The ESC beeps twice

when I connect the power cable to the pixhawk, the ESCs emit two beeps (the first lower in tone, the second higher). Also, using QGroundControl’s motor test, I only ever get these two beeps, but the motors don’t spin. What could it be) (I didn’t find this case in the ESC manual (2 beeps).)
Thanx in advance!

Hi @PaoloN -
What model ESC are you using? What vehicle autopilot?

If it is a bidirecitonal ESC, it should be initialized by a servo-style PWM signal of 1500 microsecond pulse - if it is not a Basic ESC (bidirectional) that may be why you’re not hearing the ESC initialize? You may also have plugged the signal/ground connector in backwards - the white wire on the Basic ESCs is signal, and the black ground.

Thx Tony!
I have two Bluerobotics Basic ESC, each connected to a Pixhawk with rover firmware and to a T200 Thruster. I think wiring is ok. When I switch on the pixhawk I hear only two beeps…

This is the log:
[18:21:02.137] Info: Barometer 1 calibration complete
[18:21:02.137] Info: Beginning INS calibration. Do not move vehicle
[18:21:02.629] Info: ArduRover V4.5.3 (548b0b2c)
[18:21:02.629] Info: ChibiOS: 6a85082c
[18:21:02.629] Info: Pixhawk1 00270033 3332510E 33313832
[18:21:02.629] Info: IOMCU: 420 1001 411FC231
[18:21:02.629] Info: RCOut: Initialising
[18:21:02.629] Info: IMU0: fast sampling enabled 8.0kHz/1.0kHz
[18:21:03.021] Info: Initialising ArduPilot
[18:21:03.233] Info: ArduPilot Ready
[18:21:03.233] Info: AHRS: DCM active
[18:21:03.233] Info: RCOut: PWM:1-14
[18:21:05.184] Info: EKF3 IMU0 initialised
[18:21:06.839] Info: EKF3 IMU0 tilt alignment complete
[18:21:06.952] Info: EKF3 IMU0 MAG0 initial yaw alignment complete
[18:21:10.672] Info: GPS 1: detected as u-blox at 230400 baud
[18:21:20.876] Info: EKF3 IMU0 origin set
[18:21:20.876] Info: Field Elevation Set: 83m
[18:21:25.675] Info: u-blox 1 HW: 000A0000 SW: ROM SPG 5.10 (7b202e)
[18:21:41.374] Info: Throttle armed
[18:21:41.375] Info: Throttle disarmed
[18:21:43.643] Info: EKF3 IMU0 is using GPS
[18:21:43.643] Info: AHRS: EKF3 active
[18:21:59.190] Info: Throttle armed
[18:21:59.190] Info: Throttle disarmed
[18:22:19.531] Info: Throttle armed
[18:22:19.531] Info: Throttle disarmed

When I try to test the T200, it says 'Thorottle armed", then immediatly “Throttle disarmed”. Two beeps and nothing more

This is the sound I get: 3 beeps, then the annoying 2 beeps…

Hi @PaoloN, welcome to the forum :slight_smile:

This is good, and is the expected behaviour:

That said, it sounds like both motors are making the motor phase detection beeps, but it’s unclear whether only one is making the two signal-related beeps.

You notifications log isn’t showing anything obviously wrong, so the main things I’d try/check are

  1. Check your vehicle frame, to ensure it’s configured as a boat
  2. Check the SERVOn_FUNCTION parameters to see whether your motor assignments match the outputs you’ve connected the ESCs to
  3. Make sure the vehicle is in manual mode
  4. Test vehicle arming
  5. Test the motors individually

It could also provide some peace of mind to test the motors and ESCs with a servo tester or some other PWM source for the signal, but given the ESCs are vibrating the motors to make the beeps it seems unlikely that the motors or ESCs are the problem here.

Hi, @EliotBR , thx for your reply!
I’ll try to check what you suggested. I hope I can do something, if not… expect another request for help from me! :slight_smile:

Here I am already. :slight_smile: After some testing, using the engine test procedure I was able to get the T200s to move a little. They move little and badly, to start them it is useful to help them by rotating the propellers. It almost seems like they have little power available. They also activate when I try on channels 3 and 4 and with 1 and 3 as it should be (being connected to ‘main’ ports 1 and 3 of the pixhawk).
It’s all a mystery to me.
Could it be a problem with cables not being connected well? Could it be a problem with the ESCs (I inserted them in a heat shrinkable sheath and I wouldn’t want to have damaged them while I heated the sheath with the hairdryer)?
Here two videos explaining the issue:

Thanks again for your patience and help!

The problem was simply that the contacts between the ESCs and the motors were not made properly. it was enough to redo them and the engines began to work correctly.
Thank you!!

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