Siemens S7-300 PLC's are equipped with a special port named MPI (stands for Multiport Interface).
Does any body know how to use this port in our S7 programs. Or can it be used in our conventional S7 programs at all?

Thanks
Reza Hasseli

 

Hi,
The MPI port is used for the programming off the CPU and may also used for Global Communication. Global communication can be reached out off the simatic manager on the top off the project where you see the MPI-network on the right sight of the project. Wenn you choose with the mouse on top off the MPI-network the right mousekey then you may choose "Define Global Data". In the colums you see you may choose the different CPUs in the MPI-network, click on a free colum, the hole colum colours black, with the right mousekey you can choose the CPU.

After that choose in the next colom an other CPU and the basis for MPI communication is there. Then you can type several send and receive data in the colums and save them (See help off the S7 for further instructions), wenn you put this in both the CPUs then you have MPI-communication. This simple communication is NOT for a large amount of data, see the help for the amount off data thats in a MPI-circle possible.

The S7-400 have the possibility to send and receive on the MPI-bus with SFCs. The S7-300 is only server for MPI and not a client.

A simple driver to communicate and make a simple programm for visualising is PRODAVE MPI, this is a toolbox for MPI communication from a PC with a CP5611 card. This program can used with Visual Basic to communicated with the CPU.

i hope you have the information you need,
Best regards,
Lowiek

 

Hello Reza;

The MPI (MultiPoint Interface) port is the programming port of the S7-300. It uses RS-485 standards, and also provides 24 V DC on 2 pins to power-up PC/TS-Adapters for direct or modem programming. MPI allows the programming and diagnostics of the S7-300/400 CPUs at a rate of 187,5 kB; it also allows communication to Siemens HMI, and to some 3rd party pfducts (Greyline, TCP, QuickPanel, Cutler-Hammer).

In your programs, it can be used to exchange between S7-300/400 CPUs, with Global Data configuration, or Send/Recieve blocs. You can also set-up S7-22x CPUs (S7-200 of the second generation) as MPI slaves on that same port.

Hope this helps,
Daniel Chartier

 

Reza,

There are SFC's that allow you to XMT and RCV.....
Think they are sfc13 and sfc14 which are called XPut and Xget

Ciao

 

Hello Reza,
The MPI port is mainly used to download the hardware configuration. The MPI protocol is quite similar to profibus, but it does not support baud rates greater than 38.4 kbaud. If you are using an ethernet module to communicate with an HMI or a profibus module to communicate with I/O, you will need to download the h/w configuration via MPI at least once in order to load the module's configuration. Then, depending on your setup, you may never have to use it again. The MPI port can also be used to communicate with OP's (operator panels) or similar devices that don't require a speedy baud rate. If you have a need to share data between S7-300's, the MPI ports can be connected via network and a global data table created to swap data. Hope this helps.

Regards,

Jeff Winborn
[email protected]
Industrial Systems Design
(423) 282-6088

 

Setup (33:16656) Error means in Siemenes S7 300 PLC