LC-1 Wideband 0-5v to A/F

[mattdev]

I just installed my LC-1 and made a "custom" gauge for it. All it does is reads the analog output voltage. I have both outputs set to 0-5v (wideband).

I did some math to try to relate the voltage to a/f ratio and wanted to double check it.
0v=7.35 a/f
5v=22.39 a/f

I took the difference in a/f (15.04) and divided it by 5 to get 3. So basically triple the voltage and add 7.35. So the formula is...
3v+7.35=x
v=voltage
x=a/f

Is it that easy? Seems too easy;though doing math while driving isn't.
I just wanted to double check the math so I can learn what voltages mean in a/f and eventually be able to read them w/o translating.

 

[90laserRSfwd]

looks close, just wondering why you didn't just get the gauge though?

 

[blcknspo0ln]

The issue with any interpretation of voltage to a/f is the ASSumption that it is linear. I wouldn't discount the fact that it really may not be. Do you have a logger, dsmlink, or ems? I would trust that more than going with an oddball math interpretation.

 

[2gGSX]

The issue with any interpretation of voltage to a/f is the ASSumption that it is linear. I wouldn't discount the fact that it really may not be. Do you have a logger, dsmlink, or ems? I would trust that more than going with an oddball math interpretation.

On the contrary, most widebands ARE in fact linear output devices. According to the DSMLink wiki, for "Analog Output 2" you should map 0V to 9.0:1 and 5V to 19.0:1 AFR. If you wanted to use an equation, that would be y=2x+9 or AFR = 2(voltage)+9, so for 2.5 volts...

AFR = 2(2.5) + 9 = 14:1.

 

[blcknspo0ln]

Wow, I suppose that's why it's called ASSuming. Thanks for the correction. I can't give you rep points (gave them to you too recently ) so here's a cookie :

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[turbosax2]

mattdev:

Like 2gGSX already said, I would also suggest narrowing down the range for the wb. With the factory settings of 0v=7.35 afr and 5v=22.39 afr the range is huge and little changes in afr will be harder for you to read. By narrowing the range down to 9-19 afr (or even a slightlysmaller range) the accuracy will be better. You can use the LM Programmer to change these settings.

innovatelc1orlm1install [ECMTuning - wiki]

 

[mattdev]

mattdev:

Like 2gGSX already said, I would also suggest narrowing down the range for the wb. With the factory settings of 0v=7.35 afr and 5v=22.39 afr the range is huge and little changes in afr will be harder for you to read. By narrowing the range down to 9-19 afr (or even a slightlysmaller range) the accuracy will be better. You can use the LM Programmer to change these settings.

innovatelc1orlm1install [ECMTuning - wiki]

Will do... I already programmed the simulated narrowband output as a wideband, so I will fix that up with the right voltage. I didn't get a gauge because it's $100 more, and I had this plan to make my "homemade" one read a/f, but that didn't work out so well... Why spend $100 when I can learn something new?!

 

[TurboTiger]

You can set the LC-1 to output the wideband signal 0-5v as linear. Just use the included software and cable.