Allen-bradley Company, LLC

Lester A Jones

Mark A Flood

Ronald Edwin Schultz

Wayne C Van Sickle

J Monte Roach

Gregory R Ilg

In a communication network wherein a master station periodically polls a number of remote stations to determine whether or not each remote station has data to transmit to the master, each of the remote stations is assigned to one two groups. One of the groups is designated as priority stations which commonly have very urgent data for the master station. The group of non-priority stations is sequentially polled for messages to be sent to the master station. The polling of the group of non-priority stations is periodically interrupted so that the master station may poll each of the stations in the priority group to determine if they have messages to send. Upon the completion of the polling of the priority stations, the polling of the non-priority stations is resumed. Periodically a time period occurs for inactive stations to join one of the two groups of stations on the network. This method permits stations that typically have high priority data, to transmit that information more frequently than would be possible if only one polling group of stations existed.

Communication network polling technique

A programmable controller is adapted to communicate in a token passing logical ring network in a peer-to-peer fashion. The programmable controller is a station on the network and contains an interface which implements the network protocol. The protocol requires that each station maintain an Active Node Table which stores a complete map of the logical ring and the order in which the token is passed. The Active Node Table is automatically updated by monitoring each token pass on the network, where each token pass identifies the source and destination of the token pass. The Active Node Table is used in performing all routine network maintenance functions, including passing the token, adding stations, and dropping stations. The Active Node Table allows the formation of an Active Node Status Word for use by high level processes within the station. The Active Node Table also facilitates the inclusion of data in the token pass message.

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Mentor, OH, United States of America

Lester A Jones