how to calibrate WB O2 sensor?

[StevenD57]

I have a UEGO 1000 wide band O2 system made by EFI Systems and according to the directions from the manufacturer it has a curve like this:

A/F Ratio | Volts
10:1 | 1.396
11:1 | 1.78
12:1 | 2.094
13:1 | 2.26
14:1 | 2.5
14.7:1 | 2.57
15:1 | 2.79
16:1 | 3.09
17:1 | 3.39
18:1 | 3.69
19:1 | 3.99
20:1 | 4.25

How do I enter this calibration curve data into Megatunix so the system knows how the voltage output from the WBO2 correlates to AFR?

[djandruczyk]

I have a UEGO 1000 wide band O2 system made by EFI Systems and according to the directions from the manufacturer it has a curve like this:

A/F Ratio | Volts
10:1 | 1.396
11:1 | 1.78
12:1 | 2.094
13:1 | 2.26
14:1 | 2.5
14.7:1 | 2.57
15:1 | 2.79
16:1 | 3.09
17:1 | 3.39
18:1 | 3.69
19:1 | 3.99
20:1 | 4.25

How do I enter this calibration curve data into Megatunix so the system knows how the voltage output from the WBO2 correlates to AFR?

You didn't say if your were using MS-1 or MS-2. For MS-I you would need to create a lookuptable file (same thing for megatune or tunerstudio) , for MS-2 those can be set from the gui if it's A. aone of the ones mtx knows about or B, a linear signal that you can punch in the values for and mtx generates the table, since your signal is non-linear you'd ither need to reporgram your unit wiht a linear signal or a common curve MTX knows about. See Tools -> MS-II AFR Calibrator.

[StevenD57]

I am using a MS1 ECU so where do I put this lookup table and what is the format supposed to be?
Is there an example anywhere? Is it supposed to be located in a particular directory or how do I
tell MTX where to find it?

From reading through the documentation there does not seem to be any way to reprogram this
unit to a different curve. Does that mean this WBO2 is not useable with Megasquirt?

[djandruczyk]

I am using a MS1 ECU so where do I put this lookup table and what is the format supposed to be?
Is there an example anywhere? Is it supposed to be located in a particular directory or how do I
tell MTX where to find it?

From reading through the documentation there does not seem to be any way to reprogram this
unit to a different curve. Does that mean this WBO2 is not useable with Megasquirt?

MS-1 deals with the wideband signal as a VOLTAGE ONLY. Your best bet would be to see if you can reconfigure this wideband to output a linear 0-5 volt signa, like an innovate motorsports LM-1, then use tools-> MS1 lookuptables and select the wb02_table and select the right box which will let you choose the table of choice. If you cannot reconfigure the wideband, you can make a lookuptable, but they are a bit cryptic, and since i don't know if your unit outputs a true "curve" or just changes slope at abrupt points through it's range. Most decent widebands allow you to reprogram the output curve, or set it to a linearized output.

[StevenD57]

I am looking at the files in /usr/share/MegaTunix/LookupTables and I do see several inc files there for various WBO2 units.
I looked at the format of these files and I understand the voltage column and the AFR*10 column but what is the column with the 90T to 190T fields? Can you provide any background about that? What do the entries in that column signify and what is the logic to how the numbers in that column progress? I am not understanding these:


DB 173T ; 213 4.18
DB 174T ; 214 4.20
DB 174T ; 215 4.22
DB 174T ; 216 4.24
DB 175T ; 217 4.25
DB 175T ; 218 4.27
DB 175T ; 219 4.29
DB 176T ; 220 4.31
DB 176T ; 221 4.33
DB 177T ; 222 4.35
DB 177T ; 223 4.37
DB 177T ; 224 4.39
DB 178T ; 225 4.41
DB 178T ; 226 4.43
DB 179T ; 227 4.45
DB 179T ; 228 4.47
DB 179T ; 229 4.49
DB 180T ; 230 4.51

[djandruczyk]

I am looking at the files in /usr/share/MegaTunix/LookupTables and I do see several inc files there for various WBO2 units.
I looked at the format of these files and I understand the voltage column and the AFR*10 column but what is the column with the 90T to 190T fields? Can you provide any background about that? What do the entries in that column signify and what is the logic to how the numbers in that column progress? I am not understanding these:


DB 173T ; 213 4.18
DB 174T ; 214 4.20
DB 174T ; 215 4.22
DB 174T ; 216 4.24
DB 175T ; 217 4.25
DB 175T ; 218 4.27
DB 175T ; 219 4.29
DB 176T ; 220 4.31
DB 176T ; 221 4.33
DB 177T ; 222 4.35
DB 177T ; 223 4.37
DB 177T ; 224 4.39
DB 178T ; 225 4.41
DB 178T ; 226 4.43
DB 179T ; 227 4.45
DB 179T ; 228 4.47
DB 179T ; 229 4.49
DB 180T ; 230 4.51

The only value of interest is the second column, it is the AFR *10. Not all lookuptables have the remaining data. The semicolon is the "end of valid line" so anything after that is a comment and ignored by megatunix.

