MODBUS over Serial Line for FX PLCs Overview

MODBUS over Serial Line for FX PLCs /// Overview /// MODBUS over Serial Line communication MODBUS serial communication using GX Developer Mitsubishi Electric – Start-Up document. – 20. 08. 2007

MODBUS over Serial Line for FX PLCs /// Overview /// MODBUS over Serial Line • MODBUS over Serial Line is a protocol that uses a Master-Slave technique in which only the Master device can initiate transactions (queries) and the Slaves respond by supplying the requested data to the Master or by taking the action requested in the query • Two transmission modes can be used: – ASCII : each byte is sent as two ASCII characters – RTU (Remote Terminal Unit) : each byte is sent as two 4 -bit hexadecimal characters • RTU transmission mode has twice the data density of the ASCII transmission mode thus it allows better data throughput for the same baud rate Mitsubishi Electric – Start-Up document. – 20. 08. 2007

MODBUS over Serial Line for FX PLCs /// Overview /// Communication types overview • The FX-series PLCs can communicate over a serial line using communication extension boards or communication special adapters with RS 232 or RS 485 communication interfaces • FX-series PLCs can act as either MODBUS Master or MODBUS Slave devices using developed function blocks • We analyze 2 MODBUS over Serial Line communication types for FX-PLCs: – MODBUS RTU Master functionality for FX 3 U PLCs using the dedicated MODBUS serial communication special adapter FX 3 U-485 ADP-MB – MODBUS RTU Slave functionality for FX 3 U PLCs using the dedicated MODBUS serial communication special adapter FX 3 U-485 ADP-MB Mitsubishi Electric – Start-Up document. – 20. 08. 2007

MODBUS over Serial Line for FX PLCs /// Overview /// MODBUS RTU Master functionality for FX 3 U PLCs using the FX 3 U-485 ADP-MB special adapter Mitsubishi Electric – Start-Up document. – 20. 08. 2007

MODBUS over Serial Line for FX PLCs /// Overview /// MODBUS RTU Master functionality for FX 3 U PLCs using the FX 3 U-485 ADP-MB special adapter File / Directory Description MModbus. FX 3 UMaster ADP_MB_CH 1 Project directory containing the MODBUS RTU Master communication program example for a FX 3 U PLC using a FX 3 U-485 ADP-MB MODBUS serial communication special adapter configured on Channel 1. The program example reads from and writes to two MODBUS Slave devices Modbus. FX 3 UMaster ADP_MB_CH 2 Project directory containing the MODBUS RTU Master communication program example for a FX 3 U PLC using a FX 3 U-485 ADP-MB MODBUS serial communication special adapter configured on Channel 2. The program example reads from and writes to two MODBUS Slave devices Mitsubishi Electric – Start-Up document. – 20. 08. 2007

MODBUS over Serial Line for FX PLCs /// Overview /// MODBUS RTU Slave functionality for FX 3 U PLCs using the FX 3 U-485 ADP-MB special adapter Mitsubishi Electric – Start-Up document. – 20. 08. 2007

MODBUS over Serial Line for FX PLCs /// Overview /// MODBUS RTU Slave functionality for FX 3 U PLCs using the FX 3 U-485 ADP-MB special adapter File / Directory Description MModbus. FX 3 USlave ADP_MB_CH 1 Project directory containing the MODBUS RTU Slave communication program example for a FX 3 U PLC using a FX 3 U-485 ADP-MB MODBUS serial communication special adapter configured on Channel 1. Modbus. FX 3 USlave ADP_MB_CH 2 Project directory containing the MODBUS RTU Slave communication program example for a FX 3 U PLC using a FX 3 U-485 ADP-MB MODBUS serial communication special adapter configured on Channel 2. Mitsubishi Electric – Start-Up document. – 20. 08. 2007