HMS Networks (Intesis) · Protocol gateway
INMBSMIT001I000 – Mitsubishi Electric AC (Domestic, Mr. Slim, City Multi) to Modbus RTU gateway Modbus register map
Default configuration
- Protocol
- RS485
- Port
- 502
- Unit ID
- 1
- Addressing
- 0-based
- Byte order
- Big endian
- Word order
- High word first
- Baud rate
- 9600
- Parity
- None
- Data bits
- 8
- Stop bits
- 2
This device has an RS-485 interface. Reach it through a Modbus RTU-to-TCP gateway, configured with the factory serial settings above.
Register map
| Address | Count | Name | Type | Unit | Scale | Access |
|---|---|---|---|---|---|---|
| 0 | 1 | AC unit on/off 0 = off, 1 = on. | UInt16 | - | 1 | RW |
| 1 | 1 | AC unit mode 0 = Auto, 1 = Heat, 2 = Dry, 3 = Fan, 4 = Cool; the available values depend on the indoor unit. | UInt16 | - | 1 | RW |
| 2 | 1 | AC unit fan speed 0 = Auto, 1 = Low, 2 = Mid-1, 3 = Mid-2, 4 = High; the number of speeds depends on the position of SW1-P4. | UInt16 | - | 1 | RW |
| 3 | 1 | AC unit vane position 0 = Auto, 1 = Horizontal, 2 = Position-2, 3 = Position-3, 4 = Position-4, 5 = Vertical, 10 = Swing. | UInt16 | - | 1 | RW |
| 4 | 1 | AC unit temperature setpoint -32768 = initialization value; 16..32 °C (raw 160..320 at the factory degC x10 setting), 61..90 °F. | Int16 | °C | 0.1 | RW |
| 5 | 1 | AC unit temperature reference Temperature the indoor unit's own control loop uses; -32768 = initialization value. | Int16 | °C | 0.1 | R |
| 6 | 1 | Window contact 0 = closed (default), 1 = open. | UInt16 | - | 1 | RW |
| 7 | 1 | Gateway disablement 0 = INMBSMIT001I000 enabled (default), 1 = disabled. Stored in non-volatile memory. | UInt16 | - | 1 | RW |
| 8 | 1 | AC remote control disablement 0 = remote control enabled (default), 1 = disabled. Stored in non-volatile memory. | UInt16 | - | 1 | RW |
| 9 | 1 | AC unit operation time 0..65535 hours, counts the time the indoor unit is in the 'On' state. Stored in non-volatile memory. | UInt16 | h | 1 | RW |
| 10 | 1 | AC unit alarm status 0 = no alarm condition, 1 = alarm condition. | UInt16 | - | 1 | R |
| 11 | 1 | Error code 0 = no error; 65535 (= -1 read as signed) = communication error between gateway and AC unit; any other value is listed in the manual's error-code table. | UInt16 | - | 1 | R |
| 13 | 1 | 'Open Window' switch-off timeout 0..30 minutes; factory setting 30. The count-down starts once the window contact opens. | UInt16 | min | 1 | RW |
| 14 | 1 | Modbus RTU baud rate 2400 / 4800 / 9600 (default) / 19200 / 38400 / 57600 / 76800 / 115200 bps. | UInt16 | - | 1 | R |
| 15 | 1 | Modbus slave address 1..63. | UInt16 | - | 1 | R |
| 21 | 1 | Max number of fan speeds Value depends on the position of SW1-P4. | UInt16 | - | 1 | R |
| 22 | 1 | Indoor unit ambient temperature from external sensor -32768 = no external sensor value; otherwise a temperature supplied from the Modbus side. | Int16 | °C | 0.1 | RW |
| 23 | 1 | AC real setpoint temperature Current setpoint in the indoor unit; equals register 4 when no external temperature is provided. | Int16 | °C | 0.1 | R |
| 49 | 1 | Device ID 0x0500. | UInt16 | - | 1 | R |
| 50 | 1 | Software version Gateway firmware version. | UInt16 | - | 1 | R |
| 97 | 1 | Block periodic sendings 0 = non-blocked (default), 1 = blocked; blocks resending unchanged commands to the AC system. | UInt16 | - | 1 | RW |
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Related guides
Notes
Source: HMS Networks / Intesis user manual 'Modbus RTU (EIA-485) Interface for Mitsubishi Electric air conditioners, INMBSMIT001I000', r2.8 (11/2024), section 3.2 'Modbus Registers' (3.2.1 control and status, 3.2.2 configuration). The gateway is Modbus RTU (RS-485) and exposes its own fixed holding-register map that mirrors the indoor unit; reach it through a Modbus RTU-to-TCP gateway using the factory serial settings above (9600 bps, 8-N-2, Modbus server address 1; the gateway auto-detects 8-N-1 and 8-N-2). All registers are 16-bit unsigned holding registers, big-endian. The addresses in this file are the manual's base-0 'protocol addresses' (the manual also prints a base-1 'PLC address', which is always this address + 1). Temperature registers are signed 16-bit and their magnitude follows the gateway's DIP switches (degC x1, degC x10 or degF), so the 0.1 scale factors below assume the factory default degC x10; with the x1 setting the readings are whole degrees. The gateway drives Mitsubishi Electric domestic, Mr. Slim and City Multi indoor units and is only a bridge: it holds no readings of its own. The map is fixed, no vendor tool is needed to place signals. The legacy order code is ME-AC-MBS-1.