A fault-tolerant industrial control system includes a redundant controller including a first process controller (CP1) including a first processor with a first associated memory, and a parallel connected second redundant process controller (CP2) including a second processor with a second associated memory. A redundancy link is between CP1 and CP2 for sharing data. CP1 and CP2 include logic gates exclusive of any conditional branching for performing data synchronization and calculations including a different logical arrangement for providing each of a digital output (DO), a digital input (DI), an analog input (AI), and an analog output (AO). At least one input/output (IO) module includes a first IO processor including a first memory coupled by a first leg to CP1 and by a second leg to CP2. The IO module is coupled to field devices that are coupled to processing equipment.
