<p>The normal blheli startup tones are similar to beep beep beep... boop. boop</p>

<p>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. </p>

<p><a href="https://youtu.be/_hkzm8ZXsxE?t=58" rel="noreferrer">https://youtu.be/_hkzm8ZXsxE?t=58</a></p>

CC BY-SA 4.0
2020-05-04T16:15:32.257Z
2020-05-04T16:15:32.257Z
2pacsawyer
<p>So normal startup sequence is three short beeps followed by two long beeps with different tonality. </p>

<ul>
<li>First three beeps means that ESC is powered and activated.</li>
<li>Then if the throttle signal is detect goes one long low tone beep.</li>
<li>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.</li>
</ul>

<p>Here is diagram of normal boot sequence beeps:
<a href="https://i.sstatic.net/3bTzD.png" rel="noreferrer"><img src="https://i.sstatic.net/3bTzD.png" alt="enter image description here"></a></p>

<p>There are manuals for both BlHeli_S and BlHeli_32 and they have a sections about sound sequences and what they mean.<br>
Links:</p>

<ul>
<li><a href="https://github.com/bitdump/BLHeli/blob/master/BLHeli_32%20ARM/BLHeli_32%20manual%20ARM%20Rev32.x.pdf" rel="noreferrer">BLHeli_32 manual ARM Rev32</a>  </li>
<li><a href="https://github.com/4712/BLHeliSuite/blob/master/Manuals/BLHeli_S%20manual%20SiLabs%20Rev16.x.pdf" rel="noreferrer">BLHeli_S manual SiLabs Rev16</a></li>
</ul>

<hr>

<p>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: <a href="https://github.com/betaflight/betaflight/issues/9103" rel="noreferrer">https://github.com/betaflight/betaflight/issues/9103</a>  </p>

<p>Most likely this is caused by:</p>

<blockquote>
  <p>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. </p>
</blockquote>

<p>And it can be "fixed" if you first power-on the Flight Controller and then the ESCs: <a href="https://github.com/betaflight/betaflight/issues/9103#issuecomment-546684302" rel="noreferrer">https://github.com/betaflight/betaflight/issues/9103#issuecomment-546684302</a></p>

CC BY-SA 4.0
2020-05-05T20:03:50.083Z
2020-05-05T20:12:19.257Z
2020-05-05T20:12:19.257Z
Nikita Pedorich
<p>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?</p>

CC BY-SA 4.0
2020-05-04T14:39:11.017Z
This will depend on your speed controller(s), so the question is a bit broad at the moment - do you have a specific model in mind to narrow down the scope?
Kralc
CC BY-SA 4.0
2020-05-04T14:43:06.747Z
I currently use a Holybro Tekko32 F3 40A 4-in-1 ESC but it seems like all the ESC's that I have used so far ( either 4 singles or 4in1s ) have all had the same series of beeps.  At least in quadcopters.
5zero7rc
CC BY-SA 4.0
2020-05-04T15:43:29.667Z
what does the user manual say about the beeps?
jsotola
<hardware><esc>
When I power up my flight controller and ESC's, I hear a series of beeps. What do all of the beeps mean?
5zero7rc
# When I power up my flight controller and ESC's, I hear a series of beeps. What do all of the beeps mean?

(Asked by: username_0 on 2020-05-04)

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?

**Tags:** hardware, esc

> **Comments:**
> **username_1**: This will depend on your speed controller(s), so the question is a bit broad at the moment - do you have a specific model in mind to narrow down the scope?  
> **username_0**: I currently use a Holybro Tekko32 F3 40A 4-in-1 ESC but it seems like all the ESC's that I have used so far ( either 4 singles or 4in1s ) have all had the same series of beeps.  At least in quadcopters.  
> **username_2**: what does the user manual say about the beeps?  

---

## 2 answers

### Answer by username_4 on 2020-05-05. Score: 7 | Accepted answer

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.

Here is diagram of normal boot sequence beeps:
[![enter image description here](https://i.sstatic.net/3bTzD.png)](https://i.sstatic.net/3bTzD.png)

There are manuals for both BlHeli\_S and BlHeli\_32 and they have a sections about sound sequences and what they mean.  
Links:

* [BLHeli\_32 manual ARM Rev32](https://github.com/bitdump/BLHeli/blob/master/BLHeli_32%20ARM/BLHeli_32%20manual%20ARM%20Rev32.x.pdf)
* [BLHeli\_S manual SiLabs Rev16](https://github.com/4712/BLHeliSuite/blob/master/Manuals/BLHeli_S%20manual%20SiLabs%20Rev16.x.pdf)

---

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>


---

### Answer by username_3 on 2020-05-04. Score: 5

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.

<https://youtu.be/_hkzm8ZXsxE?t=58>


---

