Siemens PROFIBUS/MPI S7 Protocol & Siemens Industrial Ethernet S7 protocol ID:8

Interface Description

IGSS32 offers an interface for connecting to Simatic S7 equipment using S7 protocol. The S7 protocol is an application layer protocol which implements functions for exchanging data between Simatic S7 series PLCs and other devices that supports the S7 protocol – e.g. PCs.

The S7 protocol can be running on either a standard PROFIBUS network or on a MPI network.

MPI network is used for connecting to the CPU port directly on S7 PLC systems. This means that no extra CP board has to be installed in the PLC. Some network parameters e.g. the baudrate is restricted on MPI type networks.

Running the S7 protocol on a PROFIBUS network requires the S7 PLC systems to have a separate CP board installed and offers the full flexibility of a PROFIBUS network e.g. mixing electrical and optical networks etc. Applicable CP boards are e.g. CP443-5 for Simatic S7/400 series and CP343-5 for Simatic S7/300 series. Other CP boards supporting S7 functions might also be applied.

The S7 protocol can also be used with Siemens Industrial Ethernet (Siemens IE). Both ISO and TCP/IP are supported as transport protocols. Siemens IE is used in the S7/300 and S7/400 series. Applicable CP boards are e.g. CP443-1 or CP443-1 IT for the S7/400 and CP343-1 for the S7/300.

Connecting a PC to either MPI or PROFIBUS network requires an interface board and some board driver software from Siemens to be installed in the PC. Connecting a PC to Siemens Industrial Ethernet requires either a standard ethernet interface board or one of the “state of the art” ethernet boards available from Siemens. Applicable interface boards are listed below.

The IGSS32 system polls the PLC equipment cyclically according to one of four user-defined time intervals. The time intervals are configurable from 100 milliseconds to 999 seconds. The system automatically groups process data in data blocks – thus fully exploiting the the communication link in relation to the present configuration.

It is possible to apply event-oriented communication. Then the PLC equipment has control over when and which data to send to the IGSS32 system. In this way the use of available communication bandwidth can be optimised. The S7 functions BSEND and BRECV is used for this purpose.

Technical Data

Electrical Interface : PROFIBUS (EN 50 170), MPI, Industrial Ethernet (Siemens IE)
Protocol : S7 protocol. S7 functions. Both TCP/IP and ISO for Siemens IE
Types of data : String, Fixed Point 8, 16, 28, 32, BCD 16, 32, Float 32, Timer, Counter, etc.
PLC types supported : S7/300 and S7/400 directly on CPU port.
S7/300 equipped with CP343-5, CP343-1 or compatible.
S7/400 equipped with CP443-5, CP443-1, CP443-1 IT or compatible.
Addressing : Node (PLC), Data type, index, bit offset. Simatic S7 Mnemonics are displayed.
Supported platforms : Windows Vista, Windows XP, Windows 2003 Server, Windows 2000
Max. telegram size : 240 bytes pr. Telegram
Throughput : Up til 6 telegrams pr. Channel pr. Second (depending on available bandwidth).
Max. number of nodes : 32 pr. CP board.
PC hardware requirements : CP5412 and S7/5412 for WindowsNT/2000
CP5411, CP5511 or CP5611 and SoftNet-S7 for WindowsNT/2000
CP1613 and S7/1613 for WindowsNT/2000/XP/2003
Standard Ethernet interface board and SoftNet-S7/IE for WindowsNT/2000/XP/2003
PC software requirements : Simatic NET version 4.0, 5.0, 6.0 or higher