AFR*10 RAW ADC (0-255) Voltage (0-5)
DB 180T ; 230 4.51

The lookuptable needs to have 256 entries, corresponding to the AFR*10 values corresponding to the input voltages from 0-5 volts (0-255 ADC counts, since MS-i has 8 bit ADC's) look at CustomWB.inc:

DB 90T ; 0 0.00
DB 90T ; 1 0.02
DB 90T ; 2 0.04
DB 91T ; 3 0.06
DB 91T ; 4 0.08

The fields are "DB" (marker for a lookuptable entry), the value of the AFR*10 with a "T" suffix, a semicolon (comment break), the ADC value corresponding to this entry and the last column is the input voltage corresponding to the ADCvalue on a 0-5 V scale. When making your own table the semicolon and all after it is not required, but it is handy to have as you can debug the table easily.

[StevenD57]

After giving your directions much thought I used gnuplot to do some curve fitting and wrote some perl to create an Lookuptable input file for a Uego1000 WB o2 unit. In case anyone else has one of these WB o2 units, do you want to include this file with Megatunix?

[djandruczyk]

After giving your directions much thought I used gnuplot to do some curve fitting and wrote some perl to create an Lookuptable input file for a Uego1000 WB o2 unit. In case anyone else has one of these WB o2 units, do you want to include this file with Megatunix?

Yes, please.

[StevenD57]

After giving your directions much thought I used gnuplot to do some curve fitting and wrote some perl to create an Lookuptable input file for a Uego1000 WB o2 unit. In case anyone else has one of these WB o2 units, do you want to include this file with Megatunix?

Yes, please.

Where do you want me to send or put the file?

[StevenD57]

I E-mailed the file to you from my yahoo account. Did you get it?

[TurboCamaro]

I am having trouble getting some lookup tables setup for some custom gauges I'm trying to make. I'm wanting to make an engine vacuum gauge and a forwad and lateral acceleration gauges which are getting Gs from an accelerometer board I hooked up to ADC6 and ADC7. I'm testing it out first on the engine vacuum gauge since this is essentially a MAP gauge with different units. I copied and renamed the kpafactor.inc file to vackpafactor.inc and changed some of the kpa values to in-Hg values. However, this datasource is not showing up in the dashdesigner once I bring in my custom gauge. Is this where I could expect to see custom lookup tables or am I missing something? Also, is there a faster way to generating lookup tables as apposed to manually editing them in a text editor? I'm not looking forward to entering 255 unique multi-decimal values for the G-meters.

Thanks for the help!

I'm running Megatunix on windows(2000 and XP)
MS-I v2.2
MSnS-Extra v. 029y4

[djandruczyk]

I am having trouble getting some lookup tables setup for some custom gauges I'm trying to make. I'm wanting to make an engine vacuum gauge and a forwad and lateral acceleration gauges which are getting Gs from an accelerometer board I hooked up to ADC6 and ADC7. I'm testing it out first on the engine vacuum gauge since this is essentially a MAP gauge with different units. I copied and renamed the kpafactor.inc file to vackpafactor.inc and changed some of the kpa values to in-Hg values. However, this datasource is not showing up in the dashdesigner once I bring in my custom gauge. Is this where I could expect to see custom lookup tables or am I missing something? Also, is there a faster way to generating lookup tables as apposed to manually editing them in a text editor? I'm not looking forward to entering 255 unique multi-decimal values for the G-meters.

Thanks for the help!

I'm running Megatunix on windows(2000 and XP)
MS-I v2.2
MSnS-Extra v. 029y4

[TurboCamaro]

Did I miss your response?

So I now see under Tool->MS1 Lookup Tables that my modified table file shows up in the list. However I'm not sure what this is allocating. I can't seem to add others and I don't understand the corrilation between this area and the gauges. I tried to search around for some documentation for it on the forums but haven't come up with anything so far.

[StevenD57]

Did you look at my other post on this subject?

http://www.msextra.com/forums/viewtopic ... 06&t=37661

This is not specific to adding custom gauges but rather how to create the lookup table file with the 255 entries in it.

[TurboCamaro]

Yup, I actually saw that post earlier today. My question isn't really about creating lookup tables but rather implimenting them. Once I create one and it's in the same directory as all of the other ones I'm not sure where to go from there. I see the list of tables from the drop-down where I can choose the one I just created but I don't know what effect this is having. Is there a corrilation of the datasources in the dashdesigner and the lookup tables in the Megatunix application?

