streaming on 5000a

[nanoballs]

HI i am quite new using picoscope with python... i cant find any streaming function.. As am trying to get a continous stream of data (some hours) from a channel at 16bit resolution and 5Ms/s i wold like not to have it in block mode but to be able to analize in real time. Has anyone something useful for it?
thanks!!

[DeadBugEngineering]

Hi, you might want to check out the "experiment" branch of the user morgatron. He implemented the streaming functionality and it seems to work fine on a P5444B. I'm not sure whether analyzing in real time and using a daq with a USB-interface go well together, tho.

[nanoballs]

thanks! il have a look to it!

[hmaarrfk]

Streaming was complicated because it required knowledge of how python's garbage collection works (at least I think so).

My worry was that you would set a buffer to stream to, then delete it. That would cause a segfault eventually. The other issue was: maybe you didn't want to use numpy. You would probably want to be super efficient if you are streaming data. Therefore, I decided to leave it to users to write the streaming code themselves.

If you find something that works, please submit a pull request. Collin and I do check this repo rather often.

[morgatron]

Oops, I just left a comment on issue #23 . Probably would've been better here. In short, I was running streaming and bulk data quite a lot a year or so ago, and based on that experience python makes it a bit harder to cause a segfault than you might think, and there's certainly ways to make it harder still. Not that my repository mentioned above is a great example.

A couple of other comments: as for not wanting to use numpy, I guess that's valid as not everyone has it installed- but then, if you're wanting do deal with large arrays in python you probably use numpy already? Otherwise I guess it'd probably work to use a builtin python 'array' object instead. As for speed, I found the major problem isn't the streaming itself, it's all the processing/visualising you inevitably want to do to which takes up CPU time and causes the streaming to skip. Ideally one runs the acquisition in a seperate process from the analysis/plotting and everything is good because the acquisition runs on it's own core.. I doubt one would want to add multiprocessing in picopython though.