ISO 20216:2015

Space data and information transfer systems — Spacecraft onboard interface services — Device data pooling service

ISO 20216:2015 is one of a family of documents specifying Spacecraft Onboard Interface Services (SOIS)-compliant service to be provided to onboard applications. ISO 20216:2015 is to define the services and service interfaces provided by the SOIS Device Data Pooling Service (DDPS). Its scope is to specify the service only and not to specify methods of providing the service, although use of the SOIS subnetwork services is assumed. ISO 20216:2015 conforms to the principles set out in the SOIS Green Book (reference [C2]) and is intended to be applied together with it.

Systèmes de transfert des informations et données spatiales — Services d'interfaces à bord des véhicules spatiaux — Service de groupage des données des périphériques

General Information

• Status: Withdrawn
• Publication Date: 10-Aug-2015
• Withdrawal Date: 10-Aug-2015
• ICS: 49.140 - Space systems and operations
• Technical Committee: ISO/TC 20/SC 13 - Space data and information transfer systems
• Drafting Committee: ISO/TC 20/SC 13 - Space data and information transfer systems
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 30-Nov-2017

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 20216
First edition
2015-08-15
Space data and information transfer
systems — Spacecraft onboard
interface services — Device data
pooling service
Systèmes de transfert des informations et données spatiales —
Services d’interfaces à bord des véhicules spatiaux — Service de
groupage des données des périphériques
Reference number
ISO 20216:2015(E)
©
ISO 2015

---------------------- Page: 1 ----------------------
ISO 20216:2015(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2015 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 20216:2015(E)
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 20216 was prepared by the Consultative Committee for Space Data Systems (CCSDS) (as
CCSDS 871.1-M-1, November 2012) and was adopted (without modifications except those stated in clause 2
of this International Standard) by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee
SC 13, Space data and information transfer systems.

© ISO 2015 – All rights reserved iii

---------------------- Page: 3 ----------------------
Recommendation for Space Data System Practices
SPACECRAFT ONBOARD
INTERFACE SERVICES—
DEVICE DATA POOLING
SERVICE
RECOMMENDED PRACTICE
CCSDS 871.1-M-1
MAGENTA BOOK
November 2012

---------------------- Page: 4 ----------------------
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE
AUTHORITY



Issue: Recommended Practice, Issue 1
Date: November 2012
Location: Washington, DC, USA

This document has been approved for publication by the Management Council of the
Consultative Committee for Space Data Systems (CCSDS) and represents the consensus
technical agreement of the participating CCSDS Member Agencies. The procedure for
review and authorization of CCSDS documents is detailed in Organization and Processes for
the Consultative Committee for Space Data Systems (CCSDS A02.1-Y-3), and the record of
Agency participation in the authorization of this document can be obtained from the CCSDS
Secretariat at the address below.


This document is published and maintained by:

CCSDS Secretariat
Space Communications and Navigation Office, 7L70
Space Operations Mission Directorate
NASA Headquarters
Washington, DC 20546-0001, USA
CCSDS 871.1-M-1 Page i November 2012
© ISO 2015 – All rights reserved

---------------------- Page: 5 ----------------------
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE
STATEMENT OF INTENT
The Consultative Committee for Space Data Systems (CCSDS) is an organization officially
established by the management of its members. The Committee meets periodically to address
data systems problems that are common to all participants, and to formulate sound technical
solutions to these problems. Inasmuch as participation in the CCSDS is completely
voluntary, the results of Committee actions are termed Recommendations and are not in
themselves considered binding on any Agency.
CCSDS Recommendations take two forms: Recommended Standards that are prescriptive
and are the formal vehicles by which CCSDS Agencies create the standards that specify how
elements of their space mission support infrastructure shall operate and interoperate with
others; and Recommended Practices that are more descriptive in nature and are intended to
provide general guidance about how to approach a particular problem associated with space
mission support. This Recommended Practice is issued by, and represents the consensus of,
the CCSDS members. Endorsement of this Recommended Practice is entirely voluntary
and does not imply a commitment by any Agency or organization to implement its
recommendations in a prescriptive sense.
No later than five years from its date of issuance, this Recommended Practice will be
reviewed by the CCSDS to determine whether it should: (1) remain in effect without change;
(2) be changed to reflect the impact of new technologies, new requirements, or new
directions; or (3) be retired or canceled.
In those instances when a new version of a Recommended Practice is issued, existing
CCSDS-related member Practices and implementations are not negated or deemed to be non-
CCSDS compatible. It is the responsibility of each member to determine when such Practices
or implementations are to be modified. Each member is, however, strongly encouraged to
direct planning for its new Practices and implementations towards the later version of the
Recommended Practice.
CCSDS 871.1-M-1 Page ii November 2012
© ISO 2015 – All rights reserved

