The Multi Conjugate Adaptive Optics RelaY (MAORY) for ESO’s Extremely Large Telescope (ELT) is an adaptive optics module offering multi-conjugate (MCAO) and single-conjugate (SCAO) compensation modes. In MCAO, it relies on the use of up to six Laser Guide Stars (LGS) and three Natural Guide Stars (NGS) for atmospheric turbulence sensing and multiple mirrors for correction, providing high Strehl and high sky coverage. In SCAO mode, a single natural source is used as reference, providing better correction but in a smaller field. MAORY will be installed at the Nasmyth focus of the ELT. It will feed the MICADO first-light diffraction limited imager and a future second instrument. MAORY is being built by a Consortium composed by INAF in Italy and IPAG in France and is currently approaching end of phase B. In this paper we describe the preliminary design of the MAORY Instrument Control System Software (ICS SW). We start with an overview of the MAORY module and then describe the general architecture of the MAORY control network and software. We then describe the main software components, with particular emphasis to those managing the NGS and LGS wavefront sensors functions and the AO off-load and secondary loops, and the main interfaces to subsystems and external systems. We then conclude with a description of the software engineering practices adopted for the development of MAORY ICS SW.
The Enhanced Resolution Imager and Spectrograph (ERIS) is a next-generation, adaptive optics assisted, near-IR imager and integral field spectrograph (IFS) for the Cassegrain focus of the Very Large Telescope (VLT) Unit Telescope 4. It will make use of the Adaptive Optics Facility (AOF), comprising the Deformable Secondary Mirror (DSM) and the UT4 Laser Guide Star Facility (4LGSF). It is a rather complex instrument, with its state of the art AO system and two science channels. It is also meant to be a "workhorse" instrument and offers many observation modes. ERIS is being built by a Consortium of European Institutes comprising MPE Garching (D), ATC (UK), ETH Zürich (CH), Leiden University (NL) and INAF (I) in collaboration with ESO. The instrument passed Final Design Review in mid-2017 and is now in the MAIT phase. In this paper we describe the design of the ERIS Instrument Software (INS), which is in charge of controlling all instrument functions and implementing observation, calibration and maintenance procedures. The complexity of the instrument is reflected in the architecture of its control software and the number of templates required for operations. After a brief overview of the Instrument, we describe the general architecture of the ERIS control network and software. We then discuss some of the most interesting aspects of ERIS INS, like the wavefront sensors function control, AO secondary loops, IFS quick-look processing and the on-line processing for high-contrast imaging observations. Finally, we provide some information about our development process, including software quality assurance activities.
MUSE Instrumentation Software is the software devoted to the control of the Multi-Unit Spectroscopic Explorer
(MUSE), a second-generation VLT panoramic integral-field spectrograph instrument, installed at Paranal in January
2014. It includes an advanced and user-friendly GUI to display the raw data of the 24 detectors, as well as the on-line
reconstructed images of the field of view allowing users to assess the quality of the data in quasi-real
time. Furthermore, it implements the slow guiding system used to remove effects of possible differential drifts between
the telescope guide probe and the instrument, and reach high image stability (<0.03 arcsec RMS stability).
In this paper we report about the software design and describe the developed tools that efficiently support astronomers
while operating this complex instrument at the telescope.
ESO is currently in the final phase of the standardization process for PC-based Programmable Logical Controllers (PLCs) as the new platform for the development of control systems for future VLT/VLTI instruments. The standard solution used until now consists of a Local Control Unit (LCU), a VME-based system having a CPU and commercial and proprietary boards. This system includes several layers of software and many thousands of lines of code developed and maintained in house. LCUs have been used for several years as the interface to control instrument functions but now are being replaced by commercial off-the-shelf (COTS) systems based on BECKHOFF Embedded PCs and the EtherCAT fieldbus. ESO is working on the completion of the software framework that enables a seamless integration into the VLT control system in order to be ready to support upcoming instruments like ESPRESSO and ERIS, that will be the first fully VLT compliant instruments using the new standard. The technology evaluation and standardization process has been a long and combined effort of various engineering disciplines like electronics, control and software, working together to define a solution that meets the requirements and minimizes the impact on the observatory operations and maintenance. This paper presents the challenges of the standardization process and the steps involved in such a change. It provides a technical overview of how industrial standards like EtherCAT, OPC-UA, PLCOpen MC and TwinCAT can be used to replace LCU features in various areas like software engineering and programming languages, motion control, time synchronization and astronomical tracking.
