Joulescope frozen - red USB text

I am currently using Joulescope UI version 0.8.16 and driver version 0.8.14. While doing measurements the UI freezes when I change the current too fast upward. It seems to work sometimes on another computer, both computers with Windows 10. When it freezes the USB indicator in the bottom right corner turns red. Only when I get the current back to where it was stable it turns back to green and the measurement continues. In the log file I get the following warning:
WARNING:2020-06-22 10:22:01,958:main.py:1407:joulescope_ui.main:status RED: d_sample_id=0, d_sample_missing_count=0

I assume it has to do with the computer. I tried to this also with only the UI open and no other USB connected - still freezing.

Hi @fma21 and welcome to the forum!

First, the indicator light turns yellow or red when samples are being dropped. Both the host software and the device handle this gracefully and return to logging data, just like you observed.

From your description, I am concerned that your Joulescope is not powered sufficiently. Can you confirm that you are connecting your Joulescope’s host USB connector directly to your host computer’s USB port? Please ensure that no hubs or docking stations are between Joulescope and your host computer.

If this does not fix the problem, here are some other things to consider:

  1. When this event occurs, is your host computer doing anything other than running the Joulescope UI? For example, are you controlling the target or power supply using your host computer?

  2. What type of current and voltage step are you injecting? Very fast edges have lots of energy. While we have tested for this, it is possible that it is coupling into the USB side somehow. We never figured out what was going on with this topic: Frequent crashes in 0.6.8.

  3. If you set your Joulescope to a fixed 10A range and then measure this event, do you see the same sample drop behavior?

I am connecting the Joulescope directly to the host computer’s USB port.

  1. I am not controlling the power supply with the computer but there are other software running. I also tried using ONLY the Joulescope UI (with no software opened in the background), but it still gets stuck sometimes.

  2. The Joulescope displays around 4.3V and 30mA. I can control the voltage with another device and want to do measurements for 3.5, 3.7 and 4.3 Volts. Especially while lowering the voltage from 4.3V back to 3.5V is can get stuck. Normally this is not a big problem, since reconnecting the USB cable solves it. But now I want to automatize the measurements with a python code, where having to reconnect the cable is a problem.

I will investigate the problem further.

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