| 摘要 |
PURPOSE:To lower the priority of a token in case the tokens of the same priority circulate consecutively, by monitoring the token with which the priority is set in a priority indicating field by a specific node. CONSTITUTION:When the priority is set at 2 or 1, the priority is stored in a priority storage part 16 by an output 21. In this case, a flip-flop 19 is turned on and the output is set at ''1''. When a token having its priority is supplied again to a receiving part 11, the flip-flop 19 is reset by the output 21. However an AND circuit 18 is turned on the drive a priority comparing part 15. Thus the part 15 compares the priority, i.e., the storage contents of the part 16 with the priority supplied this time. When the coincidence is obtained from this comparison, a priority converting part 14 is actuated to lower the priority. Then the priority is sent to a relay part 12. That is, the tokens of priorities 2 and 1 are set at 1 and 0 (non-priority) respectively, then transmitted. In this case, the storage of the part 16 is also reset via an OR circuit 17. |
