Huawei UPS2000 Series User manual

UPS2000-(6 kVA-20 kVA)
Modbus Protocol Development
Guide
Issue
02
Date
2016-03-10
HUAWEI TECHNOLOGIES CO., LTD.

Issue 02 (2016-03-10)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
i
Copyright © Huawei Technologies Co., Ltd. 2016. All rights reserved.
No part of this document may be reproduced or transmitted in any form or by any means without prior
written consent of Huawei Technologies Co., Ltd.
Trademarks and Permissions
and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.
All other trademarks and trade names mentioned in this document are the property of their respective
holders.
Notice
The purchased products, services and features are stipulated by the contract made between Huawei and
the customer. All or part of the products, services and features described in this document may not be
within the purchase scope or the usage scope. Unless otherwise specified in the contract, all statements,
information, and recommendations in this document are provided "AS IS" without warranties, guarantees or
representations of any kind, either express or implied.
The information in this document is subject to change without notice. Every effort has been made in the
preparation of this document to ensure accuracy of the contents, but all statements, information, and
recommendations in this document do not constitute a warranty of any kind, express or implied.
Huawei Technologies Co., Ltd.
Address:
Huawei Industrial Base
Bantian, Longgang
Shenzhen 518129
People's Republic of China
Website:
http://e.huawei.com

UPS2000-(6 kVA-20 kVA)
Modbus Protocol Development Guide
About This Document
Issue 02 (2016-03-10)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
ii
About This Document
Overview
This document describes the Modbus protocol used between the RMS-MODBUS01Acard, an
optional component of the UPS2000-(6 kVA-20 kVA), and its host and provides examples of
communication establishment processes.
Intended Audience
This document is intended for:
Technical support engineers
Maintenance engineers
Users
Symbol Conventions
The symbols that may be found in this document are defined as follows.
Symbol
Description
Indicates an imminently hazardous situation which, if not
avoided, will result in death or serious injury.
Indicates a potentially hazardous situation which, if not
avoided, could result in death or serious injury.
Indicates a potentially hazardous situation which, if not
avoided, may result in minor or moderate injury.
Indicates a potentially hazardous situation which, if not
avoided, could result in equipment damage, data loss,
performance deterioration, or unanticipated results.
NOTICE is used to address practices not related to personal
injury.
Calls attention to important information, best practices and
tips.
NOTE is used to address information not related to personal

UPS2000-(6 kVA-20 kVA)
Modbus Protocol Development Guide
About This Document
Issue 02 (2016-03-10)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
iii
Symbol
Description
injury, equipment damage, and environment deterioration.
Change History
Changes between document issues are cumulative. The latest document issue contains all the
changes made in earlier issues.
Issue 02 (2016-03-10)
The product type UPS2000A was added. The collection signal and alarm signal lists were
updated. The examples of communication processes with the host were changed.
Issue 01 (2015-07-14)
This issue is the first release.

UPS2000-(6 kVA-20 kVA)
Modbus Protocol Development Guide
Contents
Issue 02 (2016-03-10)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
iv
Contents
About This Document.................................................................................................................... ii
1 Communication Protocol.............................................................................................................1
1.1 Protocol Description.....................................................................................................................................................1
1.2 Glossary........................................................................................................................................................................1
1.3 Physical Interface..........................................................................................................................................................2
1.3.1 Serial Communication Electrical Standards...............................................................................................................2
1.3.2 Data Transmission Speed...........................................................................................................................................2
1.3.3 Cable Connection.......................................................................................................................................................2
1.4 Communication Mode at the Physical Layer................................................................................................................8
1.5 Command Type and Format at the Application Layer ..................................................................................................9
1.5.1 Function Code List ....................................................................................................................................................9
1.5.2 CRC Checking Algorithm..........................................................................................................................................9
1.5.3 Definition and Format for the Read Device Identifier Command ...........................................................................10
1.5.3.1 Frame Format........................................................................................................................................................10
1.5.3.2 Command Definition ............................................................................................................................................10
1.5.3.3 Frame Format Examples.......................................................................................................................................13
1.5.3.4 Query Device Identification Information Command ............................................................................................15
1.5.3.4.1 Request Frame Format.......................................................................................................................................15
1.5.3.4.2 Response Frame Format ....................................................................................................................................15
1.5.4 Definition and Format of Read Command...............................................................................................................16
1.5.4.1 Read Command Definition ...................................................................................................................................16
1.5.4.2 Read Command Format........................................................................................................................................16
1.5.4.2.1 Request Frame Format.......................................................................................................................................16
1.5.4.2.2 Response Frame Format ....................................................................................................................................16
1.5.5 Definition and Format for the Write Single Register Command .............................................................................16
1.5.5.1 Definition for the Write Single Register Command..............................................................................................16
1.5.5.2 Format for the Write Single Register Command...................................................................................................17
1.5.5.2.1 Request Frame Format.......................................................................................................................................17
1.5.5.2.2 Response Frame Format ....................................................................................................................................17
2 Modbus Card Signal List...........................................................................................................18
2.1 Collection and Configuration......................................................................................................................................18
2.1.1 Signal List Description ............................................................................................................................................18

