Hi @ikester - great to hear that Joulescope is working great for you so far!
With regards to long-term data collection, you certainly can use the UI as you mentioned. However, I recommend using the downsample_logging.py script in our pyjoulescope_examples GitHub repo. We developed this script with feedback from other Joulescope users to support long-term testing, one who has already started a VERY long test. This script keeps track along the way and allows for recovery, such as for when your computer reboots, USB has issues, Joulescope has any issues or you lose power. See the installation instructions in the README, and please don’t hesitate to post here if you run into any hurdles!
Joulescope computes energy using an infinite precision integer in units of pJ, so there is really no practical limit to how long Joulescope can run. We have done extensive long-term memory tests, and have no memory growth using the official releases.
If you do want to use the GUI for very long term testing, I recommend that you use no more than log_level WARNING (default is INFO), which you can change with File → Preferences → General → log_level. The Joulescope UI does record a log file, but this will be small with WARNING. As long as you don’t start a recording, the Joulescope UI will have no other file growth or memory growth over time. To minimize memory utilization, you can also shorten the streaming buffer by setting File → Preferences → Device → buffer_duration to 15. Keeping the UI in Multimeter view rather than Oscilloscope view also minimizes the amount of processing.
We have performed long-term testing with both the UI and downsample_logging. Our UI testing runs for about a week, and we let the downsample_logging test run for a couple of weeks. The customer running downsample logging for the longest has not announced anything publically, but you can see some other discussion here and here. We have good confidence in both the UI and downsample_logging. We are committed to supporting long-term testing using Joulescope, and we will support you in the event that you run into any issues!