Siemens SINAMICS DCM Operating Instructions Manual page 518

Descriptions of functions
10.8 Communication via MODBUS TCP
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 7 Function code (write multiple)
0258 h 8,9 Register start address
000A h 10,11 Number of registers to be written to (40601 ... 40610)
14 h 12 Number of data bytes (10 registers, each 2 bytes = 20 bytes)
0001 h 13,14 40601: C1 (activate request)
2F10 h 15,16 40602: Function 2F h (47), request length 16 bytes (10 h)
8002 h 17,18 40603: Request reference = 80 h, request identifier = 2 h (write)
0101 h 19,20 40604: DO-Id = 1, number of parameters = 1
1001 h 21,22 40605: Attribute, number of elements = 1
0461 h 23,24 40606: Parameter number = 1121
0000 h 25,26 40607: Subindex = 0
0801 h 27,28 40608: Format + number of values
4142 h 29,30 40609: Parameter value 12,15
6666 h 31,32 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 7 Function code (read)
0258 h 8,9 Register start address
0007 h 10,11 Number of registers to be written to (40601 ... 40610)
0010 h 12,13 Number of registers
Table 10- 62 Response for successful write operation
Value Byte Description
MBAP header
Number of following data bytes (20 h: 32 bytes ≙ 16 registers)
03 h 7 Function code (read)
20 h 8
0002 h 9,10 40601: DS47 Control = 2 (request was executed)
2F04 h 11,12 40602: Function code 2F h (47), response length 4 bytes
8002 h 13,14 40603: Request reference mirrored = 80 h,
response identifier = 2 (change parameter)
0101 h 15,16 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
Number of following data bytes (20 h: 32 bytes ≙ 16 registers)
03 h 7 Function code (read)
20 h 8
0001 h 9,10 40601: DS47 Control = 1 (request is processed)
2F00 h 11,12 40602: Function 2F h(47), response length 0 (fault)
0004 h 13,14 40603: Error code: 0004 Response Not Ready (response has still not been
issued)
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SINAMICS DCM Control Module
Operating Instructions, 12/2018, A5E34888669A