Siemens SIRIUS 3RW5 - Page 101

Messages and diagnostics
7.2 Function Codes
SIRIUS 3RW5 Modbus communication module
Equipment Manual, 03/2020, A5E43676481002A/RS-AC/003
101
Example
Reading in bypass operation mode "internal bypass" (Operation / bypass active):
● Address Field or slave address: The address of the 3RW5 soft starter is not entered in
the example (-).
● The CRC CHECK is not entered in the example (-).
● The bit address of "Operation / bypass active" is 0x84EF.
● As feedback, the status "Operation / bypass active" is returned with a logical one (0x01).
The remaining following bits of the transmitted byte are filled with zeros.
You will find the data table for the soft starter diagnostics in chapter Soft starter diagnostics
(Page 152).
7.2.2 Function Codes 03 (Read Holding Registers) and 04 (Read Input Registers)
These functions enable the Modbus TCP client system or the Modbus RTU master system to
read registers from the 3RW5 register memory area.
Function Codes 03 and 04 behave in the same way here and supply an identical feedback
signal. A valid offset from the register memory area is expected as the start address. Up to
125 registers per telegram can be read.
Request telegram
Modbus TCP:
Address Field
Function Code
Start address
Number of registers
7 bytes
1 byte
2 bytes
2 bytes
-
0x03
0x880F
0x0006
Modbus RTU:
Slave address
Function Code
Start address
Number of
registers
CRC
1 byte
1 byte
2 bytes
2 bytes
2 bytes
- 0x03 0x880F 0x0006 -