5922 forcing 24 bits resolution

[falkpl]

I have a PXI 5922 and I am new to the NI scope interface.  I want to read values at the 500kHz rate at the 24bit resoultion.  How do I make sure the settings are correct with the NIScope API?

Paul

[TheWoost]

Hi Paul,

The Flexible Resolution technology of the PXI-5922 allows the ADC to have the best possible resolution for the configured sample rate.  If you set the sample rate of the device to be 500kS/s, the resolution of the ADC will automatically be 24-bit.  The specifications sheet for the 5922 shows the resolutions that are available at different sample rates.  To see how the resolution is configured in your LabVIEW application, you can use the NI-SCOPE property node for Acquisition>>Resolution after the "niScope Initiate Acquisition.vi".  The shipping example "niScope EX Configured Acquisition.vi" is a good example for testing this out.

Regards,
Andrew W
National Instruments

[falkpl]

Great I will use the Acquisition>>Resolution node to validate that I am using the full 24 bits.  I need to ensure that I have the highest resolution the 500kHz is plenty fast fo this app. 

Paul

[aya1503]

Hello,
I have recently purchased a NI PXI-5922 which has flexible resolution. Is there any way that you can set the resolution at a 50 kS/s sample rate to be 16 bit instead of the automatic 24 bit? I am wondering whether the PXI can be programmed to be a low frequency spectrum analyser.

Thanks

aya1503

[Luke_G]

Hi Aya,

The Scope driver automatically configures your device to have the best resolution for a given sampling rate.  There is no way to decrease the resolution other than increasing the sample rate.  Out of curiosity, why would you want to decrease the resolution of your device?  Perhaps I don't understand your application, but I don't see how that would help with spectral analysis.

Regards,

[aya1503]

I wanted lower resolution just to keep the data file sizes small! Because a lot of the data ranges would be just capturing virtually nothing.
Thanks for the help!

[TooEagerToLearn]

Sorry to piggyback on an old conversation. How do I set the resolution of PXI 5922 to 16 bits for a sample rate of 2MHz? I don't want extra samples as I worry about it filling up the buffer. Or is that something not to be concerned about?

Also, are there any good resources on NI.com regarding record size? This is a new parameter that isn't used in daqmx but in NI Scope vis. A refresher on sample rate, number of samples, loop rate etc. would also be helpful.

Thanks!

[4Matted]

Vijay,

I would recommend you try posting this on a newer forum in order to get a higher level of community response. This will ultimately be more beneficial to you and the community as a whole as your answer will be more visible to people with similar questions. Thank you.