VEMS Community Forum
Technical => Wideband & EGT Gauge => Topic started by: Ellisd on January 14, 2009, 08:16:23 pm
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Can anyone tell me how to setup the "analoge in" in megatune to record boost? I've managed to get the gauge to display 0 - 2bar (0 - 200 kPa) but i assume their's more to it than that?, as the neddle doesn't move at all. I'm guessing i'll have to measure voltages from the map sensor at certains pressures to get some sort of scale. I'm planning on using my greddy boost controller for this
Thanks in advance :)
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Analog in is a tricky one to setup, you certainly need to measure the voltage range, then setup the values in the Analog input section of MegaTune
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well this is a far as got so far,
(http://i66.photobucket.com/albums/h261/ellisd_2006/megatunescreen.gif)
Like i said i've got it looking the way a i want it, i just need it to work the way i want ha ha ha
Since i've wired the 'analoge in' in the gauge's button won't change modes. Is this something you've heard of before? It's spliced into the map input for the ECU through a 1 - 10k variable resistor
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Yes, the button shares the same converter channel as the analogue in, there is a setting for the button threshold, that you should look at - also make sure that you are not pulling the analogue channel down to ground through the resistor.
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unfortunatelly the analog input has a pullup to 4v. So difficult to use it correctly, but read this thread, maybe help you:
http://195.159.109.134/vemsuk/forum/index.php/topic,337.0.html (http://195.159.109.134/vemsuk/forum/index.php/topic,337.0.html)
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Yeah i have read through it a few times. I'm going to get the button/display problem sorted 1st then i'll move onto measuring pressures and voltages and see about getting the boost logged. I've managed to get something logged but the numbers have no relevence to actual values. It works out roughly as 5.29 units = 1kPa gauge reads about 500 at idle (-60 kPa on boost controller) and 1400 at a 110 kPa
60 + 110 = 170 kPa
1400 - 500 = 900 units on analoge In gauge (scale 0 - 2047)
900/170 = 5.29 units per kPa (2dp)
(http://i66.photobucket.com/albums/h261/ellisd_2006/1stlogwithboost.jpg)
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With the offset ang gain you can play to read something friendly.
Take some measurement pont like me.
Yeah i have read through it a few times. I'm going to get the button/display problem sorted 1st then i'll move onto measuring pressures and voltages and see about getting the boost logged. I've managed to get something logged but the numbers have no relevence to actual values. It works out roughly as 5.29 units = 1kPa gauge reads about 500 at idle (-60 kPa on boost controller) and 1400 at a 110 kPa
60 + 110 = 170 kPa
1400 - 500 = 900 units on analoge In gauge (scale 0 - 2047)
900/170 = 5.29 units per kPa (2dp)
(http://i66.photobucket.com/albums/h261/ellisd_2006/1stlogwithboost.jpg)
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That's my job for the weekend ;D. I'll be breaking out the multimeter and footpump to measure my voltages and pressures. I'll let you's know what my result are
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Ok i've finally had some spare time and broke my multimeter out. Here's what i found:
kPa volts gauge reading
110 3.80
100 3.67
090 3.52
080 3.37
070 3.24
060 3.10 1323
050 2.95 1274
040 2.80 1213
030 2.67 1165
020 2.52 1102
010 2.38 1054
000 2.22 0995
Input calibration 255 offset 158
I couldn't get the gauge reading any higher up the scale because i wasn't quick enough to read them ::) But 100kPa was about 1400 units on the gauge. Can anyone help me make the gauge in megatune read what i want? i'll send the megatune MSQ file if that helps
http://www.yousendit.com/download/WnBUbUpURnd3TGpIRGc9PQ
(http://i66.photobucket.com/albums/h261/ellisd_2006/Untitled-2.gif)
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Are you working from the .ini configuration example I gave here?
http://195.159.109.134/vemsuk/forum/index.php/topic,337.msg3373.html#msg3373
If so you may be able to use:
{ ((5/255)*analogIn) - 995 }
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Hello!
The kPa is absolute or relative pressure?
