| 摘要 |
<p>PURPOSE:To improve the reliability of supervision of a plant by backing up a private line tying a remote plant and a central supervisory room with a general telephone line so as to prevent defect of data. CONSTITUTION:A general telephone line 4 is connected between a central supervisory room 1 and a remote plant supervisory controller 2 in addition to a private data transmission line 3. When a detection section of the plant supervisory equipment 2 detects the occurrence of a fault in the transmission system of the private line 3, a changeover means is used to select telephone network communication to maintain a transmission function of plant process data and collected data are sent to the central supervisory room upon a transmission request from the central supervisory room or periodically. Thus, the data transmission function is maintained and missing of process data is prevented and the reliability of plant supervisory control is improved.</p> |
