Recording data with DMM

[johntrich1971]

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@mh256 wrote:

Thanks for the reply, I appreciate it. I ended up using the standard open, write, close calls as recommended by  johntrich1971 which resolved my issue:

That being said, I need a column of the local time when each sample is recorded if you have any insight on ways to integrate that.

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Take a look at your data. I don't think that it is still doing what you want. You are each time writing appending the data point to an array and writing the entire array. Instead just write the individual value. Use Build Array to convert to a single element 1D array.

To get the Time column you can use channel names. Write the time in whatever format you want as a string to a "Time" channel and write the data to a "data" channel.

[RTSLVU]

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@mh256 wrote:

Thanks for the reply, I appreciate it. I ended up using the standard open, write, close calls as recommended by  johntrich1971 which resolved my issue:

That being said, I need a column of the local time when each sample is recorded if you have any insight on ways to integrate that.

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1. Why TDMS when a simple text file will do?
   1. Use the File Open or Create and Write to Text File, not TDMS
2. If you need a time column then add one
   1. Take the current time, convert it to a string, and write it to the file before you write your measurement

[mh256]

Thank you for your reply. When you say " Use Build Array to convert to a single element 1D array" -- I have the single point reading fed to the build array block, so do I'm still unsure of what change to make to follow your suggestion? Sorry, still very new to LabView, appreciate the help.

[GerdW]

Hi mh,

what about attaching your code instead of an image of your code?

[johntrich1971]

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@mh256 wrote:

Thank you for your reply. When you say " Use Build Array to convert to a single element 1D array" -- I have the single point reading fed to the build array block, so do I'm still unsure of what change to make to follow your suggestion? Sorry, still very new to LabView, appreciate the help.

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Like this:

@RTSLVU wrote:

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1. Why TDMS when a simple text file will do?
   1. Use the File Open or Create and Write to Text File, not TDMS

I assumed that this was a scaled down version of an application for which TDMS was more appropriate. A plain text file would certainly be adequate for the application as shown, but I actually like the ease of adding structure to the data in the TDMS file so will sometimes choose it even when a plain text file would be adequate.

[mh256]

Hi,

Is the suggestion then to get rid of the shift registers as so:

I don't see how to configure it as you depicted without nixing them?

Just to clarify the goal here is to continuously build up the array as the dmm measures changing voltages. Then, when the user stops the VI (at an unknown time) that array of data will save to a file alongside a column with corresponding time data.

This is actually a scaled down version of a larger VI that uses a cDAQ and produces a TDMS file format which was why I opted for that format.  In the end I'd like to the get this data to save to the same file as the thermocouple data from the cDAQ, but wouldn't be a huge deal if they did save as two separate files.

I attached the DMM code as well as the larger VI I'm trying to build -- its in the 2020 version as a heads up.

Thanks again for the input everyone.