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I can't really remeber what i did to get these values now as i've been playing about that much. The INI file i'm using is in the attached link if thats any help?
http://www.yousendit.com/download/WnBUbUpURnd3TGpIRGc9PQ
The values are relative to pressure (110kPa is equal to 1.1 bar boost) the gauge drops to about 600 when in vacuum (-60kPa on my boost gauge). I'm assuming it will still be linear
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I see that you have
map = {analogIn/10.235}
So I did a few calcs:
kpa value/10.235 Raw value
60 1323 13540.91 3357.08 55.95133333
50 1274 13039.39 2855.57 57.1113
40 1213 12415.06 2231.23 55.78075
30 1165 11923.78 1739.95 57.99833333
20 1102 11278.97 1095.15 54.75725
10 1054 10787.69 603.87 60.3865
0 995 10183.83 0.00
Average = 56.99757778
So if we use kpa = (Raw value - 10184) / 57
Raw value minus 10184 divide 57
12748 2564 44.98245614
45kpa
So you can try:
map = {(analogIn-10184)/57}
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Thanks for this. I have no idea where i've got the the /10.235 from lol. Probably just playing about sticking random numbers in and seeing what happened. I'll give this a bash tonight and see what happens. I wish you could calibrate it like the full version of megatune. Where it asks you how many kPa = x amount of volts. all these mathematical equations are just beyond me lol. A B grade at GCSE doesn't get you very far nowadays ha ha ha
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Experimentation is where I've learnt it all from (that's suggesting that I got the numbers right, they could be waaaaay off!) - I got a grade C GCE (GCSEs came in the year after I left school) if they'd made maths based on.
We could get a better value if the measurements were taken with Raw values and if we could get accurate pressure readings from a known pressure source.
I agree that it would be great if you could punch in a calibration value, and have a simple way to sort this out, but unfortunately usability is lacking in that area.
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Try this:
analog input curve 0 (0) 0
analog input curve 1 (15) 0
analog input curve 2 (30) 0
analog input curve 3 (45) 14
analog input curve 4 (60) 36
analog input curve 5 (75) 57
analog input curve 6 (90) 79
analog input curve 7 (105) 100
analog input curve 8 (120) 122
analog input curve 9 (135) 143
analog input curve 3 (150) 164
analog input curve 11 (165) 186
analog input curve 12 (180) 207
analog input curve 13 (195) 228
analog input curve 14 (210) 250
analog input curve 15 (225) 255
analog input curve 16 (240) 255
analog input calibration 32
analog input offset 0
if i make good, it will show absolute pressure in kPa
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Will looks like we're very close now! the analogue curve works a treat! it's about 5 kPa out which is almost nothing so i'm sure a little tweak will sort that. Here's a pic from the log. Max boost on my greddy controller was around 0.99 bar boost, 199 kPa total pressure :D thanks everyone for your help, and sorr for being such a pain lol
(http://i66.photobucket.com/albums/h261/ellisd_2006/1stlogwithboost-1.jpg)
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If you want to take some raw readings - pure analog values and bear in mind local air pressure when you take your base reading, I use the BBC's weather http://www.bbc.co.uk/weather/5day.shtml you will have to set your location.
Take a look at the heading Current Nearest Observations: and there's an entry Pressure (mB): which when I looked a minute ago read 1014 this translates to 101.4kpa so that would be the base point to work from on the day you take the readings.
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It's great to see that you guys got the boost logging working! Round has very good capabilities but there's definitely need to make them more easily usable. Logging boost, rpm, MAT additionally to lambda and EGT is very beneficial.
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Yes compaired to other gauges I have looked at on the market the VEMS beats them hands down on features and price. Yes the software is a little "raw" shall we say. But thanks to the people on this forum you can overcome that.
Can i just check I've under stood you last post correctly Rob?
I understand the difference between relative and apsolute pressure. When looking at the BBC's website it's saying here in Newcastle it is 1012 MB which is near enough 101 kPa so when i power the gauge up without the engine runing i should see 101.
