Siemens SIRIUS 3RW5 - Page 106

Messages and diagnostics
7.2 Function Codes
SIRIUS 3RW5 Modbus communication module
106 Equipment Manual, 03/2020, A5E43676481002A/RS-AC/003
7.2.5 Function Code 15 (Write Multiple Coils)
This function enables the writing of multiple bits from the 3RW5 bit memory area by the
Modbus TCP client system or the Modbus RTU master system.
A valid address from the bit memory area is expected as the start address. The selected
address must be designated as writable in the data tables in chapter Data tables (Page 136).
When writing several bits, they must be identified as a "writable" coherent block. A bit area
that is interrupted by read-only bits cannot be written to as a block.
Request telegram
Modbus TCP:
Address Field
Function Code
Start address
Number of bits
Number of bytes
Data
7 bytes
1 byte
2 bytes
2 bytes
1 byte
n bytes
-
0x0F
0x8200
0x0007
0x01
0x41
Modbus RTU:
Slave address
Function Code
Start address
Number of bits
Number of
bytes
Data
CRC
1 byte
1 byte
2 bytes
2 bytes
1 byte
n bytes
2 bytes
-
0x0F
0x8200
0x0007
0x01
0x41
-
Response telegram
Modbus TCP:
Address Field
Function Code
Start address
Number of bits
7 bytes
1 byte
2 bytes
2 bytes
-
0x0F
0x8200
0x0007
Modbus RTU:
Slave address
Function Code
Start address
Number of bits
CRC
1 byte
1 byte
2 bytes
2 bytes
2 bytes
-
0x0F
0x8200
0x0007
-