Odd temperature shown on VOXL ESC v2

hmlow

Hi devs

I ran the voxl-esc-spin.py tool and noticed some oddities in the reported temp.

When i run the spin test immediately once the board (was cold) has been powered up:

Note that my room temp is 25 deg C

[0] RPM: 4767, PWR: 10, VBAT: 8.22V, TEMPERATURE: 27.32C, CURRENT: 0.12A
[1] RPM: 4774, PWR: 10, VBAT: 8.21V, TEMPERATURE: 26.97C, CURRENT: 0.21A
[2] RPM: 4778, PWR: 10, VBAT: 8.17V, TEMPERATURE: 45.87C, CURRENT: 0.06A
[3] RPM: 4672, PWR: 10, VBAT: 8.20V, TEMPERATURE: 56.84C, CURRENT: 0.14A
[0] RPM: 4792, PWR: 10, VBAT: 8.23V, TEMPERATURE: 27.08C, CURRENT: 0.02A
[1] RPM: 4774, PWR: 10, VBAT: 8.21V, TEMPERATURE: 26.97C, CURRENT: 0.21A
[2] RPM: 4778, PWR: 10, VBAT: 8.17V, TEMPERATURE: 45.87C, CURRENT: 0.06A
[3] RPM: 4672, PWR: 10, VBAT: 8.20V, TEMPERATURE: 56.84C, CURRENT: 0.14A
[0] RPM: 4792, PWR: 10, VBAT: 8.23V, TEMPERATURE: 27.08C, CURRENT: 0.02A
[1] RPM: 4747, PWR: 10, VBAT: 8.20V, TEMPERATURE: 27.03C, CURRENT: 0.14A
[2] RPM: 4778, PWR: 10, VBAT: 8.17V, TEMPERATURE: 45.87C, CURRENT: 0.06A
[3] RPM: 4672, PWR: 10, VBAT: 8.20V, TEMPERATURE: 56.84C, CURRENT: 0.14A
[0] RPM: 4792, PWR: 10, VBAT: 8.23V, TEMPERATURE: 27.08C, CURRENT: 0.02A
[1] RPM: 4747, PWR: 10, VBAT: 8.20V, TEMPERATURE: 27.03C, CURRENT: 0.14A
[2] RPM: 4776, PWR: 10, VBAT: 8.17V, TEMPERATURE: 45.84C, CURRENT: 0.01A
[3] RPM: 4656, PWR: 10, VBAT: 8.20V, TEMPERATURE: 56.76C, CURRENT: 0.11A

Running the spin test 20mins later when the temps have stabilized:

[0] RPM: 4781, PWR: 10, VBAT: 8.24V, TEMPERATURE: 53.65C, CURRENT: 0.06A
[1] RPM: 4802, PWR: 10, VBAT: 8.22V, TEMPERATURE: 50.90C, CURRENT: 0.17A
[2] RPM: 4801, PWR: 10, VBAT: 8.21V, TEMPERATURE: 74.32C, CURRENT: 0.02A
[3] RPM: 4680, PWR: 10, VBAT: 8.23V, TEMPERATURE: 87.42C, CURRENT: 0.14A
[0] RPM: 4781, PWR: 10, VBAT: 8.24V, TEMPERATURE: 53.65C, CURRENT: 0.06A
[1] RPM: 4802, PWR: 10, VBAT: 8.22V, TEMPERATURE: 50.90C, CURRENT: 0.17A
[2] RPM: 4801, PWR: 10, VBAT: 8.21V, TEMPERATURE: 74.32C, CURRENT: 0.02A
[3] RPM: 4680, PWR: 10, VBAT: 8.23V, TEMPERATURE: 87.42C, CURRENT: 0.14A
[0] RPM: 4781, PWR: 10, VBAT: 8.24V, TEMPERATURE: 53.65C, CURRENT: 0.06A
[1] RPM: 4795, PWR: 10, VBAT: 8.22V, TEMPERATURE: 51.03C, CURRENT: 0.19A
[2] RPM: 4792, PWR: 10, VBAT: 8.20V, TEMPERATURE: 74.39C, CURRENT: 0.04A
[3] RPM: 4680, PWR: 10, VBAT: 8.22V, TEMPERATURE: 87.51C, CURRENT: 0.15A
[0] RPM: 4785, PWR: 10, VBAT: 8.24V, TEMPERATURE: 53.80C, CURRENT: 0.10A
[1] RPM: 4795, PWR: 10, VBAT: 8.22V, TEMPERATURE: 51.03C, CURRENT: 0.19A
[2] RPM: 4792, PWR: 10, VBAT: 8.20V, TEMPERATURE: 74.39C, CURRENT: 0.04A
[3] RPM: 4680, PWR: 10, VBAT: 8.22V, TEMPERATURE: 87.51C, CURRENT: 0.15A

IDs 3 and 4 starts with a much higher (i would say incorrect) temp compared to 1 and 2. When stabilized, all 4 seems to have gained 27-30 deg C from their respective initial temps.

Is there smth wrong?

Chad Sweet

The temp parsing code is broken. Coincidentally enough, we fixed this last night on our branch. We'll get you the pointer to cherry pick that change. Otherwise, you can just ignore for now

Alex Kushleyev

@Chad-Sweet , this is using voxl-esc python tools, the parsing should be correct. Indeed, this is odd.

@hmlow

When you just plug ESC into 8V power (power supply), can you please look at idle current draw? at 8.00V with no motors spinning, the current draw should be 30-40mA. if you see higher current draw, this probably means something is wrong with one of the ESC channels.

Also, can you briefly turn on the ESC (enough to heat up to 50C for ID3), then turn the power off and feel with your finger if it is indeed hot compared to others. Please don't touch the ESC if the reported temperature is higher than 50C.

I have never seen the temperature measurement being incorrect, so I suspect that there is some issue with the board. You can see that in steady state, the ESC ID3 is spinning 100rpm slower than others which are within 10-20rpm, so that is a sign of an issue with ID3.

Alex

Alex Kushleyev

Also can you please try voxl-esc-spin.py --power 0. -- this will not spin but get the feedback. I am curious if temperature will rise. it seems like it will, since in your first test the temperature differential was already high by the time you started the script (meaning it heated up since you applied power, before spinning).

In general, while spinning at low power, the ESC MCU temps should be around 40deg C and pretty even. ID3 seems to be heating up and heat is spreading to ID2 (next to it) and other IDs that are farther and more insulated in terms of heat transfer. Please inspect the ESC for any damage or loose solder or loose components.

hmlow

Thanks @Chad-Sweet and @Alex-Kushleyev for the suggestions.
Indeed it was a faulty ESC.

Swapped it out and all temps are look fairly similar. On idle (room temp 25deg), the ESC temp stabilizes at around 50 odd degrees C.