myRIO 1900 Analog Input sampling rate

[London]

Hi All,

I am using myRIO 1900 and standard myRIO toolkit based Analog input Express VI to acquire a sine wave that I am feeding to connector C analog input channel. 

Although the specification states aggregates sampling of 500kS/s, maximum frequency that it can properly interpret is less than 2kHz.

I used the IO/monitor (instead of my labview code) that pops out as you plug in the USB and it shows the same result.

Any idea what this limitation is? I expect it to capture up to 50kHz (1/10th of 500kS/s) signal as long as I am using only one channel.

[DanC12]

Hi, 

The myRIO has one ADC for all the AI, (see page 7/8 http://www.ni.com/pdf/manuals/376047c.pdf), So the limiting factor would normally be the number of inputs. Since you're only using the one input, this shouldn't be the issue. 

What do you mean by "properly interpret is less than 2kHz."? What does the signal look like at frequencies higher than 2kHz?

[London]

Thanks for pointing out the ADC architecture.

Last time I found 2KHz as the cut off should be some sort of error in "IO monitor". Once I do that in Labview as shown in snippet below it seems to work OK upto 50kHz.