MoTeC Global Forum

I'm currently running into some issues using i2 Pro 1.1.5.0085 when it comes to the `Corr Lap Dist` channel.

On normal laps it tracks the logged `LapDist` channel properly, and when I use the `Corr Speed` channel to generate it, the results are almost satisfactory. A normal lap will have the `Corr Lap Dist` and `LapDist` be exactly the same, as is expected when they are set up like [1].

A normal lap is shown in [2], with the two channels tracking the same value, and the Ground Speed being almost the same as the derivative of the distance channels (there is some difference due to different lines, etc.)

Then we can see the problem if there is a pit stop. In [3], there is a graph on the time mode. In [2] the Corr Lap Dist was a relatively wavy line, changing with the speed of the vehicle as it covered more or less ground, but here we see that the Corr Lap Dist channel is simply a line from 0 to ~5687, completely different from the `Lap Dist` channel. On the distance graph in [4] they don't match up either because of the miscalculation for the Corr Lap Dist channel.

Here's an album of the screenshots in case the image embeds don't work. I can also upload an export of a few laps if that would help debug this, as well.
https://imgur.com/a/OQ6FZfQ

[1]:


[2]:


[3]:


[4]:

Hi,

As this data was generated using a Non MoTeC product (iRacing), we cannot control how the data is generated.

That's fine, I'm not expecting the logged data to be different, the logged data is correct and works fine. The LapDist channel is properly changing with time.

I'm wondering why the data isn't being respected in motec? Is there something that goes wrong with a stop more than a couple seconds?

SDean wrote:Hi,

As this data was generated using a Non MoTeC product (iRacing), we cannot control how the data is generated.

I'll post this again with some more details, also with an extra math channel to illustrate the issue more clearly and to show that it's not an issue with the logged data but with the results generated by Motec i2. Below is a onedrive folder with a run at Rudskogen that has the same issues as the Daytona laps, and a run at Indianapolis road course where the pit distance actually works. I attached the whole log so they're kind of large. I can also add the workbook that I'm using if that would help.

There are 7 channels being shown in the screenshot here and what is expected of them:

• Corr Lap Dist [m]
  Generated by Motec, this should be the same as the 'LapDist' channel below.
• LapDist [m]
  Logged by iRacing, it should be linear when viewing the data in 'distance' mode.
• Corr Lap Dist vs Logged LapDist [m]
  Custom math that should be ~0 as 'Corr Lap Dist' should be generated from 'LapDist'.
  

  Code: Select all

  'Corr Lap Dist' [m] - 'LapDist' [m]

• Corr Lap Dist dt [m/s]
  Custom math that should track with the logged ground speed, though may be different due to different lines.
  

  Code: Select all

  derivative('Corr Lap Dist' [m], 1.0)

• LapDist dt [m/s]
  Custom math that should be the same as the above:
  

  Code: Select all

  derivative('LapDist' [m], 1.0)

• Ground Speed [m/s]
  Logged by iRacing, should be the speed of the car, may be different than the derivatives above but should at least be close.
• Corr Lap Dist dt vs LapDist dt [m/s]
  Custom math that should also be ~0.
  

  Code: Select all

   'Corr Lap Dist dt' [m/s] - 'LapDist dt' [m/s]

With the listed channels we can see the issues pretty clearly. The 'Corr Lap Dist' does not at all show what it should. This is a Motec generated channel, not an iRacing one. The logged 'LapDist' channel seems to properly track the lap distance, as the derivative is relatively close to the logged 'Ground Speed.'

For some reason the calculated 'Corr Lap Dist' uses a constant speed on this lap, as seen by the horizontal line in 'Corr Lap Dist dt' set at ~44.18 m/s. This is where my issues occur, not on the lap with

In the overlay (a normal lap) the deltas between the ground speed, LapDist derivative, and Corr Lap Dist derivative are very close, all within about 0.1 or 0.0001 of each other, and the delta between the 'LapDist' and 'Corr Lap Dist' is almost zero.

I hope that there can be something fixed in the next version, or maybe I have some setting wrong that I have to change.

Here's a link to the image so you can see the stats on the side which should show a bit more and not be cut off by the forum width.
https://i.imgur.com/kyUlDKA.png


https://1drv.ms/u/s!AiSe1LGCXoz0jsMgtu67TXVlVNoqEQ?e=K8fXTO

The Corrected Lap Distance calculation is pretty complicated so it could be a range of things that are causing this issue. However, looking at your data very quickly it appears that it is most likely caused by your LapDist channel going negative. In the 2 log files that don't work correctly LapDist briefly goes negative and in the log file that works it doesn't.

You can either fix that issue or use corrected speed as the calculation method instead of using your lap distance channel.

I've asked the software guys to have a look at it but unless it affects any of our devices it is unlikely to be updated.

Thank you so much for looking into this, I'll just make a channel that sets negative values to 0.