E-Mobility solutions

DCBM 400/600 Series - DC Energy Meter
Operation manual

21January2021/Version 0		Table Of Contents
1.

Safety rules���������������������������������������������������������������������������10

1.1.

Safety warning ������������������������������������������������������������������������������������ 10

1.2.

Important notices��������������������������������������������������������������������������������� 11

1.3.

Symbols and conventions������������������������������������������������������������������ 11

2.

Document information ���������������������������������������������������������12

2.1.

Document overview ���������������������������������������������������������������������������� 12

2.2.

Document issue ���������������������������������������������������������������������������������� 13

2.3.

Company details ��������������������������������������������������������������������������������� 13

2.4.

Revision history ���������������������������������������������������������������������������������� 13

2.5.

Related documents������������������������������������������������������������������������������ 13

2.6.

Abbreviations��������������������������������������������������������������������������������������� 14

2.7.

Disclaimer��������������������������������������������������������������������������������������������� 15

2.8.

Intellectual Property Rights ��������������������������������������������������������������� 15

2.9.

Third party licensing��������������������������������������������������������������������������� 15

2.10.

Warranty����������������������������������������������������������������������������������������������� 16

3.

Product introduction ����������������������������������������������������������17

3.1.

LEM and the DCBM������������������������������������������������������������������������������ 17

3.2.

DCBM in EV charging systems���������������������������������������������������������� 18

3.3.

DCBM 400/600 in EVSE ���������������������������������������������������������������������� 21

3.3.1.

DCBM in 50 kW EVSE���������������������������������������������������������������������������������������������21

3.3.2.

DCBM in 350 kW EVSE��������������������������������������������������������������������������������������������22

3.4.

Certification and compliance������������������������������������������������������������� 24

3.4.1.

Standards�����������������������������������������������������������������������������������������������������������������24

3.4.2.

Certification��������������������������������������������������������������������������������������������������������������24

3.5.

4.
4.1.

Product designation ��������������������������������������������������������������������������� 24

Device description and mechanical integration�������������26
Package content ��������������������������������������������������������������������������������� 26

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4.1.1.

Meter Unit description��������������������������������������������������������������������������������������������27

4.1.2.

Sensor Unit description �����������������������������������������������������������������������������������������27

4.2.

Mounting and unmounting������������������������������������������������������������������ 27

4.2.1.

Meter Unit�����������������������������������������������������������������������������������������������������������������27

4.2.1.1. Mounting���������������������������������������������������������������������������������������������������������������������������� 27
4.2.1.2. Unmounting������������������������������������������������������������������������������������������������������������������������ 28

4.2.2.

4.3.

Sensor Unit��������������������������������������������������������������������������������������������������������������28

Product dimensions ��������������������������������������������������������������������������� 29

4.3.1.

Meter Unit�����������������������������������������������������������������������������������������������������������������29

4.3.2.

Sensor Unit��������������������������������������������������������������������������������������������������������������30

4.4.

Connection ������������������������������������������������������������������������������������������ 31

4.5.

Cable management������������������������������������������������������������������������������ 34

4.6.

Sealing ������������������������������������������������������������������������������������������������� 34

4.6.1.

Manufacturer seals��������������������������������������������������������������������������������������������������34

4.6.2.

Installation seals�����������������������������������������������������������������������������������������������������34

4.7.

Disposing��������������������������������������������������������������������������������������������� 35

4.8.

Marking ������������������������������������������������������������������������������������������������ 36

5.

Electrical functions������������������������������������������������������������37

5.1.

Safety features ������������������������������������������������������������������������������������ 37

5.2.

Integration solutions��������������������������������������������������������������������������� 37

5.2.1.

Overview������������������������������������������������������������������������������������������������������������������37

5.2.2.

Counting direction��������������������������������������������������������������������������������������������������37

5.2.3.

Voltage side��������������������������������������������������������������������������������������������������������������38

5.2.4.

Direct counting direction connection requirements��������������������������������������������39

5.2.5.

Reverse counting direction connection requirements ���������������������������������������40

5.3.

Energy registering ������������������������������������������������������������������������������ 41

5.4.

Handling energy losses���������������������������������������������������������������������� 42

5.4.1.

Cable loss compensation ��������������������������������������������������������������������������������������42

5.4.1.1. Principle������������������������������������������������������������������������������������������������������������������������������ 42
5.4.1.2. Compensation mechanism ���������������������������������������������������������������������������������������������� 44
5.4.1.3. Setting the compensation level��������������������������������������������������������������������������������������� 45
5.4.1.4. Setting cableId value������������������������������������������������������������������������������������������������������ 45
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5.4.2.

