  DCLS (Dalian Coherent Light Source) is an FEL (Free-Electron Laser) user
facility at EUV (Extreme Ultraviolet). The primary accelerator of DCLS operates
at a repetition rate of 20 Hz, and the beam is divided at the end of the linear
accelerator through Kicker to make two 10 Hz beamlines work simultaneously. In
the past year, we have completed the upgrade of the DCLS LLRF (Low-Level
Radiofrequency) system, including setting the microwave amplitude and phase for
two beamlines based on event timing, optimizing the microwave stability, and
generating microwave excitation with the arbitrary shape of amplitude and
phase. We added two special event codes and a repetition rate division of 10 Hz
in the event timing system and set the microwave amplitude and phase by judging
the event code in LLRF. The amplitude and phase stability of the microwave was
improved with an intra-pulse feedforward algorithm. In addition, we have also
generated microwave excitation with arbitrary amplitude and phase shapes to
meet the dual beam operation in the future. Detailed information on functions
or algorithms will be presented in this paper.
