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What Is Connectivity in Industry?

Short answer

Connectivity is the ability to link machines, sensors, controllers, software systems, and platforms so that data flows continuously and reliably — horizontally between systems at the same level, and vertically from the field level up into ERP and cloud systems. The practical difficulty rarely lies in a single connection, but in the sheer number of different protocols in use: a controller from the 1980s often speaks Modbus, a modern automation system speaks OPC UA, and a cloud application speaks MQTT or HTTP. Without a translator in between, every connection stays a one-off that starts from scratch with the next machine.

Reading time 8 minutesEditorial team, inray Industriesoftware
Point-to-point links between protocols compared to a mediator that connects Modbus, OPC UA and cloud protocols end to end with pronubes

Definition: Connectivity in Industry

In classic IT environments, connectivity mostly means linking computers and systems over a network. In industry, the term is broader: it describes the ability to connect machines, sensors, controllers, software systems, and platforms so that continuous data flows emerge.

Those data flows run in two directions: horizontally between systems at the same level, say between two lines in the same plant, and vertically across the levels of the automation hierarchy. A widely used model for that hierarchy comes from the International Society of Automation (ISA) with the ANSI/ISA-95.00.01 standard, whose first part was published in 2000: from the field level with sensors and actuators, through the control and supervisory level, up to manufacturing execution systems (MES) and enterprise IT (ERP).

Level Example systems Typical protocols
Field level sensors, actuators Modbus, PROFINET
Control and supervisory level PLCs, SCADA, DCS OPC UA, Modbus, PROFINET
MES level manufacturing execution system OPC UA, MQTT, REST
ERP and cloud level enterprise software, cloud platforms HTTP, REST, MQTT

Why connectivity becomes a precondition

Production plants grow over decades. A controller from the 1980s or 1990s stands right next to a line that started up two years ago — and both are expected to deliver the same kind of data. The real problem is rarely the absence of a connection, but the sheer number of different protocols that coexist.

Modbus, for instance, was developed in 1979 by the manufacturer Modicon for its own programmable logic controllers and is still in use in many plants today. OPC UA, specified in the IEC 62541 series and first published in 2011 by the international standards body IEC, targets vendor-independent, platform-independent communication between modern automation systems instead. MQTT, in turn, originated in 1999 at IBM (Andy Stanford-Clark) and Arcom (Arlen Nipper) for satellite-based monitoring of oil pipelines, and became an official OASIS standard on 29 October 2014 — today one of the most widely used protocols for connecting individual sensors to cloud platforms.

Anyone wiring up each of these connections by hand quickly runs into a number that grows faster than the number of systems itself: with n systems each connected directly to one another, up to n(n-1)/2 possible point-to-point links can result. With ten systems, that is already forty-five possible connections; with twenty, one hundred and ninety. Each new machine does not add cost in a straight line — it adds cost against every machine already connected.

A slice of the protocol landscape

A slice of the protocols that coexist in production environments:

Protocol Origin Typical use
Modbus 1979, Modicon older PLCs, serial and Ethernet fieldbuses
OPC UA (IEC 62541) 2011 (IEC), updated 2015 vendor-independent automation, semantic interoperability
MQTT 1999 (IBM/Arcom), OASIS standard since 2014 sensors, IoT devices, cloud connectivity
HTTP/REST standard IT protocols web interfaces, APIs, ERP and cloud systems

What underpins end-to-end connectivity

  • Protocol gateways. They translate between OT protocols such as Modbus or OPC UA and IT protocols such as HTTP or MQTT, instead of integrating every machine into every target system separately.
  • Central middleware instead of point-to-point. One system takes in data from many sources and distributes it to many destinations — each machine connects once, not once per destination.
  • Consistent naming. Without consistent identifiers, data from different sources cannot be brought together even once it technically arrives at the target system.
  • Secure network crossings. Following the zones-and-conduits concept from IEC 62443, defined, monitored crossings connect individual security zones instead of running every system on one flat network.

