Thermocouple optimization - all settings on front pannel

[EngineerOneDay]

I want to create a database in LabVIEW that will contain data about thermocouples (name and calibration coefficients). This would simplify the process since I would only need to connect the sensor to the measurement card upon entering LabVIEW and then check which sensors are connected in the program before starting the measurement. This way, I wouldn't have to recalibrate the thermocouples every time. The thermocouples I will include in the database are already calibrated, meaning I already know the coefficients (y = kx). So long story short, I want to create program, where I simply plug in thermocouples, set up all settings on frontpannel with selection boxes, combo boxes...(which thermocouples im using, types, coefficients etc.) and starting measuring process. That way I would optimise and accelerate whole process for general measuring.
How can I set this up?
Thanks for any help or ideas 😄

[altenbach]

It would only be polite to give a link to the original discussion.

[Bob_Schor]

Did you try any of the suggestions you got on Reddit?  Did the code work?  If it didn't, post the code and also post the data file you generated so we can look at it and help you learn to do your own LabVIEW programming.

Bob Schor

[EngineerOneDay]

Hi, thank you for your question Bob.

I am very beginner in this software but managed to create program that reads multiple channels. Right now I have problems with displaying temperature values (values are changing randomly with random frequency) and seperating the signals, so I could calibrate them ( "+" and "x" function) individually. I am attaching block diagram and file.
Thanks for any advices.

[Bob_Schor]

Unfortunately, the VI didn't make it.  If you try to save it again (please do!), please "Save for Previous Version" and specify LabVIEW 2019 or 2021 (@GerdW and I both use these, and most long-time LabVIEW developers will be able to open VIs saved in these versions).

I would think you could programmatically (using DAQmx functions) "build" a multi-channnel Task that you could configure with, say, a FOR loop to get 16 channels configured.  Much neater and easier to understand and read than doing them one-at-a-time as you have diagrammed.

Bob Schor

[EngineerOneDay]

Hi Bob, thank you for your reply.

Uploaded older version vi now and I hope that works.
I created one at a time channel without for loop because it is much easier for me than using for loop - im quite new to this software. Will still try using for loop like you advised. 
The only problem I have right now is reading/displaying values. I use frequency 1Hz, but for some reason every 3-5 seconds values freeze and then after a bit it works again with 1Hz. Is it possible that the code is too large with too many data to process?

Regards, J

[GerdW]

Hi OneDay,

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@EngineerOneDay wrote:

Is it possible that the code is too large with too many data to process?

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Yes, it's too large. (But without "too many data to process"…)

Some things to consider:

• The whole initialisation (everything upto DAQmxStart) belongs BEFORE the loop.
• All the channel setting sbelong into an array (of clusters), the CreateChannel stuff belongs into an autoindexing loop. No need to create 16 copies of the very some code… (Use a shift register for the DAQmx task reference.)
• All the data handling after DAQmxRead belongs into an autoindexing loop, no need to create another 16 copies of the same code… (We miss the subVI in that scaling stuff.)
• NEVER delete/hide the labels of terminals in the block diagram!
• The DAQmxStop/Clear belongs AFTER the loop.

Please implement those items in your code. Then test again, debug and ask specific questions…

Which DAQ device do you use and are you sure you can read TC values at a rate of 1kS/s (as set by default in your VI)?

It's also a VERY bad idea to rename VIs before uploading: how should the main VI know about the changed name of its subVI?

On that subVI: do you really need to read that spreadsheet file for each channel again, in each iteration of your mainVI? Wouldn't it be good to load that file ONCE before the loop???

[mcduff]

Here's something to get you started. Not sure what you are doing with the spreadsheet; that's not included, see if you can figure it out. Hint follow GerdW's suggestions.