One of the biggest challenges in industrial environments is connecting legacy machines to modern digital systems. Modbus TCP plays an essential role in this process: a simple, robust and widely adopted protocol that enables industrial equipment to communicate with modern IIoT and cloud-based systems.

This article explains how Modbus TCP works and how it becomes a key enabler when integrating industrial machines into connected, data-driven architectures.

What is Modbus TCP?

Modbus TCP is an evolution of the traditional Modbus protocol, designed to work over Ethernet networks. It allows PLCs, sensors, controllers, and industrial equipment to exchange data with digital systems using a simple and reliable structure.

Its main advantages are:

• Easy implementation

• Broad compatibility with legacy and modern devices

• Low cost, no licensing required

• Reliability in demanding industrial environments

Although it does not offer advanced data modelling capabilities, Modbus TCP remains an excellent option for retrieving basic process information with low latency and minimal configuration.

Why Modbus TCP remains relevant in IIoT

In many factories, the majority of equipment was installed long before cloud computing or IIoT existed. Modbus TCP provides a bridge between this equipment and modern digital infrastructures.

It allows plant operators to:

• Access machine data that was previously isolated

• Integrate legacy systems into new IIoT architectures

• Modernize operations without replacing existing machinery

This makes it particularly valuable for companies pursuing Industry 4.0 transformation with limited investment.

Architecture: Integrating Modbus TCP into a Modern IIoT System

The most effective approach for integrating Modbus TCP in an IIoT architecture is to use an edge computing layer. At the edge, an industrial gateway communicates with machines via Modbus TCP and then sends the data to the cloud using modern protocols such as MQTT or secure APIs.

In this workflow:

• The gateway reads registers and values from Modbus TCP devices

• Converts them into structured data

• Applies filtering or preprocessing

• Sends the information securely to a cloud platform

This architecture improves interoperability and enables real-time insight while minimizing the load on plant networks.

Security Considerations

Although Modbus TCP is robust, it lacks native encryption and authentication. When integrating it into industrial IoT systems, it is essential to protect communications using:

• VPN tunnels

• Industrial firewalls

• Network segmentation between OT and IT

• Secure protocols for data transfer from edge to cloud

These measures ensure that digitalization does not introduce vulnerabilities into the industrial environment.

Operational Benefits

Integrating Modbus TCP into an IIoT architecture enables companies to:

• Unlock data from legacy equipment

• Monitor machine performance in real time

• Support predictive maintenance workflows

• Improve process efficiency

• Create a unified data layer across the factory

How CoppioT Helps

CoppioT allows companies to integrate Modbus TCP devices directly into cloud-based IIoT environments without complex programming or infrastructure development. The solution collects, processes and visualizes machine data in real time, enabling maintenance, production and operations teams to make informed decisions based on reliable insights.

This integration allows organizations to preserve the value of existing machinery while advancing toward a more connected, scalable and intelligent industrial ecosystem.