Java to Mitsubishi PLC


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Has anyone every successfully creating a communication between Java and PLC Mitsubishi?

I have java netbeans and PLC Mitsubishi, can it read data from PLC through java?
There are a number of ways and the answer depends on what you want to do.

Most answers will be "Use ModbusTCP" and there is a lot of merit to this solution. Unfortunately with Mitsubishi (at least the Q series) you have to buy their special ModbusTCP module to plug in the backplane. So if you need very simple, open register mapped communication than this is a very simple solution and you should find support for Java somewhere on the net.

The other solution is to use the standard Ethernet built into the CPU (or a separate Ethernet module plugged into the backplane on older Q series PLCs). I think its easiest to set up the PLC Ethernet to act as a TCP server and connect to it with your java program as a client. The benefit to this is that you can talk to the PLC using standard TCP/IP socket calls from Java. The real downside is that handling complex messaging in the Mitsubishi PLC can be painful. If all you need is to send a handful of simple commands to the PLC then this may be a good option. You may want to make life easy on the PLC end and require a fixed message format and things like that because doing things like parsing delimeters and breaking into different strings can be done but is a bit painful on the PLC. You will need someone with basic TCP concepts and a good understanding of the PLC programming if you go this route.

What is your OS? I believe Mitsubishi offers a control for windows (either .Net or ActiveX). This would let you talk to their PLCs using the native Mitsubishi protocol. Other communications methods are supported (serial, etc) but most people use Ethernet these days.

Most likely you would have to implement the native Mitsubishi PLC protocol (MELSEC), which is quite messy. One thing you could consider using is the ETH-1000 gateway from ICC ( to convert MELSEC protocol to any other "normal" protocol such as Modbus TCP. You could then use something like the Java Modbus Library (jamod / to implement a Java-based Modbus TCP master.

Mitsubishi created a guide to providing access to the PLC through the ETH-1000 to EtherNet/IP ( ICC iQ Quick Start Guide V1.1.pdf), and it wouldn't be difficult to switch out the EtherNet/IP server driver for a Modbus/TCP server driver instead.
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