Instruction Manual

xii IM 04L31A01-17E
Chapter 3 Serial Interface
3.1 Serial Interface Specifications ....................................................................................... 3-1
RS-232 Specifications ................................................................................................... 3-1
RS-422/485 Specifications ............................................................................................ 3-1
3.2 Connector Pin Arrangement and Signal Names, Connection Procedure, and
Handshaking Methods of the RS-232 Interface ............................................................. 3-2
Connector Pin Arrangement and Signal Names ............................................................ 3-2
Connection Procedure ................................................................................................... 3-2
Handshaking .................................................................................................................. 3-3
3.3 Terminal Arrangement and Signal Names and the Connection Procedure of
the RS-422/485 Interface ............................................................................................... 3-5
Terminal Arrangement and Signal Names ..................................................................... 3-5
Connection Procedure ................................................................................................... 3-5
Connection Example with the Other Instruments .......................................................... 3-6
3.4 The Bit Structure of One Character and the Operation of the Receive Buffer ............... 3-9
The Bit Structure of One Character ............................................................................... 3-9
Receive Buffer and Received Data................................................................................ 3-9
3.5 Configuring the Serial Interface ................................................................................... 3-10
3.6 Automatic Recovery Settings ....................................................................................... 3-14
Chapter 4 Modbus Protocol
4.1 Modbus Protocol Specifications ..................................................................................... 4-1
4.2 Configuring the Modbus Protocol .................................................................................. 4-2
4.3 Setting the Modbus Master Function ............................................................................. 4-5
4.4 Checking the Operation Status of the Modbus Master Function ................................. 4-11
4.5 Communications as a Modbus Slave .......................................................................... 4-13
Command Message Construction ............................................................................... 4-13
Specifying the Register Number .................................................................................. 4-13
Broadcast Request ...................................................................................................... 4-14
Function Code ............................................................................................................. 4-14
4.6 Modbus Slave Error Responses .................................................................................. 4-16
Message Format for Errors .......................................................................................... 4-16
Response Error Codes ................................................................................................ 4-16
When Responses Are Not Received ........................................................................... 4-16
Chapter 5 Ladder Communication Protocol
5.1 Ladder Communication Protocol Specifications ............................................................ 5-1
5.2 Setting the Ladder Communication Protocol ................................................................. 5-2
5.3 Communications with PLCs ........................................................................................... 5-5
Command Construction ................................................................................................. 5-5
Response ....................................................................................................................... 5-6
Response When Errors Occur ....................................................................................... 5-7
5.4 Communication Program for FA-M3 .............................................................................. 5-8
5.5 Communication Program for MELSEC ........................................................................ 5-13
Preparations before Communications ......................................................................... 5-13
Contents