I have a big problem to get the Pixhawk running with my Taranis plus and the X8R receiver.
What I have:
Taranis Plus with Firmware 2.0.17 and latest internal XJT non_EU update.
X8R Frsky Rx also with latest non_EU update.
3DR Pixhawk and a clone from belize
Arducopter 3.3-rc7 (also test 3.2.1)
What I did:
I flew many hours with my small grasshopper 250 very well with my old Futaba with Jeti TX system. The Jeti Rx has a CPPM out. The System is stable in all phases and all Modes.
Now I want to give my Taranis plus a try which I bought in 12/2014. So connected the X8R SBUS direct to the RCin from the Pixhawk and calibrated the Radio in Missionplaner with no problem.
The Copter flies, with the FrSky system, in stabilize as usual and very good. As soon the Mode changed to Alt.hold, Pos.hold or RTL the copter get some wobbling or unstable attitude if a interference coming up. The interference can come from a gust, or a RC input. Special when switch in Autotune the Copter become very unstable, sometime he fall out of the Sky.
Once it was possible to complete the Autotune in roll and it gives me a PID from P=0.01;I=0.01!!
I also switched off the Tx during a fast forward flight, as the RTL command came the copter wobbles very heavy, which It not does with the Jeti Rx!
What I tried to solve:
Changed old to new Firmwares on the Rx,Tx and Pixhawk,
Tried another Pixhawk, another Rx and a D4R-2.
Changed the PID in a lot of direction (I´ve experiences in tuning PID´s)
Changed in between, with exact the same setup, to my old Futaba/Jeti system without any Issue!
I've setup the system from the scratch, several times.
Bind the Tx/Rx in differend modes several times.
Had a look on the sbus out with a Oscilloscope to check the Signal.
Now I´m at the end of my knowledge and need help from the Forum to figure out the problem.
I´ve seen that the sbus signal goes to another input of the STM32F100C8T6B (IO CPU) in the Pixhawk. So maybe the Firmware of that CPU has a bug. Does the IO CPU will be update with the Firmware from the Missionplaner, or is in the STM32F100C8T6B a fixe Firmware?
I know the beaver is strange and unbelievable but true!
May be there is someone from Germany who has the same setup and like to help me personal.
All constructive inputs are welcome!
the test Copter: