PID boost control autotune.

[M30guy]

I'm starting to tune closed loop and it's a pain.
Not sure If I really understand it so an autotune would be nice here to reach boost targets rock solid with pid.

Could happen?

[muythaibxr]

What don't you understand about tuning PID?

Ken

[pit_celica]

Don't want to promote myself, but take a look at this :

viewtopic.php?f=131&t=42223

Sam

[M30guy]

What don't you understand about tuning PID?

Ken

Hi Ken.

Solenoid frequence: 19.5hz
Control interval: 30ms
Polarity: Inverted
CD%0
OD%100

These settings were changed, based on other peoples success.
I was using OpenDuty (worked perfect) before I tried PID.
39hz
10ms
Inverted
100
0


Tried to fallow the manual here using
100 for P and slowly decreased values so
that I get close to my 20psi target.
I went all the way down to 5, and it wouldn't go over my 15psi spring


So I increased target to 25psi and I think I saw maybe 1-2psi increase, but probably not from the settings.
Then I switched from inverted, to normal and hit my 290kpa boost cut and blew all my hoses off. lol

I'm not sure what is going on with it or how to make it work.

[muythaibxr]

Sounds like you have it plumbed such that you need the non-inverted output setting. PID autotune would not help you 1 bit in that situation. The manual also says that you should tune open-loop boost and the output polarity setting so that lower duties give you higher boost before tuning PID. If you do that before following the manual's PID tuning instructions it should be much easier to tune.

Ken

[M30guy]

http://www.diyautotune.com/images/produ ... ontrol.png
I used this diagram for 2-port wastegate.

You're right. I think this just needs to be tuned under "normal".

If higher duty% numbers mean more boost can I just reverse the 0-100 CD%/OD% numbers to
get the correct duty function? Does it need to have open duty tuned to boost targets before go on to pid?
Thanks for the help.

[muythaibxr]

You can't reverse it... the PID algorithm requires that lower duty = higher boost right now.

I have some changes in mind that will at least make it display what you're expecting.

So open duty must be 100, closed 0, and in your case set it to normal.

However, it is safer if you replumb it so that "inverted" is the correct setting so that hardware failure causes wastegate boost not full boost.

Ken

[M30guy]

Ken, thanks for helping me out.

I left the lines to the valve hooked up so that if the valve fails/loses power,
it will just boost off the wastegate spring. Just like in the diy diagram.

Turned it to "normal" and the duty cycle values are backwards now.
100 means closed WG. Inverted makes it act like it should.
But then PID doesn't seem to work using inverted.

Does this mean I have to switch power/ground wires on the EBC?
If I try PID the way it is, on normal, will it not work?

[muythaibxr]

If you have it plumbed right now, inverted should work. Make sure that with open loop boost, lower numbers give you higher boost, then switch on PID and go from there.

Ken

[M30guy]

Old post i know, but just wondering if this is something we can look forward to or just no way.
Never got targets to work just by cycle btw.

Which isn't too bad because I tuned it in 3rd gear so 1st-2nd won't make full boost keeping some traction.

[HidRo]

Haven't been able to mantain boost with open loop? If so, then you have a problema that you need to address before.

[M30guy]

using duty cycle flawlessly. Everything is working and wired by the book.