MDSplus Data Types
MDSplus supports numerous data types, from simple numeric or text types to complex entities which combine related information in a structure. Some of the data types are used internally for representing things such as data acquisition devices, compiled representations of expressions and data acquisition actions and you may likely never have to interact with these items. Most users will normally be accessing the primitive data types including all integer, floating point or text data types as well as several of the more complicated MDSplus data types such as signals, dimensions, with units, with errors and ranges.
Many of the MDSplus data types consist of structures or records containing two or more fields. There are built in functions in the TDI expression evaluation language for extracting these fields from the structure.
One of the more important data types provided by MDSplus is the signal, DTYPE_SIGNAL. A signal is a structure which combines a value part, optionally a raw data part, and one or more dimension descriptions. Data from measurement devices as well as analysis results are often stored as signals. Many visualization applications will generate plots of signals by plotting the value portion versus the dimensions. The value part of a signal can be an expression which references the raw data part of the signal. Support for transient recorders often use this feature by storing the raw counts values in the raw data part and then put an expression to convert this raw data to engineering units (such as voltage) in the value part of the signal. In the case of the support for a transient record, a representation of the time base would normally be stored in the first dimension part of the signal.
The following table list all the supported types. Click on the data type for more information on each type.
|Integer Data Types|
|Floating Point / Real Data Types|
|Text / String Data Type|
|MDSplus Data Types|