An automatic control variac system is designed in order to satisfy the controlling requirement of the elec- tronic accelerator developed by the Institute. Both design and operational principles

structure of the system as well as the software of industrial PC and micro controller unit are described. The interfaces of the control module are RS232 and RS485. A fiber optical interface (FOC) could be set up if an industrial FOC network is necessary

which will extend the filed of its application and make the communication of the system better. It is shown in practice that the system can adjust the variac output voltage automatically and assure the accurate and automatic control of the electronic accelerator. The system is designed in accordance with the general design principles and possesses the mer- its such as easy operation and maintenance

good expansibility

and low cost

thus it could also be used in other indus- trial branches.