| 摘要 |
PROBLEM TO BE SOLVED: To provide a daisy chain data input/output system for signaling at a high signaling speed between a main unit and sub-units in a comparatively simple constitution of a serial communication system. SOLUTION: The data input/output system 10 comprises a master unit 20 and a plurality of sub-units 30a, 30b connected with cables 40. A peripheral unit 50a, 50b and an output unit 60a, 60b are connected to each sub-unit 30a, 30b. It is capable of reading input data from a specified sub-unit 30 into the master unit 20 or writing output data from a specified sub-unit 30 into the output unit 60 according to an instruction from the master unit 20. It sends a signal from the master unit 20 to all the sub-units 30a, 30b, but compares address data sent from the master unit 20 with sub-unit identification data at the sub-unit 30, and executes or does not execute an instruction from the master unit 20, if both are equal or different, respectively. The data input/output system is suited to a supervisory system for equipment in factories, etc.
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