UPS2000-(6 kVA-20 kVA)
Modbus Protocol Development Guide
Contents
Issue 02 (2016-03-10)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
v
2.1.2 Collection Signal List ..............................................................................................................................................18
2.1.3 Configuration and Control Signal List.....................................................................................................................25
2.2 Alarms.........................................................................................................................................................................28
2.2.1 Signal List Description ............................................................................................................................................28
2.2.2 Alarm Signal List.....................................................................................................................................................28
3 Examples for the Host Communication Process ...................................................................34
A Acronyms and Abbreviations..................................................................................................37

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.
1
1 Communication Protocol
1.1 Protocol Description
This section describes the Modbus protocol used between the RMS-MODBUS01A card and
its host for command control and data exchange.
The specified functions of the Modbus protocol are:
1. The host sends a read device identifier command to obtain the UPS information.
2. The host sends a read command to obtain the specified UPS information.
3. The host sends a write command to set the relevant parameters and control actions.
The host is the master device. The information exchange is done by a request and response
method. The information and parameters of the slave devices are stored in the target registers.
The host executes the read or write command by accessing the registers. This protocol
supports one host networked with multiple slave devices. The slave devices are distinguished
by address. The address setting range is from 1 to 247. Different slave nodes correspond to
different addresses. The slave nodes connected to the same communication bus must not have
the same address.
1.2 Glossary
Master node: runs in the background and is responsible for communicating with slave nodes.
It is also the upper computer.
Slave node: in this guide, it is the RMS-MODBUS01A card. It collects information from the
UPS power modules, and is used for responding to the master node.
RS485: a serial communication standard, and supports the half-duplex serial short-range
communication.
Read device identifier command: the command is sent from the master node to the slave
nodes, and the slave nodes return the relevant UPS information.
Read command: the command is sent from the master node to the slave nodes, and the slave
nodes return the relevant register content.
Write command: the relevant parameters are packed at the master node and sent to the slave
nodes to finish the parameter setting.

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.
2
Register address: Every signal or parameter of the slave devices corresponds to an address.
The host obtains the relevant information or sets the relevant parameters. These processes are
completed by accessing these register addresses.
Slave node address: this address is the RMS-MODBUS01Acard address, set by the dual
in-line package (DIP) switch. The range is from 1 to 247.
1.3 Physical Interface
1.3.1 Serial Communication Electrical Standards
The slave nodes communicate with the master node through the RS485 or RS232 serial ports.
Information transmission method:
1. Use the RTU transmission mode of the Modbus.
2. The transmission mode for the character information is asynchronous mode using a
frame format of one start bit, eight data bits (information byte), and one stop bit. (10 bits
in total.)
1.3.2 Data Transmission Speed
The data transmission baud rate is fixed at 9600 bit/s.
When connecting to a network management system (NMS), use an RS485/232 converter with the
isolation function. Ahot-swap RS485/232 converter is not recommended.
1.3.3 Cable Connection
Step 1 Set a hardware address for the Modbus card.
The hardware address is set over S2 (RS485 address DIP switch) shown in Figure 1-1. As
shown in Figure 1-2, the address contains eight digits. If a toggle switch is set to ON, it stands
for 0. If a toggle switch is set to OFF, it stands for 1.

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.
3
Figure 1-1 DIP switch
Figure 1-2 Describes the address DIP switch S2
You can use the binary method to set the DIP switch. Table 1-1 lists the mapping between
addresses and toggle switches.
Table 1-1 Mapping between addresses andtoggle switches
Addre
ss
Toggle
Switch
1
Toggle
Switch
2
Toggle
Switch
3
Toggle
Switch
4
Toggle
Switch
5
Toggle
Switch
6
Toggle
Switch
7
Toggle
Switch
8
1
OFF
ON
ON
ON
ON
ON
ON
ON
2
ON
OFF
ON
ON
ON
ON
ON
ON
3
OFF
OFF
ON
ON
ON
ON
ON
ON
4
ON
ON
OFF
ON
ON
ON
ON
ON
5
OFF
ON
OFF
ON
ON
ON
ON
ON
6
ON
OFF
OFF
ON
ON
ON
ON
ON
7
OFF
OFF
OFF
ON
ON
ON
ON
ON

