Design_World_-_Internet_of_Things_Handbook_April_2020

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

INTERNET OF THINGS HANDBOOK

over time, rarely by the same person. Not
only does that mean more personnel handling
operating system updates and security policy
confi guration, it also means more cost in
software licensing and upgrades.
With the infl ux of data required for highly
connected, intelligent plant environments,
plant engineers are looking for more scalable
solutions; and OEMs who are looking to the
future need to consider a different set of
integration offerings for their equipment.

ENTER MQTT
MQTT, formerly MQ Telemetry Transport,
was developed in the 1990s under IBM’s
Smarter Planet initiative to provide bandwidth-
effi cient I/O communications for distributed

SCADA projects in the oil

& gas industry. Beginning

in the early 2010s, MQTT

grew in popularity to emerge

in recent years as the top

IoT-specifi c protocol. Since

then, it has been enhanced for mission-critical

industrial applications through an additional

specifi cation, called Sparkplug B (SpB).

What makes MQTT different? Effi ciency.

Cirrus Link Solutions, the company that

developed the SpB spec, reports an 80-95%

reduction in bandwidth consumption by users

who move to an MQTT infrastructure.

MQTT achieves this effi ciency using

a radically different communication model

from other protocols used for industrial

applications and IIoT. Rather than establishing

multiple one-to-one connections between

master applications and slave devices, and

then polling those devices repeatedly for

information, MQTT establishes a shared server,

known as a broker, as the endpoint for all fi eld

devices and applications (Figure 3). Devices

publish data to the broker, but they do so

only when a change occurs in a given process

variable—a feature called report by exception.

Network applications can connect to the same

MQTT broker, subscribe to updates from any

over time, rarely by the same person. Not
only does that mean more personnel handling
operating system updates and security policy
confi guration, it also means more cost in
software licensing and upgrades.

SCADA projects in the oil

& gas industry. Beginning

in the early 2010s, MQTT

grew in popularity to emerge

in recent years as the top

Figure 2: The typical industrial device contributes to

the complicated web of unsecured, point-to-point

connections that make up industrial networks.