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  3. B23 / B24

ABB B23 / B24 Modbus register map

Three-phase DIN rail energy meters of the EQ B-series (B23 direct connected, B24 CT connected), Modbus RTU over RS485

  • Official
  • 119 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.

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Communication

Protocol
Modbus RTU
Unit ID
1
Serial
9600 8E1 · 9600 baud, 8 data bits, even parity, 1 stop bit defaults
Byte / word order
ABCD · bytes big-endian, words high first
Addresses
0-based
Max read
125 registers per request

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

Map

Registers
119 holding registers
Groups
15
Revision
3 · 2026-11-10
Added
()
File
maps/abb/b23-b24.mbmap.json · 21 KB · history
SHA-256
0c721e8b5f554b6759f86de80192eefa3b5008b0a2e694423098de5854b294d6
Manufacturer
abb.com

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
Serial number Serial number holding 35072 uint32 ABCD
Firmware Firmware version holding 35080 string[8]

Sources and notes

Source: ABB, "B23/B24 User Manual", 2CMC485003M0201 revision E (2025-11-07); https://library.abb.com/d/2CMC485003M0201

  • ABB EQ meters B23 (direct, 65 A) and B24 (CT connected) with RS485, protocol set to Modbus.
  • Addresses are exactly as sent on the bus. Readable range is 0x1000-0x8EFF; any block of 1-125 registers works.
  • Quantities a model does not have read as "invalid": all FFFF for unsigned, the largest positive value for signed.
  • Basic (steel) variants, B23/B24 1xx-xxx, only have import registers.
  • The manual does not state the factory RS485 settings; check them on the meter display.
AreaAddressNameTypeAccessUnitScaleDescription
HR 20480 uint64 ABCD R kWh ×0.01
HR 20484 uint64 ABCD R kWh ×0.01
HR 20488 int64 ABCD R kWh ×0.01 Import minus export
HR 20492 uint64 ABCD R kvarh ×0.01
HR 20496 uint64 ABCD R kvarh ×0.01
HR 20500 int64 ABCD R kvarh ×0.01
HR 20504 uint64 ABCD R kVAh ×0.01
HR 20508 uint64 ABCD R kVAh ×0.01
HR 20512 int64 ABCD R kVAh ×0.01
HR 20516 uint64 ABCD R kg ×0.001 Uses the meter's CO2 conversion factor
HR 20532 uint64 ABCD R ×0.001 Uses the currency conversion factor at 0x8CE2
HR 20848 uint64 ABCD R kWh ×0.01
HR 20852 uint64 ABCD R kWh ×0.01
HR 20856 uint64 ABCD R kWh ×0.01
HR 20860 uint64 ABCD R kWh ×0.01
HR 20880 uint64 ABCD R kWh ×0.01
HR 20884 uint64 ABCD R kWh ×0.01
HR 20888 uint64 ABCD R kWh ×0.01
HR 20892 uint64 ABCD R kWh ×0.01
HR 20912 uint64 ABCD R kvarh ×0.01
HR 20916 uint64 ABCD R kvarh ×0.01
HR 20920 uint64 ABCD R kvarh ×0.01
HR 20924 uint64 ABCD R kvarh ×0.01
HR 20944 uint64 ABCD R kvarh ×0.01
HR 20948 uint64 ABCD R kvarh ×0.01
HR 20952 uint64 ABCD R kvarh ×0.01
HR 20956 uint64 ABCD R kvarh ×0.01
HR 21600 uint64 ABCD R kWh ×0.01
HR 21604 uint64 ABCD R kWh ×0.01
HR 21608 uint64 ABCD R kWh ×0.01
HR 21612 uint64 ABCD R kWh ×0.01
HR 21616 uint64 ABCD R kWh ×0.01
HR 21620 uint64 ABCD R kWh ×0.01
HR 21624 int64 ABCD R kWh ×0.01
HR 21628 int64 ABCD R kWh ×0.01
HR 21632 int64 ABCD R kWh ×0.01
HR 21636 uint64 ABCD R kvarh ×0.01
HR 21640 uint64 ABCD R kvarh ×0.01
HR 21644 uint64 ABCD R kvarh ×0.01
HR 21648 uint64 ABCD R kvarh ×0.01
HR 21652 uint64 ABCD R kvarh ×0.01
HR 21656 uint64 ABCD R kvarh ×0.01
HR 21660 int64 ABCD R kvarh ×0.01
HR 21664 int64 ABCD R kvarh ×0.01
HR 21668 int64 ABCD R kvarh ×0.01
HR 21672 uint64 ABCD R kVAh ×0.01
HR 21676 uint64 ABCD R kVAh ×0.01
HR 21680 uint64 ABCD R kVAh ×0.01
HR 21684 uint64 ABCD R kVAh ×0.01
HR 21688 uint64 ABCD R kVAh ×0.01
HR 21692 uint64 ABCD R kVAh ×0.01
HR 21696 int64 ABCD R kVAh ×0.01
HR 21700 int64 ABCD R kVAh ×0.01
HR 21704 int64 ABCD R kVAh ×0.01
HR 21804 uint64 ABCD R kWh ×0.01
HR 21808 uint64 ABCD R kWh ×0.01
HR 21812 uint64 ABCD R kvarh ×0.01 The manual's table gives kWh; kvarh assumed
HR 21816 uint64 ABCD R kvarh ×0.01 The manual's table gives kWh; kvarh assumed
HR 23296 uint32 ABCD R V ×0.1
HR 23298 uint32 ABCD R V ×0.1
HR 23300 uint32 ABCD R V ×0.1
HR 23302 uint32 ABCD R V ×0.1
HR 23304 uint32 ABCD R V ×0.1
HR 23306 uint32 ABCD R V ×0.1
HR 23308 uint32 ABCD R A ×0.01
HR 23310 uint32 ABCD R A ×0.01
HR 23312 uint32 ABCD R A ×0.01
HR 23314 uint32 ABCD R A ×0.01
HR 23316 int32 ABCD R W ×0.01 Limited to about ±21 MW; use the DMTME block above that
HR 23318 int32 ABCD R W ×0.01
HR 23320 int32 ABCD R W ×0.01
HR 23322 int32 ABCD R W ×0.01
HR 23324 int32 ABCD R var ×0.01
HR 23326 int32 ABCD R var ×0.01
HR 23328 int32 ABCD R var ×0.01
HR 23330 int32 ABCD R var ×0.01
HR 23332 int32 ABCD R VA ×0.01
HR 23334 int32 ABCD R VA ×0.01
HR 23336 int32 ABCD R VA ×0.01
HR 23338 int32 ABCD R VA ×0.01
HR 23340 uint16 R Hz ×0.01
HR 23341 int16 R ° ×0.1 -180 to +180
HR 23342 int16 R ° ×0.1
HR 23343 int16 R ° ×0.1
HR 23344 int16 R ° ×0.1
HR 23345 int16 R ° ×0.1
HR 23346 int16 R ° ×0.1
HR 23347 int16 R ° ×0.1
HR 23351 int16 R ° ×0.1
HR 23352 int16 R ° ×0.1
HR 23353 int16 R ° ×0.1
HR 23354 int16 R ×0.001
HR 23355 int16 R ×0.001
HR 23356 int16 R ×0.001
HR 23357 int16 R ×0.001
HR 23358 uint16 R 1-4
HR 23359 uint16 R 1-4
HR 23360 uint16 R 1-4
HR 23361 uint16 R 1-4
HR 4142 uint32 ABCD R W No decimals; for powers above ±21 MW

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