Siemens SIRIUS 3RW5 - Function Codes

Messages and diagnostics
7.2 Function Codes
SIRIUS 3RW5 Modbus communication module
98 Equipment Manual, 03/2020, A5E43676481002A/RS-AC/003
7.2 Function Codes
The Function Code defines the meaning of the telegram and defines the telegram structure.
Overview of the Function Codes
Function Code (decimal/hexadecimal)
Designation according to Modbus specification
01 / 0x01 (Page 100)
Read Coils
02 / 0x02 (Page 100)
Read Discrete Inputs
03 / 0x03 (Page 101)
Read Holding Registers
04 / 0x04 (Page 101) Read Input Registers
05 / 0x05 (Page 103)
Write Single Coil
06 / 0x06 (Page 105)
Write Single Register
15 / 0x0F (Page 106)
Write Multiple Coils
16 / 0x10 (Page 108)
Write Multiple Registers
23 / 0x17 (Page 110)
Read/Write Multiple Registers
Access to memory areas
Two memory areas are used in the 3RW5 Soft Starter:
● A memory area for addressing the bit information
● A memory area for addressing the register information
The Function Codes for bit information (01, 02, 05, 15) thus always access the bit memory
area. The Function Codes for register information (03, 04, 06, 16, 23) always access the
register memory area.
Whether information is read-only (r) or read/writeable (r/w) is stated in the data tables in
chapter Data tables (Page 136).