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

26-4 Industrial Communication Systems
Operator
workstation
Dedicated special
system (e.g., elevator)
Facility management
system
Management
level
Management
network
Server station/
building controller
WAN
WAN connection
to remote system
Automation
level
Automation network
DDC stations/
unit controllers
DSS (e.g., room controller)
Fieldbus
Direct I/O
connection
Field
level
M
M
FIGURE 26.1
Field, automation and management level and respective devices.
nected via some fieldbus network. While the first variant requires relative closeness of the devices and
is very cheap, the latter approach allows for spatially distributed devices and provides more flexibility.
The data point values provided by the field level (sensor values, subsystem status information) are
communicated to a server station (building controller) that also serves as a central point of integration.
Process data from the (sub)system is collected as well as integrated with data from other traditionally
stand-alone building systems such as safety alarm or access control systems. As a result all those data
points are accessible in the building controller. This unified view allows a transparent access to all building
operation data, which primarily functions as input for an integrated visualization as well as automation
functions. Hence, integration across different application domains is possible and frequently
implemented. Also, building automation functions often supervise electrical circuits and provide supervisory
control of central plants such as hot water production and air handling units. Especially the latter
allows to influence the amount of energy consumed considerably, for example, automatically based on
calendar data.
Furthermore, the building controller allows to automate sequences that involve multiple, heterogeneous
systems, and also provides the interface to facility management systems. This building management
infrastructure is typically known as the building management system (BMS). The user interface is
displayed on local workstations, which establish a connection to the server mostly via the office network
infrastructure. Using technologies from the IT domain, remote access to the building controllers is
provided.
Progress in computer engineering has led to new perspectives in building automation. Until recently,
the model described just above had to be considered no more than a rough guide. However, with ever
increasing processing power and available memory as well as the overall size and cost of end devices
© 2011 by Taylor and Francis Group, LLC