Long monitoring/capture session

Technical Discussion
2

Hi @SMADE and welcome to the Joulescope forum!

Yes, Joulescopes are made for long, uninterrupted measurements. You have a few options.

  1. You can buy large, inexpensive drives. The JS220 produces about 1 TB per day at the full 1 Msps rate. Large drives are inexpensive these days, but 2 weeks is about the max. We designed our proprietary but open source JLS file format to support nearly instantaneous read, pan and zoom of these huge amounts of data.

  2. You can specify a lower sample rate. For long captures, many customers are happy with 10 kHz, which reduces the data rate and file size by 100. We recommend using the command line rather than the UI for even greater reliability. For example:

python -m pyjoulescope_driver record --frequency 10000 --signals i,v out.jls
  1. Some customers are happy with the statistics data (2 Hz by default) for long captures. We provide the downsample_logging which also supports recovery on power loss or host computer reset. We have had customers capture full product lifecycle over many months with this script.

While we work hard to make the Joulescope UI reliable, the Python scripts remove lots of code found in the UI including PySide6, Qt6, and Nuitka. Less code means fewer latent issues for even higher reliability.

For long captures, you also need to configure the host computer to keep running all the time. See Performing long-term captures on Windows.

Does this make sense and answer your questions?