Allen-Bradley Company, LLC

Stuart B Siegel

William Edward Floro

Jeffrey H Campau

David A DiCarlo

Daniel P Noonen

John J Baier

Jeffery C Marriott

Mike Keith

Jeffery Carl Marriott

Data is exchanged between two modules of a programmable controller by originator module writing the information in an interface memory in one of the modules and the recipient module reading the information from the memory. An initialization procedure is performed before any information is exchanged in that manner. The module containing the memory writes the size of the memory for reading by the other module. Sets of test data are stored in the memory by each module and checked by the other module to determine if data can be passed accurately between the modules in both directions. Then data identifying the type of one of the modules is exchanged to insure that the other module knows the type of module with which it is dealing.

Interface between industrial controller components using common memory

A communications network is comprised of master and slave stations. The master stations may receive a master token allowing control of the network for sending messages, and a solicit token that allowing the master stations to solicit other master stations for entry into the network. A master station receiving a solicit message answers with an acknowledgement signal and may immediately begin soliciting for successors. The slave stations receiving a solicit message may not accept the master token or the solicit token but must respond with a negative acknowledgement. Slave stations enter the network to respond to messages only. The use of slave stations allows for the implementation of simpler networks and improves network efficiency. The negative acknowledgement identifies the presence of the slave stations and allows detection of duplicate network nodes.

Master slave industrial token passing network

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Canton, MI, United States of America

Stuart B Siegel