Use disk streaming when you require multiple write operations to a spreadsheet file. Disk streaming reduces the number of times LabVIEW interacts with the operating system to open and close a file. You can use disk streaming while formatting data as a spreadsheet string and writing the string to a file.
Use the following block diagram objects to format data and to stream the data to a file.
Open/Create/Replace File Function | While Loop | Format Into String Function | Write To Text File Function | Close File Function | ||||||||||||||
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Create the following block diagram to format data of different data types as a spreadsheet string and to stream the string to a file.
Note To format data of one data type as a spreadsheet string, use the Array to Spreadsheet String function. |
Customize the gray sections for your unique programming goals.
The following list describes important details about the previous diagram:
Place the Open/Create/Replace File function and Close File function outside the While Loop to create a typical disk streaming operation. | |||
The While Loop enables this VI to continuously format and write data to a file without the overhead associated with opening and closing the file in each iteration. Use shift registers to pass values from previous iterations to the next iteration. | |||
Wire input parameters from outside the While Loop to the input 1..n inputs of the Format Into String function. You can wire delimiters, such as end-of-line constant, tab constant, and so on, as input parameters to separate input data. Specify the format string input using format specifiers to format the input parameters as a spreadsheet string.
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The Write to Text File function writes the spreadsheet string to the file. |
You can improve the performance of disk streaming by buffering data using a shift register. First, initialize the shift register with a buffer of data. Next, write data to the buffer. When the buffer is full, write the buffer to disk.
Refer to the Tab-Delimited Data project in the labview\examples\File IO\Spreadsheet\Tab-Delimited Data directory for an example of streaming data to spreadsheet files. This example uses the Array to Spreadsheet String function which converts data of one data type to a spreadsheet string and writes the string to a file.
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Refer to the Buffered Stream to Tab-Delimited Text File VI in the labview\examples\File IO\Spreadsheet\Tab-Delimited Data directory for an example of buffering data when streaming data to spreadsheet files.
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