MBMap Registry
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  2. Unipi Technology
  3. Extension xG18

Unipi Technology Extension xG18 Modbus register map

Modbus RTU extension with 8 temperature measurement channels

  • Official
  • 44 registers
  • Modbus RTU
  • Revision 3 · 2026-11-10
  • Identity: firmware, serial number

Official: Written from the manufacturer's documentation, but not tested on a device yet. Check the map against the manufacturer's documentation before you write to a live device. Tested it? Report a test.

Download .mbmap.json Raw JSON View on GitHub Suggest a correction Report a problem

Communication

Protocol
Modbus RTU
Unit ID
15
Serial
19200 8N1 · 19200 baud, 8 data bits, none parity, 1 stop bit
Byte / word order
CDAB · bytes big-endian, words low first (word swap)
Addresses
0-based

Connection values are defaults: the device may be configured differently.

Map

Registers
41 holding registers, 3 coils
Groups
5
Translation tables
2
Revision
3 · 2026-11-10
Added
()
File
maps/unipi/xg18.mbmap.json · 9 KB · history
SHA-256
edcb7d622eed43cd25aba9eaba8aa905039d96a3d5c37c635137935d4956c742
Manufacturer
www.unipi.technology

Device identity

What a tool can read to check that this map fits the connected device (SPEC.md section 4.7). Registers with a role are read like any other register.

Registers
RoleRegisterAddressTypeValues
Firmware Firmware version holding 1000 uint16
Serial number PCB serial number holding 1005 uint32 CDAB

Sources and notes

Source: Extension xG18 Modbus map v1.1, Unipi technology

  • The sheets inside the document are marked v1.1 although the file name says v1.0.
  • Registers are 0-based. 32-bit values use word order CDAB (low word first). Defaults: slave address 15, 19200 bps, 8N1.
  • Registers marked Reserved in the manual are left out.
AreaAddressNameTypeAccessUnitScaleDescription
HR 0 bool bit 0 RW
HR 0 bool bit 1 RW
HR 1 int16 R °C ×0.01 Reads -32768 when the sensor is unconnected or faulty
HR 2 int16 R °C ×0.01 Reads -32768 when the sensor is unconnected or faulty
HR 3 int16 R °C ×0.01 Reads -32768 when the sensor is unconnected or faulty
HR 4 int16 R °C ×0.01 Reads -32768 when the sensor is unconnected or faulty
HR 5 int16 R °C ×0.01 Reads -32768 when the sensor is unconnected or faulty
HR 6 int16 R °C ×0.01 Reads -32768 when the sensor is unconnected or faulty
HR 7 int16 R °C ×0.01 Reads -32768 when the sensor is unconnected or faulty
HR 8 int16 R °C ×0.01 Reads -32768 when the sensor is unconnected or faulty
HR 9 bool bit 0 RW Validity flag of the channel reading
HR 9 bool bit 1 RW Validity flag of the channel reading
HR 9 bool bit 2 RW Validity flag of the channel reading
HR 9 bool bit 3 RW Validity flag of the channel reading
HR 9 bool bit 4 RW Validity flag of the channel reading
HR 9 bool bit 5 RW Validity flag of the channel reading
HR 9 bool bit 6 RW Validity flag of the channel reading
HR 9 bool bit 7 RW Validity flag of the channel reading
HR 1000 uint16 R Firmware version of the extension (raw number)
HR 1001 uint16 bits 0–7 R
HR 1001 uint16 bits 8–15 R
HR 1002 uint16 bits 0–3 R
HR 1002 uint16 bits 4–7 R
HR 1002 uint16 bits 8–15 R
HR 1003 uint16 R
HR 1004 uint16 R
HR 1005 uint32 CDAB R
HR 1008 uint16 RW ms MasterWatchDog timeout; default 5000 ms
HR 1009 uint16 R Reference voltage of the MCU (raw)
HR 1010 uint16 RW s Default 2 s
HR 1011 uint16 RW s Default 2 s
HR 1012 uint16 RW s Default 2 s
HR 1013 uint16 RW s Default 2 s
HR 1014 uint16 RW s Default 2 s
HR 1015 uint16 RW s Default 2 s
HR 1016 uint16 RW s Default 2 s
HR 1017 uint16 RW s Default 2 s
HR 1018 uint16 bits 0–12 RW Applied after saving the configuration and restarting
HR 1018 bool bit 13 RW
HR 1018 bool bit 14 RW
HR 1019 uint16 RW Slave address, 1-254; default 15
CO 1000 bool RW Clears the MWD reboot indication
CO 1002 bool RW
CO 1003 bool RW Stores the current configuration so it is used at startup

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