Specifications

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Industrial Networks In any complex assembly process, the need for rapid information
flow is critical. Conditions at any point in the process may impact
the entire process. This need for information flow often requires
that intelligent devices such as PLCs, intelligent sensors, drives,
computers, and HMI systems be interconnected by one or more
local area networks (LANs).
A LAN is a communication system designed for private use
in a limited area. LANs are used in office areas as well as in
manufacturing environments; however, LANs used in industrial
applications must be able to operate reliably in conditions
that are unsuitable for office-grade equipment. Industrial
environments typically have a high level of electrical noise and
mechanical vibration and a greater range of temperature and
humidity than found in office environments.
Specifications for industrial LANs vary considerably depending
upon the requirements of the application. Issues such as the
amount of data to be communicated, the rate at which data
must be communicated, the number of devices to be connected,
the reliability and noise immunity required, compatibility
with other networks, and cost are examples of important
considerations. In general, it is not possible for one network
type to maximize all characteristics. For example, a network
that can communicate a large amount of data in a short time
is likely to be more expensive than a network that has more
limited requirements. Therefore, many factories use a multi-level
network structure.
In the past, these networks were often proprietary systems
designed to a specific supplier’s standards. Siemens is a leader in
promoting the trend to open systems based upon international
standards developed through industry associations. Siemens
SIMATIC NET offers an integrated, industry-standard range of
industrial network solutions from industrial versions of Ethernet
to field device level networks.
Ethernet has become so popular that it is considered the
de facto standard for office communications. Industrial
Ethernet
is a high-performance network designed to IEEE 802.3
(Ethernet) and IEEE 802.11 (Wireless LAN) standards. In order
to provide the performance and reliability needed for high-
speed factory networks, Industrial Ethernet uses industrial-
grade switching technology. An Industrial Ethernet switch is
an active network component that allows multiple devices to
communicate simultaneously at high speeds.