5.5.

Four-wire measurement �����������������������������������������������������������������������������������������46

Performances��������������������������������������������������������������������������������������� 47

5.5.1.

General ��������������������������������������������������������������������������������������������������������������������47

5.5.2.

Accuracy������������������������������������������������������������������������������������������������������������������48

5.5.3.

Insulation�����������������������������������������������������������������������������������������������������������������48

5.5.4.

Operating conditions�����������������������������������������������������������������������������������������������49

5.5.4.1. Sensor Unit������������������������������������������������������������������������������������������������������������������������ 49
5.5.4.2. Meter Unit��������������������������������������������������������������������������������������������������������������������������� 49
5.5.4.3. Data link cable������������������������������������������������������������������������������������������������������������������� 49

6.

Display and navigation ���������������������������������������������������������50

6.1.

Quick start ������������������������������������������������������������������������������������������� 50

6.1.1.

STEP 1 - Power up the DCBM ��������������������������������������������������������������������������������50

6.1.2.

STEP 2 - Check transaction data���������������������������������������������������������������������������51

6.1.3.

STEP 3 - Achieve further validation�����������������������������������������������������������������������52

6.2.

General display concepts ������������������������������������������������������������������ 53

6.3.

Boot screens ��������������������������������������������������������������������������������������� 54

6.3.1.

Overview������������������������������������������������������������������������������������������������������������������54

6.3.2.

Effect of buttons �����������������������������������������������������������������������������������������������������54

6.4.

Idle screen ������������������������������������������������������������������������������������������� 55

6.4.1.

Overview������������������������������������������������������������������������������������������������������������������55

6.4.2.

Available data�����������������������������������������������������������������������������������������������������������55

6.4.3.

Effect of buttons �����������������������������������������������������������������������������������������������������55

6.5.

Transactions screens ������������������������������������������������������������������������� 55

6.5.1.

Layout of screens ���������������������������������������������������������������������������������������������������55

6.5.2.

State symbols ���������������������������������������������������������������������������������������������������������56

6.5.3.

Transaction energy register�����������������������������������������������������������������������������������56

6.5.4.

Rolling data��������������������������������������������������������������������������������������������������������������57

6.5.5.

Effect of buttons �����������������������������������������������������������������������������������������������������58

6.6.

Maintenance state������������������������������������������������������������������������������� 59

6.6.1.

Overview������������������������������������������������������������������������������������������������������������������59

6.6.2.

Layout of screens ���������������������������������������������������������������������������������������������������59

6.6.3.

Effect of buttons �����������������������������������������������������������������������������������������������������59

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6.6.4.

Available data�����������������������������������������������������������������������������������������������������������60

6.6.4.1. STATUS category��������������������������������������������������������������������������������������������������������������� 60
6.6.4.2. LIVE MEASURE category������������������������������������������������������������������������������������������������� 61
6.6.4.3. DEVICE category��������������������������������������������������������������������������������������������������������������� 62
6.6.4.4. FIRMWARE category��������������������������������������������������������������������������������������������������������� 63
6.6.4.5. CLOCK category ��������������������������������������������������������������������������������������������������������������� 64

6.7.

Error screen������������������������������������������������������������������������������������������ 65

6.8.

Index of symbols in screens��������������������������������������������������������������� 66

6.8.1.

Transaction-specific �����������������������������������������������������������������������������������������������66

6.8.2.

Metrology�����������������������������������������������������������������������������������������������������������������67

6.8.3.

Time management ��������������������������������������������������������������������������������������������������68

6.8.4.

Other data�����������������������������������������������������������������������������������������������������������������68

7.

Software concepts ���������������������������������������������������������������69

7.1.

Interfaces ��������������������������������������������������������������������������������������������� 69

7.2.

Transactions���������������������������������������������������������������������������������������� 70

7.2.1.

Concept��������������������������������������������������������������������������������������������������������������������70

7.2.2.

Conditions to start and input parameters ������������������������������������������������������������71

7.2.3.

Transaction readouts ���������������������������������������������������������������������������������������������72

7.2.4.

Memory depth ���������������������������������������������������������������������������������������������������������73

7.2.4.1. Required action following a transaction ������������������������������������������������������������������������ 73
7.2.4.2. Fallback procedure for unavailable upload��������������������������������������������������������������������� 73

7.3.

