Unified Namespace

A Unified Namespace (UNS) is one shared, structured place where every current value of the plant can be found by its location: this enterprise, this site, this area, this machine, this value. Any system that needs plant data subscribes to the namespace, instead of connecting to each machine or to each other.

Proxus builds the namespace for you. Every device you add is published in it, under the place you gave it, and every tag value appears there as it is read.

The place of a device

The levels of the namespace follow ISA-95, the international standard for the structure of a manufacturing enterprise. You set them on each device, in the device setup wizard or on the device page:

All levels are optional. A level you leave empty is skipped, so a device with only a site is published directly under that site. The place also groups devices in lists, the Trend Workspace and the Operations Center, so it is worth agreeing on names before you add many devices.

Topics

Proxus publishes the namespace over MQTT. Each value has its own topic, built from the place, the device name and the tag name:

v1/<enterprise>/<site>/<area>/<process cell>/<equipment module>/<device>/telemetry/<tag>

For the mixer from Connect your first machine:

v1/Meridian/Lyon_Foods_Plant/Processing/Dough/DOCS_TUTORIAL_MIXER_01/telemetry/Temperature

• v1 is the version of the topic structure.
• Empty levels are left out; there is no empty segment.
• In each level, any character other than a letter, a digit, _ or - becomes _. A space in Lyon Foods Plant becomes Lyon_Foods_Plant. Upper and lower case are kept.

Besides one topic per tag, each device has three more:

A new subscriber therefore sees the status and the last-seen time of every device at once, and the values as they come in.

Messages

Messages are JSON by default. A value message looks like this:

{
  "ts": "2026-10-15T19:12:35.120Z",
  "value": 62.5,
  "dataType": "Float",
  "unit": "°C",
  "quality": "Good",
  "source": "Proxus"
}

Proxus can publish the namespace as Sparkplug B instead of JSON, for systems built on that standard. The format, the summary interval and the other publishing settings are in the [UNS] section of the configuration file; see Configuration keys.

Where the namespace is published

Each edge gateway publishes the values it reads on its own built-in MQTT broker. For the SYSTEM gateway in the Docker Compose stack, that broker listens on port 1883 of the hub host. A remote gateway has its own broker, on the port chosen when it was installed.

Subscribers need credentials; the broker does not accept anonymous clients by default. MQTT and the UNS topics shows how to connect and subscribe.

In the hub, Organize > UNS Explorer shows the whole namespace as a live tree, with the values of every gateway together.

What's next

• UNS Explorer to browse the namespace in the hub.
• UNS permissions to decide who may see which part of it.
• Devices, profiles and tags for the objects behind each topic.