Daikin
Japanese VRV/VRF air conditioning — Modbus TCP integration for KNX energy management and residential split AC control.
Daikin (Osaka, Japan — founded 1924) is the world's largest HVAC manufacturer by revenue (€26B+), with European operations headquartered in Ostend, Belgium. In Europe, Daikin dominates commercial VRF under the VRV brand (Variable Refrigerant Volume — Daikin's proprietary name for VRF technology) and is a major player in residential heat pumps under the Altherma range. For KNX integrators, Daikin systems connect via Modbus TCP: commercial VRV systems use the Daikin Intelligent Touch Manager (iTM) central controller, which exposes a Modbus TCP server on the building LAN — covering all indoor units connected to the VRV system. Residential split AC units use the BRP7Z6W8 WiFi/LAN adapter, providing per-unit Modbus TCP access. Altherma heat pumps connect via the DKN Cloud BACnet/Modbus gateway. All paths feed into Weinzierl or Intesis KNX-Modbus gateways to deliver zone setpoints and energy data to the KNX bus.
Role in our panels
How we use Daikin
Daikin's Modbus TCP integration architecture varies by product line. For commercial VRV (VRV 5, VRV 5 S, VRV IV): the Daikin iTM (Intelligent Touch Manager) is the mandatory central controller. iTM connects to the VRV system via Daikin F-bus and exposes Modbus TCP registers on the building LAN (port 502). Registers cover: indoor unit on/off, operating mode (auto/heat/cool/fan/dry), setpoint temperature (0.5°C resolution), room temperature reading, fan speed, and fault codes — one register map per indoor unit address (up to 64 indoor units per iTM). KNX gateway reads iTM Modbus TCP → translates to KNX group addresses for each zone. For residential split AC (Stylish, Emura, Comfora, Ururu Sarara): the BRP7Z6W8 WiFi/LAN adapter connects to the indoor unit via the S21 proprietary port and exposes Modbus TCP plus a local REST API. One adapter per indoor unit. For Altherma heat pumps: the DKN Cloud AC BACnet/Modbus gateway interfaces to the Altherma outdoor unit and provides Modbus TCP registers for flow temperature setpoint, DHW setpoint, operating mode and SG Ready input emulation. Altherma 3 H HT supports flow temperatures up to 75°C for compatibility with existing high-temperature radiator systems (70/55°C design point). OpenTherm interface is also available for Altherma in non-KNX thermostat applications.
Panel wiring for Daikin VRV and KNX: the iTM controller connects to building LAN via RJ45 — the KNX panel includes a managed switch with a dedicated HVAC VLAN, isolating VRV Modbus TCP traffic from KNX IP router traffic. Weinzierl KNX ENO 634 Modbus TCP gateway polls iTM registers for each zone: zone temperature setpoint is written from KNX room controller group address; room temperature reading is broadcast to KNX group address for display. For residential splits with BRP7Z6W8: each adapter is on the building WiFi or IoT VLAN, accessible at a fixed IP (DHCP reservation). KNX panel includes RJ45 patch panel for wired adapters and a UniFi AP for WiFi adapters. For Altherma with DKN Cloud gateway: Modbus TCP from gateway → Weinzierl ENO 634 → KNX heating setpoint GA. SG Ready input (enabling cheap-tariff surplus heating) is wired to a KNX binary output module relay output — when the KNX energy manager detects solar surplus or cheap tariff, it writes to the binary output group address, relay closes → Daikin Altherma SG Ready terminal block activates DHW boost or buffer tank heating. Altherma SG Ready wiring in panel: KNX relay (dry contact) → 2-core cable → Altherma outdoor unit SG Ready terminals (SG1, SG2).
Used in these project types
Daikin products
Key components we install
Daikin Stylish 3.5kW Wall-Mounted Split
3.5kW wall-mounted split AC, R-32 refrigerant, A+++ energy class. Connects to KNX via BRP7Z6W8 Modbus TCP adapter (S21 port). Registers: on/off, mode (0=auto/1=heat/2=cool/3=fan/4=dry), setpoint (°C), room temperature, fan speed (auto/low/medium/high). Ururu Sarara and Emura variants share the same S21 interface. For residential KNX rooms: one adapter per unit, Modbus TCP polled by Weinzierl gateway.
Daikin VRV 5 S Outdoor Unit
VRV 5 S series outdoor unit, 10-22HP, R-32, heat pump or heat recovery. Connects to Daikin iTM via F-bus (included). iTM exposes Modbus TCP on building LAN (port 502) with register map for all connected indoor units. For KNX projects: Weinzierl ENO 634 gateway reads iTM Modbus TCP → zone setpoints and modes → KNX group addresses. VRV 5 S supports up to 64 indoor units per system, multiple outdoor units can be linked.