---------------------- Page: 6 ----------------------
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE
FOREWORD
This document is a technical Recommended Practice for use in developing flight and ground
systems for space missions and has been prepared by the Consultative Committee for Space
Data Systems (CCSDS). The Device Data Pooling Service described herein is intended for
missions that are cross-supported between Agencies of the CCSDS, in the framework of the
Spacecraft Onboard Interface Services (SOIS) CCSDS area.
This Recommended Practice specifies a set of related services to be used by space missions
to access pooled data acquired from devices over an onboard subnetwork. The SOIS Device
Data Pooling Service provides a common service interface and quality of service regardless
of the particular type of data link or protocol being used for communication.
Through the process of normal evolution, it is expected that expansion, deletion, or
modification of this document may occur. This Recommended Practice is therefore subject
to CCSDS document management and change control procedures, which are defined in the
Organization and Processes for the Consultative Committee for Space Data Systems
(CCSDS A02.1-Y-3). Current versions of CCSDS documents are maintained at the CCSDS
Web site:
http://www.ccsds.org/
Questions relating to the contents or status of this document should be addressed to the
CCSDS Secretariat at the address indicated on page i.
CCSDS 871.1-M-1 Page iii November 2012
© ISO 2015 – All rights reserved

---------------------- Page: 7 ----------------------
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE
At time of publication, the active Member and Observer Agencies of the CCSDS were:
Member Agencies
– Agenzia Spaziale Italiana (ASI)/Italy.
– Canadian Space Agency (CSA)/Canada.
– Centre National d’Etudes Spatiales (CNES)/France.
– China National Space Administration (CNSA)/People’s Republic of China.
– Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)/Germany.
– European Space Agency (ESA)/Europe.
– Federal Space Agency (FSA)/Russian Federation.
– Instituto Nacional de Pesquisas Espaciais (INPE)/Brazil.
– Japan Aerospace Exploration Agency (JAXA)/Japan.
– National Aeronautics and Space Administration (NASA)/USA.
– UK Space Agency/United Kingdom.
Observer Agencies
– Austrian Space Agency (ASA)/Austria.
– Belgian Federal Science Policy Office (BFSPO)/Belgium.
– Central Research Institute of Machine Building (TsNIIMash)/Russian Federation.
– China Satellite Launch and Tracking Control General, Beijing Institute of Tracking
and Telecommunications Technology (CLTC/BITTT)/China.
– Chinese Academy of Sciences (CAS)/China.
– Chinese Academy of Space Technology (CAST)/China.
– Commonwealth Scientific and Industrial Research Organization (CSIRO)/Australia.
– CSIR Satellite Applications Centre (CSIR)/Republic of South Africa.
– Danish National Space Center (DNSC)/Denmark.
– Departamento de Ciência e Tecnologia Aeroespacial (DCTA)/Brazil.
– European Organization for the Exploitation of Meteorological Satellites
(EUMETSAT)/Europe.
– European Telecommunications Satellite Organization (EUTELSAT)/Europe.
– Geo-Informatics and Space Technology Development Agency (GISTDA)/Thailand.
– Hellenic National Space Committee (HNSC)/Greece.
– Indian Space Research Organization (ISRO)/India.
– Institute of Space Research (IKI)/Russian Federation.
– KFKI Research Institute for Particle & Nuclear Physics (KFKI)/Hungary.
– Korea Aerospace Research Institute (KARI)/Korea.
– Ministry of Communications (MOC)/Israel.
– National Institute of Information and Communications Technology (NICT)/Japan.
– National Oceanic and Atmospheric Administration (NOAA)/USA.
– National Space Agency of the Republic of Kazakhstan (NSARK)/Kazakhstan.
– National Space Organization (NSPO)/Chinese Taipei.
– Naval Center for Space Technology (NCST)/USA.
– Scientific and Technological Research Council of Turkey (TUBITAK)/Turkey.
– Space and Upper Atmosphere Research Commission (SUPARCO)/Pakistan.
– Swedish Space Corporation (SSC)/Sweden.
– United States Geological Survey (USGS)/USA.
CCSDS 871.1-M-1 Page iv November 2012
© ISO 2015 – All rights reserved

