wilamowski-b-m-irwin-j-d-industrial-communication-systems-2011

44-6 Industrial Communication Systems
s
s
s
s
Starcoupler
Node
s
s
s s s s s
Sync node
Configuration (a)
Configuration (b)
Configuration (c)
FIGURE 44.6
Sync node distribution examples.
Table 44.1 Consequences of Faults in the Configurations Shown
in Figure 44.6
Configuration (a)
Configuration (b)
Configuration (c)
(i) The affected branch loses communication
(ii) All nodes lose communication
(i) The affected branch loses communication
(ii) Two cliques are formed; the branches without sync
nodes lose communication
(i) In the case when the branch with the sync nodes is
affected, all nodes will lose communication; when
another branch is affected, the respective branch
will lose communication
(ii) The branch with the sync nodes stays synchronized;
all other branches lose communication
number of attempts will elongate the startup time. Figure 44.6 along with Table 44.1 depicts some examples
that illustrate the effect of sync node distribution on the system behavior when either a fault affects
one branch (i) or the star-coupler (ii).
All these issues have to be considered when determining the large number of configuration parameters
and constants of the FlexRay protocol for an actual cluster implementation. Here, proper planning
and tool support are of utmost importance.
44.4.2 aUTOSAR
In practice, when designing a cluster that shall be built with hardware and software from different vendors,
the AUTOSAR standard must be considered. The goals of the latter are to provide for system-wide
Application layer
Runtime environment
Service layer
ECU abstraction layer
Microcontroller abstraction layer
Complex drivers
Basic software
Microcontroller
FIGURE 44.7
AUTOSAR layer model.
© 2011 by Taylor and Francis Group, LLC