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16 | WECM / Emerald eZA Manual
8. Setting serial configuration
Step 1: Firstly establish Modbus communication between slave inverter and master:
Step 2: Writing Register 0x0008 and 0x0009 according to Table 7 and Table 8, other values are invalid;
Step 3: Writing “0x0001” into Register 0x000A to enable new serial configuration as Step 2;
Step 4: After Step 3, Master with original configuration will losses communication with slaver, then master needs to
change to new serial configuration, rebuild the communication with slaver.
Using function code 16 to execute the serial configuration.
For example, use function code 16 to set serial configuration as below:
Baud rate: 38400 bits/s (0x9600)
Start bit: 1 bit
Data bits: 8 bits
Parity: odd
Stop: 1 bit
Modbus address is 0x55, function code is 0x10(16), initial register address is 0x0008, register quantity is 0x0003, bytes
quantity is 0x06 (3 x 2), baud rate is 0x9600(38400), ‘Parity and Stop’ parameter is 0x0002, and enable the parameters
setting 0x000A with 0x0001, CRC16 is 0xD488.
The master send format:
T-> (13:33:31:103) 55 10 00 08 00 03 06 96 00 00 02 00 01 D4 88 10
The slaver responses format:
R<-(13:33:31:114) 55 10 00 08 00 03 0C 1E
When slaver responses, it means setting successfully.
9. Modbus command and address
01 Request Frame
Slaver Address
(1 byte)
0x01
(function code)
Register Address
(2 bytes)
0x0001
(2 bytes)
CRC
(2 bytes)
01 Answer
Slaver Address
(1 byte)
0x01
(function code)
Register Number
(1 byte)
Data
(1 byte)
CRC
(2 bytes)
03 Read Frame
Slaver Address
(1 byte)
0x03
(function code)
Register Start Address
(2 bytes)
Register Numbers N
(2 bytes)
CRC
(2 bytes)
03 Answer
Slaver Address
(1 byte)
0x01
(function code)
Register Numbers
N*2
(1 byte)
Request Data1
(2 bytes)
……
(datas)
Request Data N
(2 bytes)
CRC
(2 bytes)
06 Write Frame
Slaver Address
(1 byte)
0x06
(function code)
Register Address
(2 bytes)
Write content
(2 bytes)
CRC
(2 bytes)
06 Answer
Slaver Address
(1 byte)
0x06
(function code)
Register Address
(2 bytes)
Write content
(2 bytes)
CRC
(2 bytes)
16 Write Frame
Slaver Address
(1 byte)
0x10
(function code)
Register start
Address
(2 bytes)
Registers number
N
(2 bytes)
Registers byte
number N*2
(1 byte)
Write content 1
(2 bytes)
Write content N
(2 bytes)
CRC
(2 bytes)
16 Answer
Slaver Address
(1 byte)
0x10
(function code)
Register start Address
(2 bytes)
Register number N
(2 bytes)
CRC
(2 bytes)
Figure 17 - Modbus command and address
