Siemens SIMOCODE pro Function Manual page 104

Communication
2.3 Modbus communication
Function code 15 - Write Multiple Coils
Function
This function enables the Modbus master system to write several bits from the
SIMOCODE pro 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 (see the tables in Section Modbus RTU data tables
(Page 277), "Access" column).
When writing several bits, they must be marked as a "writable" coherent block. A bit area
that is interrupted by read-only bits cannot be written to as a block.
Request message frame
Slave address
1 byte
Response message frame
Slave address
1 byte
Example
Several output bits in the area of the PIQ (process image output) of the SIMOCODE pro with
slave address 16 are to be written via Modbus. Using these bits, the motor is usually
switched on and off, "Remote/Manual" mode selected, or a reset command output.
In the case shown, the motor is to be started and "Remote" mode activated for a
SIMOCODE device operated as a direct-on-line starter (see Chapter "Example circuits" in
the manual SIMOCODE pro - application examples
(https://support.industry.siemens.com/cs/ww/en/view/109743959)):
Offset
0x0001
0x0002
0x0003
0x0004
0x0005
Value to be transferred: 00010010b = 0x12
Request message frame
Slave address
1 byte
0x10
Response message frame
Slave address
1 byte
0x10
104
Function code Start address
1 byte 2 bytes
Function code Start address
1 byte 2 bytes
Meaning
Motor off
Motor on
Test function
Emergency start
Remote
Function code Start address
1 byte 2 bytes
0x0F 0x0001
Function code Start address
1 byte 2 bytes
0x0F 0x0001
Number of bits Number of bytes Data
2 bytes n bytes
Number of bits
2 bytes
State
0
1
0
0
1
Number of bits Bytes
2 bytes 1 byte
0x0005 0x01
Number of bits
2 bytes
0x0005
SIMOCODE pro - Communication
Function Manual, 11/2018, A5E40508495002A/RS-AC/003
CRC
n bytes 2 bytes
CRC
2 bytes
Data CRC
n bytes 2 bytes
0x12 0x....
CRC
2 bytes
0x....