Difference in Leuchte channels between minimize and maximize

william : Hi. My guess of the difference between the Leuchte-commands "maximize" and "minimize" is as follows:-

There is no official information in the public domain about VAG's Leuchte channels- so I can't vouch for how VAG intended the Dimming direction channels to be used in Leuchte programming. Nevertheless, and at least in normal Pulse Width Modulation (PWM) circuits, "dimming direction" usually works like this:

First, you need to understand the PWM principle of "Duty Cycle"- which is the ratio of the ON and OFF times in the applied voltage waveform. Below are 3 x examples of different duty cycle waveforms (which I thieved from sparkfun.com):



In Leuchte programming speak, "duty cycle" corresponds to the Dimmwert setting. In a normal PWM dimming arrangement, the higher the duty cycle (or the higher the number in the Dimmwert channel), the brighter the lamp. Hence, this relationship is such that increasing the duty cycle (or the Dimmwert value) increases the effective voltage that is applied to the lamp.

However, at very low duty cycles and depending on the type of lamp (LEDs in particular), odd things can happen. Sometimes, low duty cycle settings can make LEDs flicker noticeably and in rare instances, the LEDs can actually become reversed polarized. So when PWM systems operate normally at low duty cycles, it's better to reverse the relationship between the duty cycle and the applied voltage. When this is done, there is normally an intervening circuit in the lamp arrangement that compensates for the reversed relationship.

So - my guess is that when:
Maximize is chosen for Dimming Direction - a low duty cycle setting maps to a low voltage, and a higher duty cycle setting maps to a higher voltage.
Minimize is chosen for Dimming Direction - a low duty cycle setting maps to a high voltage, and a higher duty cycle setting maps to a lower voltage. (note: I suspect that there must be an intervening circuit/software facility inside the BCM that manages the reverse relationship between the actual Dimmwert setting and the duty cycle)

Note: I've used the term "voltage" above, but in reality LED based lamps are current driven devices

Now -of the 72 x available settings for the Lichtfunktion channels, a small handful operate at normally low Dimmwert settings. For example, Blinken links aktiv (beide Phasen) is often used to dim the DRLs to zero (or a low illumination level) when the turn-signal operates - it's called "DRL wink". So, this Leuchte command uses the minimize form of dimming direction. Similarly for Blinken links/rechts Dunkelphase which often uses Dimmwert=0 - so it is accompanied with minimize, normally

Don

Thank you dv52 (Australia) and newty for your extensive explanation.

So if I understand it correctly I need to adjust the Standlicht to minimize (only standlicht on all four brake lights is flikkering when returing from turn signal/brake light).

My Setup is as follows:

Leuchte20BR LA71
Lasttyp 20
43 - allgemeine LED
Lampendefektbitposition 20
10
Fehlerort mittleres Byte DTC-DFCC 20
39
Lichtfunktion A 20
Bremslicht
Lichtfunktion B 20
Blinken links Dunkelphase
Dimmwert AB 20
80
Lichtansteuerung HD AB 20
always
Lichtfunktion C 20
Standlicht allgemein (Schlusslicht, Positionslicht, Begrenzungslicht)
Lichtfunktion D 20
Parklicht links (beidseitiges Parklicht aktiviert li & re)
Dimmwert CD 20
5
Dimming Direction CD 20
maximize
Lichtfunktion E 20
Blinken links Hellphase
Lichtfunktion F 20
nicht aktiv
Dimmwert EF 20
0
Dimming Direction EF 20
minimize
Lichtfunktion G 20
nicht aktiv
Lichtfunktion H 20
nicht aktiv
Dimmwert GH 20
0
Dimming Direction GH 20
maximize

Leuchte21BR RC8
Lasttyp 21
43 - allgemeine LED
Lampendefektbitposition 21
20
Fehlerort mittleres Byte DTC-DFCC 21
3A
Lichtfunktion A 21
Bremslicht
Lichtfunktion B 21
Blinken rechts Dunkelphase
Dimmwert AB 21
80
Lichtansteuerung HD AB 21
always
Lichtfunktion C 21
Standlicht allgemein (Schlusslicht, Positionslicht, Begrenzungslicht)
Lichtfunktion D 21
Parklicht rechts
Dimmwert CD 21
5
Dimming Direction CD 21
maximize
Lichtfunktion E 21
Blinken rechts Hellphase
Lichtfunktion F 21
nicht aktiv
Dimmwert EF 21
0
Dimming Direction EF 21
minimize
Lichtfunktion G 21
nicht aktiv
Lichtfunktion H 21
nicht aktiv
Dimmwert GH 21
0
Dimming Direction GH 21
maximize

