Siemens SINAMICS V20 Operating Instructions Manual page 171

FC6 - Write Single Register
When a message with FC = 0x06 is received, then 4 bytes of data are expected, that is, FC6
has 4 bytes of data:
● 2 bytes for the starting address of register
● 2 bytes for the register value
Byte 1 Byte 2
Address FC (0x06)
Inverter response
Byte 1 Byte 2
Address FC (0x06)
FC16 - Write Multiple Registers
When a message with FC = 0x10 is received, then 5 + N bytes of data are expected, that is,
FC16 has 5 + N bytes of data:
● 2 bytes for the starting address of register
● 2 bytes for the number of registers
● 1 byte for the byte count
● N bytes for the register values
Byte 1 Byte 2 Byte 3
Address FC Start address
(0x10)
High
Inverter response
Byte 1 Byte 2
Address FC (0x10)
SINAMICS V20 Inverter
Operating Instructions, 11/2016, A5E34559884-006
Byte 3 Byte 4
Start address
High Low
Byte 3 Byte 4
Start address
High Low
Byte 4 Byte 5 Byte 6
Number of regis-
ters
Low High Low
Byte 3 Byte 4
Start address
High Low
Byte 5 Byte 6
New register value
High Low
Byte 5 Byte 6
New register value
High Low
Byte 7 ... Byte N -
1
Number ... Register N value
of bytes
High
Byte 5 Byte 6
Number of registers
High Low
Communicating with the PLC
7.2 MODBUS communication
Byte 7 Byte 8
CRC
High Low
Byte 7 Byte 8
CRC
High Low
Byte N Byte N + Byte N +
1 2
CRC
Low High Low
Byte 7 Byte 8
CRC
High Low
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