Why are RC and Servo output min and max and Trim so different

ArduPlane Plane 3.8
1

Hello all how RC and Servo output min and max and trim are different
RC1_DZ,30
RC1_MAX,2006
RC1_MIN,988
RC1_REVERSED,0
RC1_TRIM,1494
RC2_DZ,30
RC2_MAX,2006
RC2_MIN,984
RC2_REVERSED,1
RC2_TRIM,1494
RC3_DZ,30
RC3_MAX,2006
RC3_MIN,982
RC3_REVERSED,0
RC3_TRIM,982
RC4_DZ,30
RC4_MAX,2006
RC4_MIN,982
RC4_REVERSED,0
RC4_TRIM,1494

SERVO1_FUNCTION,25
SERVO1_MAX,1900
SERVO1_MIN,1100
SERVO1_REVERSED,0
SERVO1_TRIM,1500
SERVO2_FUNCTION,19
SERVO2_MAX,1900
SERVO2_MIN,1100
SERVO2_REVERSED,1
SERVO2_TRIM,1500
SERVO3_FUNCTION,74
SERVO3_MAX,1900
SERVO3_MIN,1100
SERVO3_REVERSED,0
SERVO3_TRIM,1500
SERVO4_FUNCTION,21
SERVO4_MAX,1900
SERVO4_MIN,1100
SERVO4_REVERSED,0
SERVO4_TRIM,1500

2

the RC input values are set to match the received radio values setup during radio calibration…

the servo functions are set by SERVOx_FUNCTION…their initial range and trim are default values…the smaller range so that a servo is not overdriven (I change them to 1000 to 2000 since I use servos that can accommodate that range), they can be also used to adjust the servo travel for full throws for your installation…the trim can be used to set the servo output center value (which may be off a little due to servo wheel/arm positioning)…

the servo trim values will be altered if you used AUTO TRIM or SERVO TRIM procedures, which also can adjust the RCx_TRIM vlaues…this allows in flight trimming (RC inputs should always be at the RCx_TRIM value when centered)…read about these trim modes in the documentation…

3

I am also confused. This is in regard to my quad plane (4 tilt rotors). If I test the aileron/elevator/rudder directly through the r/c receiver, I get ‘normal’ centering and throws. I also calibrated the radio through ground control. But when I attach the servos into the Pixhawk, and power things up, the elevator servo goes to a full down position whether in qhover, qstabilize, or fbwa. The ailerons also show reduced throw. Is this perhaps due to the Pixhawk not sensing any airspeed (there is a digital airspeed sensor attached)? It makes me uneasy about doing any test hovering, much less forward flight.

4

Sorry. Found the problem. It was much easier to sort out by changing flight modes (on the bench, not for flight testing) from fbwa/qstabilize/qhover to manual/stabilize. Once I got the flight controls (aileron/elevator/rudder) neutrals set correctly and traveling in the right directions in manual mode, I changed to stabilize (airplane) mode and made adjustments to the travel directions. Then I saved the parameters and switched the flight modes back to fbwa/qstabilize/qhover and things look much better.