LSIS LSLV-S100 - Modbus-RTU Protocol

242
RS-485 Communication Features
7.3.2 Modbus-RTU Protocol
7.3.2.1 Function Code and Protocol (unit: byte)
In the following section, station ID is the value set at CM.01 (Int485 St ID), and starting address is
the communication address. (starting address size is in bytes). For more information about
communication addresses, refer to 7.4 Compatible Common Area Parameter on page 245
.
Function Code #03: Read Holding Register
Function Code #04: Read Input Register
Query Field Name
Response Field Name
Station ID
Station ID
Function(0x04) Function (0x04)
Starting Address Hi
Byte Count
Starting Address Lo
Data Hi
# of Points Hi Data Lo
# of Points Lo
…
CRC Lo …
CRC Hi
Data Hi
Data Lo
CRC Lo
CRC Hi
Query Field Name
Response Field Name
Station ID
Station ID
Function(0x03)
Function (0x03)
Starting Address Hi
Byte Count
Starting Address Lo
Data Hi
# of Points Hi
Data Lo
# of Points Lo
…
CRC Lo
…
CRC Hi
Data Hi
Data Lo
CRC Lo
CRC Hi
# number of Points
# number of Points