PID loop details


I have been working on PX4 firmware. I know have to understand do some research work on the PID loop for stabilization and how it consumes accel, gyro, and compass. I have seen some diagrams on line related to 2.9 version.
Is there some documentation or if you can give me some source code reference, I will appreciate.


They are the same I think. I haven’t got around to redrawing them.