Definition And Format Of Read Command; Read Command Definition; Read Command Format; Request Frame Format - Huawei UPS2000 Development Manual

UPS2000-(6 kVA-20 kVA)
Modbus Protocol Development Guide

1.5.4 Definition and Format of Read Command

1.5.4.1 Read Command Definition

This command can be used to read a single or multiple registers.

1.5.4.2 Read Command Format

1.5.4.2.1 Request Frame Format

Byte
Field
Descri
ption

1.5.4.2.2 Response Frame Format

Byt
e
Fiel
d
Des
crip
tion
1.5.5 Definition and Format for the Write Single Register
Command

1.5.5.1 Definition for the Write Single Register Command

This command is used to write to a single register.
Issue 02 (2016-03-10)
0 1
ADDR CMD
Control Comma
ler nd type
address
For example, the request frame is 11 03 2A F8 00 01 0F 73.
11 is the slave device address. 03 is the read command. 2AF8 is the register address. 0001 indicates the
number of registers to be read is 1. 0F73 is the CRC checking value.
0 1 2
AD CM Len
DR D gth
Con Co Dat
troll mm a
er and leng
addr type th L
ess = n
x 2
For example, the response frame is 11 03 02 00 01 B8 47.
11 is the slave device address. 03 is the read command. 02 is the length of data to be read. 0001 indicates
the first register value to be read. B847 is the CRC checking value.
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2 3 4
MSB LSB MSB
Register starting Number of
address registers n
3 4 5 6
MS MS
LSB LSB
B B
First Second
register register
value value
1 Communication Protocol
5 6
LSB LSB
CRC checking
...
L+1 L+2 L+3
...
MS
LSB LSB
B
...
Last CRC
register checking
value
7
MSB
L+4
MS
B
16