Sinee EM730 Series, Руководство пользователя

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User Manual of EM730/EM730E Series Inverter
318
≥3.5 characters
St art
8 digit s
Address
8 digit s
Function
code
N*8 bits
Dat a
2*8 bit
CRC check
≥3.5 characters
End
RTU message
PDU
2*8 bit
Address
of
regis ter
2*8 bit
Number
of
regis ters
2 * number of regi sters * 8 bits
Register content
Fig. 12-20 Schematic Diagram of Message Frame in RTU Mode
The RTU message includes the address code, PDU (Protocol Data Unit) and CRC[3
]
check.
The PDU includes the function code and data part (mainly including the register address,
number of registers, register content and the like; the detailed definitions of function codes are
different, as shown in 11.3.3Function code ).
[3]: the low byte of CRC check is in front of the high byte.
11.3.2 Address code
Address Range Purpose
1 - 247 Slave
0 Broadcast
11.3.3 Function code
The classification of MODBUS function codes is shown in Fig. 12-21.
Common function
code
User-defined
function code
Common function
code
User-defined
function code
Common function
code
1
（
0x1
）
65
（
0x41
）
72
（
0x48
）
127
（
0x7F
）
100
（
0x64
）
110
（
0x6E
）
Fig. 12-21 Classification of MODBUS Function Codes