Programmable controller for using coded I/O data technique

摘要: A programmable controller has a scanner module that couples main processor through two multidrop serial data channels to relatively large number of remotely located I/O interface racks. The executes control program examine input status coupled from devices on controlled system the racks and determines output which is system. circuit encodes stream by generating an mask work adapter word, words being appended streams are each rack in messages. selected for transmission over links limited changed since last time its associated been scanned, refresh periodically or rack, whether such not.