DS DS/EN 61158-5-17: Industrial communication networks - Fieldbus specifications - Part 5-17: Application layer service definition - Type 17 elements

1.1 Overview
The fieldbus Application Layer (FAL) provides user programs with a means to access the fieldbus communication environment. In this respect, the FAL can be viewed as a "window between corresponding application programs."
This standard provides common elements for basic time-critical and non-time-critical messaging communications between application programs in an automation environment and material specific to Type 17 fieldbus. The term "time-critical" is used to represent the presence of a time-window, within which one or more specified actions are required to be completed with some defined level of certainty. Failure to complete specified actions within the time window risks failure of the applications requesting the actions, with attendant risk to equipment, plant and possibly human life.
This standard defines in an abstract way the externally visible service provided by the different Types of the fieldbus Application Layer in terms of a) an abstract model for defining application resources (objects) capable of being manipulated by users via the use of the FAL service,
b) the primitive actions and events of the service;
c) the parameters associated with each primitive action and event, and the form which they
take; and
d) the interrelationship between these actions and events, and their valid sequences.
The purpose of this standard is to define the services provided to
1) the FAL user at the boundary between the user and the Application Layer of the Fieldbus Reference Model, and
2) Systems Management at the boundary between the Application Layer and Systems Management of the Fieldbus Reference Model.
This standard specifies the structure and services of the IEC fieldbus Application Layer, in conformance with the OSI Basic Reference Model (ISO/IEC 7498) and the OSI Application Layer Structure (ISO/IEC 9545).
FAL services and protocols are provided by FAL application-entities (AE) contained within the application processes. The FAL AE is composed of a set of object-oriented Application Service Elements (ASEs) and a Layer Management Entity (LME) that manages the AE. The ASEs provide communication services that operate on a set of related application process object (APO) classes. One of the FAL ASEs is a management ASE that provides a common set of services for the management of the instances of FAL classes.
Although these services specify, from the perspective of applications, how request and responses are issued and delivered, they do not include a specification of what the requesting and responding applications are to do with them. That is, the behavioral aspects of the applications are not specified; only a definition of what requests and responses they can send/receive is specified. This permits greater flexibility to the FAL users in standardizing such object behavior. In addition to these services, some supporting services are also defined in this standard to provide access to the FAL to control certain aspects of its operation.

APPLICATION LAYER

APPLICATIONS

BUS SYSTEMS

BUSES (DATA PROCESSING)

CIRCUIT NETWORKS

COMMUNICATION

COMPUTER APPLICATIONS

COMPUTERIZED CONTROL

CONTROL

CONTROL EQUIPMENT

CONTROL SYSTEMS

CONTROL TECHNOLOGY

DATA BUS

DATA COMMUNICATION

DATA EXCHANGE

DATA LINE

DATA LINK SYSTEM

DATA NETWORK

DATA PROCESSING

DATA SERVICES

DATA TRANSFER

DATA TRANSMISSION CONTROL PROCEDURES

DEFINITION

DEFINITIONS

DIGITAL

DIGITAL DATA

DIGITAL ENGINEERING

EDP

ELECTRICAL ENGINEERING

ELECTRONIC INSTRUMENTS

ELECTRONIC SYSTEMS

FIELD BUS

GUIDANCE SYSTEMS

INDUSTRIAL

INDUSTRIAL FACILITIES

INFORMATION INTERCHANGE

INFORMATION PROCESSING

INFORMATION TECHNOLOGY

INTERFACES (DATA PROCESSING)

OPEN SYSTEMS INTERCONNECTION

OPERATIONAL TECHNIQUES

OSI

PROCESS CONTROL ENGINEERING

SERVICES

SPECIFICATION

SPECIFICATION (APPROVAL)

TRANSMISSION MEDIA

USE

IMPLEMENTATION

BUSES (VEHICLES)

INFORMATION EXCHANGE

INTERFACES OF ELECTRICAL CONNECTIONS

INTERFACES

MECHANICAL INTERFACES