Azbil C7G

8-6
Chapter 8. Modbus TCP Communication Functions

Application section
X X
(1)
is 1 byte in hexadecimal notation. (High nibble on the left)
Following data representation

Multiple data read command (03H)
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For 1 data
(1) Function code (Read Holding Registers)
(2) First data address
(3) Number of data (= 1)
0
(1)
3
(2) (3)
● Request
● Normal response
(1) Function code (Read Holding Registers)
(2) Number of bytes (= 2)
(3) Read data
0
(1)
3
(2) (3)
● Abnormal response
(1) Error code (Read Holding Registers)
(2) Exception code (= 01H/02H/03H/06H)
8
(1)
3
(2)

For multiple data
(1) Function code (Read Holding Registers)
(2) First data address
(3) Number of data
0
(1)
3
(2) (3)
● Request
● Normal response
(1) Function code (Read Holding Registers)
(2) Number of bytes
(3) Read data (Data for the number of read data continues.)
(3)
● Abnormal response
(1) Error code (Read Holding Registers)
(2) Exception code (= 01H/02H/03H/06H)
8
(1)
3
(2)
0
(1)
3
(2) (3)
8 - 3 Description of Commands