Hi, I'm building my first quad and am having problems getting the ESCs to arm. I have followed the ESC calibration instructions, several times, but no luck. On the APM (loaded with the latest code V2.1.0) I get a solid green light indicating it is armed. Radio has been calibrated. I attached a Fluke Scopemeter to the ESC drive pins on the APM to see what was going on and found everything OK, once the APM is armed I get pulses ranging from about 1.00ms to 1.80ms as the throttle is advanced. The pulse repetition rate (frequency) was 400Hz. To test the ESC I used a pulse generator and found that the ESC will not arm at any frequency above 150Hz (1.0ms pulse width). The ESC arms correctly when connected directly to my radio receiver (50Hz rep rate, 1.0ms pulse width).
The ESC is a E-flite 30 Amp Pro. Eflite technical phone support couldn't offer any suggestions.
As I see it I have two options, buy different ESCs and hope for the best or use the ones I have and change the ESC drive frequency to 150Hz in software and reprogram the APM.
Does anyone know where in the code I can change the frequency? I am not a programmer but can usually tinker with existing code to make things work.
Any ideas or suggestion would be welcome, thanks....
Replies
Try putting
# define INSTANT_PWM ENABLED
in your apm_config file and see if that solves your problems, it worked for me
Yes, we use 400Hz to overdrive the ESCs for better performance. Yours are the first I've heard of that don't like that.
The function is called INSTANT_PWM. Here's the relevant code in the motors.pde file for whatever frame you're using:
{
5000 is the timer setting for 400hz
40000 is the timer setting for 50hz