Introduction

DLMS/COSEM – a metering
communication protocol based
on IEC 62056 series of standards
 What is DLMS ?

 Device Language Message Specification

 A metering communication protocol standardized as
IEC62056 series of standards
 IEC62056 and DLMS are not the same - 62056 family
consists of other protocol also such as 62056-
31(EURIDIS), 62056-21 etc..

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DLMS based system - overview

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DLMS based system – client server paradigm

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Communication
Protocol Evolution

Vendor specific proprietary protocol

First generation standard protocols [ Modbus,

1107, Flag]

Newer smart meter standard protocols [ANSI

C12 , DLMS/COSEM]
Issues with Proprietary protocol

• Managed by business organizations, not open to

third party
• Technological and Commercial dependence on
vendor. Utility is Locked to one vendor, hence
proprietary protocols are expensive in the long run
• Limited R&D and protocol enhancement to meet
changing utility needs – fast obsolescence. Features
become irrelevant as other technology areas make
progress

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Advantages of Open protocol

• Open to all vendors

• Governed by Non-profitable organization in
liaison with globally recognized standard
committees such as IEC
• Welcomes user inputs to enhance protocol
• Interoperability guaranteed

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First Generation Metering
Protocol limitations (like
Modbus)
• Provides a basic means to access memory location without
telling how to interpret data
• Separate driver required for each new type of meter despite
having same protocol
• Generally not found to follow OSI model – not layered, very
high dependency on specific hardware, communication
media, applications
• Lacks security features

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The right open protocol

• Standard data models and unambiguous data

identification
• Completely vendor independent -Interoperability
test definitions
• OSI model with communication and application
independence
• Robust Security features

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 Overview of
DLMS/COSEM
• DLMS/COSEM is an international standard,
maintained by the DLMS User Association and dual-
standardized under the DLMS Colored books as well
as the IEC-62056 protocol standards. The DLMS/UA
consist of about 250 members from almost 50
countries and works closely with the following
international technical committees
– IEC TC13 WG14 - Data exchange for meter reading, tariff
and load control
– CEN TC294 WG2 - Communication Systems for and
Remote Reading of Meters
– IEC TC57 WG09 - Distribution automation using DLC
systems
 DLMS User Association

120
100
80
60
40
20
0
1997 2000 2003 2006

• Formed in 1997
• 200 members
Utilities
• 5 continents
Meter and system
• 48 countries providers
System providers

Other
 The DLMS/COSEM
standards

COSEM interface object model TECHNICAL REPORT

OBIS identification system Data Companion Specification

for Energy Metering

IEC EN
COSEM
Tariff
functions Identification System
and Interface Objects 62056 13757
Class name Cardinality
Attribute(s) Data Type -61 Part1
1. logical_name
2. …..
(static)
(..)
octet-string
…..
Access
control
DLMS User Association
-62
3. …… (..) …..
device 
language
message
specification

Specific Method(s) (if required) m/o

1. ….. ….. -42
2. ….. ….. Comm. TECHNICAL REPORT
-46
setup Companion Specification
for Energy Metering
-47
COSEM
-53
Three Layer
Connection Oriented
Architecture

P
COSEM application layer DLMS User Association

R DLMS
device
language
message


Connection
specification

O Messaging
T
TECHNICAL REPORT

Companion Specification

O for Energy Metering

C
O COSEM

L Conformance Test
Tool - Specification

... DLMS User Association

device
language
message


specification
DLMS/COSEM standards

Description DLMS-UA IEC

COSEM meter object Blue Book IEC-62056-61

model and the object IEC-62056-62
identification system

Architecture and Green Book IEC-62056-53

protocols to transport IEC-62056-46
the model IEC-62056-42
IEC-62056-47

Conformance testing Yellow Book -

process

Glossary of White Book -

DLMS/COSEM terms
Application – Model -
Protocol

/ s us i on
y if le ne
o
er
s ss l
rg nd lin
g o a v ad rol e
c tro
e a l pr nt PQ n o
L nt c
En em Bi ad a
t / co A on
d o ns s co c
L I Ga
Mapping
OBIS Object identification system
A B C D E F
Energy type Channel Quantity Processing Classification Historical

COSEM Interface classes

Class name Cardinality
Attribute(s) Data Type
1. logical_name (static) octet-string
2. ….. (..) …..
3. …… (..) …..
Specific Method(s) (if required) m/o
1. ….. …..
2. ….. …..

