Back-up control system implemented with a redundancy scheme for protection against failure

摘要

A back-up control system of a redundancy configuration suited to be used for a time division switching network. The control system includes connecting paths extending from each of the load supply devices, the paths being classified into an active connecting path and a corresponding standby connecting path coupled to different ones of the load accommodating devices which are provided in a number equal to or larger than three. The total load accommodating capacity of the load accommodating devices is provided with a margin or excess capacity which is smaller than the capacity required for accommodating all full loads supplied from the load supply devices but is not smaller than the load accommodating capacity of any one of the load accommodating devices. At least one of the load accommodating devices is connected to the active connecting path and the spare connecting path which corresponds to another one than the just mentioned active connecting path. Control means is included for performing a switching operation in such a manner that, in a normal operation, the load is supplied from each of the load supply devices through the respective active connecting path to the load accommodating device to which the just mentioned load supply device is connected, while upon occurrence of failure in a given one of the load accommodating devices, the load supplied from the associated load supply device to the fault load accommodating device through the active connecting path is transferred to another one of the load accommodating devices which is connected to the associated load supply device through the standby connecting path corresponding to the above mentioned active connecting path, whereby the load corresponding to a load accommodating capacity of the fault load accommodating device is borne by the other load accommodating devices.