Providing redundant i/o adapters in machine and process controllers

摘要

Methods and apparatus for redundancy in machine or process control systems provide redundant communication adapters located with the groups of I/O modules, so that if the first communication adapter faults or becomes unavailable, a second communication adapter will perform all of the necessary functions of the first adapter. The adapters are connected to a multiplexing module for communicating input data from the I/O modules to the communication adapters, for exchanging initialization data with the first communication adapter and the second communication adapter to initialize the redundant mode of operation and for monitoring communication of the first communication adapter and the second communication adapter on the network to start up the second adapter as the primary adapter for communicating both input data and output data with the I/O modules.