Specifications

Overview Profibus DP
Quick Start Guide for the MELSEC STlite Series 2 - 1
2 Profibus DP
2.1 Overview
Profibus is one of the most widely used automation networks in Europe. It provides a wide possible
range of compatible devices while delivering fast and robust communication.
Profibus offers users the option to mix devices from different companies. It is an open network rang-
ing from simple I/O stations through to complex PLCs. The network allows extremely fast data
exchange with a wide variety of slave devices.
Profibus DP (Decentralized Peripherals) is used to operate sensors and actuators via a centralized con-
troller in production (factory) automation applications.
As this is an open network, Mitsubishi Profibus units can also be connected to master and slave
devices from other manufacturers.
Structure
A Profibus DP system consists of a master and up to 124 slaves.
● Master: A Profibus DP Master exchanges the data with the slaves via Profibus DP and controls the
bus. It transfers the data between a supervisory control (e. g. a PLC) and the decentralized
peripheral equipment. The master cyclically reads the input data from the slaves and cyclically
writes the output data to the slaves
● Slave: Profibus DP slaves are the link to the field side. They edit the input data of the peripheral
equipment for the communication with the master and output the master data to the peripheral
equipment.
All field devices are typically connected in a line structure with up to 32 nodes (master and slaves) in
one segment. The beginning and end of each segment must be terminated with a resistor. These
resistors are usually implemented as optionally activatable in the devices or plugs. If there are more
than 32 nodes or the network span is being extended, repeaters must be used to link the networks.
Fig. 2-1: Typical Profibus configuration
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Slaves