Network system using token-passing bus with multiple priority levels
First Claim
Patent Images
1. A network system using a token passing bus access-method, comprising:
- a bus type transmission path;
a plurality of nodes, coupled to said transmission path, for executing a priority processing algorithm based on a standard of an IEEE 802.4 token-passing bus or a standard of a bus functionally substantially equivalent to said token-passing bus;
a plurality of common memories respectively included in said plurality of nodes and each of said common memories having a mutually common address structure, said common memories being connected together to function as a shared virtual memory; and
a plurality of communication means, respectively included in said plurality of nodes, for communicating storage contents of said common memories of said plurality of nodes between said common memories through said transmission path in accordance with priority levels of said priority processing algorithm.
1 Assignment
0 Petitions
Accused Products
Abstract
A network system using a token-passing bus access method, comprising bus type transmission path, nodes for executing a priority processing algorithm based on a standard of an IEEE 802.4 token-passing bus, common memories respectively included in the plurality of nodes and each having a mutually common address structure, and communication circuits, respectively included in said plurality of nodes, for communicating storage contents among the common memories through the transmission path in accordance with priority levels of the priority processing algorithm.
-
Citations
27 Claims
-
1. A network system using a token passing bus access-method, comprising:
-
a bus type transmission path; a plurality of nodes, coupled to said transmission path, for executing a priority processing algorithm based on a standard of an IEEE 802.4 token-passing bus or a standard of a bus functionally substantially equivalent to said token-passing bus; a plurality of common memories respectively included in said plurality of nodes and each of said common memories having a mutually common address structure, said common memories being connected together to function as a shared virtual memory; and a plurality of communication means, respectively included in said plurality of nodes, for communicating storage contents of said common memories of said plurality of nodes between said common memories through said transmission path in accordance with priority levels of said priority processing algorithm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
-
-
14. A network system using token-passing bus access method, in which a plurality of transmission devices are coupled to a bus type transmission path, and each of said transmission devices is connected to given control instruments, each of said transmission devices comprising:
-
a media-access controller having a priority processing function to be based on a specification of a token-passing bus access method according to the IEEE 802.4 standard; a modem, coupled to said media-access controller, for transmitting and receiving data of transmission frames between said transmission path and said media-access controller; a transmission/reception-completion detector, coupled to said modem, for detecting a transmission-completion and reception-completion of the transmission frame between said modem and said transmission path; a transmission processor, coupled to said media-access controller, for governing a data transmission performed by means of said media-access controller and said modem; a timer for informing said transmission processor of a timing which determines a data transmission period of said modem; a first memory, coupled to said media-access controller, for temporarily storing data of a reception transmission frame delivered from said modem; a second memory, coupled to said first memory and being provided with a given address configuration which is common to all of said transmission devices, for storing data in accordance with address information contained in the transmission frame being transmitted or received; and a DMA controller for sending the transmission frame data stored in said first memory to said second memory; wherein the data exchanged between said transmission devices and said control instruments are classified into three or more data Dh, Dm, and Dl according to given levels regarding an urgency of the data, these data Dh, Dm, and Dl being assigned to predetermined address areas in said second memory which are common to all of said transmission devices; and said timer determines data refreshing periods Th, Tm and Tl which are common to all of said transmission devices, so that these data refreshing periods Th, Tm and Tl correspond to respective access levels of the priority processing function of said token-passing bus access method. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
-
-
26. A data transmission system having process control machines coupled through a plurality of transmission devices to a bus type transmission path, for exchanging data between said process control machines, characterized in that:
-
said transmission devices are each provided with a token-passing bus controller, which has a function for executing a priority processing algorithm as defined by an IEEE 802.4 token-passing bus or an identical processing function, and a common memory, which stores data classified into a plurality of access levels and has an address structure common to the individual transmission devices, said common memories being connected together to function as a shared virtual memory; a transmission frame transmitted through said transmission device of each control machine is received by said transmission device of another control device, and frame data is stored and updated in said common memory based on common memory address data included in said transmission frame; and transmission of data is controlled at time cycles set for the respective access levels of said common memory in association with access levels of said priority processing algorithm of said token-passing bus.
-
-
27. A data transmission system having a plurality of process control machines, each coupled through a plurality of transmission devices to a bus type transmission path, for exchanging data between said process control machines, characterized in that:
-
said plurality of transmission devices are each provided with a token-passing bus controller, which has a function for executing a priority processing algorithm as defined by an IEEE 802.4 token-passing bus or an identical processing function, a common memory, which stores data classified into a plurality of access levels and has an address structure common to the individual transmission devices, a transmission/reception detector for detecting an end of reception of a transmission frame on said transmission path or an end of transmission from a local node through a modem coupled to said token-passing bus controller, a processor, provided between said detector and said token-passing bus controller, for executing data transmission control, and a timer circuit for supplying a timing of data transmission cycles to said processor; in a startup state where a transmission state of each of said transmission devices becomes a normal state, said processor puts all of transmission requests for data with an access level having a high urgency in a queue for said token-passing bus controller; transmission requests for data with a next access level which correspond to a number of frame-number limiting values are added to a queue for that level; and a transmission request for data with a lower access level is inhibited, and after one transmission circulation of each transmission device, transmission requests for data with the next access level and said lower access level are added to queues for respective access levels, and upon reception of a signal indicating elapse of a predetermined time from said timer circuit, said processor adds transmission requests for data with the individual access levels to queues for respective access levels.
-
Specification