[djandruczyk]

Not sure why it ate my whole post. but to do what you want requires you to manually edit the proper interogation profile an realtime map (rtv_map) file specific to your firmware to add additional derived variables at the end, modeled like derived_42 and derived_43 which reference ADC6 and ADC7, use derived_19 as a reference to a derived var that uses a lookuptable conversion. Make sure to edit the top of the file and update the total number of vars, and define the new lookuptable in the interrogation profile in the [Lookuptables] section.

Beware this will break with the next release as the api's have slightly changed.

[TurboCamaro]

Alright, I think I'm following you here. I had to go find a simple ini editor that recognized the format since I usually just use Notepad.
So since I'm using MS-I MSnS-extra 029y4 I am referencing the following files, correct?:
C:\Program Files\MegaTunix\dist\Interrogator\Profiles\MS-1\SquirtnSpark-Extra-029yx.prof
C:\Program Files\MegaTunix\dist\RealtimeMaps\MSnS-Extra-029x.rtv_map

And attached are screen-shots of the areas I think you are talking about. For the total variables, I'm increasing that 56, correct?
Hopefully I can figure things out from here.

[djandruczyk]

Alright, I think I'm following you here. I had to go find a simple ini editor that recognized the format since I usually just use Notepad.
So since I'm using MS-I MSnS-extra 029y4 I am referencing the following files, correct?:
C:\Program Files\MegaTunix\dist\Interrogator\Profiles\MS-1\SquirtnSpark-Extra-029yx.prof
C:\Program Files\MegaTunix\dist\RealtimeMaps\MSnS-Extra-029x.rtv_map

And attached are screen-shots of the areas I think you are talking about. For the total variables, I'm increasing that 56, correct?
Hopefully I can figure things out from here.

Yes, you'd increase that to 58, and add two more sections at the end, modeled after 42 and 43, and using the lookuptable stuff from 19, adjusting the internal names dlog_gui_name tooltip, and dlog_field_name entries to suit your new variables, use the same offsets as 42/43 respectively. use a NEW lookuptable name that you should add into the main interrogation profile and the corresponding filename. (look at the others and you'll figure it out)

beware, that in the next release this will break slightly due to some changes in the API.

[TurboCamaro]

So I think I got it, at least to some degree. I added a derived variable and a lookup table and the references to those things. In dashdesigner my new datasource now shows up and in Megatunix my new lookup table shows up. I can assign my new gauge (engine vacuum) with the new datasource and is set to read a look-up table which is identical to kpafactor.inc except I changed all of the xxxxT numbers to corrispond to in-Hg numbers instead of kPa. My gauge is for some reason stuck at 140 with my megasquirt connected and the MAP gauge reading 94 kPa. I'm not sure where this 140 is coming from. Here's my entry in the derived variable section:

[derived_56]
keys=internal_names,dlog_gui_name,dlog_field_name,offset,source_key,lookuptable,dl_conv_expr,ul_conv_expr,tooltip,real_lower,real_upper,log_by_default
internal_names=mapvac
dlog_gui_name=VAC (in-Hg)
dlog_field_name=VAC
offset=5
source_key=map_sensor
real_lower=30
real_upper=0
lookuptable=vacuum_map
dl_conv_expr=x+30
ul_conv_expr=x-30
tooltip="VAC (in-Hg)" is the Manifold Gauge Vacuum Pressure in in-Hg - converted MAP signal
log_by_default=TRUE

I'm kind of wondering if the internal_names is defined else where and I can't just make one up here? Or am I ok?

Here's a snippit from my lookup table:
DB 7.678T ; 58 - 1.137
DB 7.383T ; 59 - 1.157
DB 7.087T ; 60 - 1.176
DB 6.792T ; 61 - 1.196
DB 6.497T ; 62 - 1.216
DB 6.201T ; 63 - 1.235
DB 5.906T ; 64 - 1.255
DB 5.611T ; 65 - 1.275
DB 5.315T ; 66 - 1.294
DB 5.020T ; 67 - 1.314
DB 4.725T ; 68 - 1.333
DB 4.430T ; 69 - 1.353
DB 4.134T ; 70 - 1.373
DB 3.839T ; 71 - 1.392
DB 3.544T ; 72 - 1.412
DB 3.248T ; 73 - 1.431
DB 2.953T ; 74 - 1.451
DB 2.658T ; 75 - 1.471
DB 2.362T ; 76 - 1.490
DB 2.067T ; 77 - 1.510
DB 1.772T ; 78 - 1.529
DB 1.477T ; 79 - 1.549
DB 1.181T ; 80 - 1.569
DB 0.866T ; 81 - 1.588
DB 0.591T ; 82 - 1.608
DB 0.295T ; 83 - 1.627
DB 0.00T ; 84 - 1.647
DB -0.3T ; 85 - 1.667
DB -0.59T ; 86 - 1.686
DB -0.89T ; 87 - 1.706
DB -1.18T ; 88 - 1.725
DB -1.48T ; 89 - 1.745
DB -1.77T ; 90 - 1.765
DB -2.07T ; 91 - 1.784
DB -2.36T ; 92 - 1.804
DB -2.66T ; 93 - 1.824
DB -2.95T ; 94 - 1.843
DB -2.95T ; 95 - 1.863*
DB -2.95T ; 96 - 1.882*
DB -2.95T ; 97 - 1.902*
DB -2.95T ; 98 - 1.922*
DB -2.95T ; 99 - 1.941*
DB -2.95T ; 100 - 1.961*

