| 摘要 |
<p>PURPOSE:To obtain an abnormality monitoring device which can judge abnormality properly even for a process which repeats fluctuation of state at a certain period. CONSTITUTION:A normal allowable range is determined as a time function for one-period fluctuation of a physical quantity which is related to the state of a process. By operating a process device, the physical quantity which actually fluctuates is compared with a previously determined allowable range. When the actual physical quantity reaches outside the allowable range (a shadow part A5, a shadow part B6, a shadow part C7), it is judged that an abnormality has occurred. The allowable range of a normal state can be specified flexibly along time instead of a fixed value. Therefore, even if a process state repeats a large fluctuation periodically, a normal abnormality judgment can be made constantly by comparison with the allowable range.</p> |
