LG MultiV is one of Europe's most widely installed VRF systems in commercial buildings — offices, hotels, retail. Unlike Panasonic (which offers a native KNX adapter), LG uses its proprietary LGAP protocol over RS-485 as the BMS integration route, converted to KNX via Modbus gateways. This guide covers the LGAP protocol, Intesis gateway configuration, Modbus register mapping, KNX group address assignment, and multi-system commissioning for a large office building.

LG MultiV architecture and LGAP protocol

LG MultiV 5 outdoor units: inverter compressor, R410A (older) or R32 (2023+ Multi V S compact), up to 64 indoor units per outdoor, modular outdoor frame connection for larger systems. Indoor unit types: 4-way cassette (LTN series), ducted concealed (LDN series), wall console (LS series). The F-BUS (LG proprietary 2-wire communication bus, RS-485 electrical) connects all indoor and outdoor units plus the BMS interface module. LGAP (LG Air conditioner Protocol) is the RS-485 slave protocol running on F-BUS: each indoor unit is a Modbus-like slave device (address 0–63). The LG PQNFB17C0 BMS interface unit (or PQNFB14A0 for older systems) connects to the F-BUS and provides an RS-485 port with LGAP protocol to external controllers. Baud rate: 9600 baud, 8N1, RS-485 half-duplex.

Intesis INMBSLAN0600000 gateway

The Intesis INMBSLAN0600000 (Modbus TCP/IP Master ↔ multiple LGAP slaves) is a DIN-rail gateway that polls LG indoor units via LGAP and exposes them as Modbus TCP registers — readable by a KNX/Modbus gateway. Hardware connections: RS-485 A/B/GND (to LG BMS interface RS-485 port), Ethernet RJ45 (to building LAN), 24V DC or 12V DC power. For KNX integration: add a KNX-Modbus gateway in series — Intesis IN701KNX or MDT KNX-Modbus — which reads Modbus TCP registers from the INMBSLAN0600000 and maps them to KNX group objects. Alternative: Intesis INKNXLGE001I000 (native LGAP-to-KNX gateway, direct F-BUS to KNX TP, maps one LG unit per gateway — more cost-effective for small systems with 1–4 indoor units).

LGAP Modbus register map

Via INMBSLAN0600000 (or equivalent Modbus TCP interface): registers are per indoor unit, base address = unit_address × 100 (e.g., unit 0 = registers 0–99, unit 1 = registers 100–199). Key registers per unit: Holding 0 = On/Off (0=off, 1=on), Holding 1 = Operation mode (0=cooling, 1=dehumidify, 2=fan, 3=auto, 4=heating), Holding 2 = Setpoint temperature (integer, unit: 0.5°C, value 32 = 16°C, value 60 = 30°C), Holding 3 = Fan speed (0=auto, 1=low, 2=medium, 3=high), Holding 5 = Room temperature feedback (integer, value 42 = 21°C, add 0 offset), Holding 10 = Filter alert (0=OK, 1=filter reset required), Holding 11 = Error code (0=OK, non-zero=fault per LG error code table). Read/write: Holding 0–4 are read/write (control), Holding 5–11 are read-only (status).

KNX group address mapping via IN701KNX

Configure Intesis IN701KNX (BACnet/IP to KNX, or Modbus TCP to KNX depending on model) via MAPS software: signal table setup for 12-unit floor: Unit 0 On/Off: Modbus register 0 → KNX DPT 1.001 → GA 7/0/0. Unit 0 Mode: Modbus register 1 → KNX DPT 20.105 → GA 7/0/1 (mode mapping: 0→3=Cool, 4=Heat, 2=Fan, 3=Auto in HVAC mode DPT). Unit 0 Setpoint: Modbus register 2 (apply formula: value/2+offset) → KNX DPT 9.001 → GA 7/0/2. Unit 0 Room temp: Modbus register 5 → DPT 9.001 → GA 7/0/3. Unit 0 Fault: Modbus register 11 (!=0 → DPT 1.001 value 1) → GA 7/0/8. Repeat for units 1–11 (GAs 7/1/0 through 7/11/8). Upload MAPS signal table to IN701KNX. Verify: ETS6 Group Monitor → send On to GA 7/0/0 → confirm LG indoor unit starts.

ETS6 visualisation and HVAC logic

With LG MultiV mapped to KNX: standard KNX visualisation (Gira X1 homeserver, IP-Symcon, Home Assistant + KNX) shows per-room thermostat control. ETS6 logic for occupancy-based HVAC: KNX presence detector GA (BEG or MDT PIR) 5/room/0 → ETS6 logical OR with access control door GA → HVAC occupancy flag GA 7/room/9 → if occupied for 5 minutes → send setpoint 21°C to LG unit. If unoccupied 30 minutes → send setpoint 26°C (energy saving). Floor-level aggregation: if all rooms unoccupied → send Off to all LG units on floor (energy saving mode). Morning pre-conditioning: ETS6 time module Monday–Friday 07:00 → set all LG units to Auto mode, setpoint 21°C → pre-condition before 08:00 occupancy. EN 15232-1 Class A control: variable setpoints + occupancy sensing = Class A energy efficiency compliance.

Large building commissioning: 48-unit system

Hotel with 48 LG indoor units (4 outdoor units × 12 units each), 4 LGAP buses: (1) LG refrigerant commissioning by LG-certified engineer (address DIP switches on each indoor unit, 0–11 per bus). (2) Wire 4 LG BMS interface units (one per outdoor) to Intesis INMBSLAN0600000 — chain RS-485 A/B/GND from BMS unit to gateway. (3) Configure INMBSLAN0600000: set 4 LGAP slave addresses per bus, 9600 baud. (4) Configure IN701KNX: load MAPS signal table with 48 units × 5 signals = 240 Modbus points → 240 KNX group objects. (5) ETS6: download group address configuration (GAs 7/0/0 through 7/47/8). (6) Test: poll all 48 units from ETS6 Group Monitor → confirm room temperature feedback from all 48 units (indicates successful LGAP communication). (7) Commission hotel PMS integration: hotel card reader (Salto SVN) sends card-in GA → HVAC occupancy for room. Card-out GA → HVAC eco mode after 5 min delay.