Development of MTCA.4 at ESS

As commissioning activities for the Linear accelerator continues at the European Spallation Source (ESS), it is highlighting important issues and development features for the MTCA.4 systems used in several key subsystems. With over 300 MTCA.4 systems deployed for Low Level Radio Frequency (LLRF), Proton Beam Instrumentation (PBI), Fast Beam Interlock Systems (FBIS), and Timing Distribution (TD), it has proved a valuable platform for fast controls. The use of MTCA.4 has also allowed for novel solutions to provide flexible but reliable controls for the facility, including expanding existing controls design and developing orphan scope. However this is not without its issues, as MTCA.4 for the scientific community is still very much on the smaller scale and reliant on only a few suppliers, with risk of obsolesce of components and changes to the standards. This makes it challenging but fun to continue developing the hardware to ensure the desired reliability for the Linac controls. This paper will describe the procedures and processes that the hardware team has taken to mitigate these issues, the current status of our MTCA infrastructure and the long term plans for its maintenance.