https://s4wiki.com/wiki/Wastegate_bypass_regulator_valve

Was reading through this and noticed a few things.


mentions that the n75 is managed by a PWM controlled when i believe it's a PID controller correct? Could we correct this to:


just for congruity of information's sake? I know you didn't type this out yourself Nyet but it could help us noobs understand it if the terminology is congruent. Unless i'm off and it actually is PWM.

Also, the links at the bottom of that page are dead:

Had to ask someone irl to get a better understanding of this:

A PWM is the amount of time a device recieves a signal or an electrical current to turn it on or off, depending on its function, over a period of time, ex: an LED is sent a signal to be on 50% of the time over 1 min(arbitrary time amount for example's sake) so the LED is turned on for 30 seconds and off for 30 seconds split into rapid increments of the 1 minute course.

A PID is the protocol that the PWM is designed to follow, for example, said LED is looking to put out 50 lumens of light. Through an algorithm, 50 lumens is found to be achieved if the LED is 'pulsed' 75% on over the course of 1 minute. So those 45 seconds of 'on' are split up rapidly between 1 minute. This "setpoint" is the P function (ex: the 75%-50 lumens)(do i have this correct?). The I and D function come in when the desired amount of lumens changes over a longer period of time and the output of the PWM is tryin to follow these desired changes. The I is how much (how many lumens, per example) the output signal overshoots and undershoots after it hits the desired setpoint and the D function is how many times it overshoots and undershoots after it hits the desired setpoint  Do i have I and D correct?

I feel like im almost there?

watched these guys:
https://www.youtube.com/watch?v=SefKQb9y_B4
https://www.youtube.com/watch?v=16Clfh5eBzg&t=944s

and read a bit and came up with this:

Derivative works on the rate of change of error in order to approach the setpoint slower, over and undershoot the setpoint fewer times and to overshoot and undershoot the setpoint to a smaller degree.

so, keeping with the same example, the LED is looking to achieve a setpoint of 75% DC. If the Proportional gain is adjusted properly the setpoint will be reached with an acceptable reaction time and will hunt a minimal of times. The derivative gain can be adjusted to reach setpoint with fewer hunts and less over and undershoot amount. The downside of this tends to be a slowing of the reaction time near approaching the setpoint.

Integral gain works to cover the rest by closing the remaining error gap by adding smaller amounts of DC until the setpoint is reached.

I now understand that as the setpoint changes, the PID functions are used together and separately, depending on how easily the setpoint is to reach. I always thought these had an operative order, P, I, then D and were always computed and reacting in that order, that is not necessarily true. I also thought they were all being computed every time the setpoint changed, that is not necessarily true either.

I'm trying to understand how their root words of derivative (to derive, or to copy/obtain from something else) and integral (integer, a whole number) pertain to the functional operation they perform, as I am expected to fully understand the concept for my employment as of late, unrelated to automotive application.

I'm still getting a grasp on the fundamental mathematics of how these work and interact but I think I have it.

And it's typically thought of the other way, with integral "covering the rest", and derivative very often nulled, or at least used sparingly and with great care -- it can cause control element hyperactivity and ultimately worse control, or a worse experience even if objectively process variable control is "better".  ME7 etc. with its patented I-limiter is a bit different than generic PID controllers and can utilize derivative, but even so a little typically goes a long way.

also, noticed this under the: Specifying requested boost section


should it read bar instead of mbar? 2.5 mbar is 0.0362594 psi