Measurements������������������������������������������������������������������������������������� 74

7.3.1.

Energy registering ��������������������������������������������������������������������������������������������������74

7.3.2.

Bidirectional current flow ��������������������������������������������������������������������������������������74

7.3.3.

Total energy registers���������������������������������������������������������������������������������������������74

7.3.4.

Transaction energy registers���������������������������������������������������������������������������������75

7.3.5.

Other measurements�����������������������������������������������������������������������������������������������75

7.4.

Data authenticity ��������������������������������������������������������������������������������� 76

7.4.1.

Overview������������������������������������������������������������������������������������������������������������������76

7.4.2.

Keys specifics���������������������������������������������������������������������������������������������������������76

7.5.
7.5.1.

Status and errors flags������������������������������������������������������������������ 77

Overview������������������������������������������������������������������������������������������������������������������77

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7.5.2.
7.5.3.
7.5.4.
7.5.5.
7.5.6.

Status/errors value field description��������������������������������������������������������������������77
Current status ���������������������������������������������������������������������������������������������������������78transactionStatus field��������������������������������������������������������������������������������������80
Errors �����������������������������������������������������������������������������������������������������������������������81
OCMF error and status fields ��������������������������������������������������������������������������������82

7.6.

Event logbook ������������������������������������������������������������������������������������� 83

7.7.

Connectivity settings��������������������������������������������������������������������������� 84

7.7.1.

IP addressing�����������������������������������������������������������������������������������������������������������84

7.7.1.1. Static addressing��������������������������������������������������������������������������������������������������������������� 84
7.7.1.2. DHCP���������������������������������������������������������������������������������������������������������������������������������� 84
7.7.1.3. DNS ������������������������������������������������������������������������������������������������������������������������������������ 85

7.7.2.

HTTP & TLS��������������������������������������������������������������������������������������������������������������85

7.7.2.1. HTTPS��������������������������������������������������������������������������������������������������������������������������������� 85
7.7.2.2. HTTP port��������������������������������������������������������������������������������������������������������������������������� 85

7.8.

Time management ������������������������������������������������������������������������������ 86

7.8.1.

Time synchronization ���������������������������������������������������������������������������������������������86

7.8.1.1. Overview���������������������������������������������������������������������������������������������������������������������������� 86
7.8.1.2. General constraints ���������������������������������������������������������������������������������������������������������� 86
7.8.1.3. Synchronization solutions������������������������������������������������������������������������������������������������ 86
7.8.1.4. Command time synchronization ������������������������������������������������������������������������������������� 87
7.8.1.5. NTP synchronization��������������������������������������������������������������������������������������������������������� 87

7.8.2.

Local time�����������������������������������������������������������������������������������������������������������������88

7.8.2.1. Time zone��������������������������������������������������������������������������������������������������������������������������� 88
7.8.2.2. Daylight Saving Time ������������������������������������������������������������������������������������������������������� 88

8.

Troubleshooting�������������������������������������������������������������������89

8.1.

Wrong statuses������������������������������������������������������������������������������������ 89

8.2.

Raised errors��������������������������������������������������������������������������������������� 91

8.3.

Other software issues ������������������������������������������������������������������������ 93

9.

Appendix - PTB type-examination certificate for DCBM94

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List of Figures
Figure 1.

Documentation information versus associated publics....................................... 12

Figure 2.

Documentation set for DCBM 400/600 product family........................................ 12

Figure 3.

Namings designating equipment and protagonists............................................. 18

Figure 4.

Product construction............................................................................................ 19

Figure 5.

Typical 50 kW architecture.................................................................................. 21

Figure 6.

DCBM in a typical 50 kW EVSE.......................................................................... 22

Figure 7.

Typical 350 kW EVSE system............................................................................. 22

Figure 8.

DCBM in a typical 350 kW EVSE........................................................................ 23

Figure 9.

Simplified list of references for 400 A current rating............................................ 24

Figure 10.

Simplified list of references for 600 A current rating ......................................... 24

Figure 11.

Full list of references for the DCBM 400/600 product family............................... 25

Figure 12.

Meter Unit dimensions......................................................................................... 29

Figure 13.

Meter Unit aperture for electrical cabinet............................................................ 29

Figure 14.

Sensor Unit dimensions...................................................................................... 30

Figure 15.

DCBM connection............................................................................................... 31

Figure 16.

Connection and wiring diagrams......................................................................... 32

Figure 17.

Sensor Unit integration........................................................................................ 33

Figure 18.