Leuchte23SL HLC10
Lasttyp 23
43 - allgemeine LED
Lampendefektbitposition 23
A
Fehlerort mittleres Byte DTC-DFCC 23
29
Lichtfunktion A 23
Standlicht allgemein (Schlusslicht, Positionslicht, Begrenzungslicht)
Lichtfunktion B 23
nicht aktiv
Dimmwert AB 23
5
Lichtansteuerung HD AB 23
always
Lichtfunktion C 23
Blinken links aktiv (beide Phasen), Auf- und Abdimmend mit p t blinken rampe
Lichtfunktion D 23
nicht aktiv
Dimmwert CD 23
10
Dimming Direction CD 23
maximize
Lichtfunktion E 23
Blinken links Hellphase
Lichtfunktion F 23
nicht aktiv
Dimmwert EF 23
70
Dimming Direction EF 23
maximize
Lichtfunktion G 23
Bremslicht
Lichtfunktion H 23
nicht aktiv
Dimmwert GH 23
80
Dimming Direction GH 23
maximize

Leuchte24SL HRA65
Lasttyp 24
43 - allgemeine LED
Lampendefektbitposition 24
1A
Fehlerort mittleres Byte DTC-DFCC 24
2A
Lichtfunktion A 24
Standlicht allgemein (Schlusslicht, Positionslicht, Begrenzungslicht)
Lichtfunktion B 24
nicht aktiv
Dimmwert AB 24
5
Lichtansteuerung HD AB 24
always
Lichtfunktion C 24
Blinken rechts aktiv (beide Phasen), Auf- und Abdimmend mit p t blinken rampe
Lichtfunktion D 24
nicht aktiv
Dimmwert CD 24
10
Dimming Direction CD 24
maximize
Lichtfunktion E 24
Blinken rechts Hellphase
Lichtfunktion F 24
nicht aktiv
Dimmwert EF 24
70
Dimming Direction EF 24
maximize
Lichtfunktion G 24
Bremslicht
Lichtfunktion H 24
nicht aktiv
Dimmwert GH 24
80
Dimming Direction GH 24
maximize


What do you guys think of this setup and do you have any suggestions?
Standlicht dimmwert 5 and change to minimize?

Thanks dv52 (Australia) !

Kind of you to help.

My tail lights are indeed RoW lights, however included with Urban Joke V1, 5 brake lights and all lamps are LED.
The yellow turn signals on the tail lights are deactivated, so only red through the tails are active for brake/turn.

The setup I sended, is working and is accepted in NL.


However the 'Standlicht' is sometimes 'flickering' when returning back from Brake/Turn signal which are brighter.

When using lasttype - 14 - kombinierte Blink- Bremsleuchten for example on my RoW tail lights I get the error code that my control module is wrongly coded.
I used the Urban Joke APP and immediately got an error code. As a newby I had to investigate further.

It took me a long long time to fix this. When I changed the lasttype to 13 - Bremsleuchten (with original Lampendefektbitposition and Fehlerort mittleres Byte DTC-DFCC) the fault was finally resolved.

I see in your reply that you suggest lasttype: 35 - kombinierte LED Blink-Bremsleuchten. I expect to get the same fault code back due to my RoW tail lights.

Is it possible to use another lasttype for this coding with LED for my RoW tail lights and does this solve the 'flickering'?

Can I also assume that Dimmwert AA is always higher than BB because of the function?

I Also thought that GH has priority over AB so that's why i coded that when braking while having the turn signal on the outer tail lights are blinking and the inner tail lights are giving brake light (constant)
I noticed in your suggestion that leuchte23 and leuchte24 are now simultaniously blinking with leuchte20 and leuchte21. I really like the feature using "Blinken links/rechts aktiv (beide Phasen), Auf- und Abdimmend mit p t blinken rampe".

So many questions...

Is it possible to send me the coding as close to mine with the above stated included but corrected for the order of the functions and hopefully resolve the flickering?

Really hope you can help.

Hi dv52 (Australia) !


I coded my tail lights as per your suggestion without "Auf- und Abdimmend...".

Even with lasttype 35 - kombinierte LED Blink-Bremsleuchten no errorcodes.

Although I coded the outer tail lights with priority of blinking over brake light so that I keep 3 positioned brake lights at all time when braking.


I still have to test it properly, because with last setting the errorcode occurred occasionally.

But I have a good feeling about this.

Thanks for your help!!
Much appreciated.