Swegon
GOLD Air Handling Units with Modbus RTU and BACnet for KNX Integration
Swegon (Kvänum, Sweden) manufactures high-efficiency air handling units for commercial and industrial buildings. The Swegon GOLD series (RX, LP, PX, CX) is the Swedish standard for demand-controlled ventilation in offices, schools, and hotels. GOLD units integrate with KNX via Modbus RTU/TCP or via LOYTEC Modbus-to-KNX gateway.
Role in our panels
How we use Swegon
Swegon GOLD RX Modbus integration: GOLD units have a built-in RS485 Modbus RTU interface (GOLD Control Panel, terminals B+/B-/GND). Baud rate 19200, parity none, stop bits 1 (GOLD-specific — not standard 8E1). Unit ID configured in GOLD Control Panel menu. Key holding registers: 1 (unit on/off, uint16: 1=on, 0=off), 2 (operating mode: 0=off, 1=auto, 2=manual, 3=override), 4 (supply air temperature setpoint, int16, degCx10), 10 (supply air temperature actual, int16, degCx10), 11 (extract air temperature), 12 (outdoor air temperature), 20 (supply air fan speed %, uint16), 21 (extract air fan speed %), 30 (heat recovery efficiency %, uint16), 40 (CO2 sensor reading, uint16, ppm), 50 (filter differential pressure warning: 0=OK, 1=change filter). MDT Modbus gateway setup: read task for temperature and CO2 every 30s, read task for alarms every 60s. Write object: register 4 for supply air setpoint from KNX DPT 9.001. LOYTEC LGATE-920 (Modbus-to-KNX gateway): automatic datapoint discovery of GOLD Modbus map and mapping to KNX GAs. BACnet/IP: GOLD RX optionally supports BACnet/IP via GOLD Net option card (GOLD NET-BACnet) — object list includes AI (analog input) for temperatures, BI (binary input) for alarms, AO (analog output) for setpoints. LOYTEC LGATE-950 then bridges BACnet/IP to KNX. Swegon WISE (IoT cloud): alternative cloud integration; local Modbus still preferred for KNX.
Swegon GOLD air handling units connect to KNX via Modbus RTU RS485 (using MDT or Weinzierl Modbus gateway) or via LOYTEC LGATE BACnet-to-KNX bridge, enabling ventilation setpoint control and CO2/temperature monitoring in KNX building automation.
Used in these project types
Swegon products
Key components we install
GOLD RX 3 Right-hand unit
3000 m3/h compact AHU. Modbus RTU RS485 on control board terminals B+/B-. Registers: fan speed (20-21), supply temp setpoint (4), CO2 (40), filter alarm (50). KNX integration via LOYTEC LGATE-920 for full datapoint mapping.
GOLD CX 50 Rooftop unit
5000 m3/h rooftop unit with heat wheel, DX cooling option. BACnet/IP via GOLD NET option card. LOYTEC LGATE-950 bridges BACnet/IP AI/BI objects to KNX groups.
GOLD NET BACnet Card
Optional BACnet/IP card for GOLD series. Enables BACnet object discovery on the AHU. BACnet device ID configurable. Used when LOYTEC LGATE-950 is the KNX bridge.
Swegon FAQ
What baud rate does Swegon GOLD use for Modbus RTU?
19200 baud, 8 data bits, no parity (N), 1 stop bit (8N1). Note: this is different from the common 8E1 setting. The unit ID is configured in GOLD Control Panel under Communication > Modbus > Address (1-247).
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