| 摘要 |
PURPOSE:To perform high-performance input and output control by interposing an input and output controller, which performs scan input and output operation and interrupted input and output operation, between a process controller and a process input and output device, and performing serial data transmission between both. CONSTITUTION:For scan transmitting operation, a process controller 1 causes a temporary start interruption and after the scan transmitting of an input and output controller 3, transmitted data are only written in a scan transmitting data memory 18, thereby transmitting the data to external equipment such as a data process input and output device (I/O)20. During scan reception, on the other hand, blocks of data transmitted from the I/O20 at a specified period are stored in a scan reception data memory 9, and the device 1 reads the data easily. Further, the controller 3 is capable of performing interrupted input and output operation, so peripheral equipment with a key inputting function is supported effectively. |
