| 摘要 |
PURPOSE:To control the priority regardless of the connection position of an IO device in a priority control system by providing a means to each IO device group to store the priority which is controlled by a signal. CONSTITUTION:When the data is transmitted and received between a data processor 1 and IO devices 2-4, the IO device obtains a service request signal in accordance with the priority that is decided by the position where the IO device is connected to the processor 1 to perform the service processing. In such a system, a signal line 102 is provided to give the mutual connection between the service request transmission states of IO devices. Then a means is provided to each IO device to store the priority which is controlled by a signal. Then the service permission signal is obtained from the processor 1 by the algorithm decided separately. Thus the service frequency is controlled.
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