Siemens SINAMICS S120 Series - Page 179

Communication via Modbus TCP
6.6 Communication via data set 47
Communication
Function Manual, 12/2018, 6SL3097-5BD00-0BP0
177
Table 6- 11 Start parameter request: Reading parameter value of r0002 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 read (40601 … 40607)
Number of registers
Table 6- 12 Response for successful read 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
2F08 h
8001 h
0101 h
0301 h
001F h
9,10
11,12
13,14
15,16
17,18
19,20
40601: DS47 Control = 2 (the request was executed)
40602: Function code 2F h (47), response lengths 8 bytes
40603: Request reference mirrored = 80 h,
response identifier = 1 (request parameter)
40604: DO-ID = 1, number of parameters = 1
40605: Format, number of elements = 1
40606: Parameter value = 1F h (31)
Table 6- 13 Response for unsuccessful read operation - read 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: Check value 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)