Most integration problems are protocol problems in disguise: a register address that is off by one, a 32-bit value with its words swapped, an OPC UA endpoint that rejects an untrusted certificate, an MQTT session that loses data on reconnect. These guides explain how Modbus, OPC UA and MQTT actually behave on the wire, and how to choose and validate them before commissioning.
Both protocols move register data between controllers, but they differ in transport, latency, and wiring. A practical comparison for retrofit and greenfield projects.
· 2 min
OPC UA and MQTT solve different problems. This guide maps each protocol to the architecture where it earns its place.
· 2 min
A reference-style guide to Modbus data tables, 0-based versus 1-based addresses, the common function codes and exception responses, with the classic off-by-one trap explained.
· 3 minBuild RTU/TCP requests, inspect bytes and validate CRC checksums.
RTU · TCP · CRC16Check byte order, numeric data types and engineering scales.
INT · FLOAT · HEXConvert and scale CSV, JSON and Modbus register data.
CSV · JSON · ModbusA practical sequence for checking offsets, signedness, byte order and scaling before register values reach a dashboard.
Both protocols move register data between controllers, but they differ in transport, latency, and wiring. A practical comparison for retrofit and greenfield projects.
· 2 minA reference-style guide to Modbus data tables, 0-based versus 1-based addresses, the common function codes and exception responses, with the classic off-by-one trap explained.
· 3 min
Why a perfectly valid register pair turns into nonsense, how IEEE 754 single precision is split across two registers and how to find the right byte and word order.
· 4 min
A practical sequence for checking offsets, signedness, byte order and scaling before register values reach a dashboard.
· 2 min
OPC UA is replacing legacy protocols as the backbone of industrial interoperability. Here is what IT engineers need to know about adoption, security, and real-world integration patterns.
· 4 minOPC UA and MQTT solve different problems. This guide maps each protocol to the architecture where it earns its place.
· 2 min
Generic OPC UA models get you interoperability; companion specs get you semantics. A field guide to the standard ecosystem.
· 2 min
What Sign and SignAndEncrypt actually change, which security policies to avoid, how application certificates and trust lists work, and the connection errors you will meet first.
· 3 min
QoS 0, 1, and 2 are often misread as reliability tiers. What they actually guarantee - and how to choose per message class.
· 2 min
Raw MQTT topics are easy to publish and hard to govern. Sparkplug B adds structure, birth certificates, and last-gasp messages.
· 2 minHow to structure MQTT topics with an ISA-95-style hierarchy, what belongs in the topic versus the payload, how retained messages and last will fit, and which anti-patterns to avoid.
· 4 min
A factory data test plan for disconnects, stale values, duplicate messages and replay behavior.
· 2 min
Design notes for reliable, secure and observable MQTT infrastructure in industrial settings: broker clustering and persistence, mutual TLS, edge brokers for buffering, session settings and monitoring.
· 3 min
Design patterns for protocol gateways that translate between Modbus, OPC UA, MQTT and REST and stay maintainable: model first, map second, and treat the gateway as a product with owners and versions.
· 3 minYou do not need to replace your Siemens S7-300 or Allen-Bradley SLC to get IIoT data. A lightweight MQTT gateway bridges legacy controllers to modern analytics without touching the control logic.
· 5 min
Fieldbus is not obsolete, and Ethernet is not automatically better. The engineering criteria that settle the debate.
· 2 min
There is no best wireless technology - only the right one for the distance, data rate, and power budget. A selection guide.
· 2 min
When Wi-Fi is too short-range and cellular is too costly, LoRaWAN fills the gap: it connects low-data-rate sensors across warehouses, yards and remote sites at low cost per device.
· 6 min
Heat, metal, vibration, and interference make factory wireless hard. How to design wireless sensor networks that survive real plants.
· 2 minThey suit different jobs: Modbus for simple device access, OPC UA for client/server communication with an information model and security, and MQTT for lightweight publish/subscribe data distribution. Many projects use them together.
Documentation may use 1-based (40001) or 0-based addresses, while the frame carries a 0-based offset. Our register addressing article explains the details.
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