I’m hoping someone can help or at least shed some light on this strange issue I’m having with my pixhawk running arducopter 3.2.1 If I connect the receivers sbus port to the pixhawk’s rc input nothing happens even though the rx is in mode 2 which makes ch 1 thru 7 pwm outputs and ch 8 becomes the sbus output. This is a sbus2 rx so it also has a dedicated sbus2 port on it. Now if I power the copter up and put the rx in mode change mode and set it to option 2 for ch8 outputting sbus it will work. Everything works just fine.
Here is the issue, if I unplug the battery to change it for a fully charged battery it will stop working unless I put the rx in mode change on power up and set it to option 2 again to output sbus on the receivers ch 8. Then things will work fine again. So I’ve gotta keep setting the rx to option 2 everytime I connect a battery to fly for it to work. I would think faulty rx, right? No, now here is the odd part. If I unplug just the rx and leave pixhawk powered up I can plug the rx in and it will continue to work fine. There is only the 1 3 wire servo cord connecting the rx to pixhawk’s rc input so when I unplug it the receiver looses power. So if it was the rx forgetting the mode setting why doesn’t it when I unplug just it? So i only have to set the mode to option 2 when pixhawk gets unplugged. So somehow pixhawk is detecting the rx being in its mode change which I wouldn’t think was possible but clearly it’s sending something out on the sbus when I set its mode.
Here is the other strange thing, if I connect the receivers sbus port to pixhawk’s rc input and I ALSO connect the sbus2 port of the receiver to pixhawk’s sbus output right next to the rc input, it all works fine! Just like its suppose to. I can change batteries, leave the copter unplugged all night long and when I connect the flight battery to go fly it will still work just fine…
So what does connecting the receivers sbus2 port to pixhawk’s sbus output doing to keep the rx and pixhawk synced up and communication properly? Now as soon as I unplug the servo plug connecting the receivers sbus2 port to pixhawk’s sbus output things stop working unless I set the receiver to mode 2 everytime I connect the battery to fly. And clearly the rx is remembering what mode it’s set to because if I unplug the rx from pixhawk it looses power just like when I disconnect the battery but it will keep working when I plug the rx back in. The only way to get things to work properly is to connect the futaba receivers sbus and sbus2 ports to pixhawk’s rc input and sbus output…
Any help in understanding what the heck is going on would help…
-Mark