Requirements

Real Time

The fast control needs the real time capability of the overall system, because the feedback control data must stand by within a few nanoseconds.

Steady-state Continuous operation

In contrast to the existing Tokamak experiments, which acts pulsed for only a few minutes or seconds at a time the Stellarator W7X works continuously about half an hour and therefore requires the development of new data acquisition and processing techniques.

Segment program

A single experiment cycle is divided into a sequence of several actions and states (segments). A scientific programme consists of a set of segments to be processed successively in a segment program. The data acquisition needs to adapt on the different segments.

Editor for Segments and Configuration

For definition of the segment program an ditor must be provided that is capable to hide implementation details from the formulation of the physical question. Moreover, the editor should be usable to create the overall system configuration for the data acquisition. All configuration and segment definition information has to be stored in a database for further use.

Time

In order to assign the data to a segment program they obtain a time stamp. Therefore the global system time must be available over the life time of the experiment and has to be very precise (approximately 10 nanoseconds).

Event handling

Because of the long experimental phases there is some need to handle events for dealing with desired or undesired phenomena.

Monitoring

While the experiment runs some dedicated data are extracted and visualized to observe it.

Data acquisition

Beneath the classical analogous digital converters (ADC) there will also be used (video) cameras and Programmable Language Controllers (PLC). The daily data volume from about 300 devices is expected to be about 1 Tera Byte after data reduction.

Data storage and retrieval

A powerful and intelligent data storage is required to store the large amount of data. Moreover, it is essential to find out desired data rapidly, even after years of operation.

Framework for Scientific data processing algorithms

For standardised development of data processing algorithms a framework is needed. By means of this framework the usability of algorithms is ensured  for online as well as offline processing.

Communication

For information exchange between Data Aquisition and Control Stations a Network Bus is working on dedicated transport mediums.

Automated Software Management

Because of the mass of data acquisition and processing host systems the ability to manage all software remote is essential. This applies for starting and stopping as well as reconfiguration and error correction.

Data Visualization

Both for online and offline processing of data proper visualization techniques needs to be evaluated resp. developed.