---------------------- Page: 8 ----------------------
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE
DOCUMENT CONTROL

Document Title Date Status
CCSDS Spacecraft Onboard Interface November Original issue
871.1-M-1 Services—Device Data Pooling 2012
Service, Recommended Practice,
Issue 1




CCSDS 871.1-M-1 Page v November 2012
© ISO 2015 – All rights reserved

---------------------- Page: 9 ----------------------
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE
CONTENTS
Section Page
1 INTRODUCTION . 1-1

1.1 PURPOSE AND SCOPE OF THIS DOCUMENT . 1-1
1.2 APPLICABILITY . 1-1
1.3 RATIONALE . 1-1
1.4 DOCUMENT STRUCTURE . 1-1
1.5 CONVENTIONS AND DEFINITIONS. 1-2
1.6 TERMS DEFINED IN THIS RECOMMENDED PRACTICE . 1-2
1.7 NOMENCLATURE . 1-3
1.8 REFERENCES . 1-4

2 OVERVIEW . 2-1

2.1 FUNCTION . 2-1
2.2 CONTEXT . 2-1
2.3 PURPOSE AND OPERATION OF THE DEVICE DATA POOLING SERVICE 2-6

3 DEVICE DATA POOLING SERVICE . 3-1

3.1 PROVIDED SERVICE . 3-1
3.2 EXPECTED SERVICE FROM UNDERLYING LAYERS . 3-1
3.3 SERVICE PARAMETERS . 3-2
3.4 DEVICE DATA POOLING SERVICE PRIMITIVES . 3-4

4 MANAGEMENT INFORMATION BASE . 4-1

4.1 GENERAL . 4-1
4.2 SPECIFICATIONS . 4-1
4.3 MIB GUIDANCE . 4-1
4.4 ACQUISITION ORDER TABLE . 4-1
4.5 ACQUISITION TIMING ACCURACY . 4-2
4.6 MAXIMUM DEVICE VALUES PER ACQUISITION ORDER . 4-2
4.7 MAXIMUM HISTORY SIZE . 4-2

ANNEX A DEVICE DATA POOLING SERVICE PROTOCOL
IMPLEMENTATION CONFORMANCE STATEMENT
PROFORMA (NORMATIVE) . A-1
ANNEX B SECURITY CONSIDERATIONS (INFORMATIVE) .B-1
ANNEX C INFORMATIVE REFERENCES (INFORMATIVE) . C-1
ANNEX D ABBREVIATIONS AND ACRONYMS (INFORMATIVE) . D-1
CCSDS 871.1-M-1 Page vi November 2012
© ISO 2015 – All rights reserved

---------------------- Page: 10 ----------------------
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE
CONTENTS (continued)
Figure Page
2-1 Device Data Pooling Service Context . 2-1
2-2 Relationship between SOIS Command and Data Acquisition Services . 2-2
2-3 Data Pool Examples . 2-3
2-4 Conceptual Architecture for Synchronizing Acquisitions with
Underlying Transport Services . 2-6

