Who's got a mapdaddy?
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If you have a mapdaddy sensor, please post your kpafactor.inc file for me. I believe it will be called kpafactor6400.inc and will be found in the megasquirt folder/your car/ mtCfg. It's in there somewhere, please search for it. It should open in notepad and you can simply copy and paste here. Thanks.
<edit>
I believe that the barofactor.inc file will contain the same information that I need if you can post that file alternatively. either file should work. thx
<edit>
I believe that the barofactor.inc file will contain the same information that I need if you can post that file alternatively. either file should work. thx
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Last edited by Ben; 10-20-2007 at 10:55 PM.
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It will look simmilar to this, but will be scaled differently for the MPX6400A sensor
; genmap 1.0 Motorola MPX4250A
KPAFACTOR: ; KPA ADC Volts (* = out of sensor range)
DB 100T ; 0 - 0.000*
DB 100T ; 1 - 0.020*
DB 100T ; 2 - 0.039*
DB 12T ; 3 - 0.059
DB 13T ; 4 - 0.078
~~~~~~~SNIP~~~~~~
DB 252T ; 252 - 4.941
DB 253T ; 253 - 4.961
DB 100T ; 254 - 4.980*
DB 100T ; 255 - 5.000*
KPAFACTOR: ; KPA ADC Volts (* = out of sensor range)
DB 100T ; 0 - 0.000*
DB 100T ; 1 - 0.020*
DB 100T ; 2 - 0.039*
DB 12T ; 3 - 0.059
DB 13T ; 4 - 0.078
~~~~~~~SNIP~~~~~~
DB 252T ; 252 - 4.941
DB 253T ; 253 - 4.961
DB 100T ; 254 - 4.980*
DB 100T ; 255 - 5.000*
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Ben, I have one called kpafactor4115 and one called kpafactor4250, both in the src folder. I am almost certain Jerry installed a 4-bar MAP in my MSPNP before he shipped it to me. Nothing called 6400.
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well it's absolutely not the 4250 file, that's the 2.5bar sensor.
Let's peak at the 4115 then, if it's a table like the one I posted that references ADC counts to MAP (in kPa) and sensor voltage output.
Let's peak at the 4115 then, if it's a table like the one I posted that references ADC counts to MAP (in kPa) and sensor voltage output.
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http://www.msefi.com/viewtopic.php?t=28880
the guy who wrote palmtune thinks it should be there. I don't have it, but I was thinking that my MS was initially set up on Jerry @ DIY's notebook, not mine. the utility that he mentions exisits, but doesn't look like it is programmed for the 4 bar.
so...I'm pretty much out of ideas, but there has to be some way to find correlate MS ADC values with MAP readings with this sensor.
the guy who wrote palmtune thinks it should be there. I don't have it, but I was thinking that my MS was initially set up on Jerry @ DIY's notebook, not mine. the utility that he mentions exisits, but doesn't look like it is programmed for the 4 bar.
so...I'm pretty much out of ideas, but there has to be some way to find correlate MS ADC values with MAP readings with this sensor.
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http://www.msefi.com/viewtopic.php?p...xh6400a#181482
#elif MPXH6400A
mapBins1 = array, U08, 170, [ 12], "kPa", 1.6197783, 2.147, 20.0, 400.0, 0
#elif MPXH6400A
mapBins1 = array, U08, 170, [ 12], "kPa", 1.6197783, 2.147, 20.0, 400.0, 0
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Right, 380/255 = 1.49...I'd bet they get that 1.62 because the sensor's real world output is not 0-5V, but something more like .2-4.8V or whatever, so you miss out on some potential resolution there. I'll try it tomorrow and see what happens.
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0-5V depends on how 5 (AKA full scale) is your power supply voltage (usually around 4.92V with a LM7805 voltage reg) and how 0 is your ground (usually 0.02 to 0.05V). So you may have to compensate for that.
Jim
Jim
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OK, I believe I've got the scale value of 1.62 figured out.
The sensor range is 20-400 kPa, or span of 380kPa. It's output range is .2-4.8 VDC, meaning it has a span of 4.6VDC.
The MS has an ADC count of 255 over 5V.
4.6VDC/5VDC = .92
.92 x 255ADC = 234.6ADC
380 kPa
------- = 1.6197783 kPa/ADC = the scale =![Biggthumpup](https://www.miataturbo.net/images/smilies/biggthumpup.gif)
234.6 ADC
The sensor range is 20-400 kPa, or span of 380kPa. It's output range is .2-4.8 VDC, meaning it has a span of 4.6VDC.
The MS has an ADC count of 255 over 5V.
4.6VDC/5VDC = .92
.92 x 255ADC = 234.6ADC
380 kPa
------- = 1.6197783 kPa/ADC = the scale =
![Biggthumpup](https://www.miataturbo.net/images/smilies/biggthumpup.gif)
234.6 ADC
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Last edited by Ben; 10-23-2007 at 03:23 PM.
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I sent my solution to the gentleman who wrote PalmLog. He noted that his base values were indeed inaccurate, but
Essentially, it looks like MegaTune's kpafactor code is inaccurate!
So my solution, while correct, is wrong! Ugh.
When displaying map in PalmTune, it's critical that the map displayed = MS internally calculated map, regardless of accuracy.
So my solution, while correct, is wrong! Ugh.
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I believe that my slope is correct, but the offset value will be wrong, with my solution erring high. I was 9.9kPa high with my calculation for the 2.5bar sensor (with the correct slope). I do not know if that same 9.9 translates over to the 4 bar, or if the value is somehow completely different, as frankly I am having a hard time figuring out the code for the 4 bar. I seem to be missing a critical part of how MT handles the 4 bar. The kpafactor.inc file for the 2.5 bar makes it pretty friggin clear, however. So at this point, I am assuming that MT makes the 4 bar calculation by multiplying a value in the 2.5bar kpafactor file by a constant.
So now I'm basing assumptions on assumptions. It's a big house of cards, and if a card on the bottom falls, then the whole thing crashes down.
I'm going to nail this, or I'm going to slit my wrists. Or both. We'll see.
So now I'm basing assumptions on assumptions. It's a big house of cards, and if a card on the bottom falls, then the whole thing crashes down.
I'm going to nail this, or I'm going to slit my wrists. Or both. We'll see.
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Matt Cramer confirms there is no mapfactor file for the 4bar. MS uses interpolation, not a look up table, for this sensor.
So if my scale is right, then the offset value I have working is 4. This was derived from guess & check, and unfortunately is prone to a larger margin of error than I would have wanted. I believe that this margin of error is within 3kPa, or less than .5psi, and relates to the MAP value displayed on the palm only. It does not affect the values generated in a datalog.
Good news is at least we were able to produce exactly accurate values for the 2.5 bar sensor.
So if my scale is right, then the offset value I have working is 4. This was derived from guess & check, and unfortunately is prone to a larger margin of error than I would have wanted. I believe that this margin of error is within 3kPa, or less than .5psi, and relates to the MAP value displayed on the palm only. It does not affect the values generated in a datalog.
Good news is at least we were able to produce exactly accurate values for the 2.5 bar sensor.