Cable management............................................................................................. 34

Figure 19.

Manufacturer seals.............................................................................................. 34

Figure 20.

Import and export energy registers matched with energy flow............................ 38

Figure 21.

Connection for direct counting direction references (DCBM_NxD_x000_0000). 39

Figure 22.

Connection for reverse counting direction references (DCBM_NxD_x010_0000)..40

Figure 23.

Counting quadrants for the DCBM...................................................................... 41

Figure 24.

Example of energy losses in an EVSE electrical circuit...................................... 42

Figure 25.

Current accuracy graphs with and without cable loss compensation.................. 43

Figure 26.

Integration examples using cable loss compensation......................................... 44

Figure 27.

Distribution of RP values depending on product designation................................ 45

Figure 28.

Integration example for four-wire measurement.................................................. 46

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Figure 29.

Sequence of screens on boot and during idle..................................................... 50

Figure 30.

Sequence of screens for beginning of transactions............................................ 51

Figure 31.

Sequences of screens for end of transactions.................................................... 51

Figure 32.

Maintenance screens which can help metrological validation............................. 52

Figure 33.

Global state machine of the display.................................................................... 53

Figure 34.

Identification of buttons....................................................................................... 53

Figure 35.

Visual distinction for legal relevance on the display............................................ 53

Figure 36.

Transaction screens layout.................................................................................. 55

Figure 37.

State machine for transaction screens................................................................ 56

Figure 38.

Transaction energy register................................................................................. 56

Figure 39.

Maintenance screens layout................................................................................ 59

Figure 40.

Transaction concept............................................................................................ 70

Figure 41.

Example of body for start request....................................................................... 71

Figure 42.

"Transaction" vs "Total" energy registers (Import or Export)............................... 75

Figure 43.

Keys specifics for signature checks.................................................................... 76

Figure 44.

Description of the 2 formats of status and errors................................................ 77

Figure 45.

Illustration of using value field, example for status register........................... 78

Figure 46.

Status field persistence....................................................................................... 78

Figure 47.

Specific reversedVoltage status persistence................................................ 79

Figure 48.

Transaction status field persistence.................................................................... 80

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List of Tables
Table 1.

Ports definition..................................................................................................... 32

Table 2.

Torque values for installation............................................................................... 33

Table 3.

Bus bar drilling..................................................................................................... 33

Table 4.

Counting direction references............................................................................. 37

Table 5.

REST API access and associated HTTP methods.............................................. 69

Table 6.

Transaction preconditions in device implementation........................................... 71

Table 7.

Required inputs to a new transaction.................................................................. 71

Table 8.

Solutions for retrieving past transactions............................................................ 72

Table 9.

Measurement results, metrologically relevant..................................................... 74

Table 10.

Solutions for signatures verification..................................................................... 76

Table 11.

List of status flags............................................................................................ 79

Table 12.

List of error flags.................................................................................................. 81

Table 13.

OCMF EF field equivalents.................................................................................. 82

Table 14.

OCMF ST field equivalents.................................................................................. 82

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1. Safety rules
1.1. Safety warning
In order to guarantee safe operation of the product and to be able to make proper use of allfeatures and functions, please read these instructions thoroughly!
Safe operation can only be guaranteed if the product is used for the purpose it has been designed
for and within the limits of the technical specifications. Ensure you get up-to-date technicalinformation that can be found in the latest associated datasheet under www.lem.com.
Terminal protection cover delivered with the product must be installed to obtain proper electricalprotection. The data link cable used between the product’s elements shall be the one delivered
by LEM.
Please noteElectrical equipment should be installed, operated, serviced and maintained only by qualified
personnel.
No responsibility is assumed by LEM International SA for any consequences arising out of the useof this material. A qualified person is one who has skills and knowledge related to the construction,
installation, and operation of electrical equipment and has received safety training to recognize
and avoid the hazards involved.
The meter must be installed inside an enclosure IP51 (indoor) or IP54 (outdoor) according to
EN 50470:2007.
DANGER! Electrical hazard - Fire hazard
When installing or changing the product, the conductor to which the product is connected must be
de-energized. Ignoring the warnings can lead to serious injury and/or cause damage!
Notice! Damage or hazards
The appropriate torque is defined by LEM (see "Table 2: Torque values for installation" and "4.2.
Mounting and unmounting")
The appropriate crimping of the connection elements is defined by the nationalities in force.

