AEM 30-0306 Pressure sensor transfer function for VCM Scanner

[Eleazer2]

I'm having trouble trying to figure out the transfer function I need to enter for my MPVI input to make the gauge read correctly in VCM scanner can someone help me out? I compared one that was already added to VCM scanner by HP and looked at AEM's website and the transfer function I see for it does not match what it shows in the VCM Scanner.

[veeefour]

It seems that gauge utilizes their MAP sensor:
https://www.aemelectronics.com/produ...p-psia-sensors

For which they provide a transfer function: "PSI = (7.5*(Voltage))-18.75"

https://www.aemelectronics.com/files...sor%20Data.pdf

[Eleazer2]

Thanks

[dr.mike]

page 7 of the 30-0306 instructions manual gives the specifics for the 0-5v output.

https://www.aemelectronics.com/files...ns/30-0306.pdf

0-5V Analog Output Scaling Formulas
psia = (12.50 * Volts) - 6.25
bar = (0.86 * Volts) - 0.430


0-5V Analog Output Scaling Table

Volts psia bar
<0.50 SENSOR ERROR
0.50 0.0 0.0
0.75 3.1 0.2
1.00 6.3 0.4
1.25 9.4 0.6
1.50 12.5 0.9
1.75 15.6 1.1
2.00 18.8 1.3
2.25 21.9 1.5
2.50 25.0 1.7
2.75 28.1 1.9
3.00 31.3 2.2
3.25 34.4 2.4
3.50 37.5 2.6
3.75 40.6 2.8
4.00 43.8 3.0
4.25 46.9 3.2
4.50 50.0 3.4
>4.50 SENSOR ERROR

[Eleazer2]

I found the data In the sheet but not sure how to input the data in the vcm scanner config can you assist?

[CCS86]

I really don't like the "transform" function in Scanner, which seems to be the default method to "condition" a signal.

• It forces you to enter the slope as a division for some reason, so you need to find the inverse of the given multiplier
• There seems to be no way to just input a transfer function and go. I was forced to choose a preset sensor file and modify the function, in order to accept.

Instead, I just add the raw voltage as a channel. Then, I create a math parameter to input the transfer function.

[2therock]

Eleazer2 How did you come out?

CCS86 speaks of what he does but not how or show examples.

[murfie]

You add the MPVI input to you channel selection.
Once in there you can leave it as the raw voltage and log that, using a user math created what ever value you want later. Maths are created under tools> math parameters or ctrl+M. To me this is the best way as its the most flexible.

The other way is to right click the MPVI input in your channel list and select transform. You can then select a predefined sensor or create a user define transform. The AEM sensor mentioned maxes at 50PSI so the closest predefined AEM pressure sensor would be pictured, not perfectly accurate but it will be close.

MPVI input transform.PNG

Here's the scaling table above converted to the exact values to use in transform to compare.

Scaling table.PNG

[2therock]

Thanks Guys, I'll try again tomorrow

[2therock]

Well I'm moving forward but still not sure footed on it.

I managed to get it showing PSI in the channel list and tried to assign it to a chart series and gauge but failed. See it in the screen shot. Its showing 10 less than the physical gauge, the gauge shows -20.
Couldn't figure out what to do next. I thought I was following your instructions but..............

See attached pic I saved years and many earlier versions. I cannot remember how to get to the slope and get it reading in a series. Sorry.

Also see my current as described.

BoostConfig.jpg

boost_config_wanted.jpg

[murfie]

Is your gauge in inHg for vacuum? -10PSI would be about -20 inHg.

[2therock]

Heh! Your finding out my math short comings.
Yes, upon reading your reply and reading my gauge paper work by default it reads - in Hg and + in PSI. So I now I'm aware the MPVI input displayed in the channel list does not swap from Hg to psi. Thanks for getting me out of that rabbit hole.

Correxct Veeefour I'm working off the AEM MAP sensor. I know some use the Barometric Pressure conversion math from the Manifold MAP but I have viewed step by step videos how to do it and had it working but it keeps going away, or not saving and I have done save layout as saves but still some how looses it. So I want to use the gauge kit in its entirety or say stand alone.

So now I will try and get it to show up in a Gauge and/or chart series. I'll not be able to try again until tomorrow night but please if you have anything towards that......

Thanks You Guys, I Hope Stay with me. I have a busy Monday and will look forward to the help here and peck at it again tomorrow PM.

[2therock]

Well I'm back and dumbfounded as ever trying to get an AEM 30-0306 boost gauge unit to display and log as displayed on the gauge.
I try to follow some of the tips here but don't know enough about or am experienced enough with the nomenclature.

I have the gauge's supplied MAP sensor in the port supplied by the Radix 1800 Magnuson supercharger.

I have the white wire going to #1 and brown to #5
I have the AEM AFR 30-0300 white on #2 and brown on #6 (its working great).

On the latest Beta

Can I please get a lead to a hand holding baby steps for dummies for this thing?

[cobaltssoverbooster]

to minimize the ground offset you need to ground the gauge out through the pro interface harness.

white wire is 0-5 volt signal from the gauge. (pin 9)
brown wire is analog signal ground (low) from the gauge. (pin 10)

add the channel that you wired it into in your channels panel. right click that and transform the channel. You can try selecting the aem boost sensor from the drop down or you can make a custom scale based on the aem manual.
PSI = (12.502*Volts) - 6.2431 is the formula that defines the pressure linear output from the aem manual.
your slope (m) = 12.502 PSI/Volt
your offset (b) = -6.2431 PSI

when you look at the transformation table and use the linear function you get an equation to fill out to define the sensor input. you show this in Post#10.

the hpt format is y= (x / m^-1) +b
in this case we know m and b by solving for the linear equation using the aem instruction manual data above.
So, m=12.502 them m^-1 = 1/12.502 = .079987202 if you use 0.08 that will be good enough for hpt.

so PSI = Volts / (0.08) + (-6.24)

[2therock]

Thanks, I'll try this tomorrow. I may need some help actually entering the expression or scale but I'll try and post a screen shot if I fudge it.

Like I see this "PSI = Volts / (0.08) + (-6.24)" but actually entering it correctly is where I my stumble.

[cobaltssoverbooster]

make your screen look like this one

[2therock]

I'm sorry if I didn't mention I am using mvpi. Not the 2

[2therock]

So mentioning I'm am using MPVI still use pins 9 & 10?

[cobaltssoverbooster]

those are the pins from the gauge...they have nothing to do with mpvi or mpvi 2.

[2therock]

Heh, thanks for hanging with me. I'm hoping AEM has it right on their end because its plugged into the back.

Right now with my stumbling around it is not even close to Boost and when idling it reads -11.** when the gauge reads 18.**

This is me on the interface.

enhanced_IO.jpg