and negative combination of the change amounts DELTAS, DELTAD. For example, if both of the change amounts DELTAS, DELTAD are +, it is judged that the output of the sensor A is excessive and, if the change amount DELTAS is + and the change amount DELTAD is -, it is judged that the output of the sensor B is excessive. Because the change amounts of the sum and difference of the sensor outputs are calculated, and abnormal sensor can be detected. |
