ISO 20242-1:2005

INTERNATIONAL ISO
STANDARD 20242-1
First edition
2005-10-15
Industrial automation systems and
integration — Service interface for testing
applications —
Part 1:
Overview
Systèmes d'automatisation industrielle et intégration — Interface de
service pour contrôler les applications —
Partie 1: Vue d'ensemble
Reference number
©
ISO 2005
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ii © ISO 2005 – All rights reserved

Contents
1 Scope.1
2    Terms and definitions .1
3    Abbreviations.2
4    Service interface concept.3
4.1 General.3
4.2 Platform adapter .4
4.2.1 Features.4
4.2.2 Device communication aspects.4
4.3 Device driver .5
4.3.1
Features.5
4.3.2 Device communication aspects.5
4.4 Device capability description .5
4.4.1 Features.5
4.4.2
Modules .6
4.4.3 Interfaces.6
4.4.4
Communication objects.7
4.4.5 Behaviour of virtual devices.7
4.5 Coordinator .7
Annex A (informative)   Use case for ISO 20242.9
A.1 Activities of users.9
A.2 Activities of vendors .9
A.3 Further activities.9
Annex B (informative)   State diagram for virtual devices .10
Annex C (informative)   Cascading of device drivers .11

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 20242-1 was prepared by Technical Committee ISO/TC 184, Industrial automation systems and
integration, Subcommittee SC 5, Architecture, communications and integration frameworks.
In addition to this part, ISO 20242 is envisaged to consist of several more parts dealing with:
• Resource management service interface;
• Virtual device service interface;
• Device capability profile template;
• Application program service interface;
• Conformance test methods, criteria and reports.

iv © ISO 2005 – All rights reserved

Introduction
The motivation for this International Standard stems from international automotive industries and their suppliers to
facilitate the integration of automation and measurement devices, and other peripheral components for this purpose,
into computer based applications. It defines rules for the construction of device drivers and their behaviour in the
context of an automation and/or measurement application.
The main goal of ISO 20242 is to provide users with:
• independence from the computer operating system;
• independence from the device connection technology (device interface/network);
• independence from device suppliers;
• the ability to certify device drivers with connected devices and their behaviour in the context of a given computer
platform;
• independence from the technological device development in the future.
ISO 20242 will not involve the development of new device families or the use of special interface technologies
(networks). It encapsulates a device and its communication interface to make it compatible with other devices of
that kind for a given application.

INTERNATIONAL STANDARD ISO 20242-1:2005(E)

Industrial automation systems and integration — Service
interface for testing applications —
Part 1:
Overview
1 Scope
This part of ISO 20242 provides an overview of the particularities of this International Standard and its use in the
computer aided testing environment.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
application program
resource designed to help users perform a specific task
NOTE In this International Standard, an application program does any task necessary to run a computer-aided test station
running, with the special requirement that communication with peripheral devices is done.
2.2
application program service interface
interface to communicate with a coordinator
NOTE This will be specified in another part of ISO 20242.
2.3
communication object
existing object which may be accessed with a communication function to read or write a value
2.4
coordinator
program with a specified interface to handle the access of an application program to one or more device drivers
and to manage real-time application aspects, synchronization and events
2.5
device capability description
text file containing information about the capabilities of virtual devices in a defined format (i.e. structure, syntax)
NOTE This will be specified in another part of ISO 20242.
2.6
device driver
program with an ISO 20242-specified interface containing service functions that call the platform adapter to access
physical devices
2.7
interface
keyword identifying a class for the description of device functions
NOTE A device function inside the device driver is an instance of such an interface.
2.8
interface driver
program handling the data transfer via a peripheral interface
2.9
module
ISO 20242-defined keyword, identifying a class for the description of virtual devices
NOTE A virtual device inside the device driver is an instance of a module.
2.10
platform adapter
program with an ISO 20242-specified interface, encapsulating the computer hardware and its periphery and
providing services to communicate with connected devices and to use other resources of the computer operating
system
2.11
resource management service interface
set of ISO 20242-specified service functions to communicate with a platform adapter
2.12
virtual device
representation of one or more physical devices and/or stand-alone program entities to provide an unambiguous
view on the resources of a communication interface
2.13
virtual device service interface
set of ISO 20242-specified service functions to communicate with a virtual device
NOTE These service functions use the Resource Management Service Interface (platform adapter) to access physical
devices and/or provide the needed capabilities by contained software tasks.

3 Abbreviations
APSI Application Program Service Interface
ASCII American Standard Code for Information Interchange
CAQ Computer Aided Quality Assurance
CAT Computer Aided Testing
CIM Computer Integrated Manufacturing
CORBA Common Object Request Broker Architecture
DCD Device Capability Description
DCPT Device Capability Profile Template
OOP Object-Oriented Programming
PA Platform Adapter
PDU Protocol Data Unit
RMSI Resource Management Service Interface
XML eXtensible Markup Language
VD Virtual Device
VDSI Virtual Device Service Interface
2 © ISO 2005 – All rights reserved

Testing Application Program (CAT)
Device Capability
Application Program Service Interface
Profile Template
Coordinator (Software)
Device
Virtual Device Service Interface
Capability
Description
(File)
Device
Device Device
Driver
Driver Driver
(Software)
(Software) (Software)
Resource Management Service Interface
Platform Adapter (Software)
Virtual Virtual
Computer Operation System
Device Device
Physical Physical Physical Physical
Device Device Device Device
Figure 1 ― Service interfaces defined in ISO 20242
4 Service interface concept
4.1 General
An essential function of an ongoing manufacturing operation is its quality assurance to make sure that high quality
is designed into the product and that the manufacturing operation produces the desired quality. For control of this
quality, test stations are implemented which may be part of the manufacturing process itself or are stand-alone
systems. The computer is an extremely effective tool to control test stations, monitor performance of processes,
collect and evaluate data, and issue quality reports.
The use of computers in test stations is called Computer-Aided Testing (CAT), which falls under the Computer-
Aided Quality Control (CAQ) heading in the Computer Integrated Manufacturing (CIM) terminology. Test stations
use measurement and automation devices to acquire data and to control test scenarios (see Figure 1).
The application programs on computers in CAT communicate with automation and measurement devices via
interfaces. This part of ISO 20242 defines the Application Program Service Interface (APSI) that contains a list of
defined services to access any number of device drivers with included virtual devices.
Device drivers are software modules with another interface defined by this part of ISO 20242, the Virtual Device
Service Interface (VDSI). They present the capabilities of peripheral devices and optional software resources inside
the driver via virtual devices. The structure of virtual devices and their status regarding communication is captured
by a device capability description (DCD). For the creation of the DCD, which is an ASCII file, this part of ISO 20242
defines the Device Capability Profile T
...