Components and data sources

The NeXus configuration components are objects constructed of NeXus base classes representing simple devices with single data sources, (e.g. counter, MCA), composite devices, (e.g. monochromators, diffractometer), structures holding metadata only, (e.g. mandatory metadata). The components can be inserted into a configuration or deleted from it without side effects.

The Components consist of the following items:

• name – a string identifying the component
• data sources – a tag specifying where the data stored in NeXus fields have to be fetched. There are the available data source types:
  • Tango attributes
  • database queries
  • data supplied by the experimental control client (ECC)
  • output of python scripts
• strategy – a tag of four strategy types: INIT, STEP, FINAL and POSTRUN, indicating whether data are captured before, during or after the scanning procedure. A NeXus field or attribute is marked with the POSTRUN tag if the information is inserted during a subsequent data processing step.
• NeXus path – an absolute position of the data inside the file. It is expected in terms of NeXus groups.