VCDS "Tag" number: what is it really?

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DV52

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Found this while trying to help a colleague on another forum:

Code:
;SW:8W5-035-041   HW:8W5-035-041 ---  Information Electr.
;Component:MU-P-LND-RW   033 0917, Coding:01940408FF0A000013511101000A00102F000DE601700104DE
;EV_MUHig6C3Gen2HBAS,001115,EV_MUHig6C3Gen2HBAS_AU49.rod
;Wednesday,19,September,2018,14:50:01:16808
;VCDS Version: Release 18.2.1 (x64)  Data version: 20180518 DS287.2
;VCID: 71AA10ACA0E8B2CCDB-8024

[B]
IDE00845-Wheel circ.,0 mm,2[/B]
Code:
;SW:5QA-919-294-B   HW:5QA-919-294 ---  Park/Steer Assist
;Component:PDC 8 KanalH07 0044, Coding:0470155811
;EV_EPHVA18AU3700000,009035,EV_EPHVA18AU3700000_009_AU37.rod
;Wednesday,15,August,2018,10:37:38:16808
;VCDS Version: Release 18.2.1 (x64)  Data version: 20180518 DS287.2
;VCID: 4BD6A244E284B81C81-801E

[B]IDE00845-Wheel circ.,1950 mm,2[/B]
Note: these values are for the same car (an Audi A3 8V).

So, the same adaptation channel appears in 2 x separate modules and with 2 x different values. Why? Why not sightly change the name of the channel and give each different Tag numbers?

Don
 
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hadez16

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You have to ask VAG.
The identifier, name, unit, ... comes from the descriptive ASAM data.

Should I go on with typos I found all over?
 
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TBAx

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Reason for different value: Infotainment doesn't need to know tyre circumference in this car, while the park/steering assist needs it.
 
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DV52

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Reason for different value: Infotainment doesn't need to know tyre circumference in this car, while the park/steering assist needs it.
TBAx: thanks for the reply- I suspect that you are correct. It's just odd (to me at least) that a module that doesn't need the wheel circ. parameter is set to "1950" - if it's a decimal number -it's not a meaningful hex number and if it's a hex number then it's a strange decimal number! And - in a module where wheel circ, is used, it's set to zero

But the more intriguing question is why give different values to EXACTLY the same channel descriptor in two separate modules where an actual measurement (in mm) is intended (these channels are not software ON/OFF or YES/NO switch settings)?

I do understand hadez16's response - yes, I've no doubt that the adaptation channels descriptors have their genesis in the ASAM data and that VCDS is faithfully reporting the original definitions. But this intriguing coincidence is not like the myriad "typos" that has tested our patience on numerous occasions - this is deliberate and intentional!

Although VCDS (and lots of competitor devices) appear to display the adaptation channel records as flat data - from the make-up of the descriptors, it's clear that at least some element of a relational database structure is present. Given this not surprising hypothesis - the use of the same record with different values is "odd" (and it has the potential to be more than a tad informative -if I only knew why)!

But thanks again for the replies!

Don
 
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