When people first hear about IEC 61850, they often assume it is simply another communication protocol like DNP3, Modbus, or IEC 60870-5-104. But this assumption is incorrect. IEC 61850 is not just a protocol—it is a full engineering language designed to describe, model, and structure the functions that make up modern digital substations and power automation systems. Where… Read More »
DNP3-IP, designed for distribution SCADA and remote telemetry, and IEC 61850, built for advanced substation automation and high-speed protection schemes, represent two fundamentally different communication approaches in modern power systems. Modern electric power systems depend on digital communication networks that connect substations, field devices, control centers, and automation systems. Two of the most important communication standards in this… Read More »
Looking for a quick, hassle-free way to decode IEC 101 frames? This free IEC 101 Decoder runs entirely in your browser and turns raw hex into clear, readable text instantly. No installs, no setup, no extra tools. Just paste your data and get answers. It also handles originator addresses and can automatically tell whether your frame uses a… Read More »
Every Modbus TCP/IP device listens on TCP port 502. This single port carries all Modbus communication over Ethernet — read requests, write commands, exception responses, and diagnostics. Port 502 is registered with IANA (Internet Assigned Numbers Authority) under the service name “mbap” (Modbus Application Protocol). It has been the standard since the Modbus TCP specification was published in… Read More »
Monitoring SCADA protocol traffic is essential for diagnosing field issues, validating protocol behavior, troubleshooting mapping or timing problems, and improving the reliability of industrial automation systems. Whether the system uses legacy serial-based protocols such as Modbus RTU, IEC 60870-5-101, or DNP3 Serial, or modern TCP/IP-based protocols such as Modbus TCP, IEC 60870-5-104, DNP3 TCP, or IEC 61850, having… Read More »
IEC 60870-5-104, commonly called IEC 104, remains one of the most widely deployed telecontrol protocols in power system SCADA networks worldwide. It extends IEC 60870-5-101 for operation over TCP/IP, enabling real-time data exchange between control centers and remote terminal units (RTUs) in electrical engineering and power system automation applications. As of early 2026, the IEC 104 base protocol… Read More »
The Application Service Data Unit (ASDU) is the core of the IEC 60870-5-104 communication protocol. It defines how information is represented and exchanged between a controlling station (SCADA master) and controlled stations such as RTUs or IEDs. If the Application Protocol Data Unit (APDU) is the message envelope, the ASDU is the payload — carrying the actual telemetry… Read More »
In modern SCADA (Supervisory Control and Data Acquisition) systems, choosing the right communication protocol can determine how efficiently, securely, and reliably data moves between control centers and field equipment. Two of the most widely used open standards are DNP3 (Distributed Network Protocol version 3) and IEC 60870-5-104. While both were designed for real-time monitoring and control, they differ… Read More »
Modern SCADA and utility automation systems face growing cybersecurity demands. The Distributed Network Protocol (DNP3)—the backbone of many control networks—has evolved to meet them. With the release of IEEE 1815-2020, the DNP3 Secure Authentication Version 6 (SAv6) specification brings authenticated encryption, centralized authorization, and simplified key management directly into the protocol. This article explains how SAv6 improves on… Read More »
DNP3 runs over IP networks using TCP or UDP port 20000. This port number is the standard for communication between SCADA masters and field devices (RTUs, IEDs) in electric utilities, water systems, and oil and gas pipelines. The IANA also registered port 19999 for DNP3 Secure (DNP3 over TLS), though it is rarely used in practice — most… Read More »