INMBSFGL001I000 Fujitsu to Modbus RTU RS-485 gateway for BMS/SCADA integration

Fujitsu RAC & VRF to Modbus RTU (RS-485) gateway via CN connector – INMBSFGL001I000

INMBSFGL001I000 is an industrial gateway that provides full bi-directional communication between Fujitsu RAC and VRF systems and Modbus RTU (RS-485) networks. The device operates as a Modbus RTU slave (EIA485), enabling direct integration with PLCs, SCADA, BMS or automation controllers using standard Modbus registers.

The gateway is wired directly to the indoor unit (via the CN connector), which allows not only control of the main AC functions (e.g. operating mode, fan speed, temperature setpoint), but also exposes diagnostic and service data to Modbus: errors, alarms and selected internal variables. In practice, this means automation logic can react to service events, while operators gain a clear, centralised view of HVAC status in the supervisory system.

The solution is designed for fast commissioning. Installation typically comes down to wiring the gateway to the AC unit and setting the built-in DIP switches (Modbus address, baud rate, temperature unit and scale). No configuration software is required and, in many installations, an external power supply is not needed. A consistent Modbus register mapping used across this product family also helps reduce engineering time in multi-brand HVAC projects.

Product features

• Modbus RTU slave (EIA485) for direct PLC/SCADA/BMS integration via Modbus registers.
• Bi-directional control and monitoring of Fujitsu RAC/VRF – from basic functions to diagnostics (errors/alarms).
• No software required: configuration via DIP switches and Modbus RTU.
• Fast “plug & set” installation – wire to the AC unit and set DIP-SW parameters.
• External power supply not required in typical installations (depending on system wiring).
• Simultaneous control of the AC unit via the IR remote controller and Modbus RTU.
• Compact size and flexible mounting: DIN rail, wall, and in selected cases even inside the indoor unit.
• Window contact function to support energy savings and reduce HVAC operating costs.
• Monitoring of internal variables, running hours counter (e.g. filter maintenance) and error indication.

Technical specification

Features:

• Modbus RTU slave device (EIA485)
• Configuration via built-in micro-switches and Modbus RTU
• Quick and easy installation (plug-in + DIP-SW settings)
• No external power supply required
• Simultaneous AC control via IR remote controller and Modbus RTU
• Reduced dimensions: 93 x 53 x 58 mm
• Mounting: DIN rail, wall, and in some AC models even inside the indoor unit
• Window contact function supports energy savings
• Total AC control & monitoring via Modbus RTU, including internal variables, running hours counter and error indication

Specification:

• Enclosure:
  • Plastic, PC type (UL 94 V-0)
  • Net dimensions (l x w x h): 93 x 53 x 58 mm / 3.7" x 2.1" x 2.3"
  • Color: light grey, RAL 7035
• Weight: 85 g
• Mounting: wall; DIN rail EN60715 TH35
• Terminal wiring (low-voltage signals): solid or stranded wires (twisted or ferruled)
  • 1 core: 0.5mm2... 2.5mm2
  • 2 cores: 0.5mm2... 1.5mm2
  • 3 cores: not available
• Modbus RTU port: 1 x EIA485, pluggable screw terminal block (2 poles + GND) with 120 Ω termination and selectable bias via switch
• AC unit port: 1 x special connector, special cable included
• Switch 1 (SW1): 1 x DIP-Switch for AC model + Modbus baud rate
• Switch 3 (SW3): 1 x DIP-Switch for Modbus RTU slave address + temperature unit (ºC/ºF) and scale (x1/x10)
• Operating temperature: 0ºC to 70ºC
• Operating humidity: <95% RH, non-condensing
• Isolation voltage: 1500 VDC
• Insulation resistance: 1000 MΩ
• Protection: IP20
• LED indicators: 2 x built-in LEDs – operating status

Warranty: 36 months

Product code: INMBSFGL001I000