Error control apparatus using restore memory for recovering from parity discordances in transmissions between controller and real-time I/O devices

摘要

An input/output device monitors the transmission of information between a processor of a programmable controller and sensors and actuators of a process to be controlled. This device includes electronic circuits adapted for calculating the parities of the digital words which pass therethrough, these parities being compared with corresponding parities calculated by the processor which thereafter invalidates the words having two different parities.