SEW-Eurodrive DHR41B, Manual

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70
Manual – MOVI-PLC® advanced DHR41B for EtherNet/IP, Modbus/TCP and PROFINET IO
8
Protocol structure
The Modbus Protocol (Modbus/TCP)
8.2.3 Service FC16 Write multiple registers
With the service FC16 Write Multiple Registers you can write a variable number of reg-
isters (see following figure).
Example Request:
Response:
Exception:
64066AXX
MBAP Header Function Code-Data(FC16)
FC
(0x10)
T- ID (0x00) Prot-ID (0x00)
UI-D
(0x00)
Length
(1+6+N)
Write Address Write WordCount
Bytes
(N)
Write Data
(1 ... N)
Byte Designation Meaning/permitted values
0 - 6 MBAP header See chapter 'Header'.
7 Function code Requested service: 16 (Write Multiple Registers)
8 Reference number (high) Offset
9 Reference number (low) Offset
10 Word count (high) Number of words (register)
11 Word count (low) Number of words (register)
12 Byte count 2* Word count
13 ... Register values 2 - ... Data bytes depending on the length
Byte Designation Meaning/permitted values
0 - 6 MBAP header See chapter 'Header'.
7 Function code Service: 16 (Write Multiple Registers)
8 Reference number (high) Offset
9 Reference number (low) Offset
10 Word count (high) Number of words (register)
11 Word count (low) Number of words (register)
Byte Designation Meaning/permitted values
0 - 6 MBAP header See chapter 'Header'.
7 Function code 90
hex
8 Exception code Fault code
0 0
I