How Do I Convert LV7.1 Datalog Files to LV8 Format?

Question

I have several LabVIEW 7.1 datalog files that generate Error 71 (File data type conflict) when I try to open them in LabVIEW 8 using the new Open/Create/Replace Datalog vi with my original typedef constants wired to the record type terminal.  Likewise, my original LV7.1 code recompiled in LV8 often generates error 116 (unflatten or byte stream read operation failed due to corrupt, unexpected, or truncated data) or error 4 (end of file encountered) when randomly accessing records in the LV7 datalog files, presumably due to changes made to the datalog file structure in LV8.  I recall one time when a dialog box popped up asking if I would like to convert the file to LV8 format.  Since this was a file currently in use on the server by LV7.1 clients, I had to reply no.  With copies of the datalog files now on my hard drive ready for conversion, I haven't seen the conversion dialog box pop up again.
How do I convert the LV7.1 datalog files to LV8 format?
Thanks,
Larry

Answer 1

Good afternoon Larry,
Thanks for posting! 
The Datalog file support in LabVIEW has changed, but the underlying
principles of the technology remains the same. 
Converting to the new format should just involve converting a few VIs to the new Datalog-specific versions.  As you can see, the new Datalog VIs appear in
their own sub palette in 8 which will help keep things simple.
Before we address the concerns with the errors, let’s first
make sure that the code has been properly converted. 
To convert your VI to the new format:
1)      Replace
the Open File VI from LabVIEW 7 with an “Open/Create/Replace Datalog” VI in LabVIEW
8.  Keep your type constant or control
wired to the “Datalog Type” input.
2)      Replace
any “Write File” VIs in LabVIEW 7 with “Write
Datalog” and triple check that your data matches the datatype wired into the
open exactly.
3)      Replace
any “Seek” VIs with “Set Datalog Position”.  The input to this VI is the number of records
to advance (check the mode set by the “from” parameter).
4)      Replace
any Reading VIs with the corresponding “Read Datalog” VI.
I suspect that if you are receiving errors saying that the
end of file has been encountered it is a result of a bad input to the “set Datalog
position” VI.  I attached a basic example
of writing a Datalog file in LabVIEW 8, and reading the results.  The rest of the functions in the new Datalog palette
should be pretty straightforward. 
Does this help?  I
would be more than happy to answer any other questions on this if you need any
additional clarification, or if this response does not address your question.
Travis M
LabVIEW R&D
National Instruments
Attachments:
Datalog8.zip ‏30 KB