300+ SCADA Protocol Articles & Guides
Deep dives on Modbus, DNP3, IEC 60870-5-101/104, IEC 61850, OPC UA, Profinet, MQTT, IEC 62443, and substation automation — written for practicing engineers.
Modbus Unit Identifier Explained: Unit ID by Scenario
Modbus Unit Identifier (Unit ID) explained by scenario: direct TCP devices, RTU gateways, multi-port gateways. Value ranges, common defaults, troubleshooting.
Modbus Broadcast Function Codes: Address 0 Explained
Modbus broadcast on address 0: which function codes support it, how serial and TCP differ, turnaround timing, gateway behavior, and when to actually use it.
Modbus Client-Server vs Master-Slave Terminology
Modbus client-server vs master-slave: the 2020 terminology change explained. What stays the same, translation table, and how to read mixed-terminology docs.
Modbus TCP MBAP Header Explained: 7 Bytes Byte by Byte
Modbus TCP MBAP header decoded byte by byte: Transaction ID, Protocol ID, Length, and Unit ID, with a real hex dump, network byte order, and common mistakes.
Modbus TCP Security Explained: TLS on Port 802
Modbus TCP Security explained: TLS on port 802, X.509 certificates, role-based access control, deployment alongside port 502, cipher suites, real setup.
Modbus Exception Codes Explained: Complete Reference
Modbus exception codes 01 through 0B in full: Illegal Function, Illegal Data Address, Slave Device Failure, and gateway errors, each with the fix that works.
Modbus Security Risks and How to Protect Your Network
Modbus security risks in practice: why the protocol has no authentication, real attack techniques on RTU and TCP, plus segmentation, firewalls, and monitoring.
Modbus TCP/IP Setup: Step-by-Step Configuration Guide
Modbus TCP/IP setup from scratch: IP planning, server and client configuration, MBAP header basics, gateway bridging to RTU, and connection troubleshooting.
Modbus TCP/IP Explained: Complete Beginner-to-Expert Guide
Modbus TCP/IP explained from the ground up: ADU structure, encapsulation across network layers, big-endian data, the client-server model, and function codes.
Modbus TCP Port 502: Setup, Security, Troubleshooting
Modbus TCP port 502 in depth: IANA registration, connection lifecycle, client limits, firewall rules, Wireshark filters, and the TLS secure variant on port 802.
Modbus RTU to Modbus TCP: Gateway Setup and Conversion
Modbus RTU to Modbus TCP conversion step by step: frame translation byte by byte, hardware and software gateway setup, Unit ID mapping, and timeout tuning.
Modbus RTU vs Modbus TCP: Frames and Key Differences
Modbus RTU vs Modbus TCP compared field by field: frame structure, CRC versus MBAP header, addressing, performance, and migrating serial devices to Ethernet.
Modbus Protocol Explained: RTU, TCP, ASCII, and Frames
Modbus protocol explained end to end: RTU, TCP, and ASCII variants, frame structure, function codes, master-slave architecture, and field troubleshooting.