LIN bus sniffer

RicardG

New member
Hi everyone,

I'm trying to read the LIN bus of an electric-Scooter.

I'm using a PEAK USB interface and I connected everything as thr manual says.

I took the wiring that goes from the ECU to the dashboard, 3 cables:
- 12v from battery (ignition ON)
- ground
- LIN cable

PEAK's scheme:

2022-08-22_16h24_52.png

And this is how I did it on the table:

IMG-20220822-WA0000.jpg


-The red wire comes from the 12V from the scooter and is connected to the PIN9 in the DB9 connector. (constant 13,2V measured)
- The Black comes from the ground of the scooter. Goes to PIN5.
- The yellow interconnects the PIN4 and 6 as both should be connected to ground.
- The blue is the LIN comm cable.


Once I open the PLIN_viewer (PEAK's soft) everything seems OK but it shows Vbat: missing as if the DB9 hasn't been powered but it is. There are 13V always.
I've also opened the Peak case to check if the internal conections are OK and it is.

2022-08-22_16h36_25.png

Because of that I cannot read anything from the bus.
I'm quite bloques right now, I tried everything without success.

If anyone could have some idea how to make it work would be much appreciated.


Regards.
 
Did you measure if the external Vbat [13V in your case] actually makes it all the way from the screw terminal to pin 9 of the DB9 connector?
The adapter board may have a wiring/soldering issue.
Is the white print on the adapter board [1-9 & GND] correct?

Paul
 
Did you measure if the external Vbat [13V in your case] actually makes it all the way from the screw terminal to pin 9 of the DB9 connector?
The adapter board may have a wiring/soldering issue.
Is the white print on the adapter board [1-9 & GND] correct?

Paul

Hi Paul, thanks for answering.

Yes, in fact I took of the PEAK's cover and checked the voltage in the inner connections and was OK.

I've tried to power the DB9 with an external power supply. Surprisingly, even with putting only 10V the Vbatt missing message disapeared!
It was like working for a while and then I've got a kind of ground error message. Maybe because the LIN cable and the power supply were having different grounds.

That's maybe a silly question: Could I interconnenct the power supply groundand the scooter ground cable?
 
Yes, you should do that - you need a common ground for all circuitry.

Paul

Thanks for your answer again.

I've set the same voltage value of the scooter in the power supply (13,2V) and if I connect both together (scooter&powersupply positives toguether and interconnected grounds), the BUS goes to active.

I just don't understand why the 13,2V from the scotter aren't valid and if I add 13,2V from the power supply then is OK. :confused:
 
I suspect the 13.2V from the scooter is very noisy.
Do I understand you correctly that you connect the external powersupply positive to the scooter supply positive? Better not do that: one power supply is enough. You might destroy scooter circuitry by connecting the external powersupply to the scooter supply.

Paul
 
Hi Paul,

Thanks for the clue.
I should check the signal with an oscilloscope but I don't have any. I will look at it.

Yes, I know to join the positives weren't the greatest idea but I neeed to look from more possibilities to understand, at least I tried to match voltages ;)


Thank you very much for your comments.
 
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