| 摘要 |
PURPOSE:To detect an abnormal place in process in its early stage by automatically deciding measured values of opening of a control valve and a flow. CONSTITUTION:An opening (x) of a control valve and a flow (y) make one set of measured value, and several or more sets of measured values are sampled to previously put the relationship between flow and opening of the control valve into a numerical formula. It is preferable to sample measured values of opening of the control valve and flow in such a manner that a difference between a measured value of flow (x) for staged increase and decrease of opening (y) of the control valve and the previous sampled value of flow is 1-2% of the maximum flow of an outflow control measuring device. Hereafter, whether the value of opening (y) of the control value is within + or -5% of the calculated value is calculated every fixed time according to a program of sequence control. The program is adapted to send a warning on judging that abnormality is caused in process or control system. |
