DLMSUA TPAK1_Intro

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IEC 62056 DLMS/COSEMworkshopPart 7
Interoperability
CBIP Conference on Advanced Metering
Infrastructure 17-19th February 2009, New
Delhi Gyozo Kmethy, DLMS UA, President
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Contents

• On interoperability
• The role of international standards
• The role of companion standards
• How DLMS/COSEM ensures interoperability
• Testing

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Inter...what?

• Interoperability ability of diverse systems to
  work together
• syntactic ability to exchange data - protocols,
  formats
• semantic data exchange produces (agreed) useful
  results
• Interconnectivity all, what has to be connected,
  can be connected (physical and abstract level)
• Interchangeability elements providing the exact
  same function
• Reaching true interoperability
• open international standards
• companion standards to reduce options, and to
  specify project specific elements that cannot be
  specified in ISs
• conformance testing
• partnership and co-operation
• discipline

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Interoperability in DLMS /COSEM

• Scope of interoperability read / write /
  execute
• International / companion standard common
  language, problem approach and solution
• Self-descriptive model logical structure,
  object list, data types
• Negotiable parameters, contexts, service set
• Conformance testing

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The role of international standards

• Open, international standards are the first
  condition of achieving interoperability
• reflect general consensus
• create common vocabulary (glossary)
• cover the widest possible range of applications
• what is mandatory, permitted and not permitted
• if IP rights apply, access under fair and equal
  terms must be provided to all
• application is generally voluntary
• use of ISs may be mandated in some cases (e.g.
  safety)
• compliance to ISs may be one way to meet legal
  requirements (e.g. EU new approach Directives)

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Politics and Intl standardization

• Politics roles
• market regulation
• removal of trade barriers
• energy policy sustainable supply, energy
  efficiency
• envionment protection
• and many more...
• Politics tools
• laws and regulations
• Directives (EU)
• standardization mandates
• RD projects
• Example from smart metering
• EC sees lack of coherent set of standards as
  barrier
• standarization mandate given to ESOs
• OPEN metering project
• build on existing standards!

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Using international standards

• International standards need to be supported by
  user groups
• closer to markets than standardization TCs
• examples DLMS UA, Euridis, M-Bus, KNX,
  Zigbee....
• Roles
• spreading awareness, promotion
• registration of standard elements
• pre-standardization, maintenance and development
• training
• user support
• sharing best practices
• conformance testing and certification

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Implementing international standards

• Implementation is the field for innovation
• May be protected by IP rights
• Use of common technology may speed up and
  facilitate achieving interoperability
• source code libraries, DLLs, chip sets

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Projects and Intl standards

• Projects should specify using Intl standards
• There are always specific conditions
• economy, determining business cases
• market organization, determining architecture
• customer base, determining functionality
• language
• electrical infrastructure
• communication infrastructure
• installation conditions
• climatic conditions etc.
• Hence the need for companion specifications
• to be developed in co-operation

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Purchaser supplier relationships

• Smart metering changes supplier purchaser
  relationships
• before one to one relationships, proprietary
  solutions
• today many to one (consortia), standards based
  solutions
• examples Dutch project, French project and in
  fact all projects
• International standards provide the common base
  for
• specifying requirements
• developing solutions
• verifying deliveries

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What to specify in companion standards - 1

• Object level
• Objects necessary to support use cases
• attributes and (optional) methods to be supported
• Interface classes to use, where choices are
  available
• e.g. Activity calendar / Schedule
• Data / Register / Extended register (client may
  support all)
• Contents of identifier objects
• Associations to support various client roles
• Application contexts
• SN referencing needs mapping but shorter
  requests
• LN referencing no need for mapping, but some
  overhead
• Ciphering or not
• Authentication contexts
• Access rights Read, Write, authentication access
  requested or not
• Security policy, secrets

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What to specify in companion standards - 2

• Object level contd
• Data organization in Profile generic objects
• e.g. billing data, event logs, snapshots
• Structure of load profiles (client can retrieve)
• capture period, length, selective access
  parameters
• Events and statuses, reference tables
• Event and alarm handling
• Scheduled tasks
• Display / Readout cycles
• Project specific elements
• Manufacturer specific elements allowed / not
  allowed

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What to specify in companion standards - 3

• Protocol level
• System architecture, interfaces
• Communication profile(s)
• Communication layer parameters
• Addressing scheme
• Performance requirements
• e.g. time to retrieve load profiles

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Requirements and use cases (NL)

• Provide periodic meter reads
• Provide actual meter reads
• Provide interval values
• Provide tamper history
• Apply threshold (load limitation)
• Disconnect
• Display consumer message
• Synchronise clock
• Update firmware (NL)

