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FG_F6_MODBUS_EN_01 / 2020-06-17
Direct access
Reminder: a byte is 8 bits long and a word is 16 bits long
Reminder: "h" indicates a hexadecimal code, "(d)" indicates a decimal code.
The
Direct access
allows the user to read/write
directly only one item
in a single frame.
The ATEQ 6
th
series instruments support two different functions in
Direct access
.
Writing N*words: 10h
Question:
Slave
address
Function
number
(10h)
Direct access
address
Number of
words to
write
Number of
bytes to
write
Data
0
…
Data
N
CRC
Byte
Byte
Word
Word
Byte
N*words
Word
Answer:
Slave
address
Function
number
(10h)
Direct access
address
Number of written words
CRC
Byte
Byte
Word
Word
Word
Reading N*words: 03h
Question:
Slave
address
Function
number
(03h)
Direct access
address
Number of words to read
CRC
Byte
Byte
Word
Word
Word
Answer:
Slave
address
Function
number
(03h)
Number of
read bytes
Data 0
…
Data N
CRC
Byte
Byte
Byte
N*words
Word