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1.2. Important notices•
Time source to set product’s time must be provided by the customer. Product must be timesynchronized to operate.
•
Product’s Ethernet interface mustn’t be exposed to a public network; network must be private andsecured.
•To ensure proper operation, product’s logbook completion must be checked periodically; the maximum
number of entries is approximately 40 000; product’s operation stops if logbook is full.
•
The product is designed with IP20, and is intended to be mounted in an enclosure with a suitable IP
rating for the final application.

Accuracy notices according to PTB type examination certificate•
The direct current meters may only be used for billing purposes in business and official traffic in acharging device and only for measuring the energy supplied to the vehicle.
•
The connection line for voltage measurement must be provided with the supplied ferrite so that themeasurement reliability is guaranteed in the event of interference.
•
For the device types DCBM_N0D_4000_0000, DCBM_N0D_4010_0000, DCBM_N0D_6000_0000
and DCBM_N0D_6010_0000, for which the compensation factor can be selected via the Ethernet
interface, the interface must be sealed or a calibrated remote station must be directly connected andsecured by means of seals. At the end of the transaction, this remote station must compare the cable ID
specified in the data tuple signed by the DC meter with the cable ID originally transferred to the DC meter.
If this comparison is valid then the data tuple can be used. The remote station can also directly overwrite
the cable ID specified in the data tuple.

1.3. Symbols and conventions
The following symbols point out critical information. They can be found either in this document oron the product.
Instruction manual

Heating

Electrical hazard

Double insulation

Warning

The following symbols aim at improving reader's experience by highlighting sections.

!

Note

i

Tip

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2. Document information
2.1. Document overview
This document relates to the DCBM 400/600 product family. Those products are direct connectedenergy meters for DC applications. This manual describes all necessary information for properuse. It is organized by topics:•

Mechanical: product mounting and integration into an electrical system.

•

Electrical: electrical functions and performances•
Software: integration of product family into information technology systems, and main softwarefeatures

Audience of this document is wide. The following visual matches sections with associated publics.
g

tin

e
ark

M

g

sin

a
rch

Pu

In

n

tio

ra
teg

Me

s

nic

a
ch

al

tric

c
Ele

are

S

w
oft

Safety rules, Document
info., Product intro.
Device description andmechanical integration
Electrical functions
Display information
Software concepts
Troubleshooting

Figure 1: Documentation information versus associated publics

This document is part of a document set. Below illustration describes the set of documents for
DCBM 400/600 product family with associated steps in product lifetime.
ce
an
ten
n
i
a
ife
&M

g

in
nn

n
io
y
tio
ss
ud
f-l
tion
lla
mi
a
t
m
d-o
era
s
o
p
n
n
O
I
C
E

st
re-

P

Datasheet
Installation manual
Operation manual
Communication Protocols manual

Figure 2: Documentation set for DCBM 400/600 product family

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2.2. Document issue
Targeted Product

DCBM 400/DCBM 600

Release scope

Public2.3. Company details
LEM International SA
Chemin des Aulx 81228 Plan-les-Ouates
Switzerland

2.4. Revision history
VersionDate

021January2021

Changes
First issue

2.5. Related documents
Name

Revision

Datasheet

Publication pending

Communication Protocols manual

Publication pending

Installation manual

Version 1

EN 50470-1

2006

EN 50470-3

2006

CISPR22 Class-B emission
IEC 62477-1
EN 62052-31

2015

IEC 62052-11

2003

IEC 61000-6-2

2016

IEC 61000-6-3

2016

RoHS
OCPP 1.6

1.6, 2.6

WELMEC 7.2 Software Guide

2015

REA-6APTB 50.7
VDE-AR-E 2418-3-100

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2.6. Abbreviations
Abbrevation

Description

Abbreviation

Description

ADC

Analog to Digital Converter

UTC

Coordinated Universal TimeAPI

Application Programming Interface

V2G

Vehicle To Grid

CCS

Combined Charging System

VP & VN

Voltage positive/negative input

CRC

Cyclic Redundancy Checksum

DC / AC

Direct current / Alternating current

DCBM

DC Billing Meter

DHCP

Dynamic Host Configuration Protocol

DNS

Domain Name System

DST

Daylight Saving Time

EMI

Electromagnetic interference

EV

Electric Vehicle

EVSE

Electric Vehicle Supply Equipment

FW

FirmwareHTTP[S]

Hypertext Transfer Protocol [Secured]

IANA

Internet Assigned Numbers Authority

ID

Identifier

Info

Information

Init

Initialization

Intro

Introduction

IP

Internet Protocol / Ingress Protection CodeIR

Infrared

JSON

JavaScript Object Notation

LED

Light-emitting diodeLR / LNR

Legally relevant / Legally non-relevant

MSB & LSB

Most Significant Bit / Least Significant Bit

MU

Meter Unit

N/A

Not applicable

NTP

Network Time Protocol

OBIS

Object Identification System

OCMF

Open Charge Metering Format

OCPP

Open Charge Point Protocol

OVC

Overvoltage Category

PTB

German Physikalisch-Technische
Bundesanstalt

REST

Representational state transfer

RMS

Root Mean Square

RNG

Random Number Generator

RTOS

Real-Time Operating System

S.A.F.E.

