MPI communication on the Profi-S-Net port of a PCD2.M480, PCD2.M5xxx or PCD3.Mxxxx

FAQ #100284

The PCD2.M480, PCD2.M5xxx and PCD3.M5xxx can be used as an MPI server (Profi-S-Net port). As the mentioned PCD's only reply to MPI requests, this functionality can be used to connect for instance an intelligent terminal that supports MPI (an OP for instance), but other MPI functions like global data exchange or event driven communication are not supported.


To use the MPI function you need to do the following:

  • early PCD2.M480 firmware versions (010 for instance) do not support the Profi-S-Net features, so the download of a new firmware version may be required
  • in PG5: make a Profi-S-Bus configuration in the hardware settings and download the hardware settings. This enables the FTP based communication services on the Profi-S-Net port, defines the Profibus address ( = MPI address at the same time) and the port settings
  • With Step7 it is possible to access the PCD media with:

    - SFC 67 X_Get

    - SFC 68 X_PUT
  • on MPI, S7 ressources are used, so you need a table that tells you how PCD Classic ressources are mapped to S7 ressources:


PCD Classic
MPI / S7
[0;8191      ]
0.0-1023.7 *)
Byte or Bit
Not for Word or Dword
[0;8191      ]
0.0-1023.7 *)
[0;1599      ]
DB 16000
[0;6396   ]

Not for Bit ,Byte or Word;
Address has to be modulo 4!
[0;16383    ]
DB 16001
[0;3999      ]
[0;1532   ]
DB[4000; 7999]
[0;65532 ]
[0;3999      ]
[0;383     ]
Not for Bit, Word or Dword
DB[4000; 7999]
[0;16383 ]

*) see remarks below:

  • if using the PCD8.D81W or VTWIN software, use the Siemens S7 driver for the PCD stations (with until version 4.75 the xx7 driver does not support the DB's mentioned in the above list). The addesses for flags and I/O are not introduced in the byte oriented format mentioned in the table, but in a bit-oriented format. This means that only multiples of 8 can be used as address. Example: to read the inputs 32 to 39, 32 has to be used as address.
  • for PCD7.D7xx terminals: the correct wiring for the MPI cable is shown in the hardware manual, use termination resistances at the ends of the bus



PCD3 / Mxxx

PCD2 / M5xxx

PCD2 / M48x

Last update: 26.05.2015 14:00

First release: 23.12.2004 16:25

Views: 8827

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