To conveniently realize precise adjustment of screwing down displacement of a general rolling mill in the production process,an easy operation and low cost screwing down device based on electro-hydraulic numerical controlling is designed by adopting a single-chip microcomputer as the controlling core and by combining with electro-hydraulic numerical controlling technique.

The paper describes the collocation and the service condition of the 386、486 DEH ⅢA type digital electro hydraulic control system used by Xiangfan Power Plant s 300MW set and presents an analytical disoussion of its functional application, problems of that emerged during operation and the actual effects of improvements which may well serve as a reference for sets of the same type.