CCSDS 871.1-M-1 Page vii November 2012
© ISO 2015 – All rights reserved

---------------------- Page: 11 ----------------------
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE
1 INTRODUCTION
1.1 PURPOSE AND SCOPE OF THIS DOCUMENT
This document is one of a family of documents specifying Spacecraft Onboard Interface
Services (SOIS)-compliant service to be provided to onboard applications.
The purpose of this document is to define the services and service interfaces provided by the
SOIS Device Data Pooling Service (DDPS). Its scope is to specify the service only and not to
specify methods of providing the service, although use of the SOIS subnetwork services is
assumed.
This document conforms to the principles set out in the SOIS Green Book (reference [C2])
and is intended to be applied together with it.
1.2 APPLICABILITY
This document applies to any mission or equipment claiming to provide a SOIS-compatible
Device Data Pooling Service.
1.3 RATIONALE
SOIS provides service interface specifications in order to promote interoperability and
development reuse via peer-to-peer and vertical standardization.
1.4 DOCUMENT STRUCTURE
This document has four major sections and three annexes:
– this section, containing administrative information, definitions, and references;
– section 2, containing general concepts and assumptions;
– section 3, containing the Device Data Pooling Service specification;
– section 4, containing the Management Information Base (MIB) for this service;
– annex A, comprising the Service Conformance Statement Proforma;
– annex B, discussing security considerations;
– annex C, containing a list of informative references.
CCSDS 871.1-M-1 Page 1-1 November 2012
© ISO 2015 – All rights reserved

---------------------- Page: 12 ----------------------
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE
1.5 CONVENTIONS AND DEFINITIONS
1.5.1 DEFINITIONS
1.5.1.1 General
For the purpose of this document the following definitions apply.
1.5.1.2 Definitions from the Open Systems Interconnection Basic Reference Model
This document is defined using the style established by the Open Systems Interconnection
(OSI) Basic Reference Model (reference [C1]). This model provides a common framework for
the development of standards in the field of systems interconnection.
The following terms used in this Recommended Practice are adapted from definitions given
in reference [C1]:
layer: Subdivision of the architecture, constituted by subsystems of the same rank.
service: Capability of a layer, and the layers beneath it (a service provider), provided to the
service users at the boundary between the service providers and the service users.
1.6 TERMS DEFINED IN THIS RECOMMENDED PRACTICE
For the purposes of this Recommended Practice, the following definitions also apply.
acquisition: The act of acquiring a sample for an acquisition order.
acquisition order: Application-defined request to the service to acquire samples periodically
and cache a history of them, so that the application can, on demand, acquire the samples from
the service without having to access the devices directly.
application: Component of the onboard software that makes use of the Device Data Pooling
service.
NOTE – Such components include flight software applications and higher-layer services.
data pool: Time-ordered cache of samples acquired for an acquisition order.
NOTE – A data pool is similar in concept to a database of the latest available data, or a
bulletin board.
device: A real hardware component or a single register within such a component.
NOTE – Examples of such components are sensors and actuators.
device identifier: Abstract identification of a device.
CCSDS 871.1-M-1 Page 1-2 November 2012
© ISO 2015 – All rights reserved

---------------------- Page: 13 ----------------------
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE
NOTE – The format of a device identifier is implementation-specific.
sample: Set of data values acquired from different devices at the same time, in response to
an acquisition order.
value: Formatted atomic unit of data that is acquired from a device.
timestamp: Time associated with a value.
NOTES
1 The format of a timestamp is implementation-specific.
2 The timestamp may indicate the time the value was generated by the device, emitted
by the device, or acquired by the service. This is implementation-specific.
1.7 NOMENCLATURE
1.7.1 NORMATIVE TEXT
The following conventions apply for the normative specifications in this Recommended
Standard:
a) the words ‘shall’ and ‘must’ imply a binding and verifiable specification;
b) the word ‘should’ implies an optional, but desirable, specification;
c) the word ‘may’ implies an optional specification;
d) the words ‘is’, ‘are’, and ‘will’ imply statements of fact.
NOTE – These conventions do not imply constraints on diction in text that is clearly
informative in nature.
1.7.2 INFORMATIVE TEXT
In the normative sections of this document (sections 3-4 and annex A), informative text is set
off from the normative specifications either in notes or under one of the following subsection
headings:
– Overview;
– Background;
– Rationale;
– Discussion.
CCSDS 871.1-M-1 Page 1-3 November 2012
© ISO 2015 – All rights reserved

