Error suppression in output units in control devices connected to automation apparatus via bus system by comparing redundant data with buffered information

摘要

A monitoring unit (2) monitors bus data. Secure output units (8) are installed for secure functions and routines and internally comprise two separate bus users. One of these units includes a buffer memory (11) which detects output information from a control device (1) and supplies it to a comparator (12) which contains redundant data relating to the second bus user and compares them with the buffered information, to start a process if there is agreement.