nRF PPKII voltage measurement in ammeter mode

RE: nRF PPKII voltage measurement in ammeter mode

ovrebekk — Fri, 07 Jun 2024 10:12:49 GMT

You welcome, glad I could help 🙂

RE: nRF PPKII voltage measurement in ammeter mode

Mohan_sp — Fri, 07 Jun 2024 04:56:46 GMT

Understood. Will make the necessary changes. Thanks for your inputs!

RE: nRF PPKII voltage measurement in ammeter mode

ovrebekk — Wed, 05 Jun 2024 14:20:52 GMT

Good to hear that you got a working solution 🙂

The X in the table means that the digital pin has been both high and low within the sample period. In order to avoid this you either have to sample at the maximum frequency (100kHz), or ensure that the frequency of the input signal is lower than the sample rate by a factor of at least 2. In this case you can still get X's in the table when the input signal is changing, but you should have at least one valid reading for each change of the input.

Best regards
Torbjørn

RE: nRF PPKII voltage measurement in ammeter mode

Mohan_sp — Tue, 04 Jun 2024 14:11:47 GMT

Hi Torbjorn,

We contacted the regional sales director and we got a workaround solution, which was to measure the voltage externally and output it to the 8 digital pins of the PPKII to get a simultaneous measurement of curret and voltage. We did that and it is working pretty well!

We did come accross one issue. On the PPKII power profiler app, the 8 digital voltages are looking normal, however, when I export the log to a CSV, I see a lot of "x" in the data. What could be the reason for this?

The external setup I am using is updating the digital channels of the PPKII at about 8.7kHz and the PPKII sampling rate is 100Hz.

PFA the log file as well

devzone.nordicsemi.com/.../ppk_2D00_20240602T120607.csv

RE: nRF PPKII voltage measurement in ammeter mode

ovrebekk — Mon, 06 May 2024 12:15:49 GMT

Hi Mohan

I agree it would be a nice feature, fingers crossed they can find some time for it.

In the mean time, the best of luck with your project 🙂

Best regards
Torbjørn

RE: nRF PPKII voltage measurement in ammeter mode

Mohan_sp — Mon, 06 May 2024 11:41:36 GMT

Hi Torbjorn,

Thanks! That would be amazing and really helpful for us! Yes, I am in touch with a regional sales director. I will forward the request to him.

I do understand it's definitely not easy to ad a feature like this, but I think a lot of people will appreciate this feature as it would give the complete picture of how the battery discharged over time. A very high sampling rate is not required. Even a 1-100Hz voltage measurement rate would be sufficient.

Thanks & Regards

Mohan Prabhakar

RE: nRF PPKII voltage measurement in ammeter mode

ovrebekk — Mon, 06 May 2024 11:03:37 GMT

Hi Mohan

This might be possible, yes, but any kind of new feature request would have to prioritized alongside all the other projects the tools team is working on. This might seem like a quick feature to add, but it needs to be added on the GUI side as well, and any new feature needs to be well tested to ensure it doesn't impact on the existing functionalities of the PPK.

Do you have the contact details of one of the regional sales directors in Nordic?
If so you can forward the request to him/her, and they will forward it internally.

Best regards
Torbjørn

RE: nRF PPKII voltage measurement in ammeter mode

Mohan_sp — Mon, 06 May 2024 05:18:15 GMT

The external voltage given to the PPK in ammeter mode is internally connected to the ADC channel 4 of the MCU. Can't the firmware be modifed to take a voltage reading at specified intervals along with the current reading?

RE: nRF PPKII voltage measurement in ammeter mode

ovrebekk — Thu, 02 May 2024 13:39:33 GMT

Hi Mohan

There are no analog inputs that you can correlate with the current reading unfortunately, only 2 digital channels.

If you have some way of measuring the voltage externally maybe you can map it to the PPK2 data in some way, by writing a timestamp or similar over the PPK2 digital channels.

Best regards
Torbjørn