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<CONTENTS>
1. Introduction ......................................................................................................................... 1-1
1.1 About communication protocols ................................................................................................................................... 1-1
1.2 Outline of Ethernet communication functions ............................................................................................................... 1-1
1.3 RS-485 (option) ............................................................................................................................................................ 1-1
1.4 Preparation .................................................................................................................................................................. 1-1
1.5 Modbus RTU protocol .................................................................................................................................................. 1-2
1.6 Modbus TCP protocol .................................................................................................................................................. 1-2
1.7 Addition of new items and map version ....................................................................................................................... 1-2
1.8 Types of communication connection structures ........................................................................................................... 1-3
1.8.1 Ethernet connection ............................................................................................................................................... 1-3
1.8.2 RS-485 connection (Slave)..................................................................................................................................... 1-4
1.8.3 RS-485 connection (Master: remote AI) (Version 1.50 or later).............................................................................. 1-5
1.8.4 RS-485 connection (master: general-purpose connection)-Read function (Ver1.60 or later) ................................. 1-6
1.8.5 RS-485 connection (master: general-purpose connection)-Write function (Ver2.20 or later) ................................. 1-7
2. Modbus slave function .................................................................................................... 2-1
2.1 Communication Protocol (Modbus TCP or Modbus RTU) ........................................................................................... 2-1
2.2 Function code .............................................................................................................................................................. 2-1
2.3 Error check (CRC calculation)...................................................................................................................................... 2-2
2.4 Error Response ............................................................................................................................................................ 2-3
2.5 Reading of input register area ...................................................................................................................................... 2-4
2.6 Read and write of holding register area ..................................................................................................................... 2-17
2.7 Other setting range .................................................................................................................................................... 2-36
3. Modbus master - Read function - ................................................................................. 3-1
3.1 Overview ...................................................................................................................................................................... 3-1
3.2 Procedure of the recording data from slave devices .................................................................................................... 3-3
3.3 Enabling the Modbus master function .......................................................................................................................... 3-5
3.4 SettingModbus1(RS485 communication setting, timeout, etc.) .................................................................................... 3-7
3.5 Setting Modbus2 (communication type) ....................................................................................................................... 3-8
3.6 Setting the cyclic reading (Modbus Master) ............................................................................................................... 3-10
3.7 Checking the cyclic read status.................................................................................................................................. 3-12
3.8 Setting of calculating channels................................................................................................................................... 3-14
4. Modbus master –Write function- .................................................................................. 4-1
4.1 Overview ...................................................................................................................................................................... 4-1
4.2 Procedure for writing data to slave devices ................................................................................................................. 4-3
4.2.1 Common settings ................................................................................................................................................... 4-3
4.2.2 Settings write(Cyclic) .............................................................................................................................................. 4-4
4.2.3 Settings write(Display) ............................................................................................................................................ 4-5
4.2.4 Settings write(Event) .............................................................................................................................................. 4-6
4.3 Setting the Write Parameter (Modbus Master) ............................................................................................................. 4-7
4.4 Setting the constant value ............................................................................................................................................ 4-9
4.5 Setting the cyclic writing ............................................................................................................................................. 4-10
4.6 Setting the display writing .......................................................................................................................................... 4-11
4.7 Setting the event writing ............................................................................................................................................. 4-12
4.8 Checking the cyclic write status ................................................................................................................................. 4-14
4.9 Execute display writing .............................................................................................................................................. 4-16