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I was attempting to build a Voltage Generation/Voltage Acquisition program, but when I try to run it, an error (Error-200088) pops up with the message: "Task specified is invalid or does not exist". I'm not sure why this is happening. I have attached the program to this message. Any advice on how to proceed would be greatly appreciated.

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Message 1 of 8

I did not open your file.  But go into max and make sure you can run the task you are trying to use in your program.  A channel in the task might have an error.


Also double check the you are calling the correct task in your program.

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Message 2 of 8

What exactly do you mean by running it in max?

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Message 3 of 8

Hello UARK,


You've only wired your task through one case of your trigger configuration case structure- you've configured the other two cases to "Use Default if Unwired", which will return an empty/unconfigured task.  You need to wire your task through each case. Also, using a default task doesn't usually make sense, so I'd recommend disabling the default option by right-clicking on the tunnel in question.


The previous reference to MAX was suggesting that you use NI Measurement & Automation Explorer to test the functionality of your device and any preconfigured task(s) you might be using.


Best Regards,

Tom L.
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Message 4 of 8

Thanks Outlaw.


I fixed the problem and attached is the latest version of the program. The signal generation side of things seems to be working perfectly now; however, I'm not seeing the acquired signal in the graphical plot. Does anybody see anything blatantly obvious in my code that is not enabling me to see the voltage response? Can anybody help with this? 




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Message 5 of 8


I opened up your VI, created a simulated device in MAX, and saw data on all the graphs.

You could also try to change the type of plot you are using to a chart? I did that and I see all data generated and previously.

Are you getting any errors when you run and cant see the data? Have you tried probing the wire to see if any data is coming out? Have you run Highlight Execution on anything? What type of debugging have you done on it?

Douglas Choisnet
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Message 6 of 8

Thank you Douglas.


I went and added the same type of waveform graph (that I was using to see my generated signal) into the acquisition side of the program (see attached). I think I did this correctly. To test this, I just wired the OUTPUT pins to the INPUT pins directly (on my SCB-68) and piggy-backed off of the INPUT pins with an oscilloscope to verify that I was indeed sending the signal I thought I was. I saw the expected response on the oscilloscope; however, I did not see the correct response on the acquisition graph.** This may not be an issue for me (although annoying), since graphing the acquired signal is not my end goal. I need to start writing the data so that I can use MATLAB to post-process my data and plot my responses.


My next step is now to write voltage in one column and an associated time stamp for each voltage reading in another column for both generated and acquired signals. I have looked at some examples out there, but none of them seem to apply to what I am trying to do. Any helpful advice on how to proceed writing my data to a simple text file (not excel spreadsheet or binary file) would be greatly appreciated.


**I did perform the Highlight Execution on my program earlier on. Neat tool.

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Message 7 of 8



What you will most likely want to do is have a loop that concatenates the current time, a tab constant, and then the value of your graph, and then save them into a file. This will allow all the time to be in the string, a tab space to seperate the data, and then the values of your data.  To save into a file, I found this article that should be very useful. 


Write some code trying to do this, and if you still run into issues, post your VI in a response and we will try to direct you where the issue is coming from.

Douglas Choisnet
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Message 8 of 8