DAQ virtualization

[tianshiz]

Hey guys,

   Right now I have a PXI-4024 with an attached 5v power source. Running a sample program to measure the voltage inputted shows the 5v graph, no problem there. Now suppose I want to attach an additional card to measure this input power as well, but I want to simluate this card in labwindows so the software believes that there is another card and gets the readings from the card (just like it gets the reading from the attached card). Is this possible? How would I go about doing this? Getting this virtual card recognized is the biggest thing, how it measures and etc are not so important at the moment.

Thanks a lot,

tianshiz

[tianshiz]

i did a bit more researching and came up finding that NI switch executive allows for the creation of virtual devices. Do you guys think that this is what I would need?

Thanks

[Jake_G]

Hey tianshiz,

I have not heard of the PXI-4024, do you mean a PXI-4021?

If this is the case then you should be able to simulate the device using Measurement and Automation Explorer in the National Instruments folder in the programs list in Windows.  There is a tutorial located here that can help with how to do this.

After you have simulated the device you should be able to recognize it in LabWindows/CVI.

If it is a Switch, there is another tutorial here on how to create and use simulated switches.

[tianshiz]

oops sorry I mean PXI-4204...

ill take a look at your links and get back to you.

thanks a lot!

[tianshiz]

it looks like the simulated device returns a sign wave, the data that it gets me isnt the same as the device itself. Can this be changed?

[Jake_G]

Hey tianshiz,

Unfortunately, all simulated devices return analog input data in the form of a full-scale sine wave with three percent of full-scale noise.

You may be able to scale the input to a very small wave and shift it to the voltage you want in software, but the actual input data will be a sine wave.

For more information on NI-DAQmx simulated devices, look here.

[tianshiz]

hey Jake,

thanks for the help. I was recommended by Roberto to consider using NI-MHDDK, do you concur this is only option left?

[Jake_G]

Hey tianshiz,

I'm afraid I'm a little unfamiliar with that particular development kit, but it may be an option.

Please take a look at Measurement Hardware Driver Development Kit (MHDDK) Frequently Asked Questions or post in the forum under it's related field, like here.