Topic Convention

Prerequisite: Understand the UNS concept and see it in action via Getting Started.

Every piece of data in the UNS has a unique address that tells you exactly where it came from and what it represents.

See It In Action

Here's how real PLC data appears in the Topic Browser:

Topic Browser showing DB1.DW20

The topic umh.v1.demo.DefaultArea.DefaultProductionLine.SIEMENS-S7._raw.DB1.DW20 tells us:

• WHERE: demo → DefaultArea → DefaultProductionLine → SIEMENS-S7

• WHAT: _raw (unprocessed device data)

• WHICH: DB1.DW20 (specific PLC register)

The Pattern

umh.v1.<location_path>.<data_contract>[.<virtual_path>].<name>

Breaking It Down

Part	Example	Purpose
umh.v1	Always umh.v1	Version prefix
location_path	enterprise.site.area.line	Physical/logical hierarchy
data_contract	_raw or _pump_v1	Data structure type
virtual_path	motor.diagnostics	Optional folder organization
name	temperature or work_order.create	The data point or action

Location Path - WHERE

The location path organizes your physical and logical structure:

• Level 0 (Required): Enterprise - your company

• Level 1: Site - physical location

• Level 2: Area - department or zone

• Level 3: Line - production line or cell

• Level 4: Machine - specific equipment

You can use ISA-95, KKS, or any naming standard. The only rule: level 0 is mandatory.

Example: umh.v1.acme.chicago.packaging.line1.filler._raw.speed

Data Contract - WHAT

The contract defines the data structure:

• _raw: Unvalidated device data for exploration

• _devicemodel_v1: Validated device models (e.g., _pump_v1, _cnc_v1)

• _businessmodel_v1: Business KPIs and aggregations (e.g., _maintenance_v1, _production_v1)

Contracts always start with underscore. They're your data's "type system."

Virtual Path - Organization

Optional segments for grouping related data:

umh.v1.acme.plant._pump_v1.motor.diagnostics.vibration
                          └─────┬─────┘
                          Virtual path for organization

Name - WHICH

The specific data point or action:

• Time-series: temperature, pressure, running

• Relational: work_order.create, batch.complete

Next Steps

• Understand payload formats for message structure

• Connect devices with bridges

• Explore with Topic Browser