L322 Accelerometer values

Graculus said:

A change in speed relative to, which is why the 'standstill' value isn't zero.
Edit: Actually, it's not a 'steady state', the rotational speed does vary, but it's the rotation that's important - it's a (relatively) constant vector acceleration.
Back to the sensors, they need to be able to measure acceleration or deceleration, hence the mid-range starting value. If it were possible to do it with resistors, it'd be a simple Wheatstone bridge array.

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Yes rotation of the earth from our perspective is a constant vector in space, but it's not acceleration. Acceleration is a change of speed or velocity, which is not happening to the car or us when stationary on the earth ! If the earth was changing speed we would have bigger issues than fixing cars !! It would require quite a large change in the 733mph for us to notice !!

Agreed the sensor probably has a non-zero output value when at rest or stationary, but the ECU should normalise this to zero so the numbers make sense !!

I rarely respond to double exclamation marks, however, for anyone else interested in the subject matter...

It references the values against a fixed value capacitor to determine the direction and rate of change.

If you have a read of the first link I found, the speed does vary, not significantly, but measurably.

Scientists reported that in 2020 Earth had started spinning faster, after consistently spinning slower than 86,400 seconds per day in the decades before. On June 29, 2022, Earth's spin was completed in 1.59 milliseconds under 24 hours, setting a new record.[3] Because of that trend, engineers worldwide are discussing a 'negative leap second' and other possible timekeeping measures.[4]

This increase in speed is thought to be due to various factors, including the complex motion of its molten core, oceans, and atmosphere, the effect of celestial bodies such as the Moon, and possibly climate change, which is causing the ice at Earth's poles to melt. The masses of ice account for the Earth's shape being that of an oblate spheroid, bulging around the equator. When these masses are reduced, the poles rebound from the loss of weight, and Earth becomes more spherical, which has the effect of bringing mass closer to its centre of gravity. Conservation of angular momentum dictates that a mass distributed more closely around its centre of gravity spins faster.[5]

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Clearly the mass of the earth changing speed will have some effect upon gravity, and therefore sensors designed to measure the rate of change of speed towards or away from the surface the vehicle is on, again, not a massive amount, but measurable - especially given that the control units calculate to eight significant decimal points.
Obviously I'm not saying that a small rotational speed change in the earth will cause the OP's issue, but it is worth noting there is a 'normalisation' routine available in later systems, I'm not sure if it exists in the earlier systems where the processing power is limited to the point of having to rely on height sensor inputs to be broadcast on HS-CAN rather than processed directly as in later systems.

It's also possible that the harshness is caused by capacitor ageing, particularly the reference capacitor in the control unit, or indeed defective dampers - or even a change in the wheel rim size not being updated in the CCF, I've found this to be the root cause in several instances with L405 / L494's in the past, I honestly can't remember if it's an editable value in L322 - it may be worth checking.

1.59mS over 24 hours is 0.0000018% so very slow acceleration, i.e. much less than 0.03m/s^2. Well less than 1/10th of the sensor reading. The diagnostic screen is wrong . . period !!

So after up dating the GAP I get these readings at standstill

J

I would suggest that those are the raw values, not calculated. So double exclamation marks or not, the diagnostic values shown are not wrong, the values shown appear to be correct - but the required values are not selected or not able to be shown. I'm not a fan of IID to be honest.
For comparison, a broader range of values from SDD, different vehicle and a later iteration of the sensor & control system but the values are broadly similar.

I thought the accelerometer thing was all about how fast or slow the body is moving (up and down) vs the wheels to work out how much damping is required?

Graculus said:

I would suggest that those are the raw values, not calculated. So double exclamation marks or not, the diagnostic values shown are not wrong, the values shown appear to be correct - but the required values are not selected or not able to be shown. I'm not a fan of IID to be honest.
For comparison, a broader range of values from SDD, different vehicle and a later iteration of the sensor & control system but the values are broadly similar.

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There are more value’s available but I did not want to clutter what I was trying to do.
Which was try to confirm to the OP what a car, which “seems” to have no issues looks like as per the values he showed.

Can you say why you are not a fan of IID?

J

My values are from a stationary vehicle with no issues also.
IID 'seems' to be a bit of a hobby to the developers - a lot is reactive to users wants / needs without any firm timescale, locking to a single VIN also seems to be gouging the clientele given systems such as Autel, TopDon etc. have similar functionality in a similar price range but for any VIN with the benefit of a wider range of vehicle manufacturer coverage.
There is also a bit of a 'hit & miss' feeling I get from comments by users, some things they do well, others, not so much - I'd also want to run it at least on a larger tablet (assuming the screen will not just scale to make everything bigger with no increase in visible fields) as a phone looks a bit 'cramped' for doing real work on.

I've never used it, my opinions are purely from comments and frustrations of others who have invested.

Graculus said:

My values are from a stationary vehicle with no issues also.
IID 'seems' to be a bit of a hobby to the developers - a lot is reactive to users wants / needs without any firm timescale, locking to a single VIN also seems to be gouging the clientele given systems such as Autel, TopDon etc. have similar functionality in a similar price range but for any VIN with the benefit of a wider range of vehicle manufacturer coverage.
There is also a bit of a 'hit & miss' feeling I get from comments by users, some things they do well, others, not so much - I'd also want to run it at least on a larger tablet (assuming the screen will not just scale to make everything bigger with no increase in visible fields) as a phone looks a bit 'cramped' for doing real work on.

I've never used it, my opinions are purely from comments and frustrations of others who have invested.

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It is developed and is being updated as they can but at the time we got ours there didnt seem to be much choice available to "joe public" I understand the VIN locking some others do it too, but as you say some dont.
I dont require to have 1 for multiple cars and if the car was sold it would probably be sold with the car.
It is left in the glove box as it is small with no leads. I dont use it on the phone unless out and about when it is needed because yes it can get cramped but to read faults and clear the phone is fine, but that has only happened one time. I use it on my I pad and find the screen size ok.
The graphing of live values is very handy. What you see in my pic. I could off got rid of the 2 boxes in the top half and just shown the values, or even a graph on the whole screen.

I have never had a problem with its use. I agree some users have issues but it has to be remembered that they are DIYers so maybe don't understand fully what they are seeing or not seeing. Also not having to go to JLR to have to be overcharged just for a fault code read/clear/reset so saves the cost of the unit.

So I guess you can add that to comments you have heard as I dont see anything negative in having it for what it has saved us or will continue too.

Its a bit like a forum about LRs nobody says how good they are they only ask when having problems. Somebody looking at this site would be scared off buying a LR you would think.

J

marjon said:

So after up dating the GAP I get these readings at standstill

J

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OK, non-zero... that points me away from this line of exploration and assures me that's within "normal" tolerance. Thank you sir!