EP0381386A2
Expired / Lapsed
EP
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Token passing communication network
Assignee: Honeywell Inc
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Filing: 1990-01-26
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Granted: —
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Expires: 2010-01-26
Abstract
Abstract A communication network has one master node (16) which maintains an active master list (AML) containing the node addresses of all nodes (12-16) to which the token will be passed. When nodes are added or deleted from the network, it is efficient in terms of data bus occupancy and individual processing time by the nodes if the successor address for each node is broadcast in a single message, and the availability of an AML makes this possible. The network has the capability of efficiently updating the AML whenever the configuration of the network is so changed.
Inventors
- 👤 John R. Aggers
- 👤 Roger R. Roth
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 00:28
CPC Classifications
H; H04; H04L; H04L12/00; H04L12/28; H04L12/40; H04L12/407; H04L12/417
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
396 words
A communications network comprising a plurality of master nodes (12-16) all connected to a single data bus (10,11) comprising a pair of electrical conductors and each node including a node address register (42) whose contents are a node address preassigned to the node, each of the nodes of the type having an active mode during which the node may provide on the data bus a plurality of different messages comprising electrical signals for communicating with the other nodes, and each of said nodes including a successor address register (51) dedicated to storing a network address different from the content of the node address register (42), said active mode of a node (12-10) being initiated responsive to receiving on the data bus (10,11) signals encoding a token message having a preselected unique identifying format and including a successor address equal to the contents of the node address register (42) of the node, and each said node further transmitting a token message including a successor address comprising the address stored in the successor address register (51) of the node (12-16) and terminating the active mode responsive to the receipt on the data bus (10,11) of a token acknowledge signal having a preselected unique identifying format, and wherein a first (16) of the master nodes includes an address memory (68) in which may be stored an active master list including the contents of the node address registers of active master nodes in the network and further, specifying a successor address for each of the node addresses included in the active master list, the system characterised by: a) in the first (16) of the master nodes (12-16), an active master list broadcast means (67) for providing signals on the data bus encoding therein an active master list message having a preselected unique identifying format and including at least a part of the active master list stored in the address memory (68); and b) in each of the master nodes, means for receiving the active master list message on the data bus (10,11) from the first of the master nodes, means responsive to the active master list message identifying format for extracting therefrom the successor address specified in the active master list for the network address of the master node involved, and means for storing the network address so extracted in the successor address register (51) of the master node involved.
Claim 2
Dependent Claim
396 words
A communications network comprising a plurality of master nodes (12-16) all connected to a single data bus (10,11) comprising a pair of electrical conductors and each node including a node address register (42) whose contents are a node address preassigned to the node, each of the nodes of the type having an active mode during which the node may provide on the data bus a plurality of different messages comprising electrical signals for communicating with the other nodes, and each of said nodes including a successor address register (51) dedicated to storing a network address different from the content of the node address register (42), said active mode of a node (12-10) being initiated responsive to receiving on the data bus (10,11) signals encoding a token message having a preselected unique identifying format and including a successor address equal to the contents of the node address register (42) of the node, and each said node further transmitting a token message including a successor address comprising the address stored in the successor address register (51) of the node (12-16) and terminating the active mode responsive to the receipt on the data bus (10,11) of a token acknowledge signal having a preselected unique identifying format, and wherein a first (16) of the master nodes includes an address memory (68) in which may be stored an active master list including the contents of the node address registers of active master nodes in the network and further, specifying a successor address for each of the node addresses included in the active master list, the system characterised by: a) in the first (16) of the master nodes (12-16), an active master list broadcast means (67) for providing signals on the data bus encoding therein an active master list message having a preselected unique identifying format and including at least a part of the active master list stored in the address memory (68); and b) in each of the master nodes, means for receiving the active master list message on the data bus (10,11) from the first of the master nodes, means responsive to the active master list message identifying format for extracting therefrom the successor address specified in the active master list for the network address of the master node involved, and means for storing the network address so extracted in the successor address register (51) of the master node involved.
Claim 3
Dependent Claim
124 words
A network according to Claim 1, characterised in that the first of the master nodes includes: a) active master list counter file means (64,65) storing a counter associated with each entry in the active master list, for decrementing the counters responsive to a counter decrement signal and issuing an absent master signal responsive to a counter achieving a preselected value, said absent master signal encoding the address of the master node with which is associated the counter achieving the preselected value; b) means for issuing a counter decrement signal (63); and c) active master list update means (70) receiving the absent master signal, for removing from the active master list the node address which equals the node address encoded in the absent master signal.
Claim 4
Dependent Claim
51 words
A network according to Claim 2, characterised in that the active master list broadcast means (67) is responsive to an update signal, and wherein the active master update means (70) includes means for issuing an update signal to the active master list broadcast means (67) responsive to the absent master signal.
Claim 5
Dependent Claim
73 words
A network according to Claim 2 or 3 characterised in that each node (12-16) includes means for including in the token messages sent by it, the contents of its node address register (42), and wherein the active master list counter file means (64) includes means (63) receiving token message signals from the data bus (10,11), for setting the counter associated with the node address included in a token message to a preselected value.
Claim 6
Dependent Claim
65 words
A network according to any of Claims 2 to 4, characterised in that the counter decrement signal issuing means (68) includes means (43,46,63) receiving token messages from the data bus, for comparing the successor address encoded in the token message with the contents of the node address register (42) in the first (16) of the master nodes, and if equal issuing a counter decrement signal.
Claim 7
Dependent Claim
116 words
A network according to any preceeding Claim, characterised in that each master node (12-16) includes means (62) for transmitting on the data bus (10,11) responsive to an active master list update inquiry message, an active master list update message encoding the contents of the node address register (42) of the master node (12-16) transmitting the active master list update message, and wherein the first of the master nodes includes a) active master list update means (70) responsive to the active master list update messages for inserting those addresses encoded in the active master list update messages into the active master list; and b) means (73) for issuing active master list update inquiry messages at preselected times.
Claim 8
Dependent Claim
53 words
A network according to Claim 6 characterised in that the active master list broadcast means (67) is responsive to an update signal, and wherein the active master update means (70) includes means for issuing an update signal to the active master list broadcast (67) means each time the active master list is updated.
Claim 9
Dependent Claim
147 words
A network according to Claim 6 or 7, characterised in that master nodes (12-16) each further are of the type transmitting a token acknowledge message including the contents of the node address register (42) of the node (12-16) transmitting the token acknowledge message, said master nodes (12-16) further including an active master list update flag register (58) having set and cleared states and entering the cleared state responsive to the master node (12-16) entering its active mode, wherein the active master list update message transmitting means (62) transmits active master list update messages responsive to the active master list update flag register (58) set state, and wherein each node (12-16) includes means for setting the active master list update flag register (58) responsive to inequality between the contents of the successor address register (51) and the node address register (42) contents transmitted in the token acknowledge message.
Claim 10
Dependent Claim
113 words
A network according to any of Claims 6 to 8, characterised in that master nodes (12-16) each further are of the type transmitting a token acknowledge message including the contents of the node address register of the node transmitting the token acknowledge message, said master nodes further including an active master list update flag register (58) having set and cleared states and entering the cleared state responsive to the master node entering its active mode and the set state upon powering up the node (12-16), wherein the active master list update message transmitting means (62) transmits active master list update messages responsive to the active master list update flag register (58) set state.
References Cited (Backward Citations)
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