FX3u 128 Question

[awankem 0]

Hi every one, can somebody brief me on a couple of issues concerning connecting an external program to Fx3U PLC from Mitsubishi . i have programed all the instruction to control the PLC with a java program. I'm sending request to read and write the different devices of the PLC using serial communication interface of the PLC. I'm using an adapter to convert from ethernet to serial port. My question is . How can i configure it to talk or response to request messages from a program on my pc . For instance i want to send it a status request message and i want it to response after a set message delay time . I will be grateful if some body can help. it is my first project. I'm a software developer. awankem

[kaare_t 155]

First of all: What serial port are you going to connect to on the PLC? (BD/ADP/232ID)? I guess you've programmed the MC protocol, since this is an open protocol with a manual/reference document. You can send requests using MC protocol and whatever external software you would like. If you have a BD/ADP card on the PLC you will have to set up the card to communicate using MC protocol (instead of CPU protocol).

[awankem 0]

I have 2 possibilities with the FX3u. one is to connect through the serial port at the F940 GOT touch pad or by using Serial adapter communication module FX3u-232-BD that we just ordered. The communication protocol i intended to used is the Computer link protocol format 1. I don't understand what you meant by programming the MC protocol ? surely i didnot , but i want to use a higher level programming language like java to send command to the PLC using computer linked Protocol. My question is do i need a software like GX Developer to set the protocol or is it possible to set it with a programmed command. I have all the instructions and the register addresses or devices i intend to read and write. I'm simply sending ascii coded Hex strings command created with java program. i still need you to enlighten me deeper on this thks.

[kaare_t 155]

I would go with the 232BD card (since you can connect directly to the PLC without the need of the GOT). You will have to set up the 232BD card with a software to make it use Computer Link Format 1. This is pretty easy to do with the software and are stored in data inside the PLC. However, your problem is that you can't send down the parameters using Java before you have initialized the BD card with Computer Link Format 1..... In other words, you will need a software to set parameters to the BD card. There exists "FX" versions of the Mitsubishi software which are cheaper than full-version software, and you could set the parameters using this.... But I guess the PLC has some code inside it.....!? Maybe the original developer could help you?

[awankem 0]

thanks Kaare, i appreciate your contribution, i just spoke to the vendors of the machine containing the PLC and they are going to send to me their expert to configure it accordingly. i will keep in touch if any other issue arises. Are you also programming in this direction? if i may ask, just curious. Have a good day Awankem

[kaare_t 155]

Hi. No, I don't do any PC Programming (Java/C/C++) so I can't help you much with your specific application. However, I've programmed some PLCs to communicate using Computer Link (the PLCs only have slave protocol so I've been into programming the Master protocol). Basically the same thing you do, except I've done it in PLCs and you are using a computer