Elktro Posted March 25, 2010 Report Share Posted March 25, 2010 I have been trying to create a channel with DAQmx Create Channel (AI-Voltage-Basic) in a Sciware GOOP class. The DAQmx gives me a task, which I start and then direct the task to the appropriate data member of the class. So far everything goes fine. However, when I retrieve the task from the data member to acquire a voltage value, I get the following error: Error -200429 occurred at DAQmx Read (Analog DBL 1Chan 1Samp).vi Possible reason(s): Measurements: Value passed to the Task/Channels In control is an empty string (or I/O control). The value must refer to a valid task or valid channels. So where did the task disappear? Please, see the attached code. DAQmx_task_test.zip Quote Link to comment
Aristos Queue Posted March 25, 2010 Report Share Posted March 25, 2010 I do not know much about SciWare's GOOP, but any refnum or resource (like a task) that is created in LabVIEW is automatically disposed when the *top-level* VI that created it goes idle. Is it possible that you are creating the DAQ task in some VI that is being called using the Run VI method of VI Server, and that VI is going idle and thus throwing out the newly created task? Quote Link to comment
Elktro Posted March 29, 2010 Author Report Share Posted March 29, 2010 Is it possible that you are creating the DAQ task in some VI that is being called using the Run VI method of VI Server, and that VI is going idle and thus throwing out the newly created task? I'm not quite sure when subVI is in a idle state, but the SubVI that creates the task goes into "SubVI waiting to run"-state. But how can I make a subVI not to go idle when exiting from a subVI? Quote Link to comment
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