Ronald A Schultz

US Patent:

47471000, May 24, 1988

Filed:

Aug 11, 1986

Appl. No.:

6/895267

Inventors:

J. Monte Roach - Ann Arbor MI
Lester A. Jones - Mentor OH
Wayne C. Van Sickle - South Euclid OH
Ronald E. Schultz - Solon OH

Assignee:

Allen-Bradley Company, Inc. - Milwaukee WI

International Classification:

H04J 326

US Classification:

370 86

Abstract:

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.