---------------------- Page: 14 ----------------------
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE
1.8 REFERENCES
The following documents contain provisions which, through reference in this text, constitute
provisions of this Recommended Practice. At the time of publication, the editions indicated
were valid. All documents are subject to revision, and users of this Recommended Practice
are encouraged to investigate the possibility of applying the most recent editions of the
documents indicated below. The CCSDS Secretariat maintains a register of currently valid
CCSDS documents.
[1] Spacecraft Onboard Interface Services—Device Access Service. Draft
Recommendation for Space Data System Practices, CCSDS 871.0-M-0. Draft Magenta
Book. Issue 0. Washington, D.C.: CCSDS, November 2012.
[2] Spacecraft Onboard Interface Services—Device Virtualization Service. Draft
Recommendation for Space Data System Practices, CCSDS 871.2-R-0. Red Book.
Issue 0. Washington, D.C.: CCSDS, October 2012.
[3] Spacecraft Onboard Interface Services—Subnetwork Synchronisation Service.
Recommendation for Space Data System Practices, CCSDS 853.0-M-1. Magenta
Book. Issue 1. Washington, D.C.: CCSDS, December 2009.
NOTE – Informative references are contained in annex C.

CCSDS 871.1-M-1 Page 1-4 November 2012
© ISO 2015 – All rights reserved

---------------------- Page: 15 ----------------------
Communication Management
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE
2 OVERVIEW
2.1 FUNCTION
The Device Data Pooling Service (DDPS) provides a standard interface that enables onboard
software (applications and high-level services) to access pooled data acquired from simple
onboard hardware devices such as sensors and actuators, without explicitly requesting an
acquisition from the real device.
2.2 CONTEXT
The Device Data Pooling Service is defined within the context of the overall SOIS
architecture (reference [C2]) as one of the Command and Data Acquisition services of the
Application Support Layer, as illustrated in figure 2-1.
Application

Mission
Layer
Specific
Applications
Application
Cmd & Data Time File & Message Device
Support Layer
Acquisition Access Packet Store Transfer Enumeration
Services Service Services Service Service
Transfer
Transport Protocol
Layer
Network Protocol
Subnetwork
Memory Device
Layer
Packet Synchronisation Test
Access Discovery
Service Service Service
Service Service
Datalink Convergence Protocols
Milbus SpaceWire CAN Wireless

Figure 2-1: Device Data Pooling Service Context
The relationship of the DDPS to the other Command and Data Acquisition services is
illustrated in figure 2-2.
CCSDS 871.1-M-1 Page 2-1 November 2012
© ISO 2015 – All rights reserved

---------------------- Page: 16 ----------------------
Communication Management
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE


Figure 2-2: Relationship between SOIS Command and Data Acquisition Services
NOTE – The DDPS makes use of the Device Access Service (DAS) and/or the Device
Virtualisation Service (DVS) to acquire data from Devices.
The DDPS provides a standard interface that enables onboard software (applications and
high-level services) to access pooled data acquired from simple onboard hardware devices
such as sensors and actuators, without explicitly requesting an acquisition from the real
device.
The benefit of the service is that its use avoids multiple acquisitions from the same device
when many applications require access to the same data, the result being reduced bandwidth
from the device and probably reduced CPU load. In addition, the application is no longer
concerned with the periodic acquisition process, the details of the location of the devices,
their physical interfaces, or how they are accessed. As a result, configuration changes
involving a change in the physical location of a device, or changes to its electrical interface;
do not require changes to the application software using that device.
Although isolated from the details of device location and interface type, the application must
still know the format of data read from the device, and the user remains responsible for
correctly interpreting those formats.
2.2.1 DATA POOL AND SAMPLES
The basic concept underlying the service is that of a data pool. A data pool is a periodically
acquired cache of samples of values acquired from a number of devices on the spacecraft.
Applications are expected to be able to access samples from that pool, i.e., independently of
the precise physical locations of the devices, without requiring detailed knowledge of the
electrical interfaces to the devices, and without triggering immediate acquisitions from the
devices. The data pool approach makes it easier to develop the onboard software, enables
CCSDS 871.1-M-1 Page 2-2 November 2012
© ISO 2015 – All rights reserved

