wilamowski-b-m-irwin-j-d-industrial-communication-systems-2011

32
Profibus
Max Felser
Bern University of
Applied Sciences
Ron Mitchell
RC Systems
32.1 Introduction..................................................................................... 32-1
32.2 Physical Transmissions.................................................................. 32-2
Asynchronous (RS-485). •. Manchester Bus Powered. •. Fiber Optics
32.3 Fieldbus Data Link..........................................................................32-5
Services. •. Framing. •. Media Access
32.4 DP System......................................................................................... 32-7
DP-Master Class 1: Controllers. •. DP-Master Class 2: Engineering
Stations. •. DP-Slaves: Field-Devices. •. Application Relations
32.5 Cyclic Data Exchange: MS0—Relation........................................32-9
Device Model. •. Initialization and Supervision of the Relation. •. .
Status of the Controller and Fail-Safe Functionality. •. Diagnostics
of the Field-Device. •. Distributed Database. •. Synchronization
of the Applications
32.6 Acyclic Data Exchange: MS1/MS2 Relations............................ 32-10
Variables. •. Device Model including Identification
and Maintenance. •. Alarm Handling. •. Procedure Calls
32.7 Application Profiles....................................................................... 32-12
References.................................................................................................. 32-12
32.1 Introduction
The Profibus (PROcess FIeld BUS) was defined by a consortium of different manufacturers and research
institutions in Germany more than 20 years ago and defined from the beginning as an open national
standard DIN 19245. It is a simple fieldbus based on an extended token passing and object-oriented
services to provide distributed control based on a simplified and adapted version of ISO 69506 manufacturing
message specification (MMS) called the fieldbus message specification (FMS). But the industry
did not want a distributed system and adopted a simple remote I/O system with centralized control.
So the Profibus-FMS was extended with an application protocol for decentralized periphery (DP) we
call here Profibus DP. To cope with the requirements of process automation, additional definitions for
transmission media and function blocks are added and collected under the name Profibus PA. All these
definitions were brought to the European standard EN50170-2. Finally, the Versions PA and DP are
today part of the international standard IEC 61158 [IEC58] and IEC 61784 [IEC84-1] under the designation
“Family 3” with subdivisions 3/1 and 3/2. The functionality of Profibus DP can further be split in
three levels: DPV0 for simple remote I/O, DP-V1 for additional acyclic data exchange, and DP-V2 for
high-performance functions like isochronous cycles and broadcast data exchange. Table 32.1 shows
their assignment.
The “PROFIBUS Nutzerorganisation” (PNO), representing the interested enterprises and institutes in this
technology, was founded as early as 1989 in Germany. Profibus is today supported by Profibus & Profinet
International (PI), an umbrella organization formed out of more than 30 Regional Profibus Associations
(RPA) on all continents like the PNO for Germany or the PTO representing the North American market.
32-1
© 2011 by Taylor and Francis Group, LLC