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 »
In power automation, reliable and secure data exchange between control centers and field devices is critical. One of the most adopted communication protocols that enables this is Distributed Network Protocol version 3 (DNP3). DNP3 communicates over TCP/UDP port 20000, which serves as the standard IP port for linking SCADA master stations with remote field units like RTUs and… Read More »
The Distributed Network Protocol (DNP3) is recognised for its efficiency and reliability in SCADA and power automation systems. The DNP3 protocol is characterized by three key operational concepts: Report by Exception, Periodic Background Polls, and Balanced Communication. These concepts enable the system to optimize bandwidth utilization while ensuring real-time monitoring of field device status. Report by Exception (unsolicited… Read More »
In industrial automation, Modbus over RS-485 is still one of the most popular and reliable ways to connect programmable logic controllers (PLCs), sensors, meters, and field devices. One key parameter that determines how well this network performs is the communication frequency. this is also called the baud rate. It defines how fast data is transmitted between Modbus master… Read More »
In a DNP3-based SCADA system, system topology refers to the physical and logical arrangement of how master stations, outstations, and communication devices are connected and interact. Designed for flexibility and reliability, DNP3 supports multiple network configurations that can be tailored to the system size, communication medium, and redundancy requirements. The most common DNP3 topologies include master–slave, multidrop, hierarchical,… Read More »
Before any data or command exchange can begin, the communication link between the controlling station (master) and controlled stations (RTUs or substation gateways) must be properly established. This process — called link initialization — ensures both sides start from a synchronized state with correct frame sequencing, clear buffers, and ready communication paths. Link initialization is part of the… Read More »
The IEC 60870-5-101 protocol (commonly known as IEC 101) is a serial telecontrol standard widely used in SCADA, power automation, and industrial control systems. It defines how data is formatted and transmitted between a controlling station (master) and controlled stations, such as RTUs or dedicated substation operation and data-handling devices. Each message on the line is called a… Read More »
The Originator Address in IEC 60870-5-101 is an optional but powerful feature that enhances message routing and command traceability in telecontrol and SCADA systems. This one-byte field, located within the Cause of Transmission (COT) section of the ASDU, allows a controlling station to explicitly identify itself when sending commands. In systems with a single master station, this feature… Read More »
The IEC 60870-5 family defines communication standards for telecontrol systems used in power, water, and industrial automation. Among these, IEC 60870-5-101 (IEC 101) and IEC 60870-5-104 (IEC 104) are the two most widely used protocols for communication between control centers, substations, RTUs, and IEDs. Although they share the same application layer, they differ in their transport mechanisms, network… Read More »