Sfere DGN175 U - Page 29

Response sequence:
Reading of N words: Function n°3
Request sequence:
Exception sequence:
Response sequence:
Writing of N words: Function n°16 Example: Reading of the displayed measure
Request sequence: Request:
Response sequence: Response with a positive measure:
measure
Writing of 1word: Function n°6 Value of the measure:
Request sequence:
0 0 19 136
Sign: 0 positive
1 negative
Slave
number
Function
6
Address
of the
word
Value of
the word
to be enf.
CRC 16
Slave
number
Function
3 or 4
1
st
word
MSB
adress
LSB
Nmbr of
MSB
words
LSB
CRC 16
Slave
number
Function
requested
with
MSB=1
Error
code
CRC 16
Slave
number
Function
3 or 4
Nmbr of
bytes
read
1
st
word
MSB
value
LSB
2
nd
word
MSB
value
LSB
CRC 16
Slave
number
Function
16
1st word
address
Nbr of
words
to enf.
Nbr of
byte to
be enf.
Value of the
words to be
enforced
CRC 16
254
03
0
206
0
2
CRC 16
Slave
number
Function
16
1st word
address
Nbr of
words
to enf.
CRC 16
254
3
4
19
136
0
0
CRC 16
Slave
number
Function
6
Address
of the
word
Value of
the word
to enfor.
CRC 16
1 byte 1 byte 2 bytes 2 bytes 2 bytes
1 byte 1 byte 2 bytes 2 bytes 2 bytes
8.3 Description of the born Modbus functions
1 byte 1 byte 2 bytes 2 bytes 2 bytes
1 byte 1 byte 2 bytes 2 bytes 1 byte n bytes 2 bytes
1 byte 1 byte 1 byte 2 bytes 2 bytes
1 byte 1 byte 1 byte 2 bytes
Values of the errror codes:
1: Unknown function code
2: Incorrect address
3: Incorrect data
9: Writing impossible
8.4 Reading in double integer format:
Slave Reading Address Number of words
Number of n words
byte 1 byte 2 byte 3 byte 4 2 bytes
byte 3 byte 4 byte 1 byte 2
p28
1 byte 1 byte 1 byte 2 bytes 2 bytes 2 bytes