Key Concepts
This page explains how WS.PEMS organizes your facilities and their data. It also gives a short definition of the other terms that you see on the screens. Each definition links to the page that explains it in full.
Organizational hierarchy
WS.PEMS organizes industrial facilities in a hierarchy:
Region
A Region is a geographic or organizational group, for example a country, a business unit or a regulatory jurisdiction. Users have their roles per region. A user sees the data of the regions where the user has a role.
Asset
An Asset is a physical industrial facility, for example a power plant, a refinery or a processing site. Each asset has one or more emission sources.
Emission Source
An Emission Source is one item of equipment that makes emissions, for example a gas turbine, a boiler, a flare or an engine. Each emission source has its own:
- Measurement tags (sensors)
- Calculation model
- Data pipeline
- Alarms
Tag
A Tag is one data point: a sensor value, a calculated value or a configuration parameter. You connect each plant tag to a Standard Tag. The standard tag defines what the value is, for example "Ambient Temperature" or "Mass flow of NOx".
Standard Tags
Standard Tags give a fixed meaning to each quantity. Their short names use engineering notation. Temperatures and pressures use station numbers. Emission tags use the component name and a suffix:
| Name | Meaning |
|---|---|
T_0 | Ambient temperature |
P_0 | Ambient pressure |
T_2 | Compressor inlet temperature |
NOx_VC | Volume concentration of NOx (ppm) |
NOx_MC | Mass concentration of NOx (mg/Nm³) |
NOx_M | Mass flow of NOx |
CO2_M | Mass flow of CO2 |
Standard tags keep the identifiers the same across assets and emission sources. See Standard tags for the full list.
Other terms
Pipeline
A Pipeline is a sequence of steps that changes raw sensor data into calculated emission values. Pipelines run on a schedule that you set. See Pipeline Manager.
Model
A Model defines how WS.PEMS calculates the emissions of an emission source. The model types are First Principle, ONNX, Custom and Simple. See Model Manager.
First-level data
First-level data is the output of a pipeline run: the calculated values for one time step. All aggregation and reporting starts from first-level data. See How emissions are calculated.
Aggregation
WS.PEMS aggregates first-level data into longer periods, step by step: STA, then SSTA and VSTA, then LTA. See Reporting periods and emission limits.
Regime
A Regime defines the regulatory rules for the aggregation: which periods to aggregate, which emission limits apply, and how to find compliance. See Regimes.
Report Template
A Report Template defines the structure and content of a report: which values it includes, how it shows them, and which period it covers. See Generate a report.
Workflows
Workflows are step-by-step processes for quality assurance: measurement, calibration, validation and uncalibration. Each workflow records the data and the decisions of each step. See Workflow Manager.
Alarms
The alarm system monitors for conditions that need attention. Alarms have four categories: Information, Warning, Alarm and Violation. See Respond to alarms.
Next steps
- Find a screen: find the screen for a task.
- Overview and dashboard: monitor your assets.