Huawei UPS2000 - Definition and Format of Read Command; Read Command Definition; Read Command Format; Request Frame Format

UPS2000-(6 kVA-20 kVA)
Modbus Protocol Development Guide
1 Communication Protocol
Issue 02 (2016-03-10)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
16
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
0
1
2
3
4
5
6
7
Field
ADDR
CMD
MSB
LSB
MSB
LSB
LSB
MSB
Descri
ption
Control
ler
address
Comma
nd type
Register starting
address
Number of
registers n
CRC checking
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.
1.5.4.2.2 Response Frame Format
Byt
e
0
1
2
3
4
5
6
…
L+1
L+2
L+3
L+4
Fiel
d
AD
DR
CM
D
Len
gth
MS
B
LSB
MS
B
LSB
…
MS
B
LSB
LSB
MS
B
Des
crip
tion
Con
troll
er
addr
ess
Co
mm
and
type
Dat
a
leng
th L
= n
x 2
First
register
value
Second
register
value
…
Last
register
value
CRC
checking
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.
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.