Subpage of AfreshTiny
relevant pins on the DSUB15 :
- dsub15pin1: Vout (Lambda output signal +) - configurable as either Narrow band, wideband 0-1v through to 0-5v; or 0-5V EGT output
- dsub15pin9: Vout-gndref (voltage output signal external reference). Remember to connect dsub15pin9 to GND - while GND of the Round (DSUB15 pin 13,14 and 15) must be connected to the GND of the receiving device
- alternatively dsub15pin9 vout-gndref can be on max 5V potential (with higher voltage on this pin, max output voltage on Vout will be limited)
Configuration - Vout modes of operation
Analog output / vout_conf setting determines the Vout mode of operation:
- linear EGT output
- NBO2 - nonlinear
- old DIY-style WBO2 output (if you don't know about this, you don't need it)
- wideband linear N Volt/lambda (note: the modes below allow higher resolution)
- wideband high resolution linear outout (only lambda=0.68 .. 1.36 used, stretched to 0..5V)
- wideband custom curve - the most powerful
Linear 0-5V EGT output
vout_conf=0
0V at -50C; 4mV/C, so 4.8V = 1150 C. Useful with a non-versatile ECU that can't accept the K-thermocouple signal directly. Eg. it allows head-temp measurement in an air-cooled engine with an ECU that does not support k-thermocouple signal directly
If you need multiple amplified K-thermocouple signals (or need the round output voltage signal for lambda), use the small and cost effective [EGT amplifier].
- Often used with multichannel dataloggers or motec, that lacks K-thermocouple inputs but has 0-5V analog inputs.
NBO2 nonlinear output
vout_conf=01
NB sensor simulator, LSM11 reference curve. This curve is mostly useful for old type NBO2 input equipped factory ECU-s only, since it has very low slope (=> hard to tune, prone to noise) at lambda=0.8 which is kindof unfortunate.
Only use it if the better wideband output modes are not practical for some reason' (factory ECU ?).
It works with many factory ECU-s, but some might get confused by the lack of heater current, or the rate of output voltage change (the NBO2 sensor fluctuates quickly during stoich condition, which is slightly different than the wideband behavior. Stoich is not too special for wideband, while it is very special for an NBO2 sensor that can basically only sense stoich threshold).
NBO2 is the "factory default" setting (it seems to work with Link ECU when the Link is set up for TechEdge lambda curve). But set (or verify) the vout_conf yourself when using vout.
Old DIY-style 0..5V output
If you don't know about this, you don't need it.
vout_conf=02
2.08V best power, 2.5V stoich. Higher is leaner. Lower is richer. (this is Ip based)
Wideband high resolution linear output
Note: round_2007-04-25 or newer firmware required for this mode to work
vout_conf=5 0..5V is
- linear 0.68 .. 1.36 lambda
- AFR 10-20 on gasoline
Note: negative curve would make more sense (0V assigned to 1.36 lambda and 5V assigned to 0.68 lambda), but this same curve is also used by other systems, so we can call it traditional:
| Volt | lambda | AFR gasoline |
| 0,00 | 0,68 | 10 |
| 0,50 | 0,75 | |
| 1,00 | 0,82 | |
| 1,50 | 0,95 | |
| 2,00 | 0,95 | |
| 2,50 | 1,02 | 15 |
| 3,00 | 1,09 | |
| 3,50 | 1,16 | |
| 4,00 | 1,22 | |
| 4,50 | 1,29 | |
| 5,00 | 1,36 | 20 |
Wideband custom curve - the most versatile, allows any output voltage for any lambda or O2%
Note: round_2007-04-25 or newer firmware required for this mode to work
vout_conf=4 is the fully configurable lambda output. In this case, 17 points (lambda => voltage) determine the output curve. Interpolation is applied between points.
Even very sharp curves possible near 1.0 lambda, for custom (nonlinear) NBO2 output.
Currently 0..255 must be specified in megatune instead of the more userfriendly 0..5V (this could be changed in round.ini). A graphical curve editor would be nice.
Any special curves can be set in this mode, eg:
- Autronic standard, 0-1v= AFR10-30
- using the near 0V part of the curve is very unfortunate (much better is 0V = error or unknown)
- 10 AFR (0.68 lambda) minimum is a bit unfortunate as well
For MegaSquirt users it may be easiest to chose Innovate LC-1 custom curve:
| Volt | lambda | AFR gasoline |
| 0,00 | 0,5 | 7.35 |
| 2,50 | 1,0 | 14.70 |
| 5,00 | 1,5 | 22.05 |
Wideband linear N Volt/lambda
Note: the "Wideband high resolution linear output" mode has better resolution in the lambda range that is most interesting for most applications. This has better fail-mode (the ECU does not try to lean out when seeing 0V !). You need the custom mode to get the best of both worlds.
vout_conf set to 32 or higher (51, 102 or 153 for 1V/lambda, 2V/lambda or 3V/lambda, respectively). Other values, like 154 also work, this can be used for finetuning with the logger or receiving system.
Useful with ECU-s that has no embedded WBO2 controller, but can accept linear WBO2 signal! Also useful if the other ECU has real WBO2 input but you don't want to use 2 WBO2 sensor.
This was tried with 3V/lambda wired in (connected to a motec).
0V (well, say < 0.2V) used for unknown (eg. sensor not heated yet)
- vout_conf=51 1V / lambda 0.65v@lambda=0.65, 1.5v@Lambda=1.5
- only when this is the only choice; or when viewing with a handheld DVM
- vout_conf=153 in MegaTune (but you can finetune with DVM or readings from the connected device) 3V / lambda was successfully tried with motec input. The input curve in Motec can be configured (allows 0..5V input range);
- 0.8 lambda => 2.4V obviously
- 1.0 lambda => 3.0V obviously
- for the curious TerminalProgram user: (Man)mttg13mttc99(mcs) to set vout_conf (position 0x13) to value 0x99(=153) manually
- not recommended (proportionally higher vout_conf):
- 4V / lambda : maximum practical (max 1.25 lambda limited by output range)
vout filter frequency
Vout is an analog signal, it is updated whenever new measurement is available. Time-constant is appr 60msec (theoretical limit is appr 1 update/15 msec, but the sensors are not this fast anyway)