acquiring thermocouple data from mutliple channel

[RJP]

Hi,
I am developping a temperature measurement data acquisition application (Using the NI-9211). I already managed to acquire data from one channel at a time and plot in on a graph.
But my final system should allow the user to select from how many channels they want to acquire data, up to  4 channels at the same time. (the NI-9211 got 4 channels).
Any hint or help on how to do that would be greatly appreciated.
Thank you

[Kenny_K]

You should be able to just use the Ni Daqmx software and use the Create Channel > AI thermocouple Channel vi (the Create Channel vi is polymorphic, meaning drop it on the block diagram and then use the drop down menu to select which function you want it to perform).  That will give you a 1D array of the analog ports that you are looking to read, and then you can progmatically select which thermocouple to display.

You should also check out the Thermocouple Examples that are shipped with LabVIEW.

[RJP]

Thank you for your help.

I got another problem now:  I am fixing the plot names to Thermo1, Thermo2 .... but whenever i run it, the plot names changes to : cDAQ1Mod4/ai0, cDAQ1Mod4/ai1 ,etc... (See attached picture).
How can I fix them permanently?
Thank you

[Joseph_Loo]

How do yo set the name? Is it through the graph properties of the chart or graph?

The way I do it is to use the property nodes of the graph. You have to select the plot then set the plot name.

[RJP]

I tried using the Property Node -> Node name, but with no luck (Can't figure out how to use it properly).
I included a picture showing how I want my interface to look like. The user chooses which channel by checking its corresponding box and the graph will only display those checked.
What is the easiest way to implement it?
Thanks for your help.

[Joseph_Loo]

You need to select the graph and get to property nodes,  active plot and plot name (this is another level below.). First set the plot which is a number between 1 to x. After you have done that, you need to set the plot name. That should work

[Devin_K]

Joseph,

That could work, although if you were continually updating and renaming the plots, you might see it flicker a bit.

An easier way would be to right-click the graph/chart and check the "Ignore attributes" option.  This will prevent the chart from taking the names from the signal source.

[RJP]

It worked, thanks a lot guys