2427895 - E1050 CAN CONNECTION LINES - Description
Description
This vehicle features a CAN network
(Controller Area Network) system of electrical connections: it involves
a software and hardware solution which is designed to manage the
resources on the vehicle in an increasingly efficient way, allowing:
- data to be shared between the various electronic units;
- the integration of several electronic units in one network;
- a high data exchange speed in the network;
- cost-effective solutions, since the number of wiring harnesses
and connectors are considerably reduced in the vehicle;
- a higher standard in terms of quality and reliability.
The advantage of using a CAN system stems
from the fact that the communication involves numerous control units
and consequently the number of signals managed is very high.For this reason the signals 'travel' on
CAN type (double) serial Bus, where one wire is associated with
the high level (H) and the other the low level (L); These CAN Bus
signals are differential, i.e. the value assigned to each bit is
represented by the different voltge of CAN-H and CAN-L.The various electronic units which make
up the system, known as network 'Nodes', are connected to the CAN
by means of communication interfaces known as transreceivers; These
connection interfaces, integrated in the actual electronic units,
form the gates for sending/reading information at the CAN or at
the serial lines.A 'transmission protocol', i.e. the set
of rules allowing the communication between two or more ECUs (called
Nodes) by means of data or data package exchanges, is required for CAN
serial line data circulation.The main element in the network is the Body
Computer.The Body Computer node 'wakes the system
up' when the ignition key is turned to the ON position (if there
is a Body Computer failure, the task of waking the system up is
entrusted to the instrument panel).The Body Computer also carries out
the functions of controlling the network, which makes it possible
to supply information on:
- the network activity status;
- the functional failure status of the individual electronic
units (nodes);
- the possible CAN failure.
The various electronic units process the
various signals coming from their sensors both for their own management
and for the other control units, to which they are sent via the CANThe specific structure adopted on
this vehicle consists of two CANs which connect nodes belonging
to two different areas:
- C-CAN for 'dynamic control' of the vehicle (high speed):
bus CAN-H and CAN-L;
- B-CAN for the management of 'bodywork functions' (low
speed): bus CAN-A and CAN-B;
- te two CAN communication networks are connected to one
another by means of a gateway for transferring joint information,
located in the Body Computer Node.
The diagnosis of the nodes connected to
the bodywork network is achieved via the CAN, whilst the vehicle
dynamic control network is diagnosed using the special K lines
See E8010 DIAGNOSTIC MULTIPLE CONNECTOR
.
The system also uses additionional 'traditional'
serial lines for the various connections; for example, in the connection
between the Body Computer and the alarm / volumetric sensors
.
The distribution of power takes place via
the junction units and/or fuse boxes, connected to the control elements
(relays and static actuators) in order to ensure the maximum level of
electrical protection and the minimum degree of wiring complexity
See E1010 SUPPLY
.