OPC DA was the workhorse of industrial communication for over two decades. It connected PLCs to SCADA systems, HMIs to historians, and control rooms to the factory floor. It worked. But the world changed. Linux grew. Cloud computing arrived. Cybersecurity became critical. And OPC DA — locked to Windows, with no encryption, dependent on a technology Microsoft has… Read More »
OT security is the practice of protecting operational technology — the hardware and software that monitors and controls physical processes — from cyber threats. This includes the systems that run factories, power plants, water treatment facilities, oil refineries, transportation networks, and any environment where digital commands drive physical outcomes. Operational technology is different from information technology. IT manages… Read More »
OPC UA Pub/Sub is a communication pattern within the OPC UA standard that allows data to flow from publishers to subscribers without requiring a direct connection between them. A publisher sends data to a message broker or network bus. Any number of subscribers receive that data independently. No handshake. No dedicated session. No request-response cycle. This is fundamentally… Read More »
SCADA security is the practice of protecting Supervisory Control and Data Acquisition systems from unauthorized access, tampering, and cyberattacks. SCADA systems monitor and control physical processes across large geographic areas — power grids, water pipelines, oil and gas networks, and transportation systems. These systems were never designed with cybersecurity in mind. They were built for reliability. For decades,… Read More »
Every Modbus message contains a function code. It is a single byte that tells the slave device what operation to perform — read coils, write registers, or diagnose communication. The Modbus specification defines multiple function codes, but in practice you will use about six of them for 95% of your tasks. The rest are either rarely implemented, vendor-specific,… Read More »
If you work with IEC 61850, you will deal with SCL files. They are the standard way to describe IED capabilities, substation configurations, and communication parameters. But the first thing that confuses most engineers is this: there are six different SCL file types. ICD, SSD, SCD, IID, CID, SED — each with a different purpose, created by a… Read More »
IEC 60870-5-104 (commonly called IEC 104) is the standard protocol for SCADA communication in power utilities, water systems, and other critical infrastructure across Europe, Asia, and the Middle East. It takes the application layer of IEC 60870-5-101 (the serial telecontrol standard) and maps it onto TCP/IP. This gives you the same proven data model — single-point indications, measured… Read More »
IEC 61850 transformed substation automation. It replaced hardwired copper connections with standardized Ethernet-based communication between intelligent electronic devices (IEDs). GOOSE messages trip breakers in under 4 milliseconds. MMS connects IEDs to SCADA systems. Sampled Values stream real-time voltage and current measurements. But this transformation came with a trade-off. By moving protection and control communications onto Ethernet, substations inherited… Read More »
Modbus was built in 1979 for a world where industrial networks were physically isolated. There was no internet, no remote access, and no reason to worry about authentication or encryption. The protocol was designed for reliability and simplicity — not security. That was fine for decades. But today, industrial control systems are increasingly connected to corporate networks, cloud… Read More »
Modbus TCP/IP brings the simplicity of the Modbus protocol onto modern Ethernet networks. Instead of serial cables and RS-485 wiring, you use standard Ethernet infrastructure — switches, routers, and Cat5e/Cat6 cables. The protocol works the same way as Modbus RTU at the application level. You still read holding registers, write coils, and use the same function codes. The… Read More »