Database structures and interfaces for W7-X

Abstract

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.

From a physics discharge program to device control—Linking the scientific and technical world at Wendelstein 7-X

“…They usually aim at specifying the behavior and state of the plasma and machine in terms of physics. [1] Moreover, many parameters have to be set, but do not change during experiments. It appears useful to hide them from diagnosticians.…”

“…There are two specialized editors to create and edit the high level parameters, the group and segment editor [1]. The group editor is an expert tool used to create the structure of high level parameters and to specify the transformation functions as well as the corresponding target paths to low level parameters.…”

“…A set of chained segments is called a scenario, and a few scenarios make up the whole experimental program. [1] At W7-X about 60 diagnostic systems with many different hardware devices will be implemented. The software representation of an individual device or system component is called a module.…”

“…All information about system configuration and experiment program specification is kept in the W7-X configuration database [1].…”

Data access and its implementation at Wendelstein 7-X

“…Every item of a sequence is stored along with a 64bit time stamp. [2,3,4] There are three types of streams:…”