DLMS messaging services

COSEM Application layer
Protocol data units
OSI / Internet lower layers
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 Data Modeling
Interface class
Object 1
Name Register
Value Logical name
Scaler unit
Value
1234 Active energy T1 1234 Kwh
Scaler_unit
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Object 2 Reset
Name
Generic template
Value
Scaler unit
Reactive energy T1 56 Kvarh Class name
Logical name
• All data in the meter are mapped to objects GET/
SET/ Attribute 2
• The model provides a functional view of the meter ACTION...
Attribute n
• Similar objects make up an interface class
Method 1
• All interface classes have the same generic structure
• All interface classes can be accessed with the same services Method n
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Object model for all energy
types

Three phase import

Register 1 active energy
Generic template Interface class
Σ Li A+ total 1.0.1.8.0.255
Class name Register Value 40153
Logical name logical_name scaler_unit kWh
Attribute 2 value
Attribute n scaler_unit Forward undisturbed
Register 2 meter volume
Method 1 reset
Meter volume 7.0.1.0.0.255,
Method n
Value 7086
scaler_unit m3

• „Abstract” objects are the same for all energy types

 NetMetering

• DLMS/COSEM standards support bi-

directional energy registers (import/export)
for all quantities
Schedule and Calendar
 Load Control and
Management

• Demand response schemes require a Load

management system to interact with the
smart meters to connect/disconnect Loads
dynamically to handle peaks
• DLMS/COSEM provides a Disconnect Control
interface class to handle this requirement
Disconnect Control
(IC:70)
 Alarms and Events/Tamper

• Standard classes and objects to model

instantaneous(real time) alarm/event and to
log(historic) them chronologically
• Application layer service to report
event/alarm on a near real time basis

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Remote Firmware upgrade

• Standard data model to remotely upgrade

and/or activate meter firmware
• Saves cost and time of utility by correcting
meter remotely and not visiting faulty meter
premise or replacing faulty meters

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 Interoperability

 Open international
standards
 Self description
 Conformance/
interoperability testing
 Vendor independence

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 Suitable for Liberalized
market
Liberalized market needs DLMS/COSEM
Suppliers often provide more than one kind of Supports multiple energy types
energy (Electricity, Gas, Water)
Increased meter data Unambiguous data identification
using OBIS codes
Geographically widespread customer base Vendor independent with
standard interface and multiple
communication media support
Multiple stake holders need meter data Role based access support
Meter data carries strategic competitor Access control and data transport
information security
 Low communication overhead

 Selective access
 Efficient data organization and presentation
using A-XDR encoding/ ASN.1 notation

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 The COSEM model supports any device
complexity

• Only 3 mandatory objects: suitable for simple

devices
• Can also handle complexity of high end smart
metering devices

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 Security
• Access security
• peer authentication: client only (LLS) or client / server
(HLS)
• association specific view of objects: list, access rights
• Security event logs
• Message security
• authentication to ensure integrity and authenticity
(legitimate source)
• encryption to prevent an illegitimate user to obtain
unauthorized information
• encrypted authentication

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 Data identification

Every object have a unique OBIS Code of six

value groups in hierarchical structure to
address
 Energy type
 Measurement channel
 Physical quantity measured
 Processing type
 Tarification
 Storage for Billing periods
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 Data identification

 Object identification system

 Thousands of standard codes for abstract,
electricity and gas
 Provision for flexibility
 Country specific
 Utility specific
 Manufacturer specific

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 Multiple Energy type
support

Utility
Back end
System
DLMS Client

Comm.
n/w
Comm.
n/w
DLMS Server

Electricity
Meter
Mbus master
DLMS Server DLMS Server DLMS Server

Electricity Gas Water Mbus slave Mbus slave

Meter Meter Meter
Gas Water
Meter Meter

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 Multiple communication media support

DLMS meter serial DLMS meter PLC DLMS meter IP DLMS meter
comm comm comm future comm

Data model Data model Data model Data model

IEC 62056-61,62 IEC 62056-61,62 IEC 62056-61,62 IEC 62056-61,62
Application Application Application Application
Layer Layer Layer Layer
IEC 62056-53 IEC 62056-53 IEC 62056-53 IEC 62056-53
HDLC LLC COSEM Transport
IEC 62056-46 IEC 61334-4-32 for IP
IEC 62056-47 Communication
Physical MAC+Phy Profile
IEC 62056-42 IEC 61334-5-1 TCP/UDP, IP layers

RS232/485 Power Line Carrier Ethernet Future

Optical port GPRS communication
PSTN/GSM modem PPP media

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 DLMS - Other key features
 Read individually or group-wise or
selectively
 Meter configuration change, time
synchronization
 Role based access based on distinct
Associations
 Meter self description
 Event notification and Data PUSH
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 Conformance testing

 Conformance Test plans part of specification

 Protocol compliance tested by Conformance
Test Tool, a tool developed by DLMS UA
 Self testing or third party testing possible
 Certificate issued by DLMS UA

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Thank You!