Mitsubishi QJ71MB91, User Manual

Page: 72 / 372

4
- 17 4.3 Protocol Data Unit Formats by Functions
4
MODBUS(R) STANDARD FUNCTIONS
(b) Frame mode of the message format
The message formats in Section 4.4 to 4.20 are based on the case in the RTU
mode.
For use in ASCII mode, convert the values into ASCII codes.
(Conversion example)
(c) Response message format
The response message formats issued from the slave to the master differs
depending on whether the slave has normally completed or failed to handle the
requested processing (read/write, diagnostics, etc.)
The formats for normal and error completions are shown in Section 4.4 to 4.20.
Figure 4.8 Conversion example from RTU mode to ASCII mode
Data
(L)
Data
(L)
(L) (L)
Data
(L)
Read points
0
(30
H
)
0
(30
H
)
3
(33
H
)
F
(46
H
)
(RTU mode)
Function code
Function
code
(01
H
)
Head coil number
(006E
H
)
Read points
(003F
H
)
Convert RTU mode to ASCII mode
(ASCII mode)
Function code
Function code
0
(30
H
)
1
(31
H
)
Head coil number
0
(30
H
)
0
(30
H
)
6
(36
H
)
E
(45
H
)
(H)
(H)
(H)
(H) (H)