Daikin Altherma 3 H HT Air-to-Water Heat Pump
Altherma 3 H HT: high-temperature ASHP producing flow temperatures up to 75°C — compatible with existing high-temperature radiator systems (70/55°C design point). 9-16kW output. Connects to KNX via DKN Cloud AC gateway (Modbus TCP). SG Ready input for solar/cheap-tariff surplus. For retrofits replacing gas boilers without radiator replacement. KNX flow temperature setpoint adjusted by weekly schedule and presence detection.
Daikin Altherma 3 R Monobloc ASHP
Altherma 3 R monobloc (all refrigerant circuit in one outdoor unit, water connections only to building). 4-16kW, R-32, COP up to 5.3. Designed for underfloor heating. Modbus TCP via DKN Cloud gateway. No F-gas certification required for installation (monobloc = no indoor refrigerant). SG Ready 2-contact input. For residential KNX villas: Altherma 3 R + KNX setpoint via Weinzierl gateway + SG Ready relay from KNX binary output.
Daikin WiFi/Modbus TCP Adapter for Split AC
WiFi and LAN adapter for compatible Daikin indoor split units. Connects via S21 proprietary port. Provides Modbus TCP (port 502) and local REST API. Modbus TCP register map: coil 1 = on/off, holding register 2 = mode (0-4), holding register 4 = setpoint (°C, resolution 0.5), input register 5 = room temperature, holding register 6 = fan speed (0=auto,1=low,2=medium,3=high). Also supports Daikin Cloud API for remote access. Essential item for KNX residential split AC integration — one BRP7Z6W8 per indoor unit.
Daikin FAQ
How does Daikin VRV integrate with KNX?
Daikin VRV systems use the Intelligent Touch Manager (iTM) as the central controller. The iTM connects to all indoor units via Daikin F-bus and exposes a Modbus TCP server on the building LAN (port 502). The Modbus register map covers each indoor unit address: on/off, operating mode (0=auto, 1=heat, 2=cool, 3=fan, 4=dry), setpoint temperature (0.5°C resolution), room temperature reading, and fault codes. A Weinzierl KNX ENO 634 Modbus TCP gateway is configured with the iTM IP address and polls the required registers on a 10-second interval. ETS6 group addresses are mapped to each register: room thermostat setpoint GA → Weinzierl → iTM Modbus write; iTM Modbus read → Weinzierl → room temperature display GA. For multi-iTM buildings, multiple Weinzierl gateways are used — one per iTM.
What is the BRP7Z6W8 and how does it work?
BRP7Z6W8 is Daikin's WiFi/LAN communication adapter for compatible split AC indoor units. It connects to the indoor unit via the S21 proprietary 3-wire connector (Tx, Rx, GND) and provides both a local REST API and a Modbus TCP interface on port 502. Modbus TCP register map for BRP7Z6W8: coil 1 = on/off (read/write), holding register 2 = operating mode (0=auto/1=heat/2=cool/3=fan/4=dry), holding register 4 = temperature setpoint in 0.5°C units, input register 5 = room temperature reading, holding register 6 = fan speed (0=auto/1=low/2=medium/3=high). The adapter connects to the building WiFi or IoT VLAN via WPS or manual SSID configuration. For KNX integration: Weinzierl ENO 634 gateway is configured with the adapter IP and Modbus TCP port 502 — one Modbus slave device per BRP7Z6W8 adapter. The adapter also supports the Daikin Cloud API for remote access outside the local LAN.
Can Daikin Altherma work as a heat source for an existing radiator system?
Yes — the Daikin Altherma 3 H HT (High Temperature) variant is specifically designed for this retrofit scenario. It produces flow temperatures up to 75°C, making it fully compatible with existing high-temperature radiator systems designed for 70/55°C flow/return. Lower-temperature Altherma variants (Altherma 3 H, Altherma 3 R) are designed for 55°C maximum flow and require underfloor heating or oversized radiators. Modbus TCP connectivity for Altherma is via the DKN Cloud AC BACnet/Modbus gateway (ordered separately). The DKN Cloud gateway provides Modbus TCP registers for flow temperature setpoint, DHW setpoint, operating mode, and SG Ready input emulation. KNX weekly schedule adjusts the flow temperature setpoint for comfort hours (e.g., 65°C) vs. setback (e.g., 45°C). SG Ready input enables surplus solar or cheap-tariff heating of DHW or a thermal buffer tank — wired as a dry contact from a KNX binary output relay to the Altherma SG Ready terminals on the outdoor unit.
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