ifm electronic RM3001 - Handbuch (Seite 40)

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1 General information
This manual describes installation and configuration options of the Heidenhain devices with Profibus-DP
interface. For applications with increased ambient temperatures the Profibus-DP gateway is to be
preferred. Encoders with integrated Profibus-DP interface are advantageous if a compact solution is
required.
In view of the certification by PNO (Profibus user organisation) all products can be used in all Profibus-DP
systems without restrictions. Among others this means that all possible baud rates, the complete address
range and the device characteristics are supported according to the Profibus device profile for encoders.
1.1 Profibus technology
Profibus is manufacturer-independent and open field bus standard defined by the international standards
EN 50170 and EN 50254. Profibus enables the communication with devices of different manufacturers.
Profibus is suited for time-critical applications as well as for complex tasks. Other technical and
manufacturer-independent information is available on the Internet (http://www.profibus.com).
1.2 Encoder device profile
The encoder device profile for Profibus-DP defines the functionality of the measuring instruments
connected to Profibus-DP. The operating functions are divided into two device classes:
Measuring instruments of class 1 offer basic functions that all Profibus-DP measuring instruments must
support. A measuring instrument of class 1 can optionally support selected functions of class 2 but these
functions must be implemented according to the profile. To support early Profibus-DP implementations the
size of the protocol data units (PDU) is limited to 16 bytes.
Measuring instruments of class 2 must support all functions of class 1 as well as of class 2.
In addition to the two classes parameters and diagnostic ranges are reserved for manufacturer-specific
functions. The position value of the measuring instrument is transferred in binary format.
The device profile can be ordered at PNO in Karlsruhe (order no. 3.062)
1.3 Abbreviations
DP Decentralised Periphery
DDLM Direct Data Link Mapper, the interface between the
PROFIBUS-DP functions and the measuring instrument software
PDU Protocol Data Unit
PI PROFIBUS International
PNO PROFIBUS Nutzerorganisation e.V. (Profibus user organisation)
PROFIBUS Process Field Bus