| 摘要 |
PURPOSE:To display data efficiently on a CRT in a real time with reduction in the frequency of display, by storing a process input/output data into an information recording medium in terms of process signals to update the data for display whenever they are changed. CONSTITUTION:A PI/O input/output processing 3 is started by a PI/O input/ output demand 2 as specified by a signal name 10 from an application program 1 to take in PI/O data 11 for the signal name 10 at a plant 5 via a PI/O unit 4 and a demand for process signal monitor processing 6 is made to monitor the signal name 10 and the PI/O data 11. In the monitor processing 6, when the signal name 10 is under monitoring, information memorized is compared with data 11 while display information 7 is updated and a screen display processing 8 is started to demand a display on a CRT 9 when it changes. When the signal name 10 is not monitored nor there is no change in the data 11, the processing is ended without starting the updating and display processing 8 of display information 7. Thus, the start of the display processing 8 and the frequency of display on the CRT 9 is reduced securing real time characteristic and the load on a computer can be reduced. |