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Use case Provide periodic meter reads

• Requirements
• Measure energy per tariff
• Store daily consumption at 1000
• Provide device ID
• Provide last 10 daily values
• Provide last 13 monthly values
• Provide status / error

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Provide periodic meter reads UML diagram
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Periodic meter reads COSEM model

• Profile captures date time stamp, status,
  register values
• Profile capture_object attribute identifies
  columns
• Profile buffer holds data
• Selective access available
• Periodic read job
• Read device ID(s)
• Read clock
• Read daily / monthly Profile buffer
• Set clock

Device ID(s)
Profile of daily values
Energy registers
Energy registers
Energy registers
Energy registers
Profile of monthly values
Activity calendar
Activity calendar

• Scripts
• activate_mask
• capture daily
• capture monthly

Clock
Single action sched.
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Interoperability on the object level

• Standard specifies
• interface classes
• attributes with data types
• selective access parameters
• methods
• use of interface classes and logical names (OBIS
  codes)
• Meter association objects provide object lists
• mapping (in the case of SN referencing)
• access rights to attributes and methods
• interface class version
• Profile objects provide capture objects column
  headers

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Interoperability on xDLMS level

• Standard provides
• service specification
• protocol specification
• formal syntax in ASN.1
• A-XDR encoding rules
• Meter provides
• data types used
• succes / error diagnostic

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Interoperability on Application layer level

• Standard provides
• services and protocols for Association
  establishment and release
• ASN.1 syntax of services
• BER encoding rules
• rules for context negotiation
• rules for security context management
• Meter supports
• application context negotiation
• authentication context negotiation
• conformance block (service set) negotiation
• security management
• success / error diagnostic

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Interoperability at lower layers

• Standard communication profiles
• service specifications
• protocol specifications
• parameter negotiation (in the case of connection
  oriented layers)

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Client capabilities - 1

• Must support all options allowed on server side
• Specified referencing style LN / SN / both
• Connect lower layers and negotiate parameters
• Negotiate and establish Application Associations
• Retrieve object list (if not known)
• Interface classes
• Data types
• Retrieve and interpret Profile structures (also
  nested)
• Retrieve scalers and units (if not known)
• Download Register activation masks, schedules
• Work with attributes and methods

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The story of the captain and the heater

• Scenario 1
• how much?
• 28!

• Scenario 2
• how much?
• 28!
• what is 28?

?
?

• Scenario 3
• how much is the pressure?
• 28!

• Scenario 4
• how much is the pressure in bars?
• the pressure is 28 bars

?
?

• Scenario 5
• (tacit)
• Captain, the pressure is 28 bars (push operation)

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Client capabilities - 2

• Support selective access
• Handle scheduled tasks
• Handle diagnostics
• Handle events and alarms
• Synchronize clock
• Manage and detect parameter changes
• Manage security
• Manage firmware download

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Conformance testing
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ISO/IEC 9646 based process
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Test tool architecture
Test Workstation
System under test (SUT)
COSEM Server
COSEM Test Client
Test programs
Device application
COSEMTest Client stack
COSEMServerStack
Physical IF
Physical IF

• Remote test method Observation and analysis of
  protocol data units

7EA00A00020023215314B77E 7EA00A2100020023734CE77E
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Process implementation

• Automatic test execution by the manufacturer or
  third party tester
• Verification / certification DLMS UA

Test plans
CTI
Test routines
1.8.1.3 12345.67
Test routines c
Test routines
Association object
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HDLC based data link layer tests
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Application layer tests
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COSEM object tests

• Validity of logical names
• Access rights to attributes
• Attribute types
• Methods not tested would change the MUT
• Multiple references
• Presence of mandatory objects
• Objects found are listed

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Conformance assessment process
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Value of testing for system integration

• Confidence in the implementation
• Test report provides information on
• the logical structure of the meter logical
  devices, associations, authentication
• information on objects
• class_id, version, Obis code, textual name, data
  types, access rights
• services and options supported
• communication parameters addresses, baud rates,
  timeouts
• diagnostic information provided for negative
  tests

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Conformance testing practical example

• Presented by CPRI

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Summary

• DLMS/COSEM provides all what is necessary for
  interoperability
• International standard, growing with requirements
• User support by DLMS UA
• Guidance to write companion standards
• examples available, e.g. Dutch specification is
  public
• Conformance testing
• Supported by many companies worldwide
• Technology bits available
• Achieving interoperability needs
• stability
• willingness
• co-operation
• discipline