Siemens SIROTEC Function Manual

Communication
11.4 Communication via MODBUS TCP
Drive functions
870 Function Manual, 11/2017, 6SL3097-4AB00-0BP5
Table 11- 34 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 11- 35 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)
11.4.7
Communication procedure
Logical error
If the device detects a logical error within a request, it responds to the controller with an
"exception response". In the response, the device sets the highest bit in the function code to
1. If the device receives, for example, an unsupported function code from the controller, the
device responds with an "exception response" with code 01 (illegal function code).
Table 11- 36 Overview of exception codes
Exception
code
Modbus name
Remark
01 Illegal function code An unknown (unsupported) function code was sent to the
device.
02
Illegal Data Address
An invalid address was requested.
03
Illegal data value
An invalid data value was detected.
04
Server failure
The device has terminated during processing.

Siemens SIROTEC Specifications

General

Brand	Siemens
Model	SIROTEC
Category	DC Drives
Language	English