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.
4
Addre
ss
Toggle
Switch
1
Toggle
Switch
2
Toggle
Switch
3
Toggle
Switch
4
Toggle
Switch
5
Toggle
Switch
6
Toggle
Switch
7
Toggle
Switch
8
8
ON
ON
ON
OFF
ON
ON
ON
ON
9
OFF
ON
ON
OFF
ON
ON
ON
ON
10
ON
OFF
ON
OFF
ON
ON
ON
ON
11
OFF
OFF
ON
OFF
ON
ON
ON
ON
12
ON
ON
OFF
OFF
ON
ON
ON
ON
13
OFF
ON
OFF
OFF
ON
ON
ON
ON
14
ON
OFF
OFF
OFF
ON
ON
ON
ON
15
OFF
OFF
OFF
OFF
ON
ON
ON
ON
16
ON
ON
ON
ON
OFF
ON
ON
ON
17
OFF
ON
ON
ON
OFF
ON
ON
ON
18
ON
OFF
ON
ON
OFF
ON
ON
ON
19
OFF
OFF
ON
ON
OFF
ON
ON
ON
20
ON
ON
OFF
ON
OFF
ON
ON
ON
21
OFF
ON
OFF
ON
OFF
ON
ON
ON
22
ON
OFF
OFF
ON
OFF
ON
ON
ON
23
OFF
OFF
OFF
ON
OFF
ON
ON
ON
24
ON
ON
ON
OFF
OFF
ON
ON
ON
25
OFF
ON
ON
OFF
OFF
ON
ON
ON
26
ON
OFF
ON
OFF
OFF
ON
ON
ON
27
OFF
OFF
ON
OFF
OFF
ON
ON
ON
28
ON
ON
OFF
OFF
OFF
ON
ON
ON
29
OFF
ON
OFF
OFF
OFF
ON
ON
ON
30
ON
OFF
OFF
OFF
OFF
ON
ON
ON
31
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
32
ON
ON
ON
ON
ON
OFF
ON
ON
Table 1-1 provides the methods for setting 1–32 addresses. You can follow binary DIP switch setting
rules to set 33–247 addresses.
Step 2 Set the communication form for the Modbus card.

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.
5
Set toggle 4 to ON, as shown in Figure 1-3. This indicates that the Modbus protocol is
enabled. If both toggles 5 and 6 are set to ON, it indicates a two-wire system. If both of them
are set to OFF, it indicates a four-wire system.
Figure 1-3 Functional DIP switch S1
Table 1-2 Description of the functional DIP switch S1
Toggle Switch
Definition
Settings
Remarks
1
Reserved
ON: 0
OFF: 1
Toggle switches 1, 2, and 3 are
used together to set a 3-bit baud
rate.
Currently, the software version
supports only a baud rate of 9600
bits/s (in this case, toggle switches
1, 2, and 3 are ON).
2
Reserved
ON: 0
OFF: 1
3
Reserved
ON: 0
OFF: 1
4
RS485
protocol toggle
switch
ON: 0
OFF: 1
0: Modbus protocol
5
Toggle switch
for selecting a
two-wire or
four-wire
system
ON: two-wire
system
OFF: four-wire
system
Toggle switches 5 and 6 must be
both ON or both OFF.
6
Toggle switch
for selecting a
two-wire or
four-wire
system
7
Control area
network
(CAN)
build-out
resistor toggle
switch
ON: match
OFF: no match
None
8
RS485
build-out
ON: match
OFF: no match
None

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.
6
Toggle Switch
Definition
Settings
Remarks
resistor toggle
switch
If the RS485 build-out resistor toggle switch is set to ON, it indicates that there is a build-out resistor.
Set the toggle switch as required.
Step 3 Insert the Modbus card into the extended card slot of the UPS, and tighten the screws, as
shown in Figure 1-4.
Figure 1-4 Inserting the Modbus card into the optionalcard slot
Step 4 Set up a network, as shown in Figure 1-5.
1. Connect the COM_1 port (the COM_2 port is used for cascading) on the Modbus card to
the RS485 port on the RS232-RS485 adapter over a network cable (a shielded twisted
pair is recommended) that meets pin sequence requirements.
2. Connect the RS232 port on the RS232-RS485 adapter to the RS232 port on the PC over
a network cable (a shielded twisted pair is recommended) that meets pin sequence
requirements.
Connecting cables for the Modbus card.

