| 摘要 |
PURPOSE:To suppress needless alarm by delaying the monitor start time of a process quantity monitor limit value by contact input information from a computer provided in a circuit. CONSTITUTION:The process quantity of plant 1 is read into computer 3 through process input device 2. Computer 3 decides whether alarm is required or not; and if required, alram output unit 4 is started to provide a constitution which issues alarm. Here, when alarm is issued in case that the limit value having a certain width is designated and the process quantity exceeds the range of the limit value, the limit value check start time is delayed by a fixed time from the change occurrence time in the contact input until the value of the analogue input which should be a monitor object enters into the range of the limit value. Then, if this delay time set is selected properly, alarm can be issued for anomaly which is generated in the course of the change if the process quantity. |
