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.
MQTT 5 Negative Acknowledgements: Reason Codes Explained
MQTT 5 negative acknowledgements: how Reason Codes signal failure in PUBACK, PUBREC, SUBACK, CONNACK, DISCONNECT. Complete failure handling reference.
MQTT 5 vs MQTT 3.1.1: Differences, Features & Migration
MQTT 5 vs MQTT 3.1.1 compared: every difference, every new feature, behavioral changes, packet-level changes, and how to decide which version to use.
CIP Device Profiles Guide: Interoperability Framework
CIP device profiles explained: how Device Type codes define interoperability. Complete profile catalog (AC Drive 0x02, Discrete I/O 0x07, Encoder 0x22, more).
CIP Motion Explained (Class 0x42 Motion Axis Object)
CIP Motion explained: distributed motion control over EtherNet/IP. Motion Axis Object (Class 0x42), control modes, CIP Sync dependency, servo drive integration.
CIP Sync Explained: IEEE 1588 PTP for Industrial Networks
CIP Sync explained: IEEE 1588 PTP for CIP networks. Time Sync Object (Class 0x43), grandmaster/boundary clocks, Best Master Clock Algorithm, offset clock model.
CIP Path Segments Explained: EPATH Encoding for Engineers
Complete guide to CIP path segments: Port, Logical, Network, Symbolic, Data segments. Decode 20 04 24 66, EPATH format, Electronic Key segment, padded vs packed.
CIP Connection Manager Object Explained (Class 0x06)
CIP Connection Manager Object (Class 0x06): the object behind Forward_Open. Services, attributes, counters, Network Connection Parameters, error codes.
MQTT 5 Reason Codes, Reason Strings, and Negative Acknowledgements
How MQTT 5 improved client feedback: expanded reason codes, reason strings, server-initiated DISCONNECT, negative acknowledgements, and CONNACK capability advertisements.
MQTT 5 User Properties Explained: Custom Metadata
How MQTT 5 user properties work: arbitrary UTF-8 key-value metadata attached to most packets, with use cases for routing, traceability, payload context, and limits.
CIP Ethernet Link Object Explained (Class 0xF6)
Complete CIP Ethernet Link Object reference (Class 0xF6): Interface Flags, MAC address, link speed, RFC 1213/1643 counters, multi-port DLR diagnostics.
CIP TCP/IP Interface Object Explained (Class 0xF5)
Complete guide to CIP TCP/IP Interface Object (Class 0xF5): IP address, subnet mask, gateway, DNS, DHCP/BOOTP, multicast configuration, TTL, attributes.
Modbus TCP S7-1500: MB_CLIENT and MB_SERVER Setup
Modbus TCP S7-1500 setup in TIA Portal: MB_CLIENT, MB_SERVER, and TCON_IP_v4 configured, MB_MODE mapped to function codes, and status codes 8200 and 809B fixed.
CIP Connection Types Explained: Transport Class 0, 1, 2, and 3
Complete guide to CIP transport classes: Class 0, 1, 2, 3 connection types, the Transport Class Trigger byte, production triggers, and Forward_Open encoding.
RS-232 DB9 Pinout: Signal Reference, Wiring, and Field Troubleshooting
he full RS-232 DB9 (DE-9) pinout with signal directions, voltage levels, null modem vs straight-through wiring, and industrial troubleshooting.
NERC CIP Compliance: Complete Guide to All CIP Standards
What is NERC CIP? All 13 standards explained, 2026 updates (CIP-003-9, CIP-012-2, CIP-015), IEC 62443 mapping, penalties, audit process
CIP Identity Object Explained: How Every EtherNet/IP Device Identifies Itself
Complete guide to the CIP Identity Object (Class 0x01): Vendor ID, Device Type, Product Code, Revision, Status, Serial Number, Reset service, electronic keying.
CIP Assembly Object Explained: How EtherNet/IP Devices Bundle I/O Data
How the CIP Assembly Object works in EtherNet/IP: input and output assemblies, instance attributes, and how the data maps into an I/O connection.
EDS Files Explained: How EtherNet/IP Devices Describe Themselves
Complete guide to CIP EDS files: structure, sections, [File], [Device], [Params], [Assembly], [Connection Manager], importing, and troubleshooting.