Function Code 15 (Write Multiple Coils) - Siemens SIRIUS 3RW5 series Manual

7.2.5

Function Code 15 (Write Multiple Coils)

This function enables the Modbus client system to write several bits from the 3RW5 bit
memory area.
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 75).
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
Address Field Function Code
7 bytes 1 byte
- 0x0F
Response telegram
Address Field
7 bytes
-
Example
Setting the bit addresses of the "Motor CW" and "Creep speed" commands to a logical one:
● Address field: The address of the 3RW5 soft starter is not entered in the example (-).
● The bit addresses of the commands are:
– "Motor CW": 0x8200
– "Creep speed": 0x8206
● The remaining bits of the byte are controlled with a logical zero (0x41).
You will find the data table for the process image output in chapter Process image output
(PIQ) (Page 81).
SIRIUS 3RW5 Modbus TCP communication module
Manual, 03/2018, A5E43676481002A/RS-AA/001
Start address Number of bits
2 bytes 2 bytes
0x8200 0x0007
Function Code
1 byte
0x0F
Messages and diagnostics
Number of bytes
1 byte
0x01
Start address
2 bytes
0x8200
7.2 Function Codes
Data
n bytes
0x41
Number of bits
2 bytes
0x0007
57