Issues with Creating Task for USB-Temp-AI Device in LabVIEW 2020

[ajerno]

I am trying to create a single task with 2 channels: 1 for voltage analog input and 1 for temperature analog input. Using InstaCal (While LabVIEW was off), I configured my USB-Temp-AI for a differential input on the Voltage port 0, and I also set a Type J thermocouple for Temperature port 0.

In LabVIEW, I used the ULx Create Channel VI and set the polymorphic select to composite AI Voltage for the first channel and connect it to a second one with the polymorphic select set to composite AI temperature. However, this does not seem to work, and I just get an empty array, but no errors.

I tried playing with the Timing VI, but if I add the Timing VI, any option that I choose results in an error. If I choose a clock source I get an error saying to use NoClock. But if I use NoClock, I get an error saying it is not supported by this task.

I have tried using only an Analog Input or just using a Composite Analog input since this seems to be something the ULx Help guide seems to reference, but it won't accept the Temperature Channel Name (Dev0/Ti0).

Any help would be appreciated.

Attached is lvulx.chm, which is the ULx Help guide I referenced.
 

lvulx.chm UlxTesting.vi

[Jeffrey]

Hello @ajerno

Normally I would set this up and test it for you, but the one device(s) I don't have in my collection of MCC devices is a USB-TC-AI or USB-TEMP-AI.

But I do believe this is what you need to do:

Note I am just using ULx create channel vi as AI Voltage and AI Temperature where you are using Composite mode (Compl AI Voltage, etc.) for both.

Also the USB-TC/TEMP-AI's cannot be clocked so don't use a ULx Timing vi, rather just use the "Wait until next ms multiple" vi native to LV and set it to an appropriate rate.  the max update rate on the USB-TC-AI is 2 Hz so 500 mS is as short as you can go.

Regards,

Jeffrey

 

 

[ajerno]

Thank you for the response @Jeffrey

I have tried a similar structure and it gave me an error. To make sure of this, I replicated your block diagram, and I got the following error:

"Error 10006 occurred at ULx Create IOTask.vi 

Possible reason(s):

Measurements: Task cannot contain a channel with the specified channel type, because the task already contains channels with a different channel type.

Create one task for each channel type."

It gets this error before it even reaches the Read.VI so it seems like it does not like these two channels together under one task.

 

[Jeffrey]

I was able to get hold of one, here is what works:

This example shows getting 2 channels each (temperature and voltage)

[ajerno]

@JeffreyThank you for the help.

That configuration does work. So it seems that at least with this device, you can't just use one task for the temperature and voltage readings.

[banksey255]

@ajerno, perhaps try creating a composite task using the ULx Create Channel VI by selecting Composite Input -> Analog -> Voltage when adding voltage inputs to the task, and Composite Input -> Analog -> Temperature when adding temperature inputs to the task.

Edit: I've subsequently realised that is what you originally tried.

 

Edited December 1, 2022 by banksey255