ALDL ECU's

[Tazzi]

Daaammnn.. Thatll need to be a separate tab by its own to play with the logs completely loaded up and sync up graphs.

Ill look into it and see what I can do. Possible but need to make sure all the engine data stuff is working happily on all the models. I know it works 100% on the VY V6 without any error messages as it doesnt disable bcm chatter.. although that sacrifices fast frames/s.

[VL400]

Yeah would be a heap of work to add, just thought Id mention it and hopefully can add to the long term feature request list.

[Tazzi]

I like it. Its a good idea!

Loading the data up onto into the graph is easy enough. Its the "shifting" that Ill have to think about.. maybe a little "slider" that can be used to move each line back/forth. Then these adjustments can then be reapplied to the total log.
Then hopefully it should all makes sense when opening up on some histogram charts ect (Something else to work out!).

[Tazzi]

Little bit unsure again now reviewing the VR freeze data section. I have assumed anything that said "A/D" means its units are voltage, so /51.2
Hopefully thats right. Will know when some real life logs or bench logs are used.

I also noticed in my VY that when I did the freeze data read. The "coolant temp" that all freeze data have didnt actually match up sometimes with the "engine data parameter" coolant temp. The calculations are the same and Im 100% sure its using the correct DTC table as everything else makes sense. Maybe if the fault reoccurs.. it updates one of the values to the 'latest' occurrence whereas the other is the first ever occurrence?

[VL400]

A/D = analog to digital. Its the raw counts from the analog voltage to digital conversion, being an 8bit conversion its 0-255 counts covering whatever range the input hardware is configured for. What that refers to in terms of voltage/temperature/percentage etc etc depends on the item.

If its the battery voltage for instance, then 0-255 covers 0-25.5V so X / 10 to convert the A/D counts to volts. TPS Voltage is 0-5V so X / 51.2 to convert counts to 0-5V.

The ECU then does conversions from the A/D counts to give some meaningful value. Take coolant temp as an example, the 0-255 counts covers a 0-5V range (so this is the coolant temp voltage in logged data), being a non-linear thermistor that is being read the ECU uses a look up table to linearise the value. You then get the coolant temp that you can use the equation (X * 0.75) - 40 to get coolant temp in degrees C.

[Tazzi]

A/D = analog to digital. Its the raw counts from the analog voltage to digital conversion, being an 8bit conversion its 0-255 counts covering whatever range the input hardware is configured for. What that refers to in terms of voltage/temperature/percentage etc etc depends on the item.

If its the battery voltage for instance, then 0-255 covers 0-25.5V so X / 10 to convert the A/D counts to volts. TPS Voltage is 0-5V so X / 51.2 to convert counts to 0-5V.

The ECU then does conversions from the A/D counts to give some meaningful value. Take coolant temp as an example, the 0-255 counts covers a 0-5V range (so this is the coolant temp voltage in logged data), being a non-linear thermistor that is being read the ECU uses a look up table to linearise the value. You then get the coolant temp that you can use the equation (X * 0.75) - 40 to get coolant temp in degrees C.

Yeeeep.. Im going to have to review the calcs completely again.
And base them directly off the ADX calculations.

I did do the battery voltage calc as X*0.1, since I understood that. I just wasnt sure if the other parameters with in eng units or where the voltage representations.

I did notice that some of them actually said "Voltage" so Ill assume those are the voltage representations.

*Edit..
Wait wait wait wait..
Soo using the CTS as the example.
The VR auto ADX has CTS Voltage A/D which has an equation of x * .019608 (or X/51.2).
Does this mean, using the exact same anlogue value (X), I can put that straight into the coolant temperature (deg celcius) equation: ((X*0.75) - 40)

Hopefully that made sense?

I think Im finally understanding what you mean VL.
I could simulate readings into a VR ecu using an arduino and pulse some pins to change the different sensor readings from 0-5v.
These anlogue values can then be converted to their voltage representations.. or to some more meaningful data such as the actual degree Celsius temperature

[Tazzi]

I feel like I just had an epiphany! Its all making sense now!

Damnn I dont even need a live car to test on.. I should be able to simulate everything straight into the sensors since almost all would be around the 5v mark Id imagine.

Just need to write some arduino code up to toggle the pins high/low and allow manipulation of the "pin toggle delay" for each sensor and should all be sweet!
Ideally using the PWM pins would be best suitable for achieving this, theres 14 on the arduino mega. Although not sure on how many sensors are on the VR?

[VL400]

An RC filter on the output of a PWM from the arduino will give you a (close to) 0-5V signal that you vary by duty cycle. It can be very accurate too, its the same method that many wideband controllers use to generate the 0-5V signal we log.

[Tazzi]

An RC filter on the output of a PWM from the arduino will give you a (close to) 0-5V signal that you vary by duty cycle. It can be very accurate too, its the same method that many wideband controllers use to generate the 0-5V signal we log.

Awesome! (Googles RC Filter)

Riiight! Dont have to be unbelievable accurate, but enough that I can adjust it happily between 0-5v.

Just to confirm on what I was doing before.
I can use the A/D readings and plug them straight into their appropriate engine units calculations?

So in the VR Freeze data, if I get a CTS A/D. I can display the data as both the voltage representation with X/51.2, and also the engine units representation with ((X*0.75) - 40). I hope thats right!

[VL400]

No, there are A/D values and converted values.

A/D are the raw counts, or filtered counts (to reduce noise on the sample). Coolant voltage from the A/D is X / 51.2
Then you may also get the converted value from the ECU - ie linearised coolant that you use the (X * 0.75) - 40 with.

Another example is throttle position, you get a 0-5V value of the voltage read by the ECU (maybe is 0.6V for closed throttle to 4V for 100%) that you use X / 51.2 to get a voltage from the A/D counts, this is the TPS A/D or TPS voltage item. The ECU then scales this so that the learnt range (say 0.6V to 4V for closed to WOT) to cover 0-100%, being an 8bit item so you can use X / 2.56 to get a 0-100% reading when converting the TPS % item. Two differernt items for different tasks in the ECU.

There are multiple RAM locations for sensor reading. Take coolant as an example, there will be a raw reading of the A/D, a filtered A/D, a linearised value, a filtered linearised value, a non-defaulted value, a defaulted value (what gets substituted/used when a fault occurs). There are then others for special parts of the code, like the last reading, the startup coolant reading .... and so on