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System Architecture

WEVA is built on a modular, containerized architecture designed for high availability within a local area network (LAN). This section details the internal components and their interactions.

Architectural Layers​

The system is partitioned into three functional layers to ensure modularity and ease of maintenance.

1. Data Acquisition Layer (Modbus/WDX)​

This layer handles all communication with field devices. It consists of the WDX Runtime (PLC Visu), which acts as the primary Modbus driver.

  • Protocol: Modbus TCP/UDP.
  • Polling: Deterministic intervals (configurable per device).

2. Application Logic Layer (Backend Server)​

The core logic of WEVA is responsible for orchestrating data flow, managing user authentication (RBAC), and processing historical data trends.

  • Persistence: Post-processed data is committed to a local SQL database.
  • Security: All API endpoints are protected by token-based authentication.

3. Visualization Layer (Web Interface)​

The frontend provides a data-dense, dark-themed interface optimized for engineering workstations.

  • Technology: Browser-based rendering (Zero-client installation).
  • Communication: Real-time updates via WebSockets or high-frequency polling.

Data Flow Diagram​

The following sequence describes how a single Modbus register value travels through the system:

  1. Field Device: A WAGO 879 Energy Analyzer generates a data point (e.g., Active Power).
  2. WDX Runtime: Queries the Modbus register via the local network.
  3. WEVA Backend: Retrieves the value from the WDX API and stores it in the database.
  4. Web Dashboard: Displays the value to the authenticated user on a graph.

Data Flow Placeholder GIF: Animation showing data moving from a PLC through Docker containers to a Browser.

Container Orchestration​

WEVA uses Docker Compose to manage dependencies and network isolation between containers.

# Conceptual overview of the container stack
services:
  weva-backend:
    image: wago/weva-backend:latest
  weva-database:
    image: postgres:15-alpine
  wdx-runtime:
    image: wdx-runtime:4.0.1

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