Power Profiler Kit II: incorrect measurement

RE: Power Profiler Kit II: incorrect measurement

Peter49 — Thu, 11 Jan 2024 17:16:18 GMT

Hello Håkon,

Directly into the USB Port of a laptop - HP ZBook with Intel Core i7 vPRo 9th Gen processor.

RE: Power Profiler Kit II: incorrect measurement

Håkon Alseth — Thu, 11 Jan 2024 09:40:41 GMT

Hello,

[quote user="Peter49"]Was your team able to provide a reason to the above issue?[/quote]

My apologies, but it seems that this has been a bit of a tough scenario to reproduce at our end.

We have not been able to reproduce this yet, unfortunately.

Could I ask about your physical setup?

Q1: Is the PPK2 connected through a USB hub? If so, is there any change if you connected directly to a USB 2.0 port instead?

Q2: Are you running on a AMD or Intel Platform?

Kind regards,

Håkon

RE: Power Profiler Kit II: incorrect measurement

Peter49 — Mon, 08 Jan 2024 16:44:55 GMT

Hello Håkon,

Was your team able to provide a reason to the above issue?

Thanks.

RE: Power Profiler Kit II: incorrect measurement

Håkon Alseth — Tue, 31 Oct 2023 14:51:20 GMT

Hello,

Thank you for sharing the files. I have reported this internally to the PPK2 team and shared your files with them.

Kind regards,

Håkon

RE: Power Profiler Kit II: incorrect measurement

Peter49 — Mon, 30 Oct 2023 16:17:41 GMT

Hello Håkon,

Unfortunately, I don't seemed to have the saved the ppk file for the first 3 screenshots above, but i do have the file for the last screenshot (this was from another test).

In this data, you can see the behaviour change from average baseline 1.521mA to 2.09mA at the ~3 hour mark after the LTE has completed and terminated the connection.

devzone.nordicsemi.com/.../ppk_2D00_20231027T192251_2D00_data_2D00_logger_5F00_BORB03.ppk

Here is a second data file with similar results

devzone.nordicsemi.com/.../ppk_2D00_20231024T230950_2D00_data_2D00_logge_5F00_BORB03.ppk

I also ran another test today, where the baseline current increased after 1 hour (after an LTE connection).
After 3.5 hours i stopped the logging and saved the file. And restarted for another 5 minutes to log the lower baseline after the restart. The time between the stop and start was less than 20 seconds.

Here are the 2 files for this test if it helps.

devzone.nordicsemi.com/.../ppk_2D00_20231030T200812_2D00_data_2D00_logger_5F00_BORB03.ppk

devzone.nordicsemi.com/.../ppk_2D00_20231030T201325_2D00_data_2D00_logger_5F00_BORB03.ppk

RE: Power Profiler Kit II: incorrect measurement

Håkon Alseth — Mon, 30 Oct 2023 15:16:53 GMT

Hi,

Thanks for providing such in-depth explanation, in addition to screenshots of the measurements.

[quote user=""]In investigating to the reason for this, i have additionally connected a DMM to simultaneously measure the current with the PPK-II.
The DMM measurement remains at 1.52mA while the PPK-II is measuring higher at ~2.00mA.

This seems to be reproducible after a long runtime > 2 hours, and after an LTE call-in where there is an increase in current possibly when the current reaches >150mA (poor signal).

Interestingly, the current measurement on the PPK-II returns to the correct measurement after the datalogger is stopped and restarted again from the PC Power Profiler App (v3.5.5). [/quote]

This is very interesting. If the PC software sampling is cycled, ie. Stop/Start sampling, without actually cutting the power; you observe the correct 1.5 mA consumption, even in the GUI software.

I checked the ppk2 fw, and it is not much that is actually "stopped" when you hit the stop sampling button, which can point towards a race-condition in the PC tool.

Do you happen to have the .ppk2 file saved, so I can share this with the PPK2-team for further analysis?

Kind regards,

Håkon