26 I ICT TODAY
Selecting appropriate media for a robust and reliable industrial Ethernet network is
imperative. Three viable media types are optical fiber, balanced twisted pair and wireless.
Their various characteristics are defined and use criteria outlined herein to help ICT
physical infrastructure designers identify the correct media choice for the industrial
environment and its specific applications.
Prior to starting the process of media selection, there are some fundamentals to
review. Industrial networks are designed to control time sensitive processes that, if
compromised, can have a significant negative impact on both safety and production.
Therefore, reliability, redundancy, and low latency are key design criteria that are always
considered as part of the logical design and, hence, become equally important when
designing the physical infrastructure. Added features of the physical infrastructure
include designing for redundancy, longevity, expandability, and the sharing of media
with other networks. A designer should consider the infrastructure to have a 20 year life
span without a significant overhaul; based on experience, some end-user clients prefer
joint use cabinets typically at the distribution level. This means that not only will the
media need to support the business information technology (IT), but also the industrial
network operational technology (OT), including building automation systems (BAS)
and security (e.g., CCTV, access control and intrusion). As a designer, it is a necessity
to table this scenario and secure a clear definition of exactly what the infrastructure is
expected to support.
By Luke Young,
RCDD
THE PROCESS
OF SELECTING MEDIA
FOR INDUSTRIAL
ETHERNET NETWORKS