Bus-method communication network system capable of seizing transmission right by using timer means at each station
First Claim
1. In a bus-method communication network system comprising a bus-method transmission path and a plurality of stations commonly connected to said transmission path for mutual communication, said stations being assigned with station numbers different from one another, a specific one of said stations having an exclusive transmission right to access to said transmission path at a specific time without the other stations being permitted access to said path, said specific station having means for transmitting an abort signal representative of abandonment of said exclusive transmission right to said transmission path so that one of the other stations can then seize the exclusive transmission right by detecting said abort signal, the improvement wherein:
- said specific station has, as a specific station number, an assigned station number and said abort signal comprises synchronization information and the specific station number, each one of said stations comprising;
station number memorizing means for storing, as a preassigned station number, a corresponding one of said assigned station numbers;
receiver means coupled with said transmission path for receiving a transmission signal on said transmission path;
abort signal detecting means for detecting said abort signal in said transmission signal when received by said receiver means and for extracting said specific station number in said abort signal as detected, said abort signal detecting means producing an abort detection signal and an address signal representative of said specific station number as extracted;
time calculating means coupled with said station number memorizing means and said abort signal detecting means for calculating a first time period depending on said extracted specific station number and said preassigned station number to produce a first time data signal representative of said first time period;
first time measuring means responsive to said first time data signal for measuring time to produce an output, as a first enabling signal, when said first time period elapses; and
seizing decision means responsive to said first enabling signal for deciding permission of seizure of the exclusive transmission right to produce a seizing signal when the permission is decided, wherein one of the stations other than said specific station can newly seize the exclusive transmission right.
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Accused Products
Abstract
A bus-method communication network has a number of stations with assigned station numbers. An exclusive right or priority of transmission is transferred from a first station to a second station by transmission of an abort signal including synchronization information and a first address assigned to the first station. In each station, a waiting time is calculated from a first station number in the detected abort signal and the station number assigned to the receiving station. When the associated waiting time elapses, another station seizes priority as a second station and transmits a paging signal having a destination address following communication data. Each station is prevented from seizing transmission priority in response to reception of the paging signal, and the station having the destination address decodes the communication data. The second station thereafter transmits the abort signal. Each station monitors any signal on the transmission line after reception of the paging signal on the transmission line after reception of the paging signal, and measures times lapse over a period determined by its assigned address number when detecting no transmitted signal. The station having the smallest address number transmits the abort signal as a first station when the time period elapses. Each station can delay transmission of the abort signal by another time period determined by the total number of stations, when the second station has no communication data.
30 Citations
22 Claims
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1. In a bus-method communication network system comprising a bus-method transmission path and a plurality of stations commonly connected to said transmission path for mutual communication, said stations being assigned with station numbers different from one another, a specific one of said stations having an exclusive transmission right to access to said transmission path at a specific time without the other stations being permitted access to said path, said specific station having means for transmitting an abort signal representative of abandonment of said exclusive transmission right to said transmission path so that one of the other stations can then seize the exclusive transmission right by detecting said abort signal, the improvement wherein:
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said specific station has, as a specific station number, an assigned station number and said abort signal comprises synchronization information and the specific station number, each one of said stations comprising; station number memorizing means for storing, as a preassigned station number, a corresponding one of said assigned station numbers; receiver means coupled with said transmission path for receiving a transmission signal on said transmission path; abort signal detecting means for detecting said abort signal in said transmission signal when received by said receiver means and for extracting said specific station number in said abort signal as detected, said abort signal detecting means producing an abort detection signal and an address signal representative of said specific station number as extracted; time calculating means coupled with said station number memorizing means and said abort signal detecting means for calculating a first time period depending on said extracted specific station number and said preassigned station number to produce a first time data signal representative of said first time period; first time measuring means responsive to said first time data signal for measuring time to produce an output, as a first enabling signal, when said first time period elapses; and seizing decision means responsive to said first enabling signal for deciding permission of seizure of the exclusive transmission right to produce a seizing signal when the permission is decided, wherein one of the stations other than said specific station can newly seize the exclusive transmission right. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification