displaying multiple sensor inputs separately

[zaq]

Using: labVIEW 8.5

This seems like an obvious question but I can't find a useful answer. I have a very basic system with one accelerometer and one shaft position sesnor, and would like to display the waveform of each on separate graphs in the same VI, running continuously. I have made a separate VI for each and they run fine independently, but when I try to combine them into one I get "Error -50103: The specified resource is reserved. The operation could not be completed as specified."

I gather this is because I have two DAQ Assistant tasks running, but I can't work out how to use just one and then separate the two channels out to process them independently.

I've attached the VI I've been trying to put together:

[gt3000 · Accepted solution]

Hello zaq,

There are two issues that can be seen from your VI.  The first is related to the DAQmx Express VIs.  A single DAQ Assistant should be used to call all the channels on the same device.  From your code, I can see that you have tried that already on the top loop. 

The second issue is that you have multiple while loops in the same VI.  It is possible to have multiple loops in LabVIEW, however the two are not synchronized in this case.  When two while loops are being used, LabVIEW will enter you only into one loop, and the second task will not execute. 

Therefore, the approach is to have a single loop, with one DAQ Assistant.  However, the Dynamic Data (blue wire) can be split to the individual channels using the 'Split Signals VI'.  This can be found in Block Diagram palette under 'Express'->'Signal Manipulation'->'Split Signals'.

I have attached a changed version of your VI which you will need to test.

Regards,

[zaq]

Hi George,

Thanks very much for this, that was a big help!

Zak

[Alexis_Koul]

Very good explanation and helped me also a lot!!

Thanks!!