Unable to reverse servo output in ArduCopter 4.0.3?

In the servo output settings I have assigned the motors 1-4 to the servo channels 1-4 and now I want to reverse the outputted signals. I already have checked the reverse Boxes and also the ServoN_Reversed Parameters are all set to 1. But the channels don’t seem to be reversed, because when I increase the Throttle RC input, the green bars in the servo output settings are still going right and the values are increasing.

I have also tested the issue in ArduPlane and here, the reversing of everything is working fine.

Please help me to reverse the outputs of the Pixhawk!
Thank you in advance

Are you trying to revers the direction of the motors?

No I’m trying to reverse the PWM signal, so that the output is max when the input is min and vice versa.

I do that on the Transmitter.

Then I can only reverse Throttle etc.
But I want to reverse the Motor outputs.

Sorry, I don’t understand what you are trying to do.

In the Servo Output Section in the Initial Setup section, you can assign functions to the outputs of the Board. You can also set the min, max and trim values. There is also one box called “reverse” to reverse the PWM output, so that the duty cycle of the output is max when the motor should spin not at all and the duty cycle is min when the motor should spin at the max rpm. My problem is, that checking the reverse box doesn’t effect anything.
I want to reverse/inverse the signal, because the outputs are connected to a circuit, which is also inverting the signal. If the signal is inverted twice, it’s the original signal again.

Its not possible to reverse the motor servo outputs. Sorry

That’s what was confusing me with a Motor Assignment.

Why?? Can I edit the code or something to make this work? Or is there something like a trick?

Because if people click reverse it would result in there motors coming on at full power

of course

You could try setting MOT_PWM_MIN to 2000 and MOT_PWM_MAX to 1000, you could also try using the reversible settings. I would be surprised if you can get it to work without at the very least a pre-arm parameter warning.

I think you would have a easier time altering whatever it is you have listening to the outputs

You could try setting MOT_PWM_MIN to 2000 and MOT_PWM_MAX to 1000, you could also try using the reversible settings. I would be surprised if you can get it to work without at the very least a pre-arm parameter warning.

That doesn’t work, I tried it on the bench test rig.

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Can you tell me what the reversible settings are? Because this setting of the mot_pwm_min/max isn’t doing anything.

Also, could the THROTTLE_REVERSE variable in the APM_Config.h file maybe do what I want?

Have you considered using the heli quad frame, then you can do what your like because there not motors. https://ardupilot.org/copter/docs/heliquads.html

ok I’m gonna try this, but what are these reversible settings and does the APM_Config.h file (see https://ardupilot.org/dev/docs/advanced-configuration-settings.html) do what I want?

no, its for rc input reverse, that setting also does not exist in the current code, that is the archived documentation.

Maybe if you gave some more information about the end goal of your project we could help better. Your feeding the motor outputs in to a mixer or some sort?

The motor outputs are going into a circuit I made. This circuit is just a simple inverter circuit with a transistor to control a bigger MOSFET transistor, which is controlling the motor. I built a inverter circuit, because it was the simplest circuit to control the mosfet. The only problem is, that it is inverting the PWM signal, but I thought it was easy for a MCU to simply invert a signal.
What are the reversible settings, you have speaked of, tho?

you using a DC motor? you have set MOT_PWM_TYPE to brushed? I think I now understand you have a active low mosfet so no voltage means on?

Yes I have a DC Motor and yes no voltage means on, but no i did not set pwm_type to brushed. Does this change something?

You can change the pwm period caculation here


It should be very easy to invert it. You will need to add pullups so you don’t get full throttle while the board is booting ect.