HDF5 is a technology developed by the HDF Group that is designed to manage large and complex collections of data, allowing for advanced relationships between data and user metadata to be structured through grouping and linking mechanisms. For HDF5 support visit HDF Group’s HDF5 support site.
Every plasma device at BaPSF is governed by a DAQ Controller. This DAQ Controller is tasked with operating and monitoring the plasma device, controlling the order of operations for an experimental run, recording data for the run, and generating the HDF5 file.
Data collected by BaPSF is classified into three types:
MSI diagnostic [device] data
MSI data is machine state recordings for the plasma device the experiment was run on. For example, MSI data for the LaPD would include diagnostics like partial gas pressure, discharge traces, magnetic field, etc.
Digitizer [device] data
This is “primary data” recorded by the DAQ digitizers. “Primary data” is any signal recorded from a plasma probe.
Control device data
Data recorded from a control device. A control device is a piece of equipment that controls some state property of the experiments. For example, a probe drive records position state info for a probe location and a waveform generator can record driving frequencies of an antenna.
The internal data structure (data-tree) of a HDF5 file looks very similar to a system file structure (see Fig. 1), where groups are akin to directories and datasets are akin to files. Not depicted in Fig. 1, each group and dataset can have an arbitrary number of key-value pair attributes constituting the component’s metadata.
In the above example, MSI diagnostic data is contain in the
group and the
Raw data + config group houses both
Digitizer data and Control device data. In addition to the
three typical Types of Recorded Data, the
Raw data + config
group contains the Data run sequence for the experimental run.
The Data run sequence is the order of operations performed by the
DAQ Controller to execute the experimental run.