Some critical process will not tolerate processor or network failure. Melfi Technologies can specify systems with redundant ControlLogix PLC processors and redundant ControlNet communications. The primary PLC processor will operate the system, while the secondary PLC processor will continuously track and update all memory addresses. In the event of primary processor or network shutdown, system control will automatically and seamlessly switch the secondary processor with no changes in the I/O state.

Upon installation of a replacement processor and/or repair of the communications network, the new processor will automatically reload the entire program and begin tracking and updating as the secondary processor. A contact output will update the instrument technicians on which processor is currently active.