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"The instruments cluster" consumer product in the field of automotive
used to study the multiplex network CAN Low Speed,
fully used in the industry.
plugged on the grid
this desk is self-standing
potentiometers
associated with a CAN network card
can directly generate frames
to interact with the displayed values
the 3 fonctionnal layers of the CAN network are investigated
a simple voltmeter is needed to measure the CAN HIGH voltage
and CAN LOW
as well as an oscilloscope
from a resource file detailed
and a tutorial,
students analyze a graphical representation of the frame
and convert in binary from the voltage levels,
then in hexadecimal, the data fields of a CAN message
The bit stuffing is highlighted
A frames analyzer on usb port
and his software
supplied with the module
captures packets on the CAN network.
a change of physical quantities on the desk
is simultaneously seen by the student on the acquisition software
by variation of bytes in the message
as well as the cluster.
The changing the engine speed
resulting in the change
of the 2 first bytes in the 0B6 message
the conversion of 6c00 in decimal gives 27648
In the manufacturer mail
extracted from the ressource file we found
the 0B6 message that included
the car speed and the engine speed
We thus obtain the conversion formula
N*0.125
27648*0.125 gives
3456 rpm
That we can check on the cluster
A partial disconnection highlights the robustness of the LS CAN network.
The total disconnection disrupts communication and sets default the cluster.
By disconnecting the two wires, the student isolates
the network card of the cluster.
And this is from the software,
that the student will compose these frames in order to control the cluster.
The aim is to set the display of the engine speed to 2500 rpm
starting from the conversion formula
2500/0.125 gives 20 000
We convert 20 000 in hexadecimal that gives 4E20
We modify the 0B6 message transmit
The cluster immediatly display the speed value
"The instruments cluster CAN Low Speed Network"
makes learning meaningful
ranging from the discovery to the self-validation.