Siemens EF 83H Series Bedienungsanleitung PDF herunterladen (Seite 25)

Overview

1-9

SIMATIC 505 PROFIBUS-FMS CP User Manual

Communication

on the PROFIBUS network can be described from both the

physical and the logical point of view

The physical view, as shown in Figure 1-5, describes a number of stations

connected to a central bus line. This view emphasizes the actual physical

layout of the network cables and devices that enable the stations to

communicate with each other

Figure 1-5

Simplified Physical V

iew of a Network

The logical view describes how communication on a PROFIBUS network

takes place through logical connections between station pairs. A logical

connection relationship consists of four parts:

Local station address

Remote station address

Local LSAP (Link Service Access Point)

Remote LSAP

For each station in the connection, the local values must be equal to the

remote values of the other station, as shown in Figure 1-6. On any station, a

local LSAP can be used for only one connection (except for FMS slaves).

Station

Local Address = 5

Remote Address = 4

Local LSAP = 8

Remote LSAP = 7

Station 4

Local Address = 4

Remote Address = 5

Local LSAP = 7

Remote LSAP = 8

Figure 1-6 Example

Connection between Stations

Network

Communication

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Siemens EF 83H Series Bedienungsanleitung Seite 25