Abstract: In a distributed type plant monitoring/controlling apparatus, data required to be synchronized with each other in a system can be synchronized with each other, and a system with high reliability and a high performance is provided. In a plant monitoring/controlling apparatus in which a plurality of clients communicated with each other via a network are arranged, the plant monitoring/controlling apparatus is equipped with one client functioning as an original client with respect to each of functions, the original client corresponding to a software server for each of the functions used to monitor and control the plant; an original client of a first function transmits data related to the first function to another client; and the another client receives the data transmitted from the first function original client to store the received data into a storage unit provided with the another client, whereby the data stored in each of other clients are synchronized.

Abstract: In a display method and a display unit, information which is required or often used by an operator is processed visually conspicuously by enlarged display or colored display in accordance with historical data such as the past running conditions of the plant, the number of times of operations by an operator, the frequency of operations, and so on, and the processed information is displayed on the display unit. The use of historical data permits an operator to readily recognize which equipment is in most need of attention due to repeated problems in the past.

Abstract: An information terminal system including a process control computer and a portable terminal device for inputting information to said process control computer and gaining information from said process control, includes component information storing means for storing information for distinguishing each one of plural components composing a plant and component identifying means for identifying a component from plural components composing a plant and existing in the direction indicated by and at the location of the portable terminal device, by using information for distinguishing each one of the plural components stored in the component information storing means.

Abstract: In a system which performs an inference based on fault tree knowledge, a guidance and a formula of definition can be displayed in a window on a CRT display screen by selecting the individual items from a fault tree on the display screen by using, for example, a soft key. For displaying an abnormal course in one display screen, only events relevant to the abnormal course is picked up, and the fault tree is then reedited, so that the reedited fault tree can be automatically displayed on the display screen.