Occupancy control system for plural serial buses

摘要

Plural stations are connected to two independent serial buses and they are permitted to occupy a first serial bus in a predetermined order under control of a bus controller. A second serial bus is used for transmitting to the bus controller an urgent bus occupancy request issued by any of the stations. Upon receipt of the urgent bus occupancy request, the bus controller permits the request-issuing station to occupy the first serial bus regardless of the predetermined order, thereby insuring a fault-free operation of the system for transmitting data between the stations.