My boost gauge is relative and show's 000 at startup. I'm guessing this will show zero at all absolute pressures, 99, 100 101 etc. Show when my boost gauge shows 1.10 Bar (110 kPa) it means 110 above atmospheric? So today that will be 211 absoulte (101 + 110 added by the turbo). And this should be what my Vems display should read/
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Thats it pretty much spot on ;D
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Every day's a school day ha ha ha
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the problem comes with the accuracy of the gauge that you're measuring the displayed boost with - I'm guessing that the Greddy controller's sensor is very accurate, but the display seems to be compensating for barometric changes.
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Yes that's what i'm thinking. The greddy gauge must just take the initial reading as zero and build ontop of that. I know the 2 gauges will show slightly different readings, but if I calibrate the curve correctly using the BBC's website I'll know both will be right. 1.1bar on the greddy will always be 1.1 over atmospheric. So it wouldn't really matter if my logs showed 210, 211 or 212 kPa's if it's setup right initially both will still be right
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Yes, there will be a little bit of a deviation.
Or wait until the BBC tell you that the air pressure is 1000mb and get out in the car double quick ;)
Rob
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well i think i'm finally sorted!!!!!!!!!!
(http://i66.photobucket.com/albums/h261/ellisd_2006/boostconfigured2.jpg)
I think I have to tweak my boost controller to smooth out the little hump at around 4K but aprt from that i'm well happy.
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Nice work, I think this is the most detailed write-up we've had on getting all of the logging features working.
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Got there in the end lol ;D
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Got there in the end lol ;D
Witch firmware are you using? and can you send me your round.ini file, today I tryed to set my boost loggig but without result, something is very wrong and I don't know what.
Right now is the only certain thing MAP-s 100kPa output voltage, it's 2,18V (audi S2 original 200kPa MAP). I have to by somekinde of precise pressure gauge to measure all other pressure points (as I understand, without that information I can't make it work right).
EDIT:
This is what I could measure today (with not very precise pressure gauge). Settings are: linear curve, calibration is 255, offsett is 0
Like I said on athmospheric pressure it shows 2180 mV @gauge 1300
@ 150kPa - 3200mV @gauge 1420
@ 200kPa - 4560mV @gauge 1585
With disconnected analog in (4V) shows gauge 1529 and to ground 1040
Now, what settings should I use to see @ megatune pressure in kPa, for logging I know how to do it, but I can't make the gauge in megatune show me these numbers what I want to see.
From these measured points and other information what I had, i made some calculations and came up with this kinde of numbers:
@ 0kPa - 0mV @gauge 1038
@ 10kPa - 191mV @gauge 1064
@ 20kPa - 412mV @gauge 1090
@ 30kPa - 633mV @gauge 1116
@ 40kPa - 854mV @gauge 1143
@ 50kPa - 1075mV @gauge 1169
@ 60kPa - 1296mV @gauge 1195
@ 70kPa - 1517mV @gauge 1221
@ 80kPa - 1738mV @gauge 1248
@ 90kPa - 1959mV @gauge 1274
@ 100kPa - 2180mV @gauge 1300
@ 110kPa - 2401mV @gauge 1326
@ 120kPa - 2622mV @gauge 1353
@ 130kPa - 2843mV @gauge 1379
@ 140kPa - 3064mV @gauge 1405
@ 150kPa - 3285mV @gauge 1431
@ 160kPa - 3506mV @gauge 1458
@ 170kPa - 3727mV @gauge 1484
@ 180kPa - 3948mV @gauge 1510
@ 190kPa - 4169mV @gauge 1536
@ 200kPa - 4560mV @gauge 1585
Today I bought one presice boost gauge also (vaacum/boost was very expensive), now i will measure all these points and see do they match.
EDIT2:
Now I came up with formula with what the showed value is going to be in kPa.
Value - 1038 / 2.62 = X kPa
With that formula I got the most lower fault percentage. Now, boost loggign should work with that... but where should I put that formula to get kPa reading in megatune?
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I'm using the latest firmware, i think it's something like the 12/2008?
