A Multiplexed Control System for the NAL Main Accelerator

The control system for the NAL Main Accelerator Ring is based on a distributed multiplex technique which uses serial transmission of digital data to link 24 service buildings to a central computer system. Each service building contains logic for conversion of serial data to parallel format and parallel to serial. Data transmission cables form a large loop that extends around the four mile circumference of the accelerator so that data transmitted from a central communications controller goes to each service building sequentially and is then returned to the central controller. The communications controller is an integral part of the interface electronics for a MAC-16 minicomputer which serves as a real-time controller for ring subsystems. The MAC-16 is connected to control console electronics and to a second minicomputer used for Main Ring power supply fine control. In the near future, the MAC-16 will be linked to an XDS Sigma II computer that serves as a central controller for the entire complex.