Lumel N31U - Implemented Functions of MODBUS Protocol; Map of the Registers

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N31U User manual
5.5.3 Implemented functions of MODBUS protocol
The following functions of the MODBUS protocol have been implemented in
the N31U meters:
• 03 (03h) – readout of registers group.
• 04 (04h) – readout of input registers group.
• 06 (06h) – single register writing.
• 16 (10h) – registers group writing.
• 17 (11h) – slave device identication.
5.5.4 Map of the registers
The register map of the N31U meter is divided into separate groups of 16-bit
or 32-bit registers. Data stored in 32-bit registers are additionally available in
the format of 16-bit registers, with the value of one 32-bit register is stored in
two 16-bit registers.
The 32-bit registers store data in the oat format compliant with IEEE-754.
Bytes sequence: B3 B2 B1 B0 – the oldest byte is transmitted as the rst. The
16-bit registers representing 32-bit values in two successive registers have
been doubled in another address space with a byte sequence: B1 B0 B3 B2.
The table below shows the register map of the N31U meter. The addresses in the
table are the physical addresses. The register number should be increased by 1
when using the programs where the addresses are provided in a logical format.
Address range Value type Description
4000 – 4024 16 bits Readout and write registers - conguration registers
4200 – 4219 16 bits Readout only registers with system parameter values
7500 – 7515 32 bits (oat) Readout only registers with measuring and calculated values.
7600 – 7668 32 bits (oat) Readout and write registers - registers with conguration data.
7000 – 7030 16 bits Readout only registers. Registers store the same data as the registers 7500-7514, where
one value is stored in two successive registers.
7200 - 7335 16 bits Readout and write registers. Registers store the same data as the registers 7600-7668,
where one value is stored in two successive registers.