ESO is in the process of implementing a new development platform, based on PLCs, for upcoming VLT control systems
(new instruments and refurbishing of existing systems to manage obsolescence issues). In this context, we have
evaluated the integration and reuse of existing C++ libraries and Simulink models into the real-time environment of
BECKHOFF Embedded PCs using the capabilities of the latest version of TwinCAT software and MathWorks
Embedded Coder. While doing so the aim was to minimize the impact of the new platform by adopting fully tested
solutions implemented in C++. This allows us to reuse the in house expertise, as well as extending the normal
capabilities of the traditional PLC programming environments.
We present the progress of this work and its application in two concrete cases: 1) field rotation compensation for
instrument tracking devices like derotators, 2) the ESO standard axis controller (ESTAC), a generic model-based
controller implemented in Simulink and used for the control of telescope main axes.
More than a decade ago, due to obsolescence issues, ESO initiated the design and implementation of a custom-made
CANbus based motion controller (CAN-RMC) to provide, together with a tailor-made software library (motor library),
the motion control capabilities for the VME platform needed for the second generation VLT/VLTI instruments. The
CAN-RMC controller has been successfully used in a number of VLT instruments but it has high production costs
compared to the commercial off-the-shelf (COTS) industrial solutions available on the market today.
In the scope of the selection of a new PLC-based platform for the VLT instrument control systems, ESO has evaluated
motion control solutions from the company Beckhoff. This paper presents the investigation, implementation and testing
of the PLC/TwinCAT/EtherCAT motion controllers for DC and stepper motors and their adaptation and integration into
the VLT instrumentation framework. It reports functional and performance test results for the most typical use cases of
astronomical instruments like initialization sequences, tracking, switch position detections, backslash compensation,
brake handling, etc. In addition, it gives an overview of the main features of TwinCAT NC/PTP, PLCopen MC,
EtherCAT motion control terminals and the engineering tools like TwinCAT Scope that are integrated into the
development environment and simplify software development, testing and commissioning of motorized instrument
functions.
The high multiplex advantage of VIMOS, the VLT visible imager and multi-object/integral-field spectrometer, makes it
a powerful instrument for large-scale spectroscopic surveys of faint sources. Following community input and
recommendations by ESO's Science and Technology Committee, in 2009 it was decided to upgrade the instrument. This
included installing an active flexure compensation system and replacing the detectors with CCDs that have a far better
red sensitivity and less fringing. Significant changes have also been made to the hardware, maintenance and operational
procedures of the instrument with the aim of improving availability and productivity. Improvements have also been
made to the data reduction pipeline. The upgrade will end in 2012 and the results of the program will be presented here.
Fabrice Madec, Kjetil Dohlen, Patrick Blanchard, Michael Carle, Alain Origné, Marc Jaquet, David Le Mignant, Rudy Barette, Gabriel Moreaux, Gilles Arthaud, Didier Ferrand, Jean-Claude Blanc, Patrick Vors, Franck Ducret, Laurence Gluck, Michel Saisse, Christophe Fabron, Philippe Laurent, Jean-Antoine Benedetti, William Bon, Marc Llored, Claire Moutou, Cécile Gry, Jean-Charles Meunier, Arthur Vigan, Lucien Hill, Maud Langlois, Jean-Louis Lizon, Vianak Naranjo, Roland Brast, Markus Feldt, Dan Popovic
SPHERE, a second-generation instrument for the VLT, is currently under performance validation before shipping to
Chile. The IRDIS sub-system, an Infra-Red Dual-Imager and Spectrograph, was integrated on the SPHERE bench last
December, and this paper tells the story of the 12 months preceding this milestone: the Assembly, integration and Tests
(AIT) performed at Laboratoire d'Astrophysique de Marseille (LAM). Key points of the AIT strategy are then presented,
and the successes and failures---human, technical, and managerial---of this adventure are discussed. We also report on
the excellent optical quality achieved, paramount to guarantee ultimate performance of the SPHERE instrument, thanks
to high-quality optical manufacture and a successfully applied alignment strategy.
