I believe I have a problem with my Pixhawk and was hoping for some help. Also posted this on rcgroups.
The issue is that when my speed controllers are hooked up to the Pixhawk they exhibit a bad sync issue. However when they are connected to my old APM (3.1) or just a receiver directly they do not exhibit these symptoms. This has resulted in 4 crashes now until I just tonight narrowed down the issue to the Pixhawk.
Can anyone advise what is going on? Here are the specs of my setup:
Afro 30A ESC's with SimonK firmware (have tried all versions, and made my own with various parameters)
Tiger MT2216-9 1100kv motors
4S 3700mah battery
Replies
Pixhawk is *NOT* outputting 2.4V levels. You either have a faulty unit (please check with the manufacturer) or did get the grounding wrong - how did you ground your setup?
These are the real voltage levels:
http://pixhawk.org/users/actuators/pwm_escs_and_servos
Hi Lorenz,
thx for your answer. GND is connected to Servo Rail.
I've tested different input methods, 5V BEC, 5V USB and 5V of current sensor supply. Always same output voltage. As you mentioned on your site, 2,4V could be enough for my ESCs. One important fact is to set 400hz for pixhawk, isn't it? So users here should be informed as well. For luck I did it already.
btw, users can check outputvoltage with multimeter by messuring between GND and Signal. To get a correct reading, u need 400hz-490hz and to multiply the voltage by 2.
Bin übrigens aus GER. Schöne Grüße!
Christian
Ardupilot automatically uses 400Hz not 490Hz when it runs on Pixhawk
Thanks Craig!
so you're saying all pixhawk users should set their timing to 400hz? can someone confirm this?
Craig, the hardware I sent you was delivered May 10, have you had a chance to test it out and if so did you find anything?
Well, I wonder what you are doing differently than I was in my video. The problem was very reproducible.
Anyway, I finally got my quad working well with the 3DR esc's and had a couple FPV flights. It feels very locked in now.
Regarding connecting ground, it might be a good idea to update the Pixhawk manual as well. The images in the "Connecting Outputs" section are a bit misleading.
http://3drobotics.com/wp-content/uploads/2014/03/pixhawk-manual-rev...
On this note - I am sitting here trying to figure out if I may have a sync issue causing flips on my original 3DR Y6 with a swapped in Pixhawk. I connected everything according to the quick start guide for the pixhawk, which certainly shows only signal wires, not to mention that with the original power distribution setup of the Y6, I'm not clear how I go about connecting each ESC's ground...
Am I missing something? Is this thread stating that 3DRs current documentation is explicitly incorrect? Does this mean I have to completely rewire my power distribution to have a properly grounded system? Or am I (hopefully) just confused about the context..?
Some clarification on this would be greatly appreciated!
Thanks
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