Again, it's useless posting that here. You need to post on MSExtra in the development section, as that's where the MS developers will see it.

 

Yes, James and Ken are pretty receptive to new idea to implement into the firmware.

I would love to see better heat management in regards to fueling--the CL Boost Control was never an issue for me no matter the temp.

Adding load to the temp correction would be greatly beneficial, that would allow you to dial out heatsoaking issues without screwing up fueling in boost when the AITs also increase.

 

Since we're on the topic of CL boost control, Can someone remind me how the PID values are set up:
do I start at 0 and keep adding until target is reached? (I know what each does)
or do I start at 100 and keep subtracting?
Cause there's all these PID's and IIRC they all work differently or at least use different methods when tuning.

I've a really solid OL boost control table now, but CL would be great

*Edit: also, is plugging my current OL table into "initial duty table" a good idea or should i drop it by like 5-10% and let CL work out the rest so it doesn't overshoot?

 

just use the sensitivity slider, input numbers if that doesn't work.

the CL control works if it deviates from the OL table; might want to experiment on what works better.

 

when you say OL table you mean initial duty table right?

cause I enabled CL boost before just for funzies, populated the boost target table, but didn't use initial duty table, and no matter what I did with the slider, the car didn't make any boost (above wg pressure). Like, it didn't work at all.

I'm guessing without the initial duty table to kick start it, it never turns on?

 

do you have overboost turned off? CL doesnt need the intial duties, but then that option shouldn't be active if it's not in use.

 

Nope, it's on and set properly. And that option was off too.

I'll try it again and see if I missed something initially, been putting it off cause OL seems to work just fine too.

 

OL works fine until the temp changes about 10-20°F

 

The PID controls are a little weird for closed loop boost. If you read the tuning guide, they want you to start at 100 value for Proportional and then reduce the number to increase gain, while the I and D factor should start at 0 and increase to turn up the gain, and then you have the slider bar thingie and the control interval... it's strange. I wish we could see more details on how the final duty cycle is calculated.

Also, you've got to look at the datalog of duty during spool up. Things can get wonky with the PID controls, regardless of whether you have initial duty table on or not.

 

Which tuning guide are you talking about? Can you post a link please?

Those weird PID values are exactly what I was talking about

 

Don't use this guide - the newer firmwares are different.

I asked a couple of times for an updated quick tuning guide on the newer firmware PIDs (with the changed PID algorithm) unfortunatly nobody listens to me...

Here:
Megasquirt Support Forum (MSEXTRA) ? Boost control advice (View topic)

I am tired of asking the same **** over and over again, maybe somebody else want's to chime in...

There are at least 3 different types of cl boost control

1. up to firmware 1.1.x or 1.2.x - without initial duty table and the aforementioned tuning advice
2. from this firmware up to some 1.3.x release - with initial duty table and a different PID type
3. from one of the pre 1.4 betas - with bias duty table and the same different than on Nr. 1 PID type

Greets

 

yeah Zaphod thanks for letting me know... I knew there was a new algorithm they were working on but I am having trouble finding comprehensive information on it. I'm not using that one right now as it doesn't seem to be ready.

the tuning guide I was reading is page 195 of this document. http://www.diyautotune.com/downloads...pro_manual.pdf


I made the thread about the feature requests:

http://www.msextra.com/forums/viewto...440240#p440240

 

The latest betas have a BIAS table instead of an initial duty table. From what I understand the process is this:

Set PID values to ZERO. Set mode to Closed loop SETUP MODE.

What this does is make the bias table equivalent to open loop but with bias instead of duty cycle. Tune the bias table so that you maintain the boost KPA you desire throughout the map. Don't tune specifically to hit boost as early as possible because even in SETUP MODE the boost controller will be at 100% until (x)kpa from your target, where 'x' is your kpa delta setting. I would advise making this number SMALL for tuning purposes. 5kpa to ZERO kpa might be appropriate when tuning bias table. Make sure you have your over boost set up.

From there, switch from SETUP MODE to SIMPLE.

Use sensitivity slider to hit and hold boost as long as possible. When you can get no more improvement from sensitivity slider, switch to ADVANCED and leave sensitivity alone, and work on PID. I will find the NEW PID instructions in a sec.

Useful threads:
http://www.msextra.com/forums/viewto...?f=125&t=58216

Also something to test which supposedly makes it easier - set proper "closed" and "open" numbers. Start at 100 and work your way down until your spool slows down. Use that number (the lowest number that spools fast) as fully closed.

 

Slider is fucked for me. It either overshoots completely, or oscillates out of control.

I'm having a hell of a time tuning the new boost control, like making me mad hell of a time. It just does different **** half the time when I don't change anything.

 

I had rock solid boost control on my MS2E setup. With a ball/spring MBC and an external gate. Funny how many YEARS ago that was, and even today closed loop EBC isn't ironed out yet on MS...

 

There are plenty of people with rock solid EBC on MS. I'm just not one of them.

 

Yeap, some had it working, others didn't. Way back some people spent quite a bit of time playing with the PID values, only to eventually discover the firmware had problems with the equations.

Honestly if I needed it and couldn't get it to work, I'd probably just buy a dedicated controller for boost if I really wanted EBC. Or if you're ok with flat boost, just do a MBC diagphram type with external gate. That combo gave me a flat boost line, like target kPa + or - about 1 kpa.... Very effective but flat, can't ramp it up which would have been nice to have.

 

My boost with EBC and Open Loop is already better than the MBC, so I'm nto complaining.

If CL will be better, it will just be cake.

 

What exactly does the slider do, mathematically speaking? Do the developers release block diagrams of the control strategy or some formulae of how final duty cycle is calculated?

 

The slider replaced fields that had be be filled in previously. E.G. For idle it was RPM's that car would be at when the valve was closed and open.

Moving those values about made the PID routine more/less sensitive. The slider makes it easier than putting numbers into boxes that didn't necessarily correlate to real life.

If you leave the PID in simple mode it uses the default PID numbers of 0-100-0 (IIRC) and you just adjust the slider to get close to what you want. Then move to advanced and play with the PID numbers.