Omron M1 Series - Page 651

8
Communications Functions
This section describes the general-purpose serial communications functions (Modbus
communication).
8-1 Communications Specifications................................................................... 8-
3
8-2 RS-485 Terminal Arrangement and Connection.......................................... 8-4
8-3 Modbus Communication Parameters........................................................... 8-5
8-4 Modbus Communication Protocol................................................................ 8-7
8-4-1 Message Configuration ................................................................................... 8-7
8-4-2 Required Communications Time ..................................................................... 8-9
8-4-3 Normal Response............................................................................................ 8-9
8-4-4 Abnormal Response........................................................................................ 8-9
8-4-5 No Response................................................................................................. 8-10
8-5 Explanation of Each Function Code........................................................... 8-11
8-5-1 Read Coil Status [01 hex]...............................................................................8-11
8-5-2 Read from Holding Register [03 hex] ............................................................ 8-12
8-5-3 Write to Coil [05 hex] ..................................................................................... 8-13
8-5-4 Write to Holding Register [06 hex]................................................................. 8-14
8-5-5 Loop-back Test [08 hex] ................................................................................ 8-15
8-5-6 Write to Multiple Coils [0F hex]...................................................................... 8-16
8-5-7 Write to Multiple Holding Registers [10 hex] ................................................. 8-18
8-5-8 Read/Write from/to Multiple Holding Registers [17 hex]................................ 8-19
8-5-9 Exception Response ..................................................................................... 8-20
8-6 Saving a Change to Holding Register (Enter Command)......................... 8-21
8-6-1 How to Issue Enter Command ...................................................................... 8-21
8-6-2 EEPROM Write Mode ................................................................................... 8-22
8-7 Modbus Mapping Function.......................................................................... 8-23
8-7-1 Operation of Modbus Mapping Function ....................................................... 8-23
8-7-2 Modbus Mapping Function Settings .............................................................. 8-23
8-7-3 Writing to Double-word Data ......................................................................... 8-25
8-7-4 Troubleshooting for Modbus Mapping Function ............................................ 8-25
8-7-5 Endian Function ............................................................................................ 8-25
8-8 Co-inverter Communication........................................................................ 8-27
8-8-1 Co-inverter Communication Parameters ....................................................... 8-28
8-8-2 Co-inverter Communication Settings............................................................. 8-31
8-9 Modbus Communication Data Lists ........................................................... 8-34
8-9-1 Coil Number List............................................................................................ 8-34
8-9-2 Register List .................................................................................................. 8-36
8-1
M1 Series Standard Type User's Manual (I669)
8