GE GFK-2193A user manual Profibus Basics, Profibus Network Overview, Bus Communication

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PROFIBUS Basics

PROFIBUS Network Overview

•PROFIBUS is an open, vendor independent FieldBus standard for a wide range of applications in industrial automation, including motion control.

•PROFIBUS is a dynamic technology that grows functionally while complying with the European FieldBus Standard EN 50 170.

•PROFIBUS Guidelines and Profiles provide the means for further technical development based on the ever-changing communication requirements of the networks, systems, and devices used in today's industrial automation applications.

PROFIBUS specifications reference three different protocols to cover a range of industrial requirements:

•PROFIBUS-DPHigh speed data communication. DP stands for Decentralized Periphery. In practice, the majority of slave applications are DP applications.

•PROFIBUS-FMSObject oriented general-purpose data communication. FMS stands for FieldBus Message Specification. FMS protocol devices may exchange data on the same bus used for DP devices.

•PROFIBUS-PAMeets requirements for intrinsic safety and non-intrinsic safety areas and includes bus powered field devices.

Note: The PROFIBUS logo is a registered trademark of the PROFIBUS International Organization. Membership in the organization is open to all individuals, companies and organizations. More information about the organization and the protocol is available at http://www.profibus.com

Bus Communication

The PROFIBUS specification defines the technical characteristics of a serial field bus system that links distributed digital controllers on the network, from field level to cell level. PROFIBUS is a multi-master system that allows the joint operation of several automation, engineering or visualization systems with their distributed peripherals on one bus. PROFIBUS distinguishes between the following types of devices:

•Master devices determine the data communication on the bus. A master can send messages without an external request when it holds the bus access rights (the token). Masters are also called active stations.

•Slave devices include motion controllers, drives, I/O devices, valves, and transducers. Slaves do not have bus access rights and can only acknowledge received messages or send messages to the master when requested to do so. Slave devices are passive stations and require only small portions of the bus protocol.

The majority of PROFIBUS-DP applications are located at the field level. The field level typically includes slave devices such as the S2K motion controller station and host devices like PLC or PC control systems for the PROFIBUS-DP master station. Operator interfaces and DCS type systems usually operate at the cell level.

GFK-2121A Chapter 1 Overview and Specifications 1-3