Software Alliance For E-mobility

SELV

Separated Extra-Low Voltage

SU

Sensor Unit

TLS

Transport Layer Security

URL / URI

Uniform Resource Locator / Identifier

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2.7. Disclaimer
LEM cannot be held liable for damage, injury or any legal responsibility incurred directly or indirectlyfrom non product quality issues such as other use of the DCBM than according to LEM written
installation instructions (see section "4. Device description and mechanical integration") or otherexternal factors.
The user shall observe safe and lawful practices, including, but no limited to, those set forth in thisdocument. Before any operation or use, please read “Safety” section carefully.
LEM reserves the right to carry out modifications on its product and documentation at the sole
discretion of LEM. Always make sure to have the latest information before placing an order. For upto-date product information, visit www.lem.com or contact your nearest LEM sales representative.

2.8. Intellectual Property Rights© Copyright 2020 LEM INTERNATIONAL SA. All rights reserved.
This document shall not be reproduced, copied, adapted, translated, arranged or modified without
written permission from LEM, and the content, in whole or in any part, shall not be used for any
purpose other than describing LEM DCBM. LEM will retain all intellectual property rights in andto this document. No license is granted by LEM to any intellectual property right. All rights not
expressly granted are reserved by LEM.
Disassembly, decompilation, reverse-engineering, decryption, or alteration of the DCBM, including
its software, are prohibited.
“LEM” and any related logos are protected trademarks owned by LEM HOLDING SA or trade
names and cannot be used for other purposes than LEM usage without specific prior written
permission.
Unless otherwise expressly granted by LEM in writing, the sale of the DCBM will not confer any
license under any patents, trademarks, trade names, or other proprietary rights owned or controlled
by LEM, its affiliates or suppliers, all rights being reserved.

2.9. Third party licensing
The DCBM includes software developped by SEGGER Microcontroller GmbH (SystemView RTT),
STMicroelectronics (STM32Cube) and ARM LIMITED (CMSIS), available under BSD license, withfollowing conditions.
Copyright © 2014 - 2020 SEGGER Microcontroller GmbH
Copyright © 2016 STMicroelectronics
Copyright © 2020 ARM LIMITED
Redistribution and use in source and binary forms, with or without modification, are permitted
provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of conditions
and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of
conditions and the following disclaimer in the documentation and/or other materials provided
with the distribution.
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3. Neither the name of the copyright holder nor the names of its contributors may be used
to endorse or promote products derived from this software without specific prior written
permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHTHOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
The DCBM includes software developped by Amazon Inc (FreeRTOS), available under MIT
license, with following conditions.
Permission is hereby granted, free of charge, to any person obtaining a copy of this softwareand associated documentation files (the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the Software is furnished to
do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies orsubstantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALLTHE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

2.10. Warranty
For information about applicable warranty for the DCBM, contact your nearest LEM sales
representative.
In the absence of any written agreement with LEM governing the sale of the DCBM to you, LEM
general terms and conditions of sale as referred on the order confirmation shall apply. LEM
disclaims all warranties of any kind, except as expressly provided in the above agreement or terms
and conditions of sale, whether express or implied, relating to the DCBM and its documentation,
including any implied warranty of merchantability, fitness for a particular purpose or noninfringement.

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3. Product introduction
3.1. LEM and the DCBM
Leading the world in electrical measurement, LEM
engineers the best solutions for energy and mobility,
ensuring that its customers’ systems are optimized,
reliable and safe.

Enabling Better Billing for EV Charging Points

The automotive world is seeing a rapid transition to electric vehicles, driven by concern for theenvironment and accelerated by legislation. For the transition to EVs to be successful, a networkof charging points is required.
Today there are increasing restrictions on how the billing must be managed: for example, theGerman Eichrecht regulations state that consumers should only be charged for the DC power
supplied and not for any power loss associated with the conversