Function Block Modbus RTU Slave (V2.2)

Version 2.2

The function blocks in "ModbusSlave" attachment provide some of the Read/Write functionalities conformed to the specifications defined by Modbus-IDA:

Supported functions :
0x01   Read n bits in CIO area                Read Coils
0x02   Read n bit in CIO area                 Read Discrete Input (V2)
0x03   Read DM data memory                 Read Holding Registers
0x04   Read CIO                                    Read Input Registers
0x05   Write 1 bit in CIO area                 Write Single Coil
0x06   Write 1 word in DM area               Write Single Register
0x08   Echo back Test                            Echo Back Test
0x0F   ***** NOT SUPPORTED ******    Write Multiple Coils
0x10   Write multiple words DM               Write Multiple Registers

Broadcast supported using slave n° 00

Supported CPU :   

  • CJ1xx-V3
  • CP1H
  • CP1L-L
  • CP1L-M


V2.1 fixe a communication problem when NT link was used on the second serial port
V2.2 fixe the response "FFFF" sent when the slave No was incorrect