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Datalogger Histograms


Mick

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Ignore will hide any cells with a cell count < "samples".

Filter will drop any samples from the bucket where the standard deviation is outside of "std dev".

Standard deviation is very useful to determine if you have highly non correlated or bad data. It is also great for filtering out noise due to transient data or slow logging rates.

I did a write up on it here a long time ago.

https://forum.hptuners.com/showthread.php?58174-Custom-graphing-software-for-logging-fuel-trims-and-recalculating-speed-density-maps

Basically the short of it is your Z data should be highly correlated with your X and Y data, eg all the values collected are roughly the same, eg the min/max are very close together.

If you had 1000 samples within a specific cell, all are roughly 0->0.1 and then 20 random samples is 1000 due to a sensor fault, the 1000 would have a huge standard deviation and the value would be dropped. This would also be excluded from the average value calculation.

https://en.wikipedia.org/wiki/Standard_deviation

1280px-Standard_deviation_diagram.svg.png

The number at the bottom is the standard deviation. So if you want to drop transient data from your log and only use the steady state data you might use a tight standard deviation of 1. If you want the extreme min/maxs you might go as high as 3.

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30 minutes ago, Roland@pcmtec said:

Unfortunately Matt has moved on to another job so datalogger development will likely be halted until we can afford more employees. We will continue to fix bugs however there won't be any new major features in the short term. 

thank you for the honest reply

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13 hours ago, Puffwagon said:

What does someone need to learn and how long to learn it before they'd be any good as an intern?

Have 5 years of prior programming experience and either a bachelors in computer science or engineering.

Most of us have 15+ years experience writing software. Darryl started in the 80s and you could say he has 40+

You actually don't need to know anything about cars to do most of what we do. Definitely helps if you do though! 

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