FX5(UC) - MODBUS TCP/IP and RS-485

3 posts in this topic

Dear Forum,

I am looking for a solution where I can select via the HMI which product is connected to the FX5UC PLC.

EITHER Product A (Mitsubishi F840 via MODBUS TCP/IP) XOR Product B ( ABB ACS-880 via MODBUS TCP/IP) XOR Product C, XOR Product D, ....


EITHER Product C (MODBUS-RS-485 SLAVE) XOR Product D ( MODBUS-RS-485 SLAVE), XOR Product E....


The MODBUS TCP/IP registers for the products are different, (maybe) IP-Addresses are different.

The MODBUS RS-485 RTU, the registers are different, the baud rate is different, the complete serial port configuration is different.


The setup which product is connect to the FX5UC is done once during commissioning.


I am wondering if the above is possible with the FX5UC.

In the good old days I remember to open a serial port, define the baud rate, etc. within the ladder code. Process the data also in the ladder code, define the registers where to write the BUS-Data, etc.

Looking on the FX5UC modbus manual, the definition of the slaves is done within the project, the data transfers are called automatically and not via the ladder code.


Can anybody answer if the above request can be done with the FX5UC?

Can I configure / open / close the TCP/IP-Modbus and RS-485Modbus via the ladder program, rather than in the "project management" tool?


Best regards

Share this post

Link to post
Share on other sites

Is it a GOT. you can just put mutlple project on a SD card and select wich one you wan to use.

As for your Question about modbus. You can also use pred defined protocol for a modbus connection.
There is an easy to se FB in the CPU FB Lib for EXEC the simple protocol.

The RS-485 is done via an instruction


Share this post

Link to post
Share on other sites

Thanks Gambit,

I just got reply from Mitsubishi that chainging baudrate etc. via user-program is not available anymore with FX5, it was available with FX3.

Anyways, I am using GOT.

It is good hint with multiple projects, thanks.

Only problem I have is I am also logging to SD-Card, software update might get more complicated.

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