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Chapter 2 Built-in Cnet communication
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2.7 Modbus Protocol
Modbus protocol is specified open protocol used between client-server, which executes reading/writing data according to
function code. Communication between devices that use Modbus protocol uses Client-server function in which only one client
processes the data.
2.7.1
Modbus Protocol
There are two communication modes of Modbus, ASCII and RTU.
1) Structure of Modbus protocol
Modbus protocol’s structure is as follows.
In case of normal communication, process step is as follows.
In case of abnormal communication, process step is as follows.
Characteristic
ASCII mode
RTU mode
Coding method
ASCII code
8 bit binary code
No. of data per
one character
Start bit
1
1
Data bit
7
8
Parity bit
Even,Odd,None
Even,Odd,None
Stop bit
1 or 2
1 or 2
Error check
LRC(Longitudinal Redundancy Check)
CRC (Cyclical Redundancy Check)
Start of frame
Colon (:)
3.5 Character no response time
Содержание XBE-DC08A
Страница 124: ...Main Chapter 1 Configuration and Operation Mode of Programs 1 27 1 Memory block diagram ...
Страница 155: ...Main Chapter 2 CPU Function 2 29 Notice For more details on the monitor refer to the XG5000 manual ...
Страница 504: ...Position Chap 6 Commands 6 61 6 11 Function blocks related to Servo Drive ...
Страница 512: ...Positioning Chapter 7 Program 7 8 manual operation 7 1 4 Parameter and Operation Data Setting 1 Parameter Setting ...
Страница 644: ...Positioning Chapter 8 Functions 8 91 ...
Страница 727: ...Positioning Chapter 9 Positioning Error Information Solutions 9 13 ...
Страница 861: ...Special Chapter 1 Embedded Analog 1 39 5 Select View Variables Comments Variables and comments are both displayed ...
Страница 1206: ...Appendix 2 Dimension App2 1 Appendix 2 Dimension Unit mm 1 CPU Type XEC DN32U 2 Positioning Type XEC DN32UP ...
Страница 1207: ...Appendix 2 Dimension App2 2 2 Analog Type XEC DN32UA ...
Страница 1209: ...Appendix 2 Dimension App2 4 XBE DC08A XBE DC16A XBE TN08A XBE TN16A XBE DR16A XBE RY08A ...
Страница 1210: ...Appendix 2 Dimension App2 5 4 Extension Cnet I F Module XBL C41A XBL C21A ...