10 March 2019 http://www.controlengeurope.com Control Engineering Europe

T

he revolutionary approach

of Industry 4.0 should not

be a one-time fundamental

change, but rather an

openness of industry to

permanent change.

Connecting to the internet boosts

the functionality and performance of

an industrial plant and its machinery,

enabling seamless integration in the

form of digital, value-added networks.

Within this, edge devices play a key

role as they are used directly in the

production module in the area of plant

and machinery.

Edge devices are tasked with lifecycle

services such as predictive maintenance,

performance management, asset

tracking or spare part management.

However, they can also be used

more generally to enable process

optimisation through Cloud-based

services. The key factors here are the

open interfaces of the edge devices,

along with extensive standardisation of

the integration. Intelligent systems can

be used uniformly by different software

systems, as well as being seamlessly

integrated into the manufacturing

environment.

Good all-rounders

It is fair to say that IT edge devices are

good all-rounders as they can be used

universally for all services. However,

there is one exception to this rule –

automation. On the face of it, this

appears to be a contradiction, since

Industry 4.0 is often seen as being

the use of technology to power all

functions within the industrial sector.

Also, converged Ethernet networks

have been implemented for several

years. A decisive step in this is TSN (Time

Sensitive Networks), which allow the

Ethernet network to be universally

integrated into real-time areas. So why

shouldn’t the IT edge device be used

universally, including automation? Or

why shouldn’t the programmable logic

controller (PLC) also be used universally

as an IT edge device?

If you analyse the requirements for

an industrial control and an IT edge

device, there are clear differences.

The programming of a PLC is adapted

to the machine, strongly function-

oriented and uses well-established

hardware and software that has already

proven itself within the application.

The basic function of a machine, or

of a machine module, only alters

if there are significant changes in

the production process. Of course,

parameters of the actual sequence

can be accessed in order to enable

flexible production within the scope of

a mass customisation. However, these

changes do not affect the modules

to such an extent as to require a new

commissioning in each instance.

As a rule, the basic control structure

with the deployed control system

remains unchanged over many years,

something which is necessary not

least in light of safety aspects. It is

unusual for a completely new PLC to

be installed during the life cycle to

increase performance. This is usually

only customary after several years, in

the course of refurbishment.

By contrast, the installation of an

IT edge device usually constitutes

an expandable platform which is

constantly adapted and built out during

the life cycle of a machine via the use of

additional services. Software updates in

short intervals are also common here.

However, no new commissioning of

the machine takes place, since safety-

relevant aspects are not affected. The

software used also meets the necessary

standards in the IT environment.

OPC UA constitutes an intersection in

communication with industrial devices,

even if signs are already on the horizon

that this communication standard is

not the only one that will be used by

IT in the industrial environment. IIoT

standards such as MQTT are also finding

in-roads here.

Consequently, the IT edge device

turns out to be completely built and

operated according to IT paradigms.

Most of all, it is not rigid or unchanged

in the life cycle of a machine or plant. It

will continuously evolve with lifecycles

far below those of automation devices.

This is necessary to keep up with IT. But

that would mean that even a PLC – an

intelligent drive in a machine – will be

replaced within five years so it can be

up to date with the latest IT standards.

This is neither economically viable nor

technically feasible.

The decoupling of IT edge devices

and automation devices provides

further advantages in plant operation.

Optimising production

If the production process is to be

optimised by new services, access to the

automation devices is necessary. This

requires suitable interfaces, including

a semantic description of the devices.

Creating these is going to be one of the

The implementation of Industry 4.0 continues to focus on the linking of industrial

production to the internet and the Cloud, and this has transformed the Internet of

Things (IoT) into the ‘Industrial Internet of Things (IIoT’), according to Gavin Stoppel.

Edge devices as a key

to Industry 4.0 success

EDGE COMPUTING