DEVICE AND METHOD FOR SERIAL DATA EXCHANGE BETWEEN MORE THAN TWO SUBSCRIBERS

摘要

For serial data exchange between more than two subscribers (T1 ... Tn), each subscriber has only one central processor (PCU) with only one serial interface (TD, RD) for data exchange, and is connected via two couplers to two independent data busses. Each of the two couplers can be switched independently from the other by the processor (CPU) to reception and/or transmission. An electronic monitoring device (watchdog) is assigned to the processor (CPU) to monitor it constantly so that, if malfunctions or faults develop, the signal lines (DE1-DE1 or DE2-DE2) are blocked for "Enable transmission" to the two couplers, thus blocking data output. A defective subscriber installation can thus be effectively taken out of service, while data traffic can continue to be carried between the remaining, correctly functioning subscriber installations via the two data busses.