Modbus Communication; Supported Modbus Function Codes; Modbus Communication Protocol - Delta DPM-C510 Operation Manual

Multi-functional power meter

M u l ti- func tio na l Power M e ter D PM -C51 0 Ope ra tion Man ua l

5.2 Modbus Communication

5.2.1

Function

Code

0x03

Read Holding Registers

0x06

Preset Single Registers

0x10

Preset Multiple Registers

When the protocol is Modbus RTU, the maximum address to be gathered with a single Modbus block read is 50

for function code 0x3, and the maximum address is 49 for function code 0x10. The function code 0xFE can be

used only when the protocol is Modbus RTU.

5.2.2

Modbus RTU mode is adopted with Modbus Master sending out the Request, in which the Function Code uses

0x03 to request response from Slave to correspond to values in Modbus address. In Response, Modbus Slave

responds to the values of Modbus address in the Master request. The packet format of IEEE754 is used for the

address of floating point numbers that corresponds to the register values found in table 5.2, using 2's

complement packet format. The format are as follows:

The packet formats (2's complement) for the address of integers that corresponds to the register values found

in table 5.2 are shown in the example below.

5 - 6

Modbus Name

Low Word

High Byte Low Byte

Description

Read the contents of read location

Preset the contents of written location

Preset the contents of written loacations

High Word

High Byte Low Byte

Read：

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