Newly designed field control module for the SNS

The low-level RF (LLRF) control system for the Spallation Neutron Source has undergone some recent hardware changes. The intended field and resonance control module (FRCM) design has been re-vamped to minimize functionality and ease implementation. This effort spans a variety of disciplines, and requires parallel development with distinct interface controls. This paper will discuss the platform chosen, the design requirements that will be met, and the parallel development efforts ongoing

Overview of the New FCM

Performance specifications were eased late last year for the LLRF control system for SNS. Physics simulations indicated that the field control requirement could be reduced from from to . In addition required functions were changed such that onboard processing for resonance control was moved to the crate controller (IOC), as well as feedforward table update and access; fewer RF channels were required (no need to provide for possible beam information via a beam diagnostics channel); no real time data link needed between the control system and the operators; and much less memory per channel was deemed appropriate. By moving the iterative learning controls onto the IOC as well, we completely eliminated the need for DSPs on the module. A collaborative effort was established between Lawrence Berkely, Los Alamos, and Oak Ridge national labs in order to develop a control system that meets these specifications [1].