CPU 31xC and CPU 31x, Technical Data 
Manual, 01/2006 Edition, A5E00105475-06 
ix 
Table of contents 
  Preface. .....................................................................................................................................................iii 
1  Guide to the S7-300 documentation ....................................................................................................... 1-1 
2  Operating and display elements ............................................................................................................. 2-1 
2.1  Operating and display elements: CPU 31xC ............................................................................. 2-1 
2.1.1  Operating and display elements: CPU 31xC ............................................................................. 2-1 
2.1.2  Status and Error Indicators: CPU 31xC ..................................................................................... 2-4 
2.2  Operating and display elements: CPU 31x................................................................................ 2-5 
2.2.1  Operating and display elements: CPU 312, 314, 315-2 DP: ..................................................... 2-5 
2.2.2  Operating and display elements: CPU 317-2 DP ...................................................................... 2-7 
2.2.3  Operating and display elements: CPU 31x-2 PN/DP ................................................................ 2-9 
2.2.4  Operating and display elements: CPU 319-3 PN/DP .............................................................. 2-11 
2.2.5  Status and error displays of CPU 31x...................................................................................... 2-13 
3  Communication....................................................................................................................................... 3-1 
3.1  Interfaces ................................................................................................................................... 3-1 
3.1.1  Multi-Point Interface (MPI) ......................................................................................................... 3-1 
3.1.2  PROFIBUS DP........................................................................................................................... 3-2 
3.1.3  PROFINET (PN)......................................................................................................................... 3-3 
3.1.4  Point to Point (PtP) .................................................................................................................... 3-5 
3.2  Communication services............................................................................................................ 3-6 
3.2.1  Overview of communication services ........................................................................................ 3-6 
3.2.2  PG communication..................................................................................................................... 3-7 
3.2.3  OP communication..................................................................................................................... 3-8 
3.2.4  Data exchanged by means of S7 basic communication............................................................ 3-8 
3.2.5  S7 communication ..................................................................................................................... 3-8 
3.2.6  Global data communication (MPI only)...................................................................................... 3-9 
3.2.7  Routing..................................................................................................................................... 3-11 
3.2.8  Point-to-point connection ......................................................................................................... 3-15 
3.2.9  Data consistency...................................................................................................................... 3-15 
3.2.10  Communication by means of PROFINET ................................................................................ 3-16 
3.2.10.1  PROFINET IO System ............................................................................................................. 3-19 
3.2.10.2  Blocks in PROFINET IO........................................................................................................... 3-20 
3.2.10.3  System status lists (SSLs) in PROFINET IO ........................................................................... 3-22 
3.2.10.4  Open communication via Industrial Ethernet........................................................................... 3-24 
3.2.10.5  SNMP communication service................................................................................................. 3-27 
3.3  S7 connections ........................................................................................................................ 3-27 
3.3.1  S7 connection as communication path .................................................................................... 3-27 
3.3.2  Assignment of S7 connections................................................................................................. 3-28 
3.3.3  Distribution and availability of S7 connection resources ......................................................... 3-30 
3.3.4  Connection resources for routing............................................................................................. 3-32 
3.4  DPV1........................................................................................................................................ 3-33