What is happening when sending PWM signal at zero to ESC

Blue Robotics Products Speed Controllers (ESCs)
1

I’m using Raspberry Pi 3 to control a T100 Thruster via a BlueESC. When the thruster is spinning, I send a PWM signal at zero microsecond to the ESC and the thruster stops. To make the thruster spin again, it seems that I have to first re-initialize the ESC by sending a “stopped” signal at 1500 μs. Why is that?

Why is happening when I send a PWM signal at zero microsecond to the ESC? Why do I have to re-initialize the ESC before I can make the thruster spin again?

What’s the difference between sending a signal at 1500 μs and sending a signal at 0 μs?

2

@Yuanjie,

The BlueESC is really designed to work between 1000 us, full reverse, and 2000 us, full forward, with 1500 us being neutral.

Why are you attempting to send a 0 us PWM signal to the BlueESC?

A 0 us PWM signal may be an undefined value for the BlueESC controller?

Regards,

TCIII AVD

3

@Yuanjie,

Tom is right, sending 0 µs is an invalid command and will produce unusual results. The reason for that is that a 0 µs pulse is the same as no pulse at all. That means that the ESC will not receive any signal and after a short time it will require re-initialization to work.

The “stopped” signal for the BlueESC is 1500 µs.

Please let us know if that helps.

-Rusty

4

@Rusty

For how long the ESC has not received any signal will it require re-initialization to work?

5

Yuanjie,

I think it only takes 3-10 seconds before it deinitializes.

-Rusty

6

Thank you