SMA SUNNY TRIPOWER 60 - Data Transmission; Reading and Writing of Data

Product Description SMA Solar Technology AG
3.4.4 Data transmission
In accordance with the Modbus specification, only a specific volume of data can be transported in
a single data transmission in a simple protocol data unit (PDU). The data also contains function-
dependent parameters such as the function code, start address or number of Modbus registers to
be transmitted. The amount of data depends on the Modbus command used and has to be taken
into account during data transmission. You can find the number of possible Modbus registers per
command in Section 3.5.
With data storage in the Motorola format "Big Endian", data transmission begins with the high byte
and then the low byte of the Modbus register.
3.5 Reading and Writing of Data
The Modbus interface can be used via the protocol Modbus TCP. Using Modbus TCP enables
read- and write access (RW) to the Modbus register.
The following Modbus commands are supported by the implemented Modbus interface:
Modbus command
Hexadecimal value
Data volume
(number of registers)
1
Read Holding Registers
0x03
1 to 125
Read Input Registers
0x04
1 to 125
Write Single Register
0x06
1
Write Multiple Registers
0x10
1 to 123
Read Write Multiple Registers
0x17
Read: 1 to 125, Write: 1 to 121
1
Number of Modbus registers transferable as data block per command
12 STP60-SunSpec_Modbus-TI-en-12 Technical Information