Author: Silva, C.M.
Paper Title Page
MOBPP04 The ELT M1 Local Control Software: From Requirements to Implementation 38
  • L. Andolfato, J. Argomedo, C. Diaz Cano, R. Frahm, T.R. Grudzien, N. Kornweibel, D. Ribeiro Gomes dos Santos, J. Sagatowski
    ESO, Garching bei Muenchen, Germany
  • C.M. Silva
    CSW, Coimbra, Portugal
  This paper presents the ELT M1 Local Control Software. M1 is the 39 m primary mirror of the Extremely Large Telescope composed of 798 hexagonal segments. Each segment can be controlled in piston, tip, and tilt, and provides several types of sensor data, totaling 24000 I/O points. The control algorithm, used to dynamically maintain the alignment and the shape of the mirror, is based on three pipelined stages dedicated to collect the sensors’ measurements, compute new references, and apply them to the actuators. Each stage runs at 500 Hz and the network traffic produced by devices and servers is close to 1.2 million UDP packets/s. The reliability of this large number of devices is improved by the introduction of a failure detection isolation and recovery SW component. The paper summarizes the main SW requirements, presents the architecture based on a variation of the estimator/controller/adapter design pattern, and provides details on the implementation technologies, including the SW platform and the application framework. The lessons learned from deploying the SW on CPUs with different NUMA architectures and from the adoption of different testing strategies are also described.  
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About • paper received ※ 20 September 2019       paper accepted ※ 09 October 2019       issue date ※ 30 August 2020  
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