No time series displayed when there are no motors #117
Description
In my fixed wing plane I set up the ESC as a servo rather than a motor, so that iNav thinks I have no motors. Did this because recent iNav fixes the ESC input PWM rate at 400Hz, and my aging ESC doesn't accept this, see iNavFlight/inav#8795 (comment).
I've just enabled blackbox, and though it appears to be recording data, the blackbox explorer shows a greatly diminished data set. No time series are displayed for the gyro or command inputs. The explorer doesn't complain about the file format, it just doesn't show any data. The FC config metadata and flight mode changes are displayed correctly, though.
Jumping to the punch line, I can work around this by configuring a dummy motor on a spare output on the FC, and sending the throttle channel both to the dummy motor and to the real ESC via the servo output. The plane behaves as before, but now the blackbox explorer behaves perfectly.
I believe this also explains an earlier report on RCG, where the user had the same problem using iNav in a glider, also with no motors. See:
I suspect that this is a problem with the explorer, rather than the logger, but haven't tried to validate this. My guess is that the explorer treats the motor data as special, and hits an edge case when there isn't any. The logger produces a readable file with length apparently proportional to the flight time. I've attached nonworking and working logs.
My setup:
- iNav 8.0.1
- AOCODARCF7MINI_V2
- Blackbox Explorer 7.0.1
- 1/32 logging interval
- OpenLog and onboard FLASH behave the same