Design_World_-_Internet_of_Things_Handbook_April_2020

eeworldonline.com | designworldonline.com 4 • 2020 DESIGN WORLD — EE NETWORK 39

IoT TECHNICAL TIPS

Store data in the cloud

or on-premises

Configure

firewall

Write code

sending to

database

Write code

to get data

Write code

to log data Log data

PC workstation

Controller or server

Sensor Install, and configure

input module

Wire sensor to

temperature

input

Figure 1: Providing even basic equipment information

to central business applications involves a complex

hierarchy of so ware and hardware systems.

where data is in highest demand—and require further software and
hardware support for integration. The most common approach requires
the use of an open platform communications (OPC) server with drivers for
each type of protocol in use on the plant network. No problem, right?
An unfortunate by-product of this model is that the more the
network grows, the more congested it becomes. Poll-response
communication protocols, like the ones mentioned, on control and
corporate networks send frequent requests for information to maintain
a sense of the state of the system and to act on the latest data.
Additionally, business applications accessing fi eld data through an OPC
network may be competing with industrial SCADA (supervisory control
and data acquisition) or historian applications on the control network for

bandwidth, with each making its own connection to fi eld devices and

requesting the same data over and over again.

All these one-to-one connections also create security issues, for

which traditional industrial protocols and equipment, like PLCs, lack

native support (Figure 2). Additional equipment and networking, like

VLANs and fi rewalls, are required to provide security after the fact.

Unfortunately, with many different protocols in use, network protections

become peppered with exceptions or become so restrictive that large-

scale integration is impeded.

Speaking of large-scale integration, these communications systems,

of course, do not maintain themselves. Every controller, every gateway,

every server and fi rewall, needs to be installed, confi gured, and updated

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