SPHERE INS is the software devoted to the control of the SPHERE "Planet Finder Instrument". SPHERE is a second
generation instrument for the VLT whose prime objective is the discovery and study of new extra-solar giant planets
orbiting nearby stars. The instrument is currently assembled and being tested. It is expected to undergo Preliminary
Acceptance in Europe before the end of 2012.
SPHERE INS, besides controlling the instrument functions, implements all observation, calibration and maintenance
procedures. It includes on-line data reduction procedures, necessary during observations and calibrations, as well as
quick-look procedures that allow monitoring the status of ongoing observations. SPHERE INS also manages the external
interfaces with the VLT Telescope Control Software, the High-level Observing Software and the Data Handling System.
It provides both observing and engineering graphical user interfaces. In this paper we give a brief review of the SPHERE
INS design. We then report about the current status of the software, the activities concerning its integration with the
Instrument and the testing and validation procedures.
The visitor instrument PIONIER provides VLTI with improved imaging capabilities and sensitivity. The in-
strument started routinely delivering scientic data in November 2010, that is less than 12 months after being
approved by the ESO Science and Technical Committee. We recall the challenges that had to be tackled to design, built and commission PIONIER. We summarize the typical performances and some astrophysical results obtained so far. We conclude this paper by summarizing lessons learned.
PIONIER is a 4-telescope visitor instrument for the VLTI, planned to
see its first fringes in 2010. It combines four ATs or four UTs
using a pairwise ABCD integrated optics combiner that can also be
used in scanning mode. It provides low spectral resolution in H and K band. PIONIER is designed for
imaging with a specific emphasis on fast fringe recording to allow
closure-phases and visibilities to be precisely measured. In
this work we provide the detailed description of the instrument and
present its updated status.
SPHERE is a second generation instrument for the VLT whose prime objective is the discovery and study of new
extrasolar giant planets orbiting nearby stars. It is a complex instrument, consisting of an extreme Adaptive Optics
System (SAXO), various coronagraphs, an infrared differential imaging camera (IRDIS), an infrared integral field
spectrograph (IFS) and a visible differential polarimeter (ZIMPOL). SPHERE INS is the software devoted to the control
of all instrument functions; it implements all the observing, calibration and maintenance procedures, the interactive GUIs
and manages the software interfaces with the observation handling system and the data flow management system.
Development of the SPHERE INS has been conducted by a team distributed over four nations. The SPHERE subsystems
are nearing completion and the integration of the whole instrument will start soon. In this paper we report on the current
status of the software and on the activities concerning its construction and integration with the SPHERE subsystems. In
particular, we will discuss how we managed development and integration within our distributed team, including the tools
that we employed to support our work.
The VLT control system is a large distributed system consisting of Linux Workstations providing the high level
coordination and interfaces to the users, and VME-based Local Control Units (LCU's) running the VxWorks real-time
operating system with commercial and proprietary boards acting as the interface to the instrument functions. After more
than 10 years of VLT operations, some of the applied technologies used by the astronomical instruments are being
discontinued making it difficult to find adequate hardware for future projects. In order to deal with this obsolescence, the
VLT Instrumentation Framework is being extended to adopt well established Commercial Off The Shelf (COTS)
components connected through industry standard fieldbuses. This ensures a flexible state of the art hardware
configuration for the next generation VLT instruments allowing the access to instrument devices via more compact and
simpler control units like PC-based Programmable Logical Controllers (PLC's). It also makes it possible to control
devices directly from the Instrument Workstation through a normal Ethernet connection. This paper outlines the
requirements that motivated this work, as well as the architecture and the design of the framework extension. In addition,
it describes the preliminary results on a use case which is a VLTI visitor instrument used as a pilot project to validate the
concepts and the suitability of some COTS products like a PC-based PLCs, EtherCAT8 and OPC UA6 as solutions for
instrument control.
The VLTI control architecture is based on a real time distributed system involving dozens of specialized computers.
Several control loops are required to run the VLTI, e.g. for fringe tracking, angle tracking, injection optimization and
vibration cancellation. These control systems rely on a low latency, deterministic shared memory mechanism. It
communicates in the form of a close ring, which includes all devices involved in those loops. Through this ring, sensor
data, intermediate filtered signals, final actuator set-points and feedbacks flow at rates up to 8 kHz. Data in this ring can
be consumed by any node asynchronously. In many cases, those signals are also the astronomical observable (e.g. the
beam combiner fluxes for astrometry) or are used offline, in order to improve the quality of the scientific data reduction
and to debug the system. With the purpose of relieving the control applications of the simultaneous need to record their
signals, a centralized generic recording device has been designed and implemented at the VLTI. In this paper, we
describe its architecture and show that by over-sampling, streaming and posterior filtering on a separate computer it is
possible to overcome the asynchronous nature of the system. We demonstrate that it is feasible to capture data in real
time, verify time reference consistency and store on disk at rates up to ~50 Mbit/s, fulfilling the current VLTI
requirements.
