Mr.Pibb

Hi. I posted this problem over on msextra, but you guys seem to be
more on the ball about this stuff.

Do these settings seem normal?
I'm trying to get a steady target of 255kpa, just to dial in PID,
but it overboosts. Cut is at 290kpa.

I'm using ms2 3.2.4.






The solenoid is hooked up like "external-wastegate" so when it losses power, there's only spring boost.

Also, while using the open-loop *duty % bassed, less duty cycle means more boost
and that works perfectly.

Any opinions or advice would be awesome.

I changed it over to
100
0
0
But haven't had a chance to test.

Leafy

iTrader: (1)

Can you make your plot for this just have target boost, actual boost, error % and correction % all on the same section? From what I've learned with closed loop controls you 0 them out, increase the P till it oscilates, then back it down, then increase the I till it oscilates then bring it back down. And if you're having difficulties with oscilation add in some D. Also normally the P and I values are negative, if they're positive the system works backwards, IE if there is an error positive values make the error worse. I dont know if MS flips the neg and positive so it make sense for normal people or not.

Mr.Pibb

Hi leafy.
I looked but can't find those %.

If you feel like it here's the very short datalog.

18psi

iTrader: (76)

this isn't romraider lol

Leafy

iTrader: (1)

I was hoping he would figure out what the synonyms are in MS. Everything has different names for everything. And at worse if boost error % doesnt exist he can calculate it, I'm assuming you can make custom PIDs in MS.

Braineack

iTrader: (62)

best answer: tune

Mr.Pibb

So the way it is looks like it's working properly?

Braineack

iTrader: (62)

did you say you had an external wastegate or not?

Mr.Pibb

External wastegate and it's hooked up like "external 2-port wastegate" in the diy
diagram.

If the EBC is turned off it'll just run off of wastegate spring pressure.

Braineack

iTrader: (62)

so at 100 0 0, you're shooting past your boost target?

Mr.Pibb

I'll post back when I get some tuning time later this week.
Thanks for helping brain.

Mr.Pibb

at
100
0
0

It still overboost. No change.









Now choosing inverted only goes to wastegate spring pressure.

What should I try out next?
It looks like inverted is working that solenoid alittle harder.
If the boost duty on that is correct, then the valve stays closed at cruise.
Can't be good for the valve can it?

Should I change closed duty % to 100 and open to 0?

Any advice or opinions are welcomed.

Braineack

iTrader: (62)

if 100 0 0, and inverted makes you go to wastegate, now you need to start lowering p, and tune cl boost control.

Mr.Pibb

Cool.
Problem solved. Just needed to be switched to inverted.
It doesn't say that in the manual.

P-10 I-0 D-0 in this pull.






When it says to turn P down until it overshoots alittle, by how much
do I need to see it overshoot?
And when "I" is adjusted it'll bring initial boost spike down while leveling off the high rpm boost drop?
Does "I" create boost oscillation?

In the manual it read to me that "I" is just to keep boost flat, but it looks pretty flat to me, so move on to 'D' to keep target to redline?

Braineack

iTrader: (62)

im surprised its so close with those numbers. could be due to your method of EWG.

most of us end up like 20 20 80 or so.

Mr.Pibb

Yeah it's pretty interesting. I think because 'i' and 'd' is at 0,
but once I touched 'i' then 'p' needed to be raised or it would spike hard.

P-18
I-15
D-0

Boost target set to 230kpa because 255kpa would wheelspin.
After overshoot, it would settle to 231-228kpa.

Seems real close to target but do I just simple turn 'P' up to get ride of the
overshoot? It goes to 247kpa.
Any input would be very appreciated. It's my first time tuning this.

Braineack

iTrader: (62)

I might add in a touch more I, maybe a little D and see how it goes. but that looks pretty good to me right now.

Mr.Pibb

Great success.

Every time I brought up "D", it would also need some "I", but when
I put in "I", then "D", needed to be brought up. HA.

Basically "I" made it osculate and "D" made it smooth but tapered boost down.
Never ending cycle.

So in all I just left it at
P:21
I:30
D:140

It spiked 1-2psi over my target but went right back down and fallowed my target within 5kpa max.
Pretty much on target. Let me know what you think. If I can get it better ect.

Basically doing 19-20psi and ramping it up to 23psi after 6k. I'm going to try and do ramp up to 27psi though.

Thanks a ton for the help.



There was alittle traffic, so couldn't rev it out.

Braineack

iTrader: (62)

yep looks good. you went about it perfectly and ended up with numbers like I'd expect.

Leafy

iTrader: (1)

Read up on how closed loop control works. D slows response, its the damping. P is for oscillation. I is for drift. P will make it get to a value and the more the faster it will move but not necessarily the correct value. I will make it target the correct value but it wont be steady. D slows down oscillation, but it also slows down response. So with a P control you can make it hold a steady value. With an I control you can make it average the correct value. And D a control... well that doesnt do anything on its own. A PID control puts all 3 together. Double check that I didnt mix up what I and P, I do that sometimes.