Control issues of insertion devices

Insertion devices play crucial roles in new generation light source. Magnetic performance is the most important consideration factor during the design and construction phase. However, control performance is also an important issue from operation point of view. Motion control performance, residual field compensation scheme and control response time for continuous change in gap or phase during energy scan scenario is typical consideration to evaluate control performance of insertion devices. How to eliminate orbit excursion due to gap or phase change is also an important issue. Various methods have been used to address the problems. Detailed of these issues about insertion devices control are discussed