Mitsubishi FX3u-ENET port question

[FONT=&quot]Good morning all[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]I've inherited a PLC system that has two Q01 and 6 FX2n PLCs[/FONT]
[FONT=&quot]The FXs have a FX3u-ENET module.[/FONT]
[FONT=&quot]There is quite a bit of PLC to PLC data exchange and all of that is working well, no issues.[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]There is one port on each of the FX3u-ENETs that configured to communicate with KepwareEX[/FONT]
[FONT=&quot]Settings are TCP, Unpassive, Send, Procedure exists(MC), Disable, No Confirm and a port of 5001[/FONT]
[FONT=&quot]This also works… most of the time. [/FONT]
[FONT=&quot]Occasionally (after 4/5 weeks) I’m seeing all comms stopping on these connections (not at the same time but within days) the other connections PLC to PLC and any MELSOFT continue fine. Stopping or restarting Kepware does not help. The only solution at present is to reset the PLC with is not ideal.[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]I’m wondering if the PLCs are not closing the port for some reason.[/FONT]
[FONT=&quot]I do find Mitsubishi Ethernet comms very versatile but somewhat complex and this one has got me beat. [/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]There is no PLC code for this port[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]Any ideas, is there a reset or close port function I could use if a heartbeat is lost?[/FONT]

Chris Taylor said:

[FONT=&quot]Good morning all[/FONT]
[FONT=&quot]Any ideas, is there a reset or close port function I could use if a heartbeat is lost?[/FONT]

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I have some experience with Melsec Ethernet communication and many years ago I had to figure out a way to reset the Ethernet port. This is not easy and almost nobody does it. Normally all the parameters are configured in the GX Developer or GX Works project and the Melsec processor will send those parameters at startup. That is why when you change any communication parameters it is necessary to restart the actual processor!

The only way (that I can figure out, at least) to be able to dynamically reset the Ethernet interface is by writing a program that sends those parameters to the Ethernet module and have the required logic to trigger that initialization algorithm, when for instance, the communication is lost. Normally the easiest way to figure out how to configure the Ethernet modules it to search for sample programs for the Melsec A series which needed a program to configure all the required parameters (buffers, whether it is active, passive or "unpassive") and so on. If you do not find such information I can try to dig some files and help you, but other members of this forum are far more knowledgeable and you may get better advice a bit later.

It may be better to try to analyze why the communication stops working, although this may require complex analysis with Wireshark.

I have had some experience on the Q series and the FX, On the Q, we found that TCP was difficult to get it talking and suspected it might fall over on occasions, I spoke to Kepware & they said UDP was better, true enough it worked a treat, over 6,000 tags were being read/written and in 5 years never had a problem. I also had a conversation with another engineer from another company and they struggled with TCP but UDP worked well, also the guy told me that they did not have to alter the Ethernet card it worked with only 5 original TCP Melsec connections. I have only tried the FX3U ENET on TCP on port 5551 so cannot say if it will work on UDP. Will give it a try if I can and leave it running.

Thanks all


Parky, I'll try a UDP connection,

Are you saying that they didn't have to setup a port? in any event I can setup a spare channel.

I have just looked at the Kepware Mitsi driver help file it appears that for the ENET module they use Ethernet encapsulation on TCP so I assume that it uses the MC Protocol, I have no idea if UDP with this setup will work, I know it works on the QJ71 Ethernet but have not tried it on the FX, however, The Q series does not need ethernet encapsulation. I have an FX3 with the ENET card & I will try it next week if I get time. It may be that I have sent you down the wrong path as for some reason the FX ENET card is done in a different way. I have just pulled out the Q series I did some 10 years ago & there is no UDP connection set up in the parameters of the QJ71 and it definitely works. In actual fact it has 8 MC Protocol channels and is using Kepserver UDP, MX component TCP for recipe handling & of course programming protocol.

I have just done a quick test and on the ENET module you do need UDP enabled, see attached pics for setting on GX Configurator & Kepware, I have not shown some of the settings as these are as standard so not changed, I have this running at the moment also monitoring via GXWorks so trying to hammer it hard but I am limited on time.

Above and beyond Parky


We have Kepware setup as TCP, using the Mitsubishi Ethernet Driver, are you using the Mitsubishi FX Net Driver?


I won't get to site for a couple of weeks, but I will have a play when I do


Thank you very much.

If you look at the pics I'm using the Mitsubishi ethernet driver on UDP and set up a couple of UDP connections in the ENET card ports 5000 & 5001. It would not work without the UDP connections. so I have set it up as per the ENET config & Kepware shown. I think the FX driver is for a built in ethernet port
also set it as IEEE802.3.

parky said:

I have just done a quick test and on the ENET module you do need UDP enabled, see attached pics for setting on GX Configurator & Kepware, I have not shown some of the settings as these are as standard so not changed, I have this running at the moment also monitoring via GXWorks so trying to hammer it hard but I am limited on time.

Click to expand...

Hi parky,

In the above solution provided, the target device port number is missing from attachment-Config2.png
I think you just need to expand the window and it will be there on extreme right.

Actually I am also facing issue in FX3GE PLC where network port goes down after few days.
So it would be very much helpful if you could do this similar setting with UDP for FX3GE PLC with Kepware/KepserverEX and share.

This is the one I used for both programming (MC Protocol) & UDP for Kepserver.
Attached, is a screenshot & a zip of the configurator file.

a friend told me about these ports, I will show him these files, I hope it will be useful to him, but thanks in advance

I did actually get this working correctly, it was remiss of me not to post about it. I'm at that site on Friday, I'll grab some data and post it.

parky said:

This is the one I used for both programming (MC Protocol) & UDP for Kepserver.
Attached, is a screenshot & a zip of the configurator file.

Click to expand...

Hi parky,

This may work fine for FX3U PLC models where the communication is established with FX3U ENET card and the config is done in FX Configurator.

In my case it's FX3GE PLC with on board ethernet and where config is done through GX Works 2 itself. So, it's bit different than your suggested config.

Also there is no availability for changing protocol as by default it takes MC Protocol only and there is no option to set send or receive (Fixed Buffer column) as in your case.

Vick005: I was a little confused, as the original post was for Enet not built in, perhaps you should have started a new post rather than tagging onto this one, I do not have access to FX3G so could not try it, have you ensured the port settings are correct your post shows 65535 which is obviously wrong & I do agree that Kepware does not like certain settings i.e. TCP did not work on a Q series (Kepware recommended UDP) & I seem to remember that MC protocol caused me some issues some years ago.

Any Solutions?

Hi Chris,
I have the same issue, saw that you found the problem. Would you be able to share your findings? Thanks!!