| 摘要 |
PURPOSE:To shorten the monitor necessary time for one circulation of all slave stations and thus to realize the quick monitoring of the data by sending the code row of several words showing the presence or absence of the fault with every input/output unit back to the master station from the slave station for detection in case some fault is detected. CONSTITUTION:The master station unit carries out the sequential calling of the slave stations independently by the data collection order given from process function circuit 11, and the data sent back from the slave station are tested at scan detection part 18. Then each slave station unit sends back the one-word code row containing the bit showing the presence or absence of the fault of corresponding input/output unit 16 to the sequential calling through part 18, and part 18 tests the code row to monitor the resence or absence of the fault. Part 18 repeats the sequential calling of the slave stations while no fault is detected. And in case some fault is detected, circuit 11 sends back the code row of several words showing the presence or absence of the fault from the corresponding slave station every input/output unit 10. The code row sent back is then tested to perform the fault detection in detail. Thus, the monitor time required for a circulation of all slave stations can be shortened, securing the quick monitoring of the data. |
