Industrial Communications

Communication protocols and standards in automation: OPC, MQTT, REST API, Modbus, PROFINET and more.

Industrial communications are the backbone of any modern automation system. They allow PLCs, HMIs, SCADAs, and historians to exchange data reliably and securely throughout the plant.

From classic protocols like OPC DA and Modbus RTU/TCP, to the latest such as OPC UA, MQTT, and REST API interfaces, this section brings together articles on configuration, integration, and best practices for the main industry standards.

We also cover SNMP for industrial network device management, connectivity with SQL databases applied to historians and SCADAs, and the design of industrial Ethernet networks using simulation tools like GNS3.

OPC DA and OPC UA standards: KEPServer, RSLinx, Simatic Net, OFS, DAServer, TwinCAT OPC configuration and more.

OPC DA (Data Access) is the classic COM/DCOM-based variant for real-time communication between OPC servers and clients. Widely supported by major PLC and SCADA manufacturers.

OPC UA (Unified Architecture) is the cross-platform, secure successor to OPC DA. It does not depend on COM/DCOM, includes a semantic information model and native encryption. It is the recommended standard for new installations and Industry 4.0.

View OPC articles

Lightweight publish/subscribe messaging protocol, ideal for industrial IoT and IIoT applications.

MQTT operates over TCP/IP with a central broker model where clients publish and subscribe to topics. Its low bandwidth consumption makes it ideal for M2M communications and edge computing.

Broker configuration (Mosquitto, HiveMQ), MQTT clients on Siemens/Allen Bradley PLCs, and connection with SCADA platforms and cloud historians.

View MQTT articles

Integration of industrial systems with web services through REST APIs. Connecting PLCs, SCADAs, and historians with modern applications.

REST APIs allow automation systems to communicate with web applications, cloud databases, and external services using standard HTTP/HTTPS, facilitating vertical integration in IIoT architectures.

View REST API articles

One of the most established and widely used protocols in industrial automation: serial (RTU/ASCII) and Ethernet (TCP).

Modbus RTU is transmitted over RS-232/RS-485 and is the de-facto standard for drives, instrumentation, and field devices. Modbus TCP encapsulates the same protocol over Ethernet networks.

Available articles: Modbus RTU network simulation, frame analysis with Wireshark, and security testing over Modbus TCP.

View Modbus articles

Monitoring and management of industrial network devices (switches, routers, gateways) from monitoring systems.

SNMP allows querying and configuring network devices via MIB OIDs. It is the standard protocol for monitoring plant network infrastructure: interface status, traffic, and hardware alarms.

View SNMP articles

Concepts, simulation, and analysis of Ethernet networks applied to the industrial environment.

Industrial network design with redundant topologies, VLAN configuration, STP/RSTP protocol to prevent broadcast storms, and simulation with GNS3 before deploying to production.

View Networking articles