calculated PIDS

[sweetdiesel]

has anyone made there own?

I read through page 91-93 on the EFI bible and to me its blah blah blah
no offence to EFI but im even more confused now?

so i went into EFI -v7 -user config -calculated pids and im still lost


what im trying to do is hook up a autometer sensor to my v2 and read it with EFI i have the first part figured out,now im onto the pid part and i am stumped.
now im trying to take the easy way out, and ask someone here how?

 

[LarryJewell]

has anyone made there own?

I read through page 91-93 on the EFI bible and to me its blah blah blah
no offence to EFI but im even more confused now?

so i went into EFI -v7 -user config -calculated pids and im still lost


what im trying to do is hook up a autometer sensor to my v2 and read it with EFI i have the first part figured out,now im onto the pid part and i am stumped.
now im trying to take the easy way out, and ask someone here how?

:yup:

 

[McRat]

I've never played with that, but I really need to look at it.

I'm to the point where I just want to see the raw voltage and I'll be happy.

 

[LBZ]

I looked at it and you almost need to be a programmer to set it up. It's much easier to make a graph and read raw voltage and then plot it IMO.
It's too bad we couldn't take EFI and a pressure sensor (transducer) and say 0psi = .1 and 5v = 100psi and tell it to plot/calibrate itself to read the sensor voltage that way. Our data aquisition programs at work use this principle. That way they can be recalibrated easily if say we switch different pressure transducer's around with different cables that have different resistance values or they have a little interference disrupting the lower voltage range for whatever reason.
I'm not sure if this is what EFI is saying we can do or not because I too am really confused on how it's done and what the end result is!!

 

[Killerbee]

If you open the scan tool, you will find AD1 and AD2 already created for the external 5V sensor. (EXT.AD1 and EXT.AD2 are in volts)

If you send me your email address I will email you a templated Calc_pids file. Not a template actually, it just has a few calculated pids I did, you just repeat the logic

 

[LarryJewell]

If you open the scan tool, you will find AD1 and AD2 already created for the external 5V sensor. (EXT.AD1 and EXT.AD2 are in volts)

If you send me your email address I will email you a templated Calc_pids file. Not a template actually, it just has a few calculated pids I did, you just repeat the logic

you can forward to me, i'll see that he gets them

 

[LBZ]

And in case Larry's computer goes down, I'll take keep a back-up copy for him!!
[email protected]

 

[Bluemax]

And incase all of their computers go down I'll be the backup-backup.

 

[Killerbee]

Attached an example of several calculated pids. Some of these may be useful. The one I added for this thread is is number 7, and is hypothetical. You must know the voltage relationship of your specific sensor. In this case, I created a drive pressure PID (just a guess) that uses a hypothetical 3 bar sensor that is linearly scaled at 9 psi per volt. The value returned will come from the entered formula,

"{EXT.AD1}*9"

where EXT.AD1 is the voltage returned, it is multiplied by 9 to get PSI, then subtract local barometric, 14.1 in my case. Easy

Remember to select AD1 from the PID list, as well as the new CALC.Drivepressure PID, or you won't see logged data.

 

[sweetdiesel]

KB

thanks so much,ive used fingers calculated PID long time ago for crank angle degrees and a few others that people posted,however i never really learned to build them my self
Do you just open note pad and build it there or modify the existing ones in EFI?

either way thanks,and ill keep working on this

seems like i am taking the easy way out this way

 

[Killerbee]

Yes, you just edit the calc_pids file. Sometimes the hard part is finding the file. For me it is here:

C:\Documents and Settings\Michael\My Documents\EFILive\V7\User Configuration

once you edit it and replace it (keep a copy of the original just in case), test the output. If the logged data doesn't jibe with common sense, probably a formula mistake.

It may seem like the easy way, that is because some things are not hard, just elusive. EFI didn't make this one easy to do, there is no interface for it.

One useful pid that is useful, and easy to build, is one that reports the difference between actual rail pressure and commanded rail pressure. You make up your own name for it, and become the author:

Difference Between Actual And Desired Fuel Rail Pressure
{CALC.FRPERR}
Expression:
MPa = {GM.FRPACT.MPa}-{GM.FRPDES.MPa}

It gives immediate feedback on CP3 tweaks, lift pump operation, etc

If you wanted a pid that was useful for tweaking highway mpg, I would come up with something that measured fuel consumption over distance traveled. Maybe something like:

Economy Ratio{CALC.EconomyRatio}
Expression:
= {SAE.VSS}*5000/({GM.FUELQ_MAIN_DMA}*{SAE.RPM}

 

[sweetdiesel]

thanks,I appreciate the info

 

[sweetdiesel]

Ok Michael again thanks for the PID

it is actually easier than i thought,so looking at your PID file it appears that for adding extra calculated pids you just continue to add to the PID file

basicly i want to use 2 Aux inputs, The one is working and i assume i just make the formula using Aux 2 now and add it under the aux 1 text?


Did i just confuse the heck out of you?

 

[LarryJewell]

you did me

 

[Killerbee]

Yes that is exactly what you do. There are 2 parts in the calc-pids file that you define

The "Add slot definitions here" section, and the
"PRN - Parameter Reference Numbers" section.

Just integrate AD2 into the formula you believe calculates the value you want to see.

SD, what I do is just copy/past the format of the preceeding pid, 007 in the case of the file above, and modify it with my new formula...etc.

 

[sweetdiesel]

Perfect Thanks

After further examination of your PID I kinda figured thats what you do
I like some of the pids you have in there.