Taking as an example the focal plane control system for the largest optical telescope being built in our country, the paper focuses on Universal Motion and Automation Controller (UMAC) based servo control system with high accuracy, and analyzes its design scheme. The scheme analysis and preliminary test demonstrate a broad outlook of UMAC based application in complex control systems with high precision, real time, fast action, easy adaptation and open architecture. A brief research summary and a preliminary test of the Focal Plane Control System (FPCS) are presented. The FPCS is one of components for the control system of Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST), which is a national large scientific project. The design scheme features distributed, hierarchical and expansible network architecture with UMAC based control technology. A number of advanced techniques are integrated with some control software and hardware, which presents a solution to requirements of precision, real time and open architecture for the FPCS in the design of large optical astronomical telescopes.