HL-LHC will bring a number of challenges to controls technologies. This work package deals with developments needed to cope with new requirements derived from the need to ensure very high availability in the LHC.
A new-generation data logging system will deliver greater throughput and capacity for logging diagnostics data, and will also provide a low-latency, scalable means of conducting analysis on that data. With the deployment of many new technologies, and the inevitable presence of teething issues, equipment groups and accelerator specialists will need larger amounts of diagnostics data, and their ability to conduct analysis and extract conclusions rapidly will impact the availability of the machine. With the technology currently used in the logging system, extraction and analysis can take hours or even days depending on the data set. Using modern technologies based on clustering and running analysis on the servers instead of on the client premises, these latencies will be taken to acceptable levels in the HL-LHC era.
The need for more diagnostics will impact the choice of fieldbus technologies in the lower tier of the control system as well. In particular, the limited (2.5Mb/s) bandwidth of the WorldFIP fieldbus will be a serious limitation and will inflict prohibitive delays on some equipment groups as they try to gather enough diagnostics to find the reasons for a given failure. This WP includes the development, testing, validation and deployment in selected locations of a modern radiation-tolerant fieldbus solution based on 100Mb/s Ethernet.
The new fieldbus technology will allow linking of the Front End Computers (FEC) to the Distributed I/O Tier (DIOT), where the equipment groups will host the electronics that interface directly to the accelerator. A common modular DIOT platform, factoring in common blocks needed by all equipment groups (radiation-tolerant power supplies, inter-board communications, remote diagnostics...) will also be provided as part of this WP. The different blocks will benefit from the scrutiny and review of many developers and users, and this will result in increased robustness of the platform, and ultimately better availability for the LHC. A specific subtask will be devoted to assessing the reliability and coming up with design recommendations to increase it. Equipment groups will customize this modular platform through the design of dedicated add-in boards, and their re-use of the common blocks will allow them to focus more energy on the design of these dedicated components, increasing their performance and robustness.