Mitsubishi QSeries ModbusTCP in Multi-CPU enviroment

Dear Friends,

I am having trouble to setup a QJ71MT91 Modbus TCP module in multi-CPU environment (CPU1 & CPU2). After i download and reset both CPU, the error 3303 shown and mentioned something about the automatic refresh parameter.

The modbus module is control only by CPU1.

My question is should i set exactly same parameter for the module? like the switch setting, automatic refresh and automatic connection. I tried set them identical in both CPU but still encounter the error 3303.

Any idea?

Thanks a lot!
Yeap

Sorry was new to Mitsubishi PLC. Really appreciate if someone in the forum can help me on this as I cannot figure out from the help file or manual.

To be specific:

Currently I am planning to install a new Modbus TCP module in multi-CPU Q series PLC

Modbus TCP Module - QJ71MT91

CPU1 - Q03UDECPU

CPU2 - Q03UDCPU

The new card will be control by CPU1, so after i configure the card in both CPU1 and CPU2. There is an error showing 3303 SP.PARA ERROR.
Explanation of the error is in a multiple CPU system, the automatic refresh setting or other parameter setting was made to the intelligent function module under control of another station.

So I tried to delete the configuration in CPU2 but no luck, and also some try and error on the MB TCP card configuration but no luck.

Anyone can guide me on how to setup the modbus tcp card in this kind of environment? is the MB TCP card must be identical in both CPU? or some setting must be off in CPU2?

I tried format the CPU and redownload but the same error still showing, really appreciate the help as I am already struggle some time for the setting.

Although I have never done MB on Mitsubishi and cannot really help, you state you have two CPU's are these both Mitsubishi, if so why are you using Modbus ?
A little more information would be helpful on the structure of the network.
Also are you using the utility package to set the cards or programmatically.
I do believe also one of them has to be a slave not both masters but this is a guess.
Also is this multiple CPU's in the same rack or two different PLC's

Are these also communicating to other MB slaves that are not Mitsubishi ?
I find it a little confusing why you are using MB, Normally you would use NET-H cards, these are easy to configure, just hardware address for nodes and configure the Send/Receive Areas in the B registers. of the master.

Dear Parky,

Sorry I didnt make it clear.

I am having 2 CPU in same rack to handle the logic and also cc-link card.
these 2 CPU work together with Mitsubishi multi-cpu concept that both of them handle different things but they are sit in the same rack. the concept is in program we can select which IO card / intelligent module control by which CPU.
The communication between this two CPU is fine.

Currently a new request from user to read MB TCP slave devices. So in order to read the MB Slave equipment, the intelligent modbus tcp module QJ71MT91 is purchased and added to the PLC rack. I have read some tutorial and guideline on how to configure the MB card. But is limited info on how to set them right in the multi-cpu enviroment.

I am not sure should I set the card identical in both CPU1 and CPU2 or there are some setting need to be different ? after i download to CPU, i receive message 7000 that the multicpu is down, due to the error 3303 that automatic refresh setting is not correct.

Hope you can provide some help on this.

Sorry, I have no experience on the MB card and only a little on using Multiple CPU's and you may find not many people have done this configuration. I think you might need to contact Mitsubishi for advice.

Thanks! at least you are the only one that reply to me. Really appreciate it

Hi koyeap. I have some experience with Mitsubishi, but never done this setup. If you would post your programs I can try to have a look at them. Unfortunately, I have only one PLC in my lab so I cannot test. But I can have a loo at your programs with GXWorks and GXDeveloper to see if I can make sense of the error message that you have shown in the picture. The logic of your application is not necessary only the settings for the IO cards is enough

Dear AlfredoQuintero,

That is great!! Really appreciate it!

I am using GX Work2, the program CPU1 is the main controller, and CPU2 is the second controller
I have a few version of modification, for this attached one is I tried to set the TCP card identical in both CPU but still receive error 3303.

What I want is actually just make the modbus TCP card run without multiCPU error.

Hope you can give me some clue.

Are you trying to set the parameters for the MB card in both CPU's I believe you may only be able to set them in one, then use the CPU to CPU messages to transfer data. Although both may have the card I/O slot perhaps trying to let both CPU's to control it will probably not work, just a guess.

You have selected to control QJ71MT91 from CPU1, but you have installed it also on CPU2, as it is under Intelligent Function Module. I would try to delete it from Project pane, but it's assignment should be left under PLC Parameter->I/0 Assignment.

Hi Yeap, sorry for my late answer. I finally had the time to look at your issue. My GX Works2 is in Japanese so I did some translation and investigated your inquiry. Since I have never done this setup (nor have the modules at hand, hence cannot test) I cannot be sure this will work. So please have a look at the screenshot below, with my interpretation of the Mitsubishi documentation. The GX Works2 online help seems to suggest that only the automatic refresh settings needs to be deleted from the second or redundant CPU, which is called the other CPU or tagouki (他号機) in the documentation. I think you need to configure the QJ71MT91 on both CPUs, but for the second, just leave this setting empty. It would be interesting to know if this would solve your issue. Good luck.

Dear goghie and AlfredoQuintero,

Thanks a lot for your advise. As the actual unit is currently running and I have no time slot from factory to shut the PLC down for testing. I will try to get a testing unit and update if I manage to solve the issue.

Dear Parky,

Would try both suggestion from AlfredoQuintero and goghie.
No choice but will go try and error, nothing much i found from Mitsubishi manual.

Finally

Dear All,

My testing unit just arrived yesterday.
I finally found a configuration that give no error.
In CPU 1 I configure the modbus communication card, in CPU 2 I only configure the PLC parameter.

Thanks guys for the help