The METIS instrument control system

Abstract

METIS, the Mid-infrared ELT Imager and Spectrograph, will be one of the first-generation ELT instruments. It has an Instrument Control System (ICS) that allows the instrument to operate in various observing modes, using a multitude of mostly cryogenic mechanisms such as filter wheels, linear stages (e.g. to move mirrors and masks), a derotator, piezo mechanisms for high-speed or high-accuracy displacements (e.g. for pupil stabilization, for adaptive optics field selection and modulation, ...), a chopper, and so on. Thermal and vacuum control of the cryostat on the other hand is handled by a dedicated PLC-based system and is not described in this paper. The ICS is built using the ESO ELT instrument framework, which provides the basic building blocks to control the mechanisms, along with the interface to the telescope and its services, from the low-level pointing and tracking system, the real-time Single Conjugate Adaptive Optics (SCAO) system, to the high-level sequencer-based observing system. In this paper we provide an overview of the ICS electronics, the low-level software running on a Beckhoff PLC, and finally the high-level software running on a Linux workstation. As a detailed description of the entire system is out of scope of the paper, we focus instead on the general design, implementation and testing principles. We show how a fast real-time network (EtherCAT) and off-the-shelf industrial I/O, together with the services provided by the ELT instrument framework, can meet the requirements of ELT instruments, and how they can offer an elegant solution to technically demanding problems such as the high-speed synchronization between a chopper and a detector controller. Finally, we demonstrate how a modular electronics design, a flexible software architecture, and a strong focus on simulation can alleviate some of the organizational challenges of building, integrating and testing an ICS of a complex instrument, which subsystems are developed by institutes in different locations.

Authors 26

1. Wim Pessemier

   KU Leuven

   Affiliation as printed

   KU Leuven (Belgium)

2. Gert Raskin

   KU Leuven

   Affiliation as printed

   KU Leuven (Belgium)

3. W. De Meester

   KU Leuven

   Affiliation as printed

   KU Leuven (Belgium)

4. Wannes Verstraeten

   KU Leuven

   Affiliation as printed

   KU Leuven (Belgium)

5. Kwinten Missiaen

   KU Leuven

   Affiliation as printed

   KU Leuven (Belgium)

6. Muhammad Salman

   KU Leuven

   Affiliation as printed

   KU Leuven (Belgium)

7. Maddalena Reggiani

   KU Leuven

   Affiliation as printed

   KU Leuven (Belgium)

8. Hans Van Winckel

   KU Leuven

   Affiliation as printed

   KU Leuven (Belgium)

9. Bart K. Vandenbussche

   KU Leuven

   Affiliation as printed

   KU Leuven (Belgium)

10. Mario J. Kiekebusch

    European Southern Observatory

    Affiliation as printed

    European Southern Observatory (Germany)

11. Dan Popovic

    European Southern Observatory

    Affiliation as printed

    European Southern Observatory (Germany)

12. Benoît Serra

    European Southern Observatory

    Affiliation as printed

    European Southern Observatory (Germany)

13. A. Amorim
    Affiliation as printed

    CENTRA (Portugal)

14. Jean-Christophe Barrière

    Commissariat à l'Énergie Atomique et aux Énergies Alternatives

    Affiliation as printed

    CEA (France)

15. Thomas Bertram
16. Peter Bizenberger

    Max Planck Institute for Astronomy

    Affiliation as printed

    Max-Planck-Institut für Astronomie (Germany)

17. Olivier Corpace

    Commissariat à l'Énergie Atomique et aux Énergies Alternatives

    Affiliation as printed

    CEA (France)

18. Yigit Dallilar

    University of Cologne

    Affiliation as printed

    Univ. zu Köln (Germany)

19. Martin Kulas

    Max Planck Institute for Astronomy

    Affiliation as printed

    Max-Planck-Institut für Astronomie (Germany)

20. Dirk Lesman

    Netherlands Institute for Radio Astronomy

    Affiliation as printed

    ASTRON (Netherlands)

21. Ivan Lloro

    Netherlands Institute for Radio Astronomy

    Affiliation as printed

    ASTRON (Netherlands)

22. Lars Mohr

    Max Planck Institute for Astronomy

    Affiliation as printed

    Max-Planck-Institut für Astronomie (Germany)

23. Phil M. Parr-Burman

    UK Astronomy Technology Centre

    Affiliation as printed

    UK Astronomy Technology Ctr. (United Kingdom)

24. Chad Salo Aachen Leiden Univ. (Netherlands)

    Leiden University

    Affiliation as printed

    Leiden Univ. (Netherlands)

25. Roy van Boekel

    Max Planck Institute for Astronomy

    Affiliation as printed

    Max-Planck-Institut für Astronomie (Germany)

26. Shiang‐Yu Wang

    KU Leuven

    Affiliation as printed

    KU Leuven (Belgium)