How can you use the series of beeps you hear when powering up to diagnose issues with your equipment? Should all of the beeps be synchronized or is it ok if they are slightly off? Are there different patterns you might hear and if so, what do they all mean?
So normal startup sequence is three short beeps followed by two long beeps with different tonality.
- First three beeps means that ESC is powered and activated.
- Then if the throttle signal is detect goes one long low tone beep.
- Then if throttle is zero goes one long high tone beep. This signal means the end of the start sequence and ESC is ready to run.
There are manuals for both BlHeli_S and BlHeli_32 and they have a sections about sound sequences and what they mean.
Regarding the slight de-sync of startup tones it looks like this is not a problem and just something to do with Betaflight boot process and happens only with Bi-directional DShot enabled: https://github.com/betaflight/betaflight/issues/9103
Most likely this is caused by:
Some ESC's first entering boot mode because the signal line from the FC is not readily booted and doesn't provide stable signal level before the ESC is booting.
And it can be "fixed" if you first power-on the Flight Controller and then the ESCs: https://github.com/betaflight/betaflight/issues/9103#issuecomment-546684302
The normal blheli startup tones are similar to beep beep beep... boop. boop
The first 3 beeps are the ESC's powering on and initializing then there's a pause followed by two more beeps which means the throttle signal has been received.