How to wire Durandal to PM07?

PX4 Autopilot Flight Controllers 💻
1

I’m trying to build a coaxial heli, and I’ve got a few Holybro components, but I’m not exactly sure how to wire them.

I have the Durandal flight controller, PM07 power board, and a pair of Tekko32 F3 ESCs to drive the 2 coax motors. Each motor requires 3 PWM outs for the servos controlling thrust vector, and 1 PWM for the ESC controlling motor throttle, for a total of 8 PWM signals.

Wiring the batteries to the PM07 and wiring the PM07 to the 2 ESCs seems pretty straight forward.

But I don’t see how to get the PWM control signals from the Durandal to the PM07. The docs say the wiring is the same as the Pixhawk4, but the Pixhawk4 has a single PWM out that can plug right into the PM07 PWM in, but I’m not seeing an equivalent on the Durandal.

Any ideas?

2

You don’t need to plug into the PM07 the servo channel outputs are on the FC.
On a Pixhawk 4 there are no servo 3 pin outputs so you do need to use the PM07.

3

Ah, that makes sense, thank you. Two follow-up questions that are related:

  1. Would I plug the output of a BEC to, say, the RC IN 3 pin port to power the PWM’s + rail?

  2. Since my 2 ESCs would get power from the PM07, how would I wire the signal? Directly from the PWM outs of the Durandal like the servos?

4

The ESCs do NOT get power from the PM07 - the power pins are not connected.
You solder the ESC power wires directly to the BEC (I use XT60 connectors for this but really no need to).
The servo cables can not carry enough current (20- 40 amps)
If you have not seen this it might help:
https://docs.px4.io/v1.9.0/en/assembly/quick_start_pixhawk4.html
(I don’t solder the ESCs to the M points on the BEC and neither should you)

5

The ESCs do NOT get power from the PM07 - the power pins are not connected.

I’m not sure exactly what you mean, but an image in the pixhawk mini quick start is actually close to describing what I think you meant.

Anyway, given that diagram, I finished the block diagram of my project that I think will work.

Does it make sense to you?

6

I just meant that you need the ESC power connection right from the BEC.
That looks correct. I missed the fact you had a servo in the mix, so yes you will need to power the servo power rail.

7

Thank you, you’ve ben very helpful.

8

Thank you for getting back.
You deserve credit for asking a question in a way that could be answered!