Hi @confused and welcome to the Joulescope forum!
The Rasberry Pi is quite special since it contains a unique graphics engine. The Raspberry PI 3 and older are all 32-bit, while the 4 can be either 32-bit or 64-bit making things even more interesting. I tried unsuccessfully to get the Joulescope UI running on a Raspberry Pi 4 a year ago. Here’s the GitHub issue. Perhaps the Joulescope UI will work now, but it’s not something we support. The less stressful approach is to use an Intel-based platform with Linux (Ubuntu), Windows, or macOS.
Now, the Raspberry Pi 4 is perfectly capable of running downsample_logging.py. I am not surprised that you are running into issues with more than 3 Joulescopes.
Unfortunately, USB 3 still limits you to 2 or 3 Joulescopes, depending upon the host system. USB 3 is actually two entirely separate things in one: a USB 2 “differential” pair (low-speed, full-speed, high-speed), and one or more new super-speed differential pairs. Joulescopes work on the USB 2 “differential” pair. Using a USB 3 port does nothing to change this, and the system is still limited to USB high-speed operation. USB 3 is a confusing mess, and the USB-IF is not helping.
Joulescopes always transmit full-rate data, unless you use the on-instrument statistics computation. With downsample_logging, you can pass the
--source sensor option, and it will work with the 6 attached Joulescopes! The limitation is that the on-instruments statistics always run at 2 Hz. Note that downsample_logging will capture data from multiple connected Joulescopes.
Does this help? If you could provide more detail on exactly what you want to collect, I am happy to help figure out a way to accomplish it. Here are some questions:
- Is 2 Hz statistics sufficient?
- If not, what sampling rate do you want? Note that CSV, TXT or sqlite are all impractical for full-rate 2 Msps data. For example, Excel can only open 1,048,576 rows, or about 1/2 second.
- Is a “live feed” of text statistics printed to the console sufficient? Or do you really want a UI?
- What do you intend to do with this data? Are you analyzing it in real-time? Visually viewing it in realtime? Analyzing it offline with python? Something else?