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The W7-X experiment of the IPP, under construction in Greifswald Germany, is designed to operate in a quasi-steady-state scenario. The database structures and interfaces used for discharge description and execution have to reflect this continuous mode of operation. In close collaboration between the control group of W7-X and the data acquisition group a combined design of the data structures used for describing the configuration and the operation of the experiment was developed. To guarantee access to this information from all participating stations a TCP/IP portal and a proxy server were developed. This portal enables especially the VxWorks real-time operating systems of the control stations to access the information in the object-oriented database. The database schema includes now a more functional description of the experiment and gives the physicists a more simplified view of the necessary definitions of operational parameters. The scheduling of the long discharges of W7-X will be done by predefining operational parameters in segments and scenarios, where a scenario is a fixed sequence of segments with a common physical background. To hide the specialized information contained in the basic parameters from the experiment leader or physicist an abstraction layer was introduced that only shows physically interesting information. An executable segment will be generated after verifying the consistency of the high-level parameters by using a transformation function for every basic parameter needed. Since the database contains all configurations and discharge definitions necessary to operate the experiment, it is very important to give the user a tool to manipulate this information in an intuitive way. A special editor (ConfiX) was designed and implemented for this task. At the moment the basic functionality for dealing with all kind of objects in the database is available. Future releases will extend the functionality to defining and editing configurations, segments and scenarios with task-specific versions.

WENDELSTEIN 7-X is a long pulse experiment. One discharge may last up to 30 min and is segmented into many time intervals. A set of chained segments is called a scenario, and a few scenarios will make up the experiment program. For physical reasons segments of the experiment program must be available in a reasonable order. This means that physical programs need to be pre-planned and technical parameters need to be adjusted in the long run. All information necessary for this purpose is stored in the W7-X configuration database. To create, view and modify this information, an effective and user-friendly tool, the ConfiX editor, is needed. The ConfiX editor is a specialized editor for processing objects in the W7-X configuration database. It is used to prepare and describe the process of discharges. ConfiX is mainly used for three cases of application, namely to (1) define configurations, (2) prepare segment descriptions and (3) specify scenario descriptions. This contribution will give an overview of the purpose and functions of the ConfiX editor.

Surveillance cameras and imaging diagnostics gain significance for plasma fusion experiments. They will become an integral part of the data acquisition system for the Wendelstein 7-X (W7-X) stellarator. In the scope of long duration discharges (∼30 min), as intended for W7-X, the data rate produced by numerous imaging systems will be huge. Data acquisition, processing, monitoring and archiving are to be carried out in continuous mode during the discharge. Upcoming large fusion experiments, such as W7-X and ITER, demand a paradigm shift regarding the future approach of scientific data analysis: The guideline should be the avoidance of permanent human inspection and interaction . Therefore, data acquisition for W7-X is designed to facilitate the implementation and configuration of data processing modules. The proper design of system components such as AnalysisModules (image processing) and TimeGroupModules (relevant for data acquisition performance) is essential to reduce image data before transmission to the archive. Pattern recognition will be offered as one approach to condense image data without loss of significant information. During the start-up phase of each experimental campaign that is operating in a new parameter regime, science images will have to be archived with high temporal, spatial, and dynamical resolution in order to derive significant patterns that will build up a pattern library.

Wendelstein7-X as well as the future ITER are new generation fusion devices, designed for long pulses or even steady-state operation. A large number of diagnostic systems will be implemented to investigate the behavior of the plasma. On the contrary to the previous shot oriented operation, long pulses require continuous sampling, archiving and displaying of collected data. The amount of data, that has to be handled, is some magnitudes higher and requires new techniques for compression, archiving and retrieval. In this paper, we give a status report on the progress of developing the data acquisition system of Wendelstein7-X. A prototype system was built to demonstrate all the required features for long pulse operation. This system includes three sample DAQ stations typical to the experiment, the timing system, the monitoring subsystem and the data archive.

An editor is to be developed to specify the system configuration of large and long-term physical experiments subject to permanent evolution. Based on this configuration, control programs are to be defined for long-duration experimental runs for the complete system as well as for subsystems if operated independently. The key model abstractions which have been developed for the description of such a system and serve as a basis for the data model used by the editor are presented.

To improve the plasma position and shape control system in ASDEX Upgrade, it is constantly expanded by the integration of data acquisition systems of important and interesting diagnostics. Usually the main responsibility of data acquisition systems is to collect data and subsequently put it into a data base archive system from where it is later analysed. The obligation now is also to simultaneously process the acquired data with an appropriate algorithm and send the pre-processed data in real-time to the plasma control system during a discharge. To achieve this requirements the used hardware must provide enough processing power and the operating system has to meet some real-time constraints. To avoid the burden of using proprietary real-time operating systems the trend is to use Open Source variants mainly based on Linux. Some of these solutions also allow us doing real-time capable communication using standard Ethernet hardware. By way of an example the implementation process of a prototype of a real-time data acquisition system based on a multi-core processor and Xenomai is demonstrated. Other possible solutions like Realtime Linux and their differences to Xenomai which we propose as the most sophisticated real-time framework for Linux are discussed in this paper.

The coupling of continuous data acquisition and continuous online analysis keeping up with the acquisition is one of the features the W7-X data acquisition system is designed for. As proof of principle of this concept the magnetic diagnostics have been implemented. The magnetic diagnostics measure time derivatives of the magnetic fluxes and the signals have to be time integrated accordingly. Both measurement and analysis tasks are executed on a single PC based system. The configuration of both hard- and software of the system is presented. Special focuses are the task of software integration of a user supplied online analysis function into the data acquisition system and the incorporation of the complete system into the W7-X segment concept in use by the control system. The complete installation has been tested at the WEGA Stellarator experiment. Because WEGA is capable of continuous steady state plasma operation the practical suitability of the installation for W7-X could be demonstrated successfully.

The increasing number of data acquisition stations and setups in laboratory environments at Wendelstein 7-X does already produce a considerable amount of data by now. Diagnosticians want to view the acquired data in a comfortable way and use them for calculations in their own test and analysis algorithms. To prepare for full operation of W7-X, a reasonable approach is to provide data access methods that stay as close as possible to the final data access concept. This requires taking care of the special needs of W7-X regarding continuously acquired data, segment based parameter switching and synchronization of data from different diagnostics. Therefore, a data access interface has been designed and implemented considering continuous data acquisition as well as usability and performance issues. The interface and its usage in different software environments (e.g. high level scientific programming languages) will be explained. Also, the integration of user defined off line analysis algorithms will be described. Additionally, the DataBrowser will be presented. The DataBrowser is a Java application that can browse continuously acquired data of different kind, provides several types of plots including zooming functions to display the data and the corresponding parameters and offers export functions to save selected data locally.