VIII - "Externals"

[ file formats | config file | SpaDAQ || main help index ]


1. WinSPA's file formats

Even though in principle NetCDF files are self-describing, the variables in WinSPA files are described in detail below.

The file format NetCDF is

You can find many resources for and about this file format in the world wide web, for example

Note: If you want to import/export NetCDF files with the programming language Delphi, you can use the same interface library that was developed for WinSPA. It is an improved version of the Delphi NetCDF interface declaration by Sandy Ballard of Sandia.

Global attributes

The global attributes are defined in all NetCDF files saved by WinSPA. They describe the type of the file and contain information about the WinSPA release the file was created with.

Name of NetCDF variable Full name Comments
Title Title of the file. This describes the type of the file.
History History of file changes. Contains only the creation by default.
Creator Program that created the file. Contains "WinSPA".
Version Version of the creating software. Version and date of the WinSPA release the file was created with.

The different file "types" WinSPA uses are:

Note: WinSPA accepts also 2D scans with scan units Volts as SEM scan and vice versa.

General scan information

The general scan information parameters are the same for all WinSPA save files, independent of the scan type. They describe how the scan data were acquired (gate time, scan time, min/max counts, cycles, etc.).

Name of NetCDF variable Full name Units Comments
MinCnts Minimum number of counts within scan -- ...
MaxCnts Maximum number of counts within scan -- ...
CycleCnt Number of scan cycles with averaging -- ...
TStart Start time of scan Days since 12/30/1899 ...
TStop Stop time of scan Days since 12/30/1899 ...
TStartRel Relative start time of scan msecs. since t=0 of stop watch ...
GateTime Counter gate time msecs. ...
Interrupted Scan interrupted? 0 = no, 1 = yes ...
RawData Scan data unaltered? 0 = no, 1 = yes ...
Comment User's comment to scan None (string variable) As entered in the "comment" field in the respective "file settings" group box.
Usr1,Usr2,Usr3,Usr4 User defined values #1..#4 Unknown A legacy of Spa4.1d only. Not used or written by WinSPA. May only contains values, if a .d2d file was imported and saved as a WinSPA file.
Sample information

The global sample parameter settings are saved for documentation.

Name of NetCDF variable Full name Units
SName Surface name None (string variable)
SLConst Surface lattice constant Å
SSHeight Surface step height Å
Data scaling information

The original scan data and the scaling of the data are fundamentally distinguished in WinSPA. Consequently there are explicit variables which only affect the scaling of the scan data upon loading the respective scan data file.

Name of NetCDF variable Full name Units Comments
ScMinCnts Min. value to display Counts ...
ScMaxCnts Max. value to display Counts ...
MinXValue X axis start ... ...
MaxXValue X axis stop ... ...
SclType Type of scaling (lin/log) -- 0 = lin, 1 = log

The zoom for all 2D scan data (2D, SEM, RSM) is described by a rational fraction consisting of numerator and denominator, where both are small integer numbers.

Name of NetCDF variable Full name Units Comments
ScMinCnts Min. value to display Counts ...
ScMaxCnts Max. value to display Counts ...
CTIndex Index of used colour table -- As in table of color tables.
CTInvert Invert color table? -- 0 = no, 1 = yes
SclType Type of scaling (lin/log) -- 0 = lin, 1 = log
XZoomNum X zoom numerator -- X zoom factor.
XZoomDenom X zoom denominator -- X zoom divider. Yet unused
YZoomNum Y zoom numerator -- Y zoom factor.
YZoomDenom Y zoom denominator -- Y zoom divider. Yet unused
Scan data
For each of the five scan modes of WinSPA (1D, 2D, RSM, SEM, I(t)) there is one set of parameters for the range of the measurement and the scan data.

2. The configuration file

WinSPA saves all global settings into a configuration file (config.txt) in the program path. You can open this file with any text file editor and make changes in it. Specifically, if you want to add other surfaces to the presets list, just enter the parameters for name, step height and lattice constant into the config file, separated by " / " (space slash space).


3. The library SpaDAQ

The library SpaDAQ creates an abstraction layer around all "real" data acquisition (DAQ) hardware accesses. WinSPA can therefore immediately work with any DAQ hardware, if a dynamic link library with the name SpaDAQ.dll is present and supplies the same functions as the original one.

If you are interested in testing another commercially available DAQ hardware with WinSPA or developing a new DAQ hardware for SPA-LEED instead of the antique PCI-20001 system, please contact Omicron NanoTechnology for further details.