| 摘要 |
PURPOSE:To prevent malfunctions with an on-line digital controller by supplying twice or more the input data from a process through an FF circuit for input card to deliver the normal data to a bus when the coincidence is obtained between those input data and also detecting the coincidence of data on different buses through a detecting means for PIO control card. CONSTITUTION:When data are supplied from a process input card 10, a PIO control 3 delivers an input pulse 9f and the input signal given from a process is stored to an FF10c. Then the address data is delivered to an address bus 9b, and the input strobes are supplied twice or more by all means through an input strobe bus 9d for fetching data. Then the normal input data is transferred to a CPU1 via a PIO bus 9 after the coincidence is secured between two fetched data. Thus the abnormal signals produced by the card loading/ unloading actions are not fetched as data. While the discordance is detected by a discordance detecting circuit 3b in case the data on a data bus 9c is disturbed by the loading/unloading actions of the card 10 while the output strobe is delivered onto an output strobe bus 9e of the bus 9. In this case, a retrial is carried out instantaneously to avoid an error output. |