Four steps to end-to-end connectivity

  1. Take stock

    Which systems exist, which protocol does each one speak, and how well is that documented?

  2. Choose a mediation layer

    A gateway or middleware that covers the protocols already in use, instead of building a one-off solution for every machine.

  3. Define naming

    A consistent structure before data starts flowing at scale — it is hard to standardize after the fact.

  4. Connect and monitor incrementally

    Start with the most important or most accessible systems, check data quality, then expand.

What connectivity is not

  • Not a single protocol. Connecting only via OPC UA or only via MQTT rarely covers the entire system landscape.
  • Not a cybersecurity measure on its own. Connectivity creates data flows; it does not replace network segmentation or access control.
  • Not a one-time project. Plants, systems, and protocols change — the connections have to keep pace.
  • Not a substitute for data quality. A connection delivers data, but no guarantee that it is correct, complete, or current.

Common pitfalls in practice

  • Undocumented legacy protocols. Controllers with no current documentation, whose exact behavior only a handful of people still understand.
  • Security concerns around network access. Many OT systems were never designed to be connected to a corporate network or the internet.
  • Missing interface expertise. Knowledge of how to bridge IT and OT protocols is concentrated in a handful of people at many companies.
  • Accumulated one-off connections. Individual departments have built their own point-to-point links that nobody fully oversees anymore.
The honest part

More connectivity also means a larger attack surface: every new connection is another crossing that has to be monitored. An approach such as the NAMUR Open Architecture (NOA) addresses this by routing monitoring and optimization data through a second, parallel channel instead of changing the existing, safety-critical automation system itself. Not every system needs the same depth of connection, either: a simple meter reading needs less protection than a safety-relevant process controller.

How pronubes builds connectivity

pronubes is the platform between the shop floor and IT — and that is exactly where connectivity starts.

  • pronubes Edge translates between protocols such as Modbus, OPC UA, and MQTT, making machine data available in a single, consistent format.
  • pronubes Zones keeps naming consistent across every connected system.
  • pronubes Insights makes the combined data usable for analysis, without every application having to build its own connection to the machine.

That turns individual connections into a structure that grows with every new machine, instead of starting over from scratch each time. More on the platform

Key terms explained
Modbus
Communication protocol for industrial controllers, developed in 1979 by the manufacturer Modicon.
OPC UA
Vendor-independent communication standard for automation, specified in the IEC 62541 series.
MQTT
Lightweight messaging protocol developed in 1999, an official OASIS standard since 2014.
Middleware
Software that mediates between different systems and converts their data into a shared format.
ISA-95
Standard from the International Society of Automation for the interface between the enterprise and control levels.
NAMUR Open Architecture (NOA)
Concept for a second, parallel data channel for monitoring and optimization, without changing the existing automation system.
Ask us

Frequently asked questions

Is connectivity the same thing as IT/OT convergence?

No, but the two belong together. Connectivity creates the technical precondition — working connections across protocols and systems. Convergence builds on that, describing controlled data exchange across the boundary between IT and OT.

Isn’t a single protocol like OPC UA enough?

Often, yes, in newly built plants. But as soon as older controllers speaking Modbus or another legacy protocol are in the mix, a single protocol rarely covers the entire system landscape.

How safe is it to connect old controllers?

Directly, often not very, since many OT systems were never designed for network access. A protocol gateway or middleware between OT and IT, combined with network segmentation, reduces that risk substantially.

What does a lack of connectivity cost?

Mostly time and information silos: data that would technically exist cannot be brought together, because every connection is a one-off that has to be rebuilt for the next machine.

Does every machine need to be connected to the same depth?

No. The right level of depth depends on the purpose — a simple meter reading needs a different connection than a safety-relevant process controller.

Get started

A translator between your protocols, not a one-off fix per machine.

30 minutes on your protocol and system landscape: which connections exist today, where middleware fits in, and where connectivity fails in practice.

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pronubes is a product of inray Industriesoftware GmbH. Over 30 years of industrial software made in Germany. Innovative and reliable for manufacturing companies.

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