Allen-bradley Company, LLC

Jack F Toma

Mark A Flood

Robert R Sepsi

Michael D Kalan

Charles Martin Rischar

William B Cook

Robert D Law

Bradley J Bittorf

D Alan Graham

David E Mohnke

The present invention constitutes a data crossloading system for use with a programmable controller system having primary and secondary (or 'back-up') systems each of which have redundant hardware components and have data structures associated with these components. The present invention further relates to the interconnection of the hardware components and to the processes for providing redundant data structures which enable a secondary or back-up system to rapidly and effectively assume control when a malfunction occurs in a primary control system. Both systems are connected via the same remote data links to common I/O racks which interface to sensing and output devices on the equipment being controlled. Data structure information in the primary system is specially crossloaded to the secondary system so that when a malfunction occurs that shuts down the primary system, the secondary system can begin execution of the same control programs and input and output the same data to the same I/O racks based on up to date data from the primary system. The crossloading of the data is accomplished through the use of special backup modules in both the primary and secondary (backup) control systems connected by a high speed communications link. Communications take place through the use of program utilities which establish a tightly coupled communications network between the primary and secondary systems. Additionally, on-line editing is enabled in stages so that when either control system can not properly execute the edit it is rejected. This system insures that edits can not take place in the primary system without being concurrently implemented in the secondary system.

Programmable controller backup system

A programmable controller governs the operation of a piece of equipment by executing machine language instructions compiled from a ladder diagram type control program. The control program as stored in the controller includes not only compiled machine language instructions, but also a tokenized version of the source code from which certain machine language instructions were compiled. The source code is provided only for those portions of the machine language program which cannot be easily decompiled to produce the corresponding source code. This program storage facilitates subsequent editing of the stored program via a terminal connected to the programmable controller. During the editing process, the original ladder diagram can be reconstructed from a combination of the machine language instructions and the tokenized version of the source code. In doing so, the machine language instructions, which have a one-to-one correspondence with the source code instructions, are decompiled using conventional techniques. However, the tokenized version of the source code is used to recreate the portions of the ladder diagram for which each machine language instruction does not have a unique one-to-one correspondence with a source code instruction. This program storage technique enables the control program to be easily edited using the version stored in the programmable controller without requiring access to the original source code from which the program was compiled.

Programmable controller having a stored program with both machine

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Parma, OH, United States of America

Jack F Toma