BS EN 61158-4-20:2014
$189.07
Industrial communication networks. Fieldbus specifications – Data-link layer protocol specification. Type 20 elements
| Published By | Publication Date | Number of Pages |
| BSI | 2014 | 46 |
1.1 General
The data-link layer provides basic time-critical messaging communications between devices in an automation environment.
This protocol provides a means of connecting devices through a partial mesh network, such that most failures of an interconnection between two devices can be circumvented. In common practice the devices are interconnected in a non-redundant hierarchical manner reflecting application needs
1.2 Specifications
This International Standard specifies
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procedures for the timely transfer of data and control information from one data-link user entity to a peer user entity, and among the data-link entities forming the distributed data-link service provider;
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the structure of the fieldbus DLPDUs used for the transfer of data and control information by the protocol of this standard, and their representation as physical interface data units.
1.3 Procedures
The procedures are defined in terms of
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the inter actions between peer DL-entities (DLEs) through the exchange of fieldbus DLPDUs;
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the interactions between a DL-service (DLS) provider and a DLS-user in the same system through the exchange of DLS primitives;
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the interactions between a DLS-provider and a Ph-service provider in the same system through the exchange of Ph-service primitives.
1.4 Applicability
These procedures are applicable to instances of communication between systems which support time-critical communications services within the data-link layer of the OSI or fieldbus reference models, and which require the ability to interconnect in an open systems interconnection environment.
Profiles provide a simple multi-attribute means of summarizing an implementation’s capabilities, and thus its applicability to various time-critical communications needs.
1.5 Conformance
This International Standard also specifies conformance requirements for systems implementing these procedures. This standard does not contain tests to demonstrate compliance with such requirements.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 6 | English CONTENTS |
| 8 | INTRODUCTION |
| 9 | 1 Scope 1.1 General 1.2 Specifications 1.3 Procedures 1.4 Applicability 1.5 Conformance |
| 10 | 2 Normative references 3 Terms, definitions, symbols and abbreviations 3.1 Reference model terms and definitions |
| 11 | 3.2 Service convention terms and definitions |
| 12 | 3.3 Common terms and definitions |
| 13 | Figures Figure 1 – Relationships of DLSAPs, DLSAP-addresses and group DLaddresses |
| 14 | 3.4 Additional Type 20 definitions |
| 20 | 3.5 Common symbols and abbreviations 3.5.1 Data units 3.5.2 Miscellaneous |
| 21 | 3.6 Additional Type 20 symbols and abbreviations |
| 22 | 4 Data-link layer protocol specification 4.1 Overview |
| 23 | 4.2 Parameters, timers and variables 4.2.1 Parameters |
| 24 | 4.2.2 Timers 4.2.3 Variables |
| 25 | 4.3 Logical link control 4.3.1 General DLPDU structure Figure 2 – DLPDU Structure Figure 3 – Delimiter Structure |
| 26 | Figure 4 – Construction of 1-octet address field |
| 27 | Figure 5 – Construction of 5-octet address field Figure 6 – APDU format |
| 28 | 4.3.2 DLPDU specific encoding and procedures |
| 29 | 4.3.3 Framing 4.3.4 Error detection Figure 7 – DLPDU framing |
| 30 | 4.3.5 Slave response to communication error Figure 8 – Two dimensional parity detection |
| 31 | Figure 9 – Communication error response DLL payload Tables Table 1 – Slave response to communication error Table 2 – Communication error code values |
| 32 | 4.4 Medium access control 4.4.1 Overview |
| 33 | Figure 10 – MAC state machines Figure 11 – Master controlled medium access |
| 34 | 4.4.4 Token passing summary Figure 12 – Burst mode controlled medium access Table 3 – Token passing |
| 35 | 4.4.5 XMIT machine Figure 13 – XMIT state machine Table 4 – XMIT state transitions |
| 36 | 4.4.6 RECV machine Figure 14 – RECV state machine |
| 37 | 4.4.7 Slave MAC machine Table 5 – RECV state transitions |
| 38 | Figure 15 – Slave MAC state machine |
| 39 | Table 6 – Slave MAC state transitions |
| 40 | 4.4.8 Master MAC machine Figure 16 – Master MAC state machine |
| 41 | Table 7 – Master MAC state transitions |
| 43 | 4.5 DL-management-information Table 8 – Master DL parameters Table 9 – Slave DL parameters |
| 44 | Bibliography |
