SCPI communication speed

Applications, development tools, FPGA, C, WEB
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dafa
Posts: 1
Joined: Fri Nov 18, 2016 9:22 am

SCPI communication speed

Post by dafa » Thu Jun 29, 2017 4:30 pm

Hi all,

I use SCPI commands to get the 125 MHz sampled data from the RedPitaya. As I noticed, the SCPI communication is quite slow. I have now measured the execution time of the API C functions with a C-program (Meas1) and a further measurement at the same settings from the PC with the SCPI commands in a Python-program (Meas2).

Meas1: Python-program ---> SCPI-server ---> API ---> FPGA
Meas2: C-program ---> API ---> FPGA

For example it takes 0.2 ms in the C-programm to get the data and in the Python-program it takes 600.2 ms. In the SCPI-server I lose about 600 ms, regardless of the amount of data I transfer from RedPitaya to my PC. Since I would like to acquire as much data as possible, this delay really limits my project.

Is the SCPI communication in general slow or where exactly lies the bottleneck?
Is there a possibility to make the SCPI communication faster?

Thanks a lot!
Last edited by dafa on Tue Jul 18, 2017 1:59 pm, edited 1 time in total.

izi
Posts: 34
Joined: Wed May 27, 2015 11:49 am

Re: SCPI communication speed

Post by izi » Wed Jul 05, 2017 11:09 am

We are aware SCPI is slow.

Some of the issues are linked to a missing feature in the FPGA code,
and to an ugly workaround in the C API (a delay to make sure buffer is filled with data before trigger).
This will be improved after rewriting the FPGA code and API (we are currently writing the API and debugging the new FPGA code).

The existing SCPI code will not be fixed before this major changes are done.

werefkin
Posts: 1
Joined: Tue Jan 26, 2021 4:16 pm

Re: SCPI communication speed

Post by werefkin » Tue Jan 26, 2021 4:22 pm

izi wrote:
Wed Jul 05, 2017 11:09 am
We are aware SCPI is slow.

Some of the issues are linked to a missing feature in the FPGA code,
and to an ugly workaround in the C API (a delay to make sure buffer is filled with data before trigger).
This will be improved after rewriting the FPGA code and API (we are currently writing the API and debugging the new FPGA code).

The existing SCPI code will not be fixed before this major changes are done.
Hi!

I would like to know, did you resolve this issue since that time? I am running SCPI data acquisition as well, and the time needed to get the data is around 250 ms, independently on the frequency.

The question is -- how is it possible to speed up the data acquisition?

Best regards

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