Download Binary Data File over Serial Port

[JMorgan]

I need help setting up a .vi that I can use to download a binary data file from a dos-based system. I will send the system a command, say ascii "DOWNLOAD", and then the remote system will send me a binary data file that will be approx. 600MB. I won't be doing any display/manipulation using labview, I will just need to have the option available in LV to recieve the file.

Any examples would help a programmer that is new to LV and is getting a little desperate.

[Dennis_Knutson]

A VISA Read doesn't care whether the data it's getting is binary or ASCII. Where you might have problems is detecting that file transfer is complete. If you have enable termination character set to True in the VISA Configure Serial Port, the read will stop as soon as the termination character is detected. The default termination character is 0xA or a linefeed. You probably don't want to use this. If the file is terminated with a character or string of characters that you now will be unique, you can use this. If there is no unique termination character at the end of the file, the next best thing is to know the file size exactly and set the byte count of VISA Read to that number. Based on file size and baud rate, you would also need to adjust the VISA timeout value. Another way to do this is to transfer the data in pieces and write to a file as soon as the data is received. The reading of data would then be terminated when there are no more bytes available at the serial port. I've attached a LabVIEW 7.0 program that should give an idea of the last approach.