Zimmer, C.M. Chabot, D. Colocho, W.S. Ding, Y. Nelson, J. JACoW Publishing Geneva, Switzerland 2226-0358 978-3-95450-238-7 10.18429/JACoW-ICALEPCS2023-TUPDP131 English 895-898 feedback cavity linac controls electron Contribution to a conference proceedings 2024 2024-02 https://doi.org/10.18429/JACoW-ICALEPCS2023-TUPDP131 https://jacow.org/icalepcs2023/papers/tupdp131.pdf SLAC recently commissioned a new continuous-wave, MHz repetition-rate Superconducting (SC) Linear Accelerator (Linac). This accelerator can produce a 4 GeV electron beam that drives two dedicated Hard and Soft X-ray Undulator lines as part of the Linac Coherent Light Source (LCLS) Free Electron Laser. A new Python-based longitudinal feedback is used to control the electron beam energy and bunch length along the accelerator. This feedback was written to be simple, easily maintainable and easily portable for use on other accelerators or systems as a general-purpose feedback with minimal dependencies. Design and operational results of the feedback will be discussed, along with the Graphical User Interfaces built using Python Display Manager (PyDM).