Table A-29
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 A-30
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)
A.1.4.7
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 A-31
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.
Process data monitoring time (setpoint timeout)
The "Setpoint timeout" only applies for access to process data (40100 ... 40109, 40110 ...
40119). The "Setpoint timeout" is not generated for parameter data (40300 … 40522).
Communication
A.1 Communication
Industrial Security
Configuration Manual, 08/2017, A5E36912609A
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