I want to make a calibration setup for BLDC ESC in the simulink model. I'm using arduino mega (3,9,10,11 pins) and quatro 30Ax4 esc. Normally I can set it to it's max, min, and incrementally increase/decrease duty cycle with transmitter throttle signal by mapping (1000,2000,160,255) and there is no problem. But when I try to map it 0,255 it doesnot work (sounds every 2 seconds like a throttle signal is abnormal).

I need two suggestions;

1. why I cannot map the signal on the full range (0-255).

2. is it possible to make calibration by just sending the max and min values such as shown in the figure instead of using any mapping techniques?



1 Answer 1


Missing a few information, so I will assume the following: - Using the instruction analogWrite() to send pulses to the ESC. - Not using the Mega pin 4 or 13. - your map() instruction is converting from your receiver pulse length to your analogWrite() function.

ESC require a pulse between 1000uS and 2000uS. Therefore, analogWrite(160) is about a 1280uS pulse. (as per analogWrite() reference note, the PWM frequency is 490Hz) Sending a PWM lower than 125 will send an invalid pulse length.

Some ESC wont arm if the pulse length is off by even a few uS, so it's good to calibrate them when you do a change in your map() function.

Can't help you for your Simulink model

  • $\begingroup$ I wrote the pin numbers you can see them above. I amnot using arduino IDE just simulink. you mean that I cannot use full range (0-255) and my min command should be 125 and also I cannot use switching calibration procedure. right? $\endgroup$
    – lsn
    Commented Mar 12, 2019 at 21:42
  • $\begingroup$ Why not using the Servo blocks. It will provide you the right pulse length and higher precision. Sending a PWM value of 255 doesn't send a pulse but keep the line at HIGH. So the highest value you could send is 254. $\endgroup$
    – Kojoe
    Commented Mar 13, 2019 at 13:44

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