In all honesty z0tya did all the hard work. I just fine tuned the table he posted on here
I'll send my INI file tonight when i get in from work. The boost is pretty much spot on now, but i still need to tweak the vacuum as it goes wrong at the very bottom end (only a 5kPa out though). The fine tuning was really guess work, I used a footpump and my electronic boost controller to get an accurate figure (i went up in steps of 10kPa) Then i was a case of altering the figure in the table closest to what I wanted and see what change it made. It was trial and error
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Today I made measurements at 100kPa to 200kPa with 10kPa step. The values are almost similar to these what i calculated.
Now seems that boost log works fine for me:
(http://ranz.planet.ee/S2/logi.JPG)
Now the only problem (not wery big) is that megatune does not show me values in kPa. Also my RPM input has some random spikes down, i don't know what is the problem with that. Also the button doesn't work anymore, at setting 128 and holding the button down for few seconds, it shows me analog in at the bottom field, but holding it a little bit longer, it showed something like -FA at both fields. Tried to play with different settings also, but without result.
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Yes we have the rpm spikes too. It seems to bug or some hw error. But the log usable apart from the rpm spikes.
If you play with the curve, you get abs pressure in the log and the gauge too.
Some maths:)
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If you play with the curve, you get abs pressure in the log and the gauge too.
Some maths:)
I have played with the curve and with the calibration, but i don't get even close to that what I want.
How to understand the analog in curve, what do these values mean?
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If you want to have a go using my config file, just click on the link below to download it
https://www.yousendit.com/download/UmNKd0VBdWNubVd4dnc9PQ
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I tried your settings, no good for me :(
Can anyone explain me what does the calibration mean, and to what does rows in analog in curve answer to?
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Hi, I am a bit confused because you said in an earlier post that boostlogging was fine for you.
What has happened to change that?
What is it that you are aiming for?
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Boost logging works fine, but the gauge in megatune doesn't.
I measured different pressure points and writed up values from megatune. From that i got formula for logging: (value - 985)/3.15 then log shows me pressure in kPa.
But I want to get the megatune (then gauge shows that to) show value in kPa-s. As i understand, for that i need to change calibration value and analog in curve, but i don't understand them... what does they exacly do. Right now my settings are: calibration 255, offset 0 and analog in 0 - 15 - 30 - 45 etc.
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With little help from z0tya my system works now how I wanted to. Now i can see boost in kPa at gauge to and offcourse log it.
Ho did I do it:
S2 3B original 200BAR MAP
I connected my compressor variable output (with gauge: 0 to 2,5BAR) directly to MAP input.
z0tya gave me somekinde of numbers what he calculated, I inserted them and started to play with them.
Calibration setting 32, offset 0
First I needed to get 100 reading at atmosphere pressure, changed numbers at analog in to get it.
Now raised compressor oputput to 0,5BAR and played with numbers to get reading 150, then output to 2BAR and played to get 200 reading. After that tested other readings, 0,1BAR - 110, 0,2BAR - 120, 0,3 - 130 etc. I din't have to change any more numbers at analog in curve becase it was enough only measure 3 points (0BAR - 1,5BAR - 2BAR).
These are numbers from analog in curve:
0 - 0
1 - 0
2 - 0
3 - 0
4 - 0
5 - 0
6 - 0
7 - 0
8 - 18
9 - 30
10 - 55
11 - 106
12 - 145
13 - 180
14 - 220
15 - 225
16 - 240
First 7 rows are 0 becase they din't change the reading, also are 15 and 16 set to linear in because they din't cange nothing also.
Now i borrowed my friends ECU what has 300BAR MAP and did the same thing.
Calibration 64, offset 0
Measured 5 points (0 - 0,5 - 1 - 1.5 - 2BAR) to get right reading (played vith analog in curve) and other readings between measured points where rigt also.
These are numbers from this analog in curve:
0 - 0
1 - 0
2 - 0
3 - 0
4 - 0
5 - 0
6 - 0
7 - 0
8 - 5
9 - 15
10 - 41
11 - 74
12 - 106
13 - 136
14 - 169
15 - 225
16 - 240
First 7 and 2 last are same as it was previously.
Now i'm wating my order from vems and when my stuff arrives, I'll measure the VEMS 300BAR MAP also.
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As long as you've got the information you need then we're all happy! Thanks to z0tya for his help.