MultiWii

Multiwii pro board v2 RED from HK

My ACC z axis is constant 255 value when still. Is this normal or is my ACC defective? (Yes i calibrate) Thanks!

Yes, that is normal when cal'ed.
The Z axis is measuring the Earth's gravity and should be at max when cal'ed.
X & Y should be zero. If you tilt the FC board 90° then Z will be zero and either X or Y will go to 255 depending on which is aligned up/down.
If the turn the FC over then Z will go to -255.