[djandruczyk]

So I think I got it, at least to some degree. I added a derived variable and a lookup table and the references to those things. In dashdesigner my new datasource now shows up and in Megatunix my new lookup table shows up. I can assign my new gauge (engine vacuum) with the new datasource and is set to read a look-up table which is identical to kpafactor.inc except I changed all of the xxxxT numbers to corrispond to in-Hg numbers instead of kPa. My gauge is for some reason stuck at 140 with my megasquirt connected and the MAP gauge reading 94 kPa. I'm not sure where this 140 is coming from. Here's my entry in the derived variable section:

[derived_56]
keys=internal_names,dlog_gui_name,dlog_field_name,offset,source_key,lookuptable,dl_conv_expr,ul_conv_expr,tooltip,real_lower,real_upper,log_by_default
internal_names=mapvac
dlog_gui_name=VAC (in-Hg)
dlog_field_name=VAC
offset=5
source_key=map_sensor
real_lower=30
real_upper=0
lookuptable=vacuum_map
dl_conv_expr=x+30
ul_conv_expr=x-30
tooltip="VAC (in-Hg)" is the Manifold Gauge Vacuum Pressure in in-Hg - converted MAP signal
log_by_default=TRUE

OK: get rid of "source_key" in he keys line as well as the "source_key=map_sensor" line, that is only for special case vars that use different conversions based on some specific ecu state. (a nasty kludge essentially) The other issue is your lookuptable, the values are ONLY allowed to be positive integers, so since you want a floating point value you make use of both the lookuptable AND the conv expressions. The way it works is ECU -> lookuptable ->conversion (if present) ->screen

So, do something like make your lookuptable be from 0-3000, and use a x/100 conversion expression to get it to 0-30., or 0-300 and a divide by 10. You can use most any algebraic math for conversion expressions.

I'm kind of wondering if the internal_names is defined else where and I can't just make one up here? Or am I ok?

MegaTunix SHOULD error out on startup if you duplicated an already existing internal name, though I'd have to double check that for sure.

Here's a snippit from my lookup table:
DB 7.678T ; 58 - 1.137
DB 7.383T ; 59 - 1.157
DB 7.087T ; 60 - 1.176
DB 6.792T ; 61 - 1.196
DB 6.497T ; 62 - 1.216
DB 6.201T ; 63 - 1.235
DB 5.906T ; 64 - 1.255
DB 5.611T ; 65 - 1.275
DB 5.315T ; 66 - 1.294
DB 5.020T ; 67 - 1.314
DB 4.725T ; 68 - 1.333
DB 4.430T ; 69 - 1.353
DB 4.134T ; 70 - 1.373
DB 3.839T ; 71 - 1.392
DB 3.544T ; 72 - 1.412
DB 3.248T ; 73 - 1.431
DB 2.953T ; 74 - 1.451
DB 2.658T ; 75 - 1.471
DB 2.362T ; 76 - 1.490
DB 2.067T ; 77 - 1.510
DB 1.772T ; 78 - 1.529
DB 1.477T ; 79 - 1.549
DB 1.181T ; 80 - 1.569
DB 0.866T ; 81 - 1.588
DB 0.591T ; 82 - 1.608
DB 0.295T ; 83 - 1.627
DB 0.00T ; 84 - 1.647
DB -0.3T ; 85 - 1.667
DB -0.59T ; 86 - 1.686
DB -0.89T ; 87 - 1.706
DB -1.18T ; 88 - 1.725
DB -1.48T ; 89 - 1.745
DB -1.77T ; 90 - 1.765
DB -2.07T ; 91 - 1.784
DB -2.36T ; 92 - 1.804
DB -2.66T ; 93 - 1.824
DB -2.95T ; 94 - 1.843
DB -2.95T ; 95 - 1.863*
DB -2.95T ; 96 - 1.882*
DB -2.95T ; 97 - 1.902*
DB -2.95T ; 98 - 1.922*
DB -2.95T ; 99 - 1.941*
DB -2.95T ; 100 - 1.961*