Check a ADC with PXI-6259

[sxs707]

I use the M Series DAQ PXI-6259 in LabWindows/CVI ADE, and now I want to verify whether a 8-bit ADC working properly or not.

The input of the ADC is a sine wave and I acquire the 8-bit digital data (in Digital Format or Port Format ) each time the A/D convertion is completed. Next I want to regenerate the sine wave with the acquired digital data using 6259.

The analog channel supports only 64-Bit Floating-Point Numbers data format but not Unsigned and Signed Integers data format, have to I scale the acquired digital data to 64-Bit Floating-Point Numbers data format according to the amplitude of the sine wave and then regenerate the waveform ??

If so, have to I specifie the APFI0 or APFI1 as the source of the DAC reference voltage?

Thank you very much for your help.

Sxs707

[Dennis_Knutson · Accepted solution]

The DAQmx Write does support both signed and unsigned writes. Open Library>NI-DAQmx>Write Functions and find DAQmxWriteBinaryI16, DAQmxWriteBinaryU16, etc.

[sxs707]

Hi,Dennis,

have to I specifie the APFI0 or APFI1 as the source of the DAC reference voltage?

[sxs707]

Hi, Dennis,

Thanks very much for your help .I'm so sorry but i make a mistake in the above reply and now i try my best to convey my question clearly:

There are both DAQmxWriteBinaryI16 and DAQmxWriteBinaryU16. If I write the native data acquired from ADC to 6259 without any scaling using one of the two functions, have to I specifies both APFI0/APFI1 as the source of the DAC reference voltage and the amplitude of the sine wave as the value of the DAC reference voltage? Thanks.

[Dennis_Knutson]

What is the input range of ADC that you are testing? I'm not sure about the APF10/APF11 but offhand, I would think you want the reference voltage of the ADC and the 6259 to be the same. I don't see where you would use the amplitude of the sine wave.

[sxs707]

Hi ,Dennis,

Thanks for your help, now I see that I do need to set  the reference voltage of the ADC (but not  the amplitude of the sine wave ) and the 6259 to be the same. Thanks again.