Miguel.itlac

PLC to PLC communication

13 posts in this topic

Posted (edited)

Hello everyone

Does anybody knows how to estblish a communication between 2 Mitsubishi CPUS with modbus?

THey are RCPU and FXCPU

 

Edited by Miguel.itlac

Share this post


Link to post
Share on other sites

simple PLC comm is easiest just setting up parameters and communicating over the standard ethernet port

 

Share this post


Link to post
Share on other sites

FXCPU is useless information.  There have been FX model CPUs since the 80s.  Need a complete model.  Like FX2N, FX3U, etc.

1 person likes this

Share this post


Link to post
Share on other sites

Posted (edited)

Yes sorry, I mean FX5CPU, im New with Mitsubishi software etc, but i know that the simple communication is the easiest, but my boss told me that with modbus is easier and  i actually dindt catch the whole idea maybe someone can explain it better here.

thank you in advance 

Edited by Miguel.itlac

Share this post


Link to post
Share on other sites

The RCPU (iQR) & FX5 (iQF) have built in "Simple PLC Communications". 

As Gambit said, you only have to configure the settings to establish comms between the 2 PLCs using their Ethernets..

The only recommendation is to use either the RCPU or the FX5 to do the talking. The comms allows the transfers of PLC Data & bit registers between the 2 PLCs.

You pnly need to configure the comms from 1 of the PLC.

Eg. Say you use the RCPU to do the transfer of registers. You configure the RCPU settings to transfer D100 to D150 to the FX5 memory at D1100 to D1150. You do not need to perform any setup at the FX5 PLC. (apart from the IPaddress to be in same range)  When the RCPU is rebooted, it will perform the transfer. This also applys to registers it Reads from the FX5 PLC.

 

 

Share this post


Link to post
Share on other sites

yes i understand that, but there is another system where modbus tcp is implemented, and there must be communicating each other 

Share this post


Link to post
Share on other sites

well just add a modbus port in the ethernet device settings

For the client  there is a FB in the CPU list

Share this post


Link to post
Share on other sites

Posted (edited)

2 hours ago, Miguel.itlac said:

yes i understand that, but there is another system where modbus tcp is implemented, and there must be communicating each other 

Ok but what is your question ? Will the other system be the client or the server ?

all you have to do to make them modbus servers is to add a modus port to the ethernet settings

The FX5U CPU has a FB for modbus read write. just look under the CPU FB in GX works 3 

Edited by Gambit

Share this post


Link to post
Share on other sites

I actually have a FX5UC with only  the modbus TCP connection module in the Ethernet configuration without any library or FB and i can write with a modbus  View TCP tool so no problem to this point, but my RCPU will be my Client and is not possible to add a Modbus TCP connection module as in my FX5UC, so  to this CPU I added the Client library MEU+RCPU_ModbusTCP_00B, added and active connection module pointing to the IP and port of my FX5UC and configure the client FB to talk to my Fx5UC is that correct??

My conclusion is then, that the MODBUS TCP connection module works only as a server am i Right?

Share this post


Link to post
Share on other sites

Yes Both the FX5U and de iQ-R CPU have the modbus server for which you only need to setup a port.

When you want to use them as a client then there is a FB for the FX5U. 

For the iQ-R you need the library you mentioned.

Alternatively you can also use the pre-defined protocol function.

 

.

Share this post


Link to post
Share on other sites

one more question is, when all communication is set up, how do I get the data, i mean if i send a value in my RCPU in D0 to the FX5UC will i get this value in same Device?

How is the mapping in this Case?

once i did it with a weintek HMI and i Read memory devices Ms from 8193= M0 so i Wonder if its the same when modbus is implemented.

Share this post


Link to post
Share on other sites

There is a default mapping between Mitsubishi devices and modbus devices. (You can change it if you want but is not needed)

So if you write to holding register 0 (40000) you will write it into D0

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now