How to measure 2 analog input signal simultaneously

[Disciple]

Hi,

    I have a PCI 6023E, Labview 8.2.1 and using NI_DAQmx. I trying to use measure voltage

across two different channels: AI4 and AI7. I trying to read voltage on a transformer, so AI7 would

be for the primary side and AI4 would be for the secondary. But when i trying run my program I get an

error message: "The specified resource is reserved. The operation could not be completed as specified."
In my program I have to two DAQ Assistant VI one for each channel. Would that cause 

the problem? Is it pssible to measure two signals using one DAQ, if so how can i go about that?

Thanks

 PJ 

[Dennis_Knutson]

Of course using two DAQ Assistants will cause the error. Did you even search the forum for the error code or error message you are getting? The same error has been reported numerous times. In fact, this is the second time today that I've answered the exact same question.

To repeat the answer, put both channels in a single DAQ Assistant.

[Zyrmax]

Hello PJ,

Use one Singe DAQ assistant then use the Split Signals from "Express/ Sig Manip" to extract each on signal and treat it seprately. 

Here is a small example.

[John_P1]

Just to confirm what the others have already said, you need to include all of your analog input channels into the same DAQ assistant.  The reasoning is that timing resources (sample clock, trigger circuitry, etc.) are shared between AI channels.  You can still configure channel properties (such as voltage range and terminal configuration) independently within a single DAQ assistant, but timing parameters must be shared between channels.

If you were using AO as well, this would be a separate task (and a separate DAQ assistant) since the AO circuitry has its own resources from AI.  The E series user manual is a good source of information if you are more interested about the hardware--for now I would follow the advice from Zyrmax's post if you need to access the channels independently in software.  Don't hesitate to ask if you have any questions.  Thanks for posting and have a great day!

-John

[greentea2]

Hi All,

I am having the same issue of measuring 2 analog input signals simultaneously despite using a single DAQ Assistant and the Split Signal.  When I run the program I get the following error: Error 2147024882: Labview ran out of memory. When I go directly into the DAQ Assitant and "Run" the program, I get an error 5202. When I searched what this error can mean, it was associated with the AMD microprocessor (which I do have). Any thoughts?

Thank you

[Leah-L]

Hi greentea2,

In the interest of keeping our discussion forums searchable and easier for others to access, it's always best to post separate issues onto a different thread. If you think it is related to another discussion forum, sometimes it is best to reference the older post in a new post.

As far as your error 2147024882 goes, it might be helpful to know how long you are running your code before you recieve this error, as well as what your sample rate is on your two channels. It might also be helpful to post your code so that we can look for any obvious flaws in your program architecture. 

Leah