RRFusion- My Fusion Brain plugin for RR

**thwack** · 08-28-2008, 06:58 PM

Hey Sonic,

Recovered from the weekend?? Having any lunk in finding time to have a look at this?

Thanks
Thwack

**Blue ZX3** · 08-28-2008, 07:34 PM

That weekend must have dazed him pretty good, me thinks...

**Sonicxtacy02** · 08-29-2008, 09:05 AM

Originally Posted by Blue ZX3

That weekend must have dazed him pretty good, me thinks...

i guess so.. i completely forgot to follow up before now lol

Originally Posted by thwack

Hey Sonic,

Recovered from the weekend?? Having any lunk in finding time to have a look at this?

Thanks
Thwack

i think i have a "small" grasp at what ur trying to do here. Basically u wish for me to create a new analog type "voltage divider" which uses the formula you've posted above to manipulate the data? If so, thats no problem.

**thwack** · 08-29-2008, 07:42 PM

That's exactly it!!!

If you create the input type voltage divider, convert the FB input to voltage and then allow a custom input number from the ini to multiply the voltage that would cover all voltage dividers.
IE:

In rrfusion.ini
FBANALOG2TYPE = 6 //Voltage Divider
FBANALOG2CORRECTION = 0.232

This way in logic: FB reads 3.42v and then divides by 0.232 so ANALOG2 would read 14.74v (3.42/0.232)

**h3rk** · 08-29-2008, 09:08 PM

Originally Posted by thwack

If you create the input type voltage divider, convert the FB input to voltage and then allow a custom input number from the ini to multiply the voltage that would cover [HL]all[/HL] voltage dividers.

Works great for sensors that output a range of voltages at a constant current, or buffered output.
But for many sensors, like ones where the resistance of the sensor changes with the parameter being measured, the current will change as the parameter changes, thus changing the measured voltage non-linearly (the changing parameter is in the numerator and denominator of the actual ratio: Vout=Vin(Rvar/(Rvar+Rstatic)). This, unfortunately, is not a case where a simple, static ratio can be applied. But maybe this can be accounted for with just a little more math behind the scenes.
Not trying to rain on any parades, just stating a precaution, and offering food for thought.

**thwack** · 08-29-2008, 09:17 PM

I stand corrected. h3rk is correct that the situation I propose is not correct in ALL circumstances.

In the situation I have described, the resistance needs to be static. I had envisioned that this would be used to measure voltages larger than the Fusion Brain can handle natively. ie. a car's system voltage / battery voltage.

Perhaps the type would need to be a "Static Voltage Divider" and then the variable divider could be covered with the "Custom Equation" type that has also been proposed where the equation is also taken as an input.

Thanks h3rk for pointing out some circumstance that I had not considered.

Thwack

**Sonicxtacy02** · 08-30-2008, 07:56 AM

hey as long as you guys can present me with formulas i can add then to RRF

**thwack** · 08-30-2008, 08:52 AM

Is there anything special about the formulas? Do we need to have the conversion from raw units to volts in the formula?

If not can you please add the formula I mentioned for the static voltage divider.

ANALOG#=Vin/Correction

Where Vin is FB voltage and correction is defined in ini file.
Thanks
Thwack

**Sonicxtacy02** · 08-30-2008, 11:08 AM

nothing special at all.. the raw number is what all formulas are based on.. and if the converted value has a needed suffix be sure to specify. I will add the formula above on tuesday when i return to work.

Nevermind .. i dont think it'll matter one way or the other

File is available post 1. Since i consider this a sub-release, i did not update documentation. However you MUST backup your rrfusion.ini then check out the included .ini for the correction format

**thwack** · 08-30-2008, 05:41 PM

So the above formula should be:

ANALOG# = ((ANALOG#RAW*(5/1023))/ANALOG#CORRECTION)

Where ANALOG# is formatted label
ANALOG#RAW is FB raw input
ANALOG#CORRECTION is from ini file
And the suffix is "V"

Thanks Sonic,
looking forward to tuesday
Thwack