Siemens 6RA8085-6DS22

Descriptions of functions
10.8 Communication via Modbus TCP
SINAMICS DCM DC Converter
548 Operating Instructions, 12/2018, A5E34763375A
10.8.5.3
Examples: Write parameter
Table 10- 60 Write parameter request: Writing the parameter value of p1121 from device number 17
Value
Byte
Description
MBAP header
10 h
0258 h
000A h
14 h
7
8,9
10,11
12
Function code (write multiple)
Register start address
Number of registers to be written to (40601 … 40610)
Number of data bytes (10 registers, each 2 bytes = 20 bytes)
0001 h
2F10 h
8002 h
0101 h
1001 h
0461 h
0000 h
0801 h
4142 h
6666 h
13,14
15,16
17,18
19,20
21,22
23,24
25,26
27,28
29,30
31,32
40601: C1 (activate request)
40602: Function 2F h (47), request length 16 bytes (10 h)
40603: Request reference = 80 h, request identifier = 2 h (write)
40604: DO-Id = 1, number of parameters = 1
40605: Attribute, number of elements = 1
40606: Parameter number = 1121
40607: Subindex = 0
40608: Format + number of values
40609: Parameter value 12,15
40610: Parameter value
Table 10- 61 Start parameter request: Writing the parameter value of p1121 from device number 17
Value
Byte
Description
MBAP header
03 h
0258 h
0007 h
0010 h
7
8,9
10,11
12,13
Function code (read)
Register start address
Number of registers to be written to (40601 … 40610)
Number of registers
Table 10- 62 Response for successful write operation
Value
Byte
Description
MBAP header
03 h
20 h
7
8
Function code (read)
Number of following data bytes (20 h: 32 bytes ≙ 16 registers)
0002 h
2F04 h
8002 h
0101 h
9,10
11,12
13,14
15,16
40601: DS47 Control = 2 (request was executed)
40602: Function code 2F h (47), response length 4 bytes
40603: Request reference mirrored = 80 h,
response identifier = 2 (change parameter)
40604: DO-ID = 1, number of parameters = 1
Table 10- 63 Response for unsuccessful write operation - write request still not completed
Value
Byte
Description
MBAP header
03 h
20 h
7
8
Function code (read)
Number of following data bytes (20 h: 32 bytes ≙ 16 registers)
0001 h
2F00 h
0004 h
9,10
11,12
13,14
40601: DS47 Control = 1 (request is processed)
40602: Function 2F h(47), response length 0 (fault)
40603: Error code: 0004 Response Not Ready (response has still not been
issued)