KNX OPC UA Server: Lingg & Janke KNX Virtual and SCADA Connection

Übersicht der KNX Virtual Architektur

KNX Installation (TP bus)
        │
        ▼
KNX IP Router / IP Interface (KNXnet/IP)
        │  (UDP multicast or unicast)
        ▼
KNX Virtual (Windows/Linux server)
  ├── KNXnet/IP tunnelling client
  ├── ETS6 group address import (XML / .knxproj)
  ├── DPT → OPC UA data type mapping
  └── OPC UA server (opc.tcp://server_ip:4840)
        │
        ▼
OPC UA Clients:
  ├── Siemens Desigo CC
  ├── Schneider EcoStruxure Building Operation
  ├── Ignition SCADA (Inductive Automation)
  └── Any IEC 62541-compliant client

KNX Virtual Einrichtungsablauf

Step 1: KNXnet/IP connection
  Settings → KNX → Connection type: KNXnet/IP tunnelling
  IP address of KNX IP router (e.g. 192.168.1.10)
  Tunnelling port: 3671 (default)
  Test: KNX bus status indicator shows green

Step 2: ETS6 group address import
  Option A: Export from ETS6 → File → Export Group Addresses
            Format: XML (OPC UA compatible) or CSV
  Option B: Import full .knxproj file directly
  Settings → Import → select exported file
  All group addresses appear in the node browser

Step 3: OPC UA endpoint configuration
  Settings → OPC UA → Endpoint URL:
  opc.tcp://192.168.1.50:4840
  Port 4840 is the IANA-assigned OPC UA default
  Change only if firewall rules require alternate port

Step 4: Security mode
  None:          No authentication, no encryption (testing only)
  Sign:          Certificate-based authentication, no encryption
  Sign+Encrypt:  Certificate authentication + TLS encryption
  Recommended for production: Sign+Encrypt

Desigo CC OPC UA-Integrationsschritte

1. Desigo CC Workstation
   → System Management → Network → Add OPC UA server
   → Endpoint URL: opc.tcp://192.168.1.50:4840
   → Security: Sign+Encrypt (recommended)

2. Certificate exchange:
   → Export KNX Virtual server certificate
   → Import into Desigo CC OPC UA trusted servers
   → Export Desigo CC client certificate
   → Import into KNX Virtual trusted clients list
   → Connection status: Connected (green)

3. Browse and import KNX nodes:
   → Expand node tree: Root → KNX → Main Group → Sub Group
   → Drag variable nodes to Desigo CC Floor Plan asset structure
   → Assign display names matching CAFM room numbering

4. Bind to Desigo CC functions:
   → Alarms: right-click Boolean variable → Create Alarm
   → Trends: right-click Float variable → Create Trend Log
   → Graphics: drag data point to Desigo CC graphic template

Ignition SCADA OPC UA → KNX-Energieüberwachung

Ignition Designer → OPC Connections → Add OPC UA server
  Server URL: opc.tcp://192.168.1.50:4840
  Security: Sign+Encrypt
  Certificate: accept KNX Virtual cert (Ignition auto-trusts)

Tag Browser → OPC → Browse KNX Virtual nodes:
  Root/KNX/Energy/FloorB1/Zone01_kWh → drag to Tag Editor
  Tag name: FloorB1_Zone01_Energy
  Data type: Float (from DPT 12.001 / OPC UA UInt32)
  Deadband: 0.01 kWh

Historian configuration (for ISO 50001 trending):
  Tag history → Sample mode: On Change
  Storage provider: Ignition Historian (TimescaleDB)
  Max age: 5 years (ISO 50001 baseline requirement)

EnMS dashboard (Ignition Perspective):
  Zone kWh bar chart (monthly, year-over-year)
  Peak demand (kW) time-series per zone
  Energy intensity: kWh per m² per month
  Export to Excel: Ignition Report Module → XLSX

OPC UA-Abonnementkonfiguration

Subscription parameters (configured in OPC UA client):
  Publishing interval:    500ms (minimum update rate)
  Lifetime count:         1200 (600 seconds before timeout)
  Max keep-alive count:   20   (10 seconds between heartbeats)
  Max notifications:      0    (unlimited per publish cycle)

Monitored item parameters (per node):
  Sampling interval:  500ms (same as publishing interval)
  Queue size:         1 (latest value only)
  Discard oldest:     true

Deadband configuration (prevents unnecessary publishes):
  Temperature nodes:      Absolute ±0.1°C
  Energy total (kWh):     Absolute ±1 kWh
  Power demand (kW):      Absolute ±0.05 kW
  Lighting dimmer (%):    Absolute ±0.5%
  Binary (on/off):        No deadband (always publish changes)

Network impact example:
  2,000 KNX nodes, 500ms publishing interval, 90% static:
  Without deadband: 4,000 OPC UA publish messages/second
  With deadband:    ~200 messages/second (only changed values)
  Network load reduction: 95%