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

15-4 Industrial Communication Systems
Remote industrial domains/subsidiary/customer sites
Office subdomains
Real-time domain
Mobile devices
Office domain
Industrial domain
VAN domain A
Industrial segment
Domain
converted
via ra
Van domain B
VAN domain C
Public and private
telecommunication
networks/Iinternet
Industrial WLAN domain
Single device integration
(e.g., tele control)
Industrial backbone
Mobile devices
Industrial
WLAN domain
Intrinsic safety
domain
Individual industrial subdomains
Real-time domain
within a domain (or subdomain), one or more automation devices (ADs), fieldbus systems, and infrastructure
components exist. A domain keeps track of engineered relations between VAN devices that
are the end points of a configured communication line between the local domain and the related other
domain [DHH08]. The connected end points are linked via a tunnel, which seems to be a (virtual)
communication line between the distributed application objects (runtime objects). Once the tunnel has
been established, the data exchange between the distributed runtime objects follows the rules of the
used fieldbus system (e.g., PROFINET with connected PROFIBUS or other connected fieldbus systems).
These rules are well known by the automation engineer.
All devices with the same object model can interact by using the VAN infrastructure. As an example,
the standardized runtime object model of PROFINET [IEC61158,IEC61784] can be used as a common
object definition. Within the VAN device architecture also, other object models can be used if they are
based on the VAN communication stack. Devices with other object models can be connected through a
VAN proxy device (VAN-PD).
15.2.1 Domains
Remark
All systems are shown generally as a bus. Depending on the real system
it may be any type of topology including a ring.
FIGURE 15.3 Different VAN domains related to different automation applications. (From Specification of the
Open Platform for Automation Infrastructure, Deliverable D02.2-1. Topology Architecture for the VAN. Virtual
Automation Domain. European Integrated Project VAN FP6/2004/IST/NMP/2-016969 VAN Virtual Automation
Networks, 2006. With permission.)
To connect distributed application objects, a VAN infrastructure, which offers VAN characteristics, is necessary.
The VAN characteristics are defined for domains [PNO05,N07]. The expression “domain” is widely
used to address areas and devices with common application purposes (Figure 15.3). A domain is a logical
group of VAN devices. The devices related to a VAN domain may reside in a homogeneous network domain
(e.g., local industrial domain). However, depending on the application, additional VAN-relevant devices may
be only reached by crossing other network types (e.g., by WAN type communication) or they need to use
proxy technology to be represented in the VAN domain view of a complex application.
A VAN domain can include given industrial domains (equipped with ADs and connected via industrial
communications, e.g., fieldbus), completely or partially. Thus, an industrial domain can consist of
segments related to a VAN domain (VAN segment) or of segments that are not related to a VAN domain
(Figure 15.3) [N08].
© 2011 by Taylor and Francis Group, LLC