Sampling Rate and Simultaneous Programs

[Will]

Hello,

I have seen a lot of contradictory information online regarding the sampling frequency of the Analog Discovery 2 ADC channel. Is it possible to sample at around 30 MHz for 20s and store the data in a csv for example with a time stamp?

Second Is it possible to run several processes on the board simultaneously such as:

1) 2x analog read and data storage

2) motor control 

3) Waveform generator

assumming I have enough cores on my computer to run there respective programs.

 

 

[JColvin]

Hello @Will,

I have moved your question to a more appropriate section of the forum.

I am not certain if the specs you listed (30 MHz for 20 seconds and record the data) is possible; I will have to defer to @attila on that one. The main drawback from my understanding is keeping that amount of data in memory so that it can then be saved/stored on your computer. A record mode where the data is both sampled and stored is available, but it runs slower to account for USB transfer speeds (as far as I understand it).

It is certainly possible to run several possible processes simultaneously including the analog reading, motor control, and waveform generator simultaneously. I do not think cores will really be an issue for Waveforms since I don't think (again deferring to @attila) that individual processes operate on their own thread.

Thanks,
JColvin

[attila]

Hi @Will

The Analog Discovery Scope ADC rate is 100MHz. 
At this frequency or divisions of this it can store triggered captures of 8k samples / channel or 16k smp/ch with 2nd device configuration.

In record mode the data is streamed over USB which limits the rate to about 1M smp/sec.
In the WaveForms application the record length is limited to 16M samples/channel.
Script or custom application can be used to record more, unlimited samples.

The instruments in the device are running independently: scope, awg1, awg2, logic analyzer, pattern generator

You can try the WF application in demo mode, browse the help in this and look at the SDK Python examples:

https://reference.digilentinc.com/waveforms3

Related posts:

 

[Will]

Hi @attila,

Thanks for your reply although I am bit confused. Just to clarify:

With a custom script, it is possible to achieve my desired sampling rate and store all the data over my required sampling time?

If so where do I store my data? If USB transfer is too slow and on-board memory  insufficient, how will a custom script alleviate these problems?

 

 

[attila]

Hi @Will

The recording mode (from the WF app or custom app) streams data over the USB 2.0 interface which limits the maximum Scope sampling rate to about 1Msps.
The WF app records into PC memory and displays the captured data. You can do further processing on it if needed and you can export it in various formats CSV, TXT, TDMS, binary data file, image.
In custom app or script you do whatever you need with the data, record in memory, process it, save directly to file...