Knock Detected as histogram?

[VX L67 Getrag]

I was just wondering I know you can setup the knock retard as degree's as a histogram, but not sure if you can set knock detected as a histogram & if so how could it be done?

[The1]

do you mean history table or just on the graph? Either way just setup the knock bitmask as a value and use this as calc "X & 0x01" then setup your history table or use it in the graphing window.

[VX L67 Getrag]

Sorry Yeah history table (histogtam is HP tuner talk).

Thanks for the reply but not sure what you mean by set the calc up as X & 01, I've attached jpgs of me trying to set as value not bitmask?

[VL400]

Change the equation from X to X & 01

[VX L67 Getrag]

really so does the & 01 need to be in brackets or anything or just as it was typed x & 01? B.T.W. thanks VL

EDIT: So I guess being a bitmask 0 will be not set & 1 will be set?

Sorry for being a lame just hadn't done it before!!!!!

[VL400]

There is more information here .. https://pcmhacking.net/forums/view ... %26#p16603

You can just make the calc X & 1. The byte item will toggle to a 1 when knock is detected. You wont always see the flag set as it can be cleared between logging frames.

[VX L67 Getrag]

Thanks, I looked at other adx's I had today & sorted it thank you!

Funny about that other thread as I knew I'd done similar before, I still never did figure out what the bit value was for learnt knock for each blm for the PCM to know how much of what timing table to run off!

[VX L67 Getrag]

So the answer to this I can only assume as it was a 30minute+ drive & got NO knock detected even with running average AT ALL, but still got a lot of knock retard & was even after PCM had been discconected so hadn't learnt anything that there is just noise interference causing it to pull timing before the fact & the knock sensor tables need to be dulled?

[VX L67 Getrag]

If you are seeing retard & not actual knock is the best method of adjustment the knock ignore time to be increased?

This writing is taken from a person with a good understanding on this site:

The ignore counts/time is the knock duration or intensity
(1 count = 15.26us). The ignore time is used to ignore some counts before signalling that knock is present and start counting how many above that are measured.
Say ignore is 30 and during the knock window 50 are measured the PCM will calc the knock retard on 20.
Another example, say ignore was 30 still but only 10 were measured the PCM would not retard the spark.

As far as the PCM is concerned Time is just counts of a particular interval...
so blame it on the guy who decided to call it counts in the first place!

there is also ignore time Vs RPM during High Load Downshift, & then there's add on timers which I can only assume it may add that time on before it recovers?

[The1]

as i understand it looking at the knock code it goes like this, im not 100% though.

the knock bitflag is set to 1 if all ignore time and addon times have runout and knock is still being detected.
knock bitflag is cleared back to 0 after the checksum in the frame.
The Amount to retard or the shown Retard Degrees is calculated by the Attack Rate Minus Recovery Rate.

So it would seem that sometimes tunerpro would miss the knock flag in a frame and you dont get to see it, but if there is retard then it has knocked and ignore time and addon time has been exceed and it is now retarding timing.

Obviously by the factory the Retard Amount would be aggressive, so for extra performance you could increase the recovery rate or decrease the attack rate so retard is less aggressive.

You would increase the ignore time or addon time if it could be proven that you are getting false knock.

I have found the knock system pretty good overall, generally if false knock is being detected you will see retard keep going and massive timing being taken out for long periods, i have found in some cases that shoving some foam between the protector shield and knock sensor will help block out unwanted trigger noises a bit like a sock.