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Reserved task error

Hello,

 

I am trying to measure voltage from two BNCs and one wheatstone, and then graph it. The two BNCs run fine together, but when I add the wheatsone channel I receive a reserved task error. How can I know which task is already in use? And how can I fix it?

 

Thanks in advance for your time and effort,

Ben G

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At a guess, read the error message 😉

It's not obvious what's going on from the picture, but I'd say you're having problems with the analog input sampling clock, or something similar.

 

In the top part of the image, you have two channels in the same task. In the bottom part, you have a separate task entirely, using an analog input task with the same device (cDAQ1).

I'd guess some combination of the case structures is acceptable, but when you have both running they conflict regarding the analog input clock.

 

Put them all in the same task (if necessary by repeatedly calling the DAQmx Create Virtual Channel node without branching the task wire) and then your problem is probably going to go away.

 

If I misunderstood or guessed badly, upload the VI and give more information about the problem (in particular, the error message and the desired behaviour), along with anything you think might be helpful. Better to have too much information than too little.


GCentral
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Here is the VI.

 

I have tried to put them in the same channel, but then receive Error -200431: Selected physical channel does not support the measurement type required by the virtual channel you are creating.

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bump.

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@1eyedjack wrote:

Here is the VI.

 

I have tried to put them in the same channel, but then receive Error -200431: Selected physical channel does not support the measurement type required by the virtual channel you are creating.


Hmm. If they don't throw that error separately, I don't see why they would throw it together, assuming that you use separate Create Virtual Channel nodes for the different types and connect only "acceptable" (physical) channels.

 

The error message tells you that the channel you wired doesn't support the measurement type - usually this is because e.g. it's an analog input channel, but you're using it as a pressure bridge input (even though really that's still just making an Analog Input measurement, if I recall correctly).

 

If you really can't get it working with a "fancy" virtual channel type, you could consider using the more basic Analog Input and then scaling the results yourself, although I understand that that's less than totally desirable...


GCentral
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