Dave_24's explaination of how to use PID control of PWM

via IRC

link to his page

<Dave24_> NickLaTec?: you need to let the pid controller control the valve directly

<Dave24_> no magic afterwards

<NickLaTec?> what do you mean no magic afterwards?

<Dave24_> just something like 0x80 + pid output = duty_cycle (0-FF scale)

<Dave24_> pid output is signed

<NickLaTec?> yup

<Dave24_> thats it

<Dave24_> than tune the pid to be fast enough

<Dave24_> without being 'jumpy'