The Unified Namespace (UNS) stack, explained with real tools

By PlantWired · Last reviewed October 16, 2026

A Unified Namespace (UNS) is an architecture pattern where every system in a plant publishes its current state to one shared, structured place — usually an MQTT broker — instead of wiring point-to-point integrations between each pair of systems.

Consumers (MES, historians, dashboards, AI tools) subscribe to the data they need. Adding a new system means connecting it once to the namespace, not to every other system.

Below are the usual layers, with the tools our directory lists for each and what they are listed as connecting to. Integration data is editorial; always confirm with the vendor.

1. Connectivity (PLCs → standard protocols)

Translate PLC and device protocols into OPC UA or MQTT.

Cirrus Link MQTT Modules · Cirrus Link · Per-module license
MQTT/Sparkplug B modules for Ignition that enable report-by-exception data movement between edge and enterprise.
Listed with: Ignition, Ignition Edge, HiveMQ, AWS IoT SiteWise, Azure IoT
Kepware KEPServerEX · PTC · Per-driver/suite license
Driver-based OPC UA/DA server with a large library of PLC and device protocols, used as a universal translator on the plant floor.
Listed with: Ignition, AVEVA PI System, ThingWorx, SIMATIC WinCC, FactoryTalk View, Canary Historian, Proficy iFIX
HiveMQ · HiveMQ · Open-source + enterprise tiers
Enterprise MQTT broker frequently used as the backbone of a Unified Namespace architecture.
Listed with: Ignition, Cirrus Link MQTT Modules, Litmus Edge, AWS IoT SiteWise, Azure IoT
Litmus Edge · Litmus · Subscription
Industrial edge platform for collecting, normalizing and forwarding machine data.
Listed with: HiveMQ, Ignition, Azure IoT, AWS IoT SiteWise
Matrikon OPC UA Tunneller · Honeywell · Per-product license
OPC connectivity products, including classic-to-UA tunnelling, from Honeywell's Matrikon line.
Softing dataFEED · Softing · Per-product license
Family of OPC UA and MQTT gateways for reading data from Siemens and Rockwell PLCs.
Node-RED · OpenJS Foundation · Free (open source)
Open-source flow-based tool for wiring protocols, APIs and devices together; common at the edge.
Listed with: HiveMQ, EMQX
EMQX · EMQ Technologies · Open-source + enterprise tiers
High-throughput MQTT broker available as open source and enterprise editions.
Listed with: Node-RED
Eclipse Mosquitto · Eclipse Foundation · Free (open source)
Lightweight open-source MQTT broker, often the first broker in a pilot.
Listed with: Node-RED

2. MQTT broker (the namespace itself)

Holds the live, hierarchical topic tree that everything publishes to and subscribes from.

3. Edge & contextualization

Normalize, model and add context (site/area/line/asset) before data reaches the broker or the cloud.

Ignition Edge · Inductive Automation · Per-device license
Lightweight Ignition edition for field devices and panels that collects and forwards data to a central system.
Listed with: Ignition, Cirrus Link MQTT Modules, HiveMQ
Flow · Flow Software · Subscription
Industrial information hub that turns raw historian and SCADA data into contextualized KPIs and reports.
Listed with: Ignition, Canary Historian, AVEVA PI System, Power BI
Siemens Industrial Edge · Siemens · Device + app subscriptions
Edge computing platform for running containerized apps next to SIMATIC automation.
Listed with: SIMATIC WinCC, Insights Hub, Azure IoT
AVEVA Edge · AVEVA · License
Compact HMI/SCADA for machine builders and embedded panels (InduSoft lineage).
Listed with: AVEVA PI System, AVEVA System Platform
FlowFuse · FlowFuse · Free tier + subscription
Managed platform for running, securing and scaling many Node-RED instances in industrial settings.
Listed with: Node-RED
HighByte Intelligence Hub · HighByte · Subscription
Industrial DataOps software that models and contextualizes OT data before sending it to cloud or IT systems.
Listed with: Ignition, AWS IoT SiteWise, Azure IoT, HiveMQ

4. SCADA / HMI

Operators' view and control; often both a publisher to and consumer of the namespace.

