Hitachi L700 SERIES Instruction Manual page 177

The formats of the query and response frames are described below.
Message configuration: Query
(i) Slave address
The slave address is a number 1 to 32 that is assigned to the inverter (slave) beforehand. (A query is
received by the inverter having the same slave address as that specified in the query.)
The query with the slave address set to "0" is broadcasted to all the connected inverters.
With a broadcast query, the master system can neither read inverter data nor perform a loopback test.
(ii) Data
The data contains a functional instruction.
The L700 series inverter supports the following Modbus data format:
Data name
Coil data
Register data
(iii) Function code
The function code specifies the function to be executed by the inverter.
The table below lists the function codes supported by the L700 series inverter.
Function codes
Function code
01h Reads the coil status.
03h Reads registers.
05h Writes data to a coil.
06h Writes data to a register.
08h Performs a loopback test.
0Fh Writes data to multiple coils.
10h Writes data to multiple registers.
Header (silent interval)
Slave address
Function code
Data
Error check code
Trailer (silent interval)
1-bit binary data that can be referenced and changed
16-bit data that can be referenced and changed
Function
4 - 115
Chapter 4 Explanation of Functions
Description
Maximum number of data
bytes in a message
4
8
2
2
-
4
8
Maximum data count in a
message
32 coils (in units of bit)
4 registers (in units of byte)
1 coil (in units of bit)
1 register (in units of byte)
32 coils (in units of bit)
4 registers (in units of byte)