Two teams of scientists and engineers at Max Planck Institut fuer Extraterrestrische Physik and at the European Southern Observatory have joined forces to design, build and install the Laser Guide Star Facility for the VLT.
The Laser Guide Star Facility has now been completed and installed on the VLT Yepun telescope at Cerro Paranal. In this paper we report on the first light and first results from the Commissioning of the LGSF.
The Multi Unit spectroscopic Explorer (MUSE) is a second generation VLT panoramic integral-field spectrograph operating in the visible wavelength range. MUSE has a field of 1 x 1 arcmin2 sampled at 0.2x0.2 arcsec2 and is assisted by a ground layer adaptive optics system using four laser guide stars. The simultaneous spectral range is 0.465-0.93 μm, at a resolution of R~3000. MUSE couples the discovery potential of a large imaging device to the measuring capabilities of a high-quality spectrograph, while taking advantage of the increased spatial resolution provided by adaptive optics. This makes MUSE a unique and tremendously powerful instrument for discovering and characterizing objects that lie beyond the reach of even the deepest imaging surveys. MUSE has also a high spatial resolution mode with 7.5 x 7.5 arcse2 field of view sampled at 25 milli-arcsec. In this mode MUSE should be able to get diffraction limited data-cube in the 0.6-1 μm wavelength range. Although MUSE design has been optimized for the study of galaxy formation and evolution, it has a wide range of possible applications; e.g. monitoring of outer planets atmosphere, young stellar objects environment, supermassive black holes and active nuclei in nearby galaxies or massive spectroscopic survey of stellar fields.
KEYWORDS: Control systems, Spectrographs, Telescopes, Computer architecture, Calibration, Observatories, Sensors, Camera shutters, Process control, Software development
FLAMES is a complex observational facility for multi-object spectrography installed at ESO VLT UT2 telescope at Paranal. It consists of a Fibre Positioner that feeds GIRAFFE, a medium-high resolution spectrograph, and UVES, a high resolution stand-alone spectrograph operational in slit mode since 1999. The Positioner is the core component of FLAMES. It is a rather large and complex system comprising two spherical focal plates of approx. 90 cm in diameter, an exchanger mechanism, R-θ robot motions and a pneumatic gripper mechanism with a built in miniature CCD camera. The main task of the Positioner is to place a fibre (button) at a given focal plate position with accuracy better than 40 microns. The fibre positioning process is performed on the plate attached to the robot while an observation is being performed on the plate attached to the telescope rotator. The whole instrument is driven by software designed in accordance with the VLT Common Software standards, allowing the complete integration of the instrument in the VLT environment. The paper mainly focuses on two areas: the low level control and the performance of the Fibre Positioner; and the high level coordinating software architecture that provides facility for parallel operations of multiple instruments.
OzPoz is a multi-fiber positioner to feed spectrographs from a Nasmyth focus of VLT Unit Telescope 2. The concept follows that of the 2dF system on the AAT: a robot re-positions magnetically attached buttons on one of a pair of steel plates while the other plate is observing. But the large scale and the curvature of the VLT Nasmyth focal surface led to the design being very different. Its combination of large moving elements with high precision and the need to survive severe earthquakes presented special challenges. Electrical interlocking of the many functions had to be very comprehensive to minimize risks of damage to the instrument and harm to personnel. Despite the valuable inheritance from 2dF, considerable effort had to be devoted to software to fit the ESO VLT environment and to deal with the complexity of the interacting elements. Integration on the VLT commenced in March 2002, followed by commissioning runs with Giraffe in June, August, and October. Some instrument defects were uncovered during installation and commissioning but none was fundamental and they were readily fixed in between night runs. The time taken to reconfigure a plate, an average of ten seconds/fiber, meets specification and the accuracy of alignment of fiber apertures with stars is limited mostly by the astrometry of target fields.
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