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.
7
Figure 1-5 Connecting cables for the Modbus card
Figure 1-6 shows the RJ45 port pins. For port pin definitions and cable connections, see Table
1-3.
Figure 1-6 RJ45 ports
Table 1-3 Pinson an RJ45 port
Pin
No.
Signal
Corresponding Signal of RS232-RS485
Adapter
Two-wire system
Four-wire system
1
Four-wire system: RS485 TX+
Two-wire system: A
A
RS485 RX+
2
Four-wire system: RS485 TX–
Two-wire system: B
B
RS485 RX-
3
None
N/A
N/A
4
Four-wire system: RS485 RX+
N/A
RS485 TX+
5
Four-wire system: RS485 RX–
N/A
RS485 TX–
6
GND
N/A
N/A

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.
8
Pin
No.
Signal
Corresponding Signal of RS232-RS485
Adapter
Two-wire system
Four-wire system
7
None
N/A
N/A
8
None
N/A
N/A
----End
1.4 Communication Mode at the Physical Layer
After the slave nodes are powered on or reset, and run steadily, the slave nodes respond to the
read or write commands. When the slave nodes receive the relevant command, the slave
nodes return the queried information to the master node under normal conditions. Under
abnormal conditions, the slave nodes return the specific error codes corresponding to the error
types.
Table 1-4 lists the error codes.
Table 1-4 Error code list
No.
Name
Description
0x01
Invalid function code
Slave nodes received
unsupported or incorrect
function codes.
0x02
Invalid parameter
Slave nodes received invalid
function code parameters.
0x03
Invalid data
Slave nodes received invalid
data such as CRC checking
error.
0x04
Slave node execution failed
Slave nodes failed to
respond to the command.
0x05
Reload the start command
Slave nodes are busy.

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.
9
1.5 Command Type and Format at the Application Layer
1.5.1 Function Code List
Function Code
Meaning
Remarks
0x03
Read command
Continuously read a single
or multiple registers.
0x06
Write single register
command
Write commands to a single
register.
0x2B
Read device identifier
command
N/A
1.5.2 CRC Checking Algorithm
unsigned short count_CRC(unsigned char *addr, int num)
{
unsigned short CRC = 0xFFFF;
int i;
while (num--)
{
CRC ^= *addr++;
for (i = 0; i < 8; i++)
{
if (CRC & 1)
{
CRC >>= 1;
CRC ^= 0xA001;
}
else
{
CRC >>= 1;
}
}
}
return CRC;
}

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.
10
1.5.3 Definition and Format for the Read Device Identifier
Command
1.5.3.1 Frame Format
Command frame:
Byte
0
1
2
3
4
5
6
Field
ADDR
CMD
MEI
ReadDev
ID
Target ID
LSB
MSB
Desc
ripti
on
Controlle
r address
Functio
n code
MEI
type
ReadDev
ID
Object
ID
CRC checking
Response frame:
The response frame is not fixed. The frame depends on the object ID.
1.5.3.2 Command Definition
This command code allows reading identifiers and added packages that are relevant to the
physical and function description of the remote devices.
Simulate the port of the read device identifier as an address space. This address space consists
of a set of addressable data elements. The data elements are objects to be read, and the object
IDs determine these data elements.
A data element consists of three elements:
Basic device identifier:All objects are mandatory such as the manufacturer name,
product code, and revision version.
Normal device identifier: Except the basic data objects, the device provides additional
and optional identifiers and data object description. Define all types of objects according
to standard definitions, but the execution of this type of objects is optional.
Extension device identifier: Except the basic data objects, the device provides additional
and optional identifiers and special data object description. All these data are related to
the device.
Object ID
Object Name
or
Description
Type
Mandatory or
Optional
(M/O)
Category
0x00
Manufacturer
name
ASCII character
string
M
Basic
0x01
Product code
ASCII character
string
M
0x02
Main revision
version
ASCII character
string
M
0x03-0x7F
N/A
N/A
N/A
Normal