---------------------- Page: 17 ----------------------
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE
configuration changes in the spacecraft design to be easily tolerated, and increases the re-use
potential of the software.
The attributes of the pool are samples of values from real devices. Each sample is a set of
values from a related set of devices, along with the acquisition time for that set of values.
The acquisition interval for a sample is independent from all other samples in the pool. A
short, application-defined ordered history of samples is held in the pool.
The relationship between the data pool, the samples, and the individual values read from
devices is illustrated in figure 2-3.
Data Pool 1 (N1=6, H1=5)
N1 values per sample
Value Acquistion Timestamp
Data Pool 2 (N1=3, H1=8)
N2 values per sample
Value Acquistion Timestamp

Figure 2-3: Data Pool Examples
NOTES
1 There are N values per sample and H samples in a data pool. These vary per data pool
and are defined when the acquisition order is added by the user to the Device Data
Pooling Service.
2 Validity metadata is also stored with each value acquired. This could be a simple flag
indicating if the acquisition failed or the result metadata from the acquisition. When a
sample of values is read by a user, the associated validity metadata for the values in
the sample is also returned to the user.
CCSDS 871.1-M-1 Page 2-3 November 2012
© ISO 2015 – All rights reserved
History =
H1 samples per
data pool
History =
H2 samples per data pool

---------------------- Page: 18 ----------------------
ISO 20216:2015(E)
CCSDS RECOMMENDED PRACTICE FOR SOIS DEVICE DATA POOLING SERVICE
To request the history of samples, an application provides to the service the logical identifier
for the acquisition order and a history depth. The service then returns an indication to the
application that contains a time-ordered list of samples, acquisition times, and results of the
acquisitions.
2.2.2 SAMPLE ACQUISITION
Multiple acquisitions can be requested by different users on the same devices. The service
implementation is responsible for optimizing the actual acquisitions performed to avoid over-
sampling while still meeting all the users’ requirements. The service uses either the Device
Access Service (reference [1]) or the Device Virtualisation Service (reference [2]) to actually
make the acquisition.
Upon making an acquisition and if requested by the user when the acquisition order was
created, the service sends an indication to notify the application of the outcome of the
acquisition; if the acquisition was successful, the notification indicates that a new sample is
available for reading. The application can then immediately acquire the sample (thus being
synchronized with the acquisition itself), defer the acquisition of the sample to a later time,
or ignore the notification altogether. Therefore, there are three use cases for how the
application obtains an acquired sample:
a) aperiodic acquisition of the history (or subset of the history) of the samples, i.e.,
immediate read of samples whenever the user wants;
b) periodic acquisition of the history (or subset of the history) of the samples
synchronized with the acquisition period, i.e., read of the samples whenever an
acquisition indication is received;
c) periodic acquisition of the history (or subset of the history) of the samples not
synchronized with the acquisition period, i.e., read of the samples on a period not
synchronized with the acquisitions.
NOTE – With the third case, there is no guarantee that the period of the acquisitions
and the period of the user’s reading of the samples will remain synchronized.
It is an implementation issue if synchronization is maintained, e.g., by the use
of a common clock source.
2.2.3 PRE-CONFIGURATION AND DYNAMIC CREATION OF ACQUISITION
ORDERS
The service supports the offline pre-configuration of static acquisition orders, such that no
dynamic adding, removing, starting, or stopping of acquisition orders is required. This is
useful for
...