If max left from PID calculation “pwmDrive” = -255
from code pwmDanffos = (pwmDrive/2)+128;
(-255/2) + 128 = ~ 0 min duty cycle
if max right PID calculation “pwmDrive” = 255
(255/2) + 128 = ~ 255 max PWM duty cycle
If pwmDrive from PID calculation 0 , no stering error PWM 128 , valve close
sorry about my english