Vishay Micro-Measurements System 7000 Programmer’s Reference Manual
Page 38 of 142
3.14 Acquiring and Decoding Recorded Data
3.14.1 Identifying and Reading the Data File
When a card on the System 7000 is configured to record data, the recorded data is stored into a data file
on the card’s compact flash. This file has the extension “.7KD”. You must download the file from the
card and then decode the data in the file. After the file has been successfully downloaded, it is
recommended that you delete the file from the card in order to preserve disk space.
A header file (extension “.7KH”) is stored along with the data file. The header file contains information
such as the number of scans recorded and the time scanning started. You do not have to download or use
this information, but is recommended that you also delete this file.
The LabVIEW instrument driver provides VIs for reading and deleting files. The ActiveX automation
interface provides methods. The process is more difficult when done at a low-level.
NI LabVIEW
The NI LabVIEW instrument driver has a single function that handles identifying, downloading,
and deleting the last data and header files.
The “Read Last Scan Data” VI returns information about the last scanning session including the
name of the last data file, the size of the last data file, the number of scans recorded, and the time
the scan session started. It also returns the contents of the last scan data file. It will delete the
data file and the associated header file.
If you choose not to use this VI there are other VIs that allow you to perform these operations
independently. You will need to use these if you power-cycle or reset the scanner between taking
the data and attempting to download. (The scanner does not maintain the last data file name in
permanent memory.)
Be aware that you may need to tweak the default timeout for reading the blocks of file data as the
timing varies depending on the speed of your PC and Ethernet connection
ActiveX
The ActiveX automation interface has three methods that handle identifying, downloading, and
deleting the last data and header files.
The “GetLastDataFileInformation” method retirms the name of the last data file, the size of the
last data file, the number of scans recorded, and the time the scan session started. The method
“ReadLastDataFile” downloads the contents of the last recorded data file. The method
“DeleteLastDataFile” deletes that last data file (and associated header file).
If you choose not to use this routine there are other methods that allow you to perform these
operations independently. You will need to use these if you power-cycle or reset the scanner
between taking the data and attempting to download. (The scanner does not maintain the last data
file name in permanent memory.)
Be aware that you may need to tweak the default timeout for reading the blocks of file data as the
timing varies depending on the speed of your PC and Ethernet connection.
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