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.
11
Object ID
Object Name
or
Description
Type
Mandatory or
Optional
(M/O)
Category
0x80-0xFF
N/A
N/A
N/A
Extension
Request PDU:
Function Code
1 byte
0x2B
MEI Type
1 byte
0x0E
ReadDevID Code
1 byte
0x01/0x02/0x03/0x04
Object ID
1 byte
0x00 to 0xFF
Request parameter description:
Function code: 43 (decimal), 0x2B (hexadecimal).
MEI type: The MEI type of 14 (0x0E) assigned to the device identifier port.
The ReadDevID has four access types:
−0x01: request to obtain the basic device identifier (stream access)
−0x02: request to obtain the normal device identifier (stream access)
−0x03: request to obtain the extension device identifier (stream access)
−0x04: request to obtain the special device identifier (special access)
If the identifier data is not suitable for individual responses, you can require several request
and response transactions. The object ID byte provides the first identifier code obtained. For
the first transaction, the client must set the object ID to 0x00 to obtain the start of the device
identifier data. For the subsequent transactions, the client must set the object ID to the value
returned by the previous responded server.
If the object ID does not match any known object, the server points to the object numbered
0x00 (from the start).
For single access, the ReadDevID code is 0x04. The object ID in the requesting process
provides the obtained object identifier code.
If the object ID does not match any known object, the server returns an abnormal code
numbered 0x02 (invalid data address).
Response PDU:
Function Code
1 byte
0x2B
MEI Type
1 byte
0x0E
ReadDevID Code
1 byte
0x01/0x02/0x03/0x04
Consistency Level
1 byte
N/A
More
1 byte
0x00/0xFF

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.
12
Next Object ID
1 byte
Object ID number
Object Number
1 byte
N/A
Object ID List
1 byte
N/A
Object Length
1 byte
N/A
Object Value
1 byte
N/A
Response parameter description:
Function code: 43 (decimal), 0x2B (hexadecimal).
MEI type: The MEI type of 14 (0x0E) assigned to the device identifier port.
ReadDevID code: same as the request ReadDevID, 0x01, 0x02, 0x03, or 0x04.
Consistency level: The consistency level for the device identifiers and types of supported
accesses.
−0x01: basic identifier code (stream access only)
−0x02: normal identifier code (stream access only)
−0x03: extension identifier code (stream access only)
−0x81: basic identifier code (stream access and single access)
−0x82: normal identifier code (stream access and single access)
−0x83: extension identifier code (stream access and single access)
More: If the identifier code is 0x01, 0x02, or 0x03 (stream access) and the identifier data
does not match the single response, you can require several request and response
transactions.
−0x00: The object is no longer usable
−0xFF: Other identifier objects are usable, and more Modbus transactions are
required
For the ReadDevID code 0x04 (single access), this field must be set to 0x00.
Next object ID: If more is 0xFF, require the next object identifier code. If more is 0x00,
set to 0x00 (unused).
Object number: returned object identifier number in the response process.
For single access, the object number is 0x01.
Object 0.ID: the first object identifier code (stream access) or requested object identifier
code (single access) returned by the PDU.
Object 0.length: the byte length of the first object.
Object 0.value: the value of the first object (the byte of the object 0.length).
…
Object N.ID: the last object identifier code in the response process.
Object N.length: the byte length of the last object.
Object N.value: the value of the last object (the byte of the object N.length).
Abnormal response PDU:
Function Code
1 byte
0xAB

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.
13
Exception Code
2 byte
N/A
1.5.3.3 Frame Format Examples
The following are some request examples of the read device identifiers of the basic device
identifiers:
In this example, all objects are returned to one response PDU.
Request
Response
Domain
Value
Domain
Value
Function Code
0x2B
Function Code
0x2B
MEI Type
0x0E
MEI Type
0x0E
ReadDevID Code
0x01
ReadDevID code
0x01
Object ID
0x00
Consistency Level
0x01
More
0x00
Next Object ID
0x00
Object Number
0x03
Object ID
0x00
Object Length
0x16
Object Value
"Company
identifier"
Object ID
0x01
Object Length
0x0A
Object Value
"Product code"
Object ID
0x02
Object Length
0x05
Object Value
"V2.11"
If one device needs several transactions to process responses, execute the following
transactions.
First transaction:
Request
Response
Domain
Value
Domain
Value
Function Code
0x2B
Function Code
0x2B

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.
14
Request
Response
MEI Type
0x0E
MEI Type
0x0E
ReadDevID Code
0x01
ReadDevID code
0x01
Object ID
0x00
Consistency Level
0x01
More
0xFF
Next Object ID
0x02
Object Number
0x03
Object ID
0x00
Object Length
0x16
Object Value
"Company
identifier"
Object ID
0x01
Object Length
0x1A
Object Value
"Product code"
Second transaction:
Request
Response
Domain
Value
Domain
Value
Function Code
0x2B
Function Code
0x2B
MEI Type
0x0E
MEI Type
0x0E
ReadDevID Code
0x01
ReadDevID code
0x01
Object ID
0x02
Consistency Level
0x01
More
0x00
Next Object ID
0x00
Object Number
0x03
Object ID
0x02
Object Length
0x05
Object Value
"V2.11"