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Writing data to two files simultaneously

Hi all -- I am trying to log data from thermocouples using a cDAQ while also logging voltage measurements from an Agilent 34401A multimeter.  I believe I have both Vis written okay as they seem to work independently, but when  I put them together in the same VI, the voltage data doesn't get written nor is that file even created.  I wouldn't be opposed to them being written to the same file, but also couldn't seem to get that to work.  Any help is greatly appreciated!!


block diagram full image.png

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I cannot open your VI (I assume the file you attached that has an extension of ".vi" is a LabVIEW VI file created by some (unknown) Version of LabVIEW.  I need to be able to view your code in order to understand (and to even see) what you are trying to do.


Bob Schor

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The upper loop does not have any file IO at all and also stops on error. It is possible there is an error?


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Hi Bob,


Thank you for the reply.  I am using LabView 2020.  Is there a specific way I should go about attaching my VI so you're able to open it?  Perhaps an option here:



I attached the VI to this thread again as is in 2020.

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Hi altenbach,


Thank you for the reply.


I believe the upper loop has a file I/O here(?):


I don't think there is an error in that upper loop since I can run it without the bottom voltage loop and it collects the thermocouple data as expected.  Also, it would send an error message if so right? As is, this VI captures the data from the upper loop/thermocouples, but the bottom loop dedicated to creating and logging data from the multimeter doesn't seem to be working.

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@mh256 wrote:

I believe the upper loop has a file I/O here(?):



Thanks. For me this was impossible to really tell, because I don't have and DAQ drivers installed and all these VIs were blank. 😉

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