Exchanging data in processing system, esp. for process control - transferring messages in communications with header fields contg. message identifiers

Data are exchanged in a data processing system contg. at least two terminals joined by a bus. A message is transferred in a communication contg. at least one header field and data field. The leading header field identifies the communication and defines its priority which determines its access to the bus. Links between at least two terminals via the bus are directed, activated and deactivated and used to exchange messages. Monitoring information is added to the header field contg. a message code for later identification of the message transferred by the communication. USE/ADVANTAGE - Motor vehicles, robots, medical monitoring and analysing appts., lifts. Reliable communications with long data sets achieved with aid of acknowledgements. Allows configuration or initialisation of components to be segmented and transmitted at low expenditure. Can be used with communication protocol such as CAN.