| 摘要 |
<p>PURPOSE:To have failure sensing in which the requisite time and the sensing probability are well balanced, by counting the consecutive occurrences of the calculated change amount exceeding No.1 threshold, and comparing with the predetermined No.2 threshold. CONSTITUTION:Input/output signals are measured by a measuring means 1100, and on the basis of result from measuring, the change amount of input/output signal is calculated by a calculating means 1200 at certain intervals, and the obtained change amount is compared by a comparing means 1300 with the predetermined No.1 threshold. On the basis of the result from comparison, a counting means 1400 counts the consecutive occurrences of the change amount exceeding No.1 threshold, and a judging means 1500 compares the count with the predetermined No.2 threshold - if the count exceeds the No.2 threshold, it is judged that the input/output signal is in failure. Accordingly eventual noise inclusion in the input/output signal causing temporary enlargement of the apparent signal change amount indicated by the input/output signal does not meet the continuity condition, so that no misjudgement will be placed. Thus well balanced failure sensing can be done.</p> |
