DAXmx - Existing VI won't access Current Inputs and TC Inputs within same Loop

[sonicpursuit]

Hi

I am trying to run an existing, working VI using a new Laptop and Version of Labview. The VI originally ran under Version 6 and we have now upgraded to Version 7.1

The Laptop has a 6036E card connected to an SC2345 chassis with four SCC-C120 and four SCC-FT02 modules.

The VI has eight individual DAQmx objects tasked together and read within one sinple While loop. However, when I ran this using the new setup, it just displays NaN in all objects.

I broke apart the existing configuration and found that I could read all the TC channels together or all the Current channels together, but not both of these two groups together.

I then replaced the individual DAQmx objects with a DAQ Assist object and again this worked for Current and TC channels seperately. Obviously the DAQ assist object is type specific so I created a second DAQ assist within the same loop.

When I run this VI it displays ERROR 50103 (reserved recource). This leads me to believe that I will unable to access TC and Current modules on the same loop?

Any clues as to why this VI worked before but may have a problem due to new Version of Labview or different Laptop?

Or any suggestions/examples as how to handle two DAQ assists reading channel data together?

I have attached a screen-shot of the existing DAQ read section

Many thanks.

[Stuart_R]

Hi there,

The NaN, as you my know refers to 'Not a number' and you normally see this during a calculation such as taking the square root of a negative number or something similar. Are you seeing any DAQmx errors being generated or does everything run fine but your not getting the correct data?

Inside the Measurement & Automation explorer, what data do you see if you use the Test Panels (right click on the desired module and select Test Panels from shortcut menu)?

Is it possible to post your code so that I can try and run it here? Your image doesn't show how you display the data and if there is any additional calculation taking place.


The problems that you have hit whilst using multiple DAQ Assistants simultaneously is expected and these cannot be executed simultaneously due to the code being used behind the scenes. There isn't a problem doing this with the low level code that you've attempted so I'd like to have a better look at it.

Many thanks,

Stuart

[sonicpursuit]

Hi Stuart,

               I think Iv'e managed to fix it. The problem seemed to be related to the individual Current "create virtual channel" sections. I deleted all the individual tasked channels and used a control box on the "global virtual task" node of the "create DAQmx task". This allowed me to browse via the Assistant wizard to both the Current and TC channels, which I couldn't do using one "DAQmx Assistant" object.

In the original VI, the parameter values for the existing current virtual channel objects are the same as the settings that I have used with the wizard so I'm not sure what is wrong with them or why it used to work with our old Setup.

But the other method works, so all is good.

Thanks for your response though. If you have any thoughs please let me know for interest.

[Stuart_R]

I would probably put this down to a slight error in the way you were addressing channels or something similar. If you've worked around it now then at least thats the main thing 😉