Ignition · Inductive Automation · Per-server license, unlimited tags
Web-deployed SCADA/HMI platform licensed per server with unlimited tags and clients; widely used as a hub for plant-floor data.
Listed with: Kepware KEPServerEX, Sepasoft MES Modules, Canary Historian, HiveMQ, Cirrus Link MQTT Modules, Tulip, AWS IoT SiteWise, Litmus Edge, Flow, Inductive Automation Ignition Perspective, Apache Kafka / Confluent, MongoDB, HighByte Intelligence Hub
AVEVA System Platform · AVEVA · License/subscription
Object-based supervisory platform (Wonderware lineage) for standardized SCADA across lines and sites.
Listed with: AVEVA PI System, AVEVA MES, AVEVA InTouch HMI
Proficy iFIX · GE Vernova · License
HMI/SCADA product from the GE Proficy family, common in process and utilities applications.
Listed with: Proficy Historian, Kepware KEPServerEX, Proficy Plant Applications
SIMATIC WinCC · Siemens · License
Siemens SCADA/HMI family tightly integrated with TIA Portal and SIMATIC controllers.
Listed with: Kepware KEPServerEX, Opcenter, Siemens Industrial Edge, Insights Hub
FactoryTalk View · Rockwell Automation · License
Rockwell HMI software (Machine and Site editions) designed around Logix controllers.
Listed with: FactoryTalk Historian, Kepware KEPServerEX, Plex Smart Manufacturing Platform, FactoryTalk Optix
WinCC Open Architecture · Siemens · License
Highly scalable, platform-independent SCADA from Siemens (ETM) used for large distributed systems like utilities and transport.
Listed with: Siemens Industrial Edge
WinCC Unified · Siemens · License
Web-based successor generation of WinCC, engineered in TIA Portal for panels and PC stations.
Listed with: SIMATIC WinCC, Siemens Industrial Edge
Proficy CIMPLICITY · GE Vernova · License
Client/server HMI/SCADA from GE used in discrete manufacturing and infrastructure.
Listed with: Proficy Historian

5. Historian & time-series storage

Keeps the history the namespace (which holds current state) does not.

Canary Historian · Canary Labs · Tag-based license
Time-series historian focused on lossless compression, fast trending and simple tag-based licensing.
Listed with: Ignition, Kepware KEPServerEX, Seeq, Power BI
AVEVA PI System · AVEVA · Enterprise license/subscription
Enterprise operational data infrastructure (formerly OSIsoft PI) for collecting, storing and contextualizing time-series data.
Listed with: Kepware KEPServerEX, Seeq, Power BI, AVEVA System Platform, Flow, Azure IoT
Proficy Historian · GE Vernova · License
Time-series historian in the Proficy suite for archiving process data at site and enterprise level.
Listed with: Proficy iFIX, Proficy Plant Applications, Seeq
FactoryTalk Historian · Rockwell Automation · License
Rockwell-branded historian for collecting Logix and plant data at machine and site level.
Listed with: FactoryTalk View, AVEVA PI System, Seeq
InfluxDB · InfluxData · Open source + cloud tiers
Open-core time-series database often used as a lightweight historian.
Listed with: Node-RED, Grafana
TimescaleDB · Tiger Data · Open source + cloud tiers
PostgreSQL extension for time-series and sensor data, positioned for IIoT telemetry.
Listed with: Grafana
dataPARC · Capstone Technology · License
Process data analytics and historian suite popular in pulp & paper and chemicals.
Listed with: AVEVA PI System

6. Analytics & industrial AI

Consume contextualized history to find root causes, predict and optimize.

Insights Hub · Siemens · Subscription
Cloud IoT and analytics offering from Siemens (formerly MindSphere).
Listed with: Siemens Industrial Edge, SIMATIC WinCC
Seeq · Seeq · SaaS subscription
Advanced analytics app that lets engineers investigate and model historian data without exporting to spreadsheets.
Listed with: AVEVA PI System, Canary Historian, Proficy Historian, FactoryTalk Historian, Power BI
Proficy Operations Hub · GE Vernova · License
Web app builder for dashboards and operator apps on top of Proficy data.
Listed with: Proficy Historian, Proficy Plant Applications
TrendMiner · TrendMiner · Subscription
Self-service time-series analytics for process engineers working on historian data.
Listed with: AVEVA PI System
Cognite Data Fusion · Cognite · Enterprise subscription
Industrial data platform that builds a contextualized model across OT, IT and engineering data.
Listed with: AVEVA PI System, Azure IoT

Questions to answer before you choose

Which MQTT payload convention will you standardize on (e.g. Sparkplug B vs. plain JSON)?
Where is context (asset hierarchy, units) added — at the edge, or in a hub?
What must stay on-premises vs. go to the cloud?
Who owns the topic structure and naming rules?

Sources

Tool descriptions, pricing models and integration links come from the PlantWired directory, compiled from each vendor's public website (linked on every tool page). See our methodology. Not a recommendation; verify with vendors.

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