multiple ai channels mixup

[Ice__man]

Hello everybody

I have a strange problem that I can't seem to find any help for, I hope that someone here can help me.

I am running Labview 8.2 with an 6009 USB DAQ,

I am trying to sample three ai channels, that works like a charm sometimes, I run my program and the right voltage shows up in the right displays,

then i stop the program and start it again then suddenly the channels switch, for example the flow voltage display shows the pressure voltage and vice versa, even if

I did not change anything.

I am using DAQ assistant for sampling these channels and then I use split signals to get three outputs.

I hope someone out there can help me:(

[ChillyWilly]

Hello,

It does sound strange.  Can you attach the vi to the message, I have the same card and can test it in my system if you want.

Also, you may want to go into Measurement and Automation and create a task with the three channels then go into your VI and use the DAQmx read.vi  to read the task.  From there you can use either waveform vis or cluster functions to separate the signals depending on how you set up DAQmx read (waveform or dbl array).

I hope this helps you.

[johnsold]

I was looking through the archives for other USB6009 information and saw a note about a similar problem which was related to timeout errors terminating a scan improperly. I think this was using an early version of DAQmx Base. You mention stopping the program and then restarting to get the error. How do you stop the program? Are you using the Abort button? The Abort button should not be used except for shutdown of runaway code as it does not allow for orderly resetting before quitting.

Lynn

[Ice__man]

Here is the vi that I am fighting with;)

[johnsold]

I don't have DAQmx or the DAQ Assistant (not supported on Mac OS) so I cannot test your VI. I looking at it I notice that the Stop button is wired to one of the DAQ Assistants and not to the others. I am speculating, but it may be that pressing the stop button while the first DAQ Assistant is running stops it, but then the others run one more time before the loop exits, prehaps causing some confusion. It might be better to just stop the loop, which will happen after all the code inside the loop has completed execution on that iteration.

Lynn

[ChillyWilly]

I tried your vi and i did not see the problem of the signals switching.

Perhaps somebody at NI can better assist you with this.