DAQ Assistant, Analog output and Analog Input

[lakersrl]

Hello,

Im looking to include both DAQ Assistant for Analog output and Analog Input channels. Im trying to use the select signal VI to acquire specific channels for analog input and analog output. Any advice towards this? It seems that I cannot include both DAQ assistant output and input VIs within my main VI? How would you increase the number of channels usable by the select signal VI, I believe it only has 8 channels, where I need more than this. I tried to use two select signal VIs with different channels but this doesnt seem to work. Any help would be greatly appreciated.

Thanks

[RavensFan]

You can't have a DAQ assistant handle both analog inputs and outputs at the same time.  You need to use two different DAQ assistatns.

Are you talking about the "Select Signals" Express VI?  It looks like it is limited to 8 signals.  If you need more, then you are going to have to learn how to do things beyond using big, boxy, blue Express VI's.  If you right click on an express VI and select Open Front Panel, it will turn it into a subVI you can look at and see how it is really handling things behind the scenes and do it yourself that way.

[lakersrl]

Im trying to use different DAQ assistants, with different Select Signals VI. I want the Analog output DAQ assistant with secific analog output channels that the Select Signals VI selects and the analog input DAQ assistnat with specific analog input chanls that another Select Signals VI accepts. Is this possible? Seperate output channels for one Signal VI and seperate input channel VI for another Signal VI?

[lakersrl]

Also, is it possible to use Select Signals VI with the DAQ assistant for analog output, he wiring is a little different than the wiring for the DAQ assistant for analog input.

[lakersrl]

Error -200294 appears from the DAQ assistant AO. Any help on how to fix this?

Not enough samples were written to satisfy the initial data transfer request condition.

To successfully start a generation, increase the number of samples initially written to the buffer before starting.  Alternatively, decrease the number of samples required to start by changing the data transfer request condition.

End of Data Sample Number: 0
Minimum Value: 1

Task Name: _unnamedTask<3>

[JustinP]

Hello, 

The Select Signals VI inputs a set of signals and allows you to choose which signal(s) are passed on to the next function in the LabVIEW code, it does not select the physical input/output channel. For analog input you can split the signals with the Split Signals VI and can separate the displays or logging of the signals as needed. For the analog output you will have to change the channel configuration in the DAQ Assistant to output on different channels, this is because the channels are configured and then the signal is written to a buffer and then to the channel that was configured. As for the error you are getting, this means that the signal that you sent to the DAQ Assistant didn't match the samples that you configured the DAQ Assistant to output.  Ensure that the signal that you are generating has enough samples to match the Samples to Write.  

Thank you,

Justin  

[stetbu]

Hello,

   I have DAQmx USB-6001.

   Can DAQ Assistant configure a task for analog input and analog output at same task?

   if not, configure a task for analog input and other task for analog output, can a project add two task.mxb together?

Thanks

[RavensFan]

Reread the earlier messages in this thread.

No a DAQ assistant can't have an analog input and analog output.

Create two different DAQ assistants.

[stetbu]

Thanks for reply.

How to add two different DAQ Assistant  into one project?

[Dennis_Knutson]

The exact same way you dropped the first assistant onto the block diagram except you select analog output when you configure it (assuming you selected analog input for the first).