Zaphod

Hi guys,

As I will be using me already installed Zeitronix ZT-2 WB with the Megasquirt, I had a look at the Megatune 2.25 and there is just the otion of the non-linear wideband output of the ZT-2 and that makes the AFR Target tables to read in Volt. (the newer ZT-2 have a non-linear, as well as a linear output)

As I don't wnat't to hassle with the AFR/Volt calculation all the time (and I am used to deal with AFRs from the EMU) I had a look at the background of the lambda sensors in Megasquirt.

There is the lambdaSensors.ini file within the Megatune2.25/mtCfg/ folder. In this file there seem to be all the calculation algorithms for the AFR calculation from the voltages comming from the WBO2.

like for the Innovate 0-5v 10-20:1 AFR

#elif INNOVATE_0_5_LINEAR
afr = { 10 + egoADC * 0.039216 }
lambda = { afr / 14.7 }
TargetAFR = { 10 + afrtarget * 0.039216 }
TargetLambda = { TargetAFR / 14.7 }

Would it be possible to change this ini-file to match the ZT-2 linear output?
Zeitronix descibes the function for the AFR at the linear output as follows:

"The Linear Wideband Output transfer function is AFR=2xV+9.6"

This is were my knowledge at this point ends - I don't know what the string egoADC means, it is not the sensor voltage - because otherwise it wouldn't fit the AFRs.

Just a thought to make the life for the ZT-2 user a bit easier. Any ideas?

Zaphod

O.K. found some more new background (at least for me, I suppose the pro's already know this...)

In a thread at msextra.com:

Q:
I was looking at the formula in lambdasensors.ini and for the LM-1, the formula is: 10 + egoADC * 0.039216. I'm confused on what the 0.039216 value is for because it doesn't look like [O2] * 2 + 10 to me.

A:
The difference is one is working against O2 volts (0-5) the other is ADC (0-255)
ADC 0 = 0V
ADC 255 = 5V

so:
5/255 = 0.01960784313
so:
2*0.01960784313 = 0.03921568627

Therefore:
10 + egoADC * 0.039216
and
10 + O2volts * 2
are the same

So in the case of the ZT-2 it would be:
afr = { 9.6 + egoADC * 0.039216 }
lambda = { afr / 14.7 }
TargetAFR = { 9.6 + afrtarget * 0.039216 }
TargetLambda = { TargetAFR / 14.7 }

Greets

WestfieldMX5

Just digging up an old thread because I wanted to do the same thing.
I think what you describe only works in MS1, but not in MS2. I modified the lambdasensors.ini as well and found that the uploaded table is still the default table, unchanged. MS2 doesn't look at lambdasensors.ini when it uploads the table.
I still would like to know where it goes looking for the formula/table/.inc though.
The only way to upload a different table is by doing it directly in MegaTune - Tool - Calibrate AFR table. Choose Generic Lineair WB and enter 2 points from the formula's curve.

Zaphod

That is a fix for Megatune - it won't help your MS.

MSx/Extra EFI • View topic - Changing lambdaSensors.ini for Zeitronix WB ?

Here is some more.

For the MS-2 you can also send the value to your MS (at least with Tuner Studio, which I am using now) but at the moment I don't know how to set in Tuner Studio to shwo the correct values. (I am using the non linear ZT-2 output which is supportet by the MS and Tuner Studio and Megatune)

WestfieldMX5

It works for me. I had a .3 offset with my AFR and after entering 2 points in Generic WB, my AFR is spot on.
In my working dir, I had a afrTable.log with inside the following text, followed by my custom uploaded table. So MegaTune definitely uploads the custom table to the MS2

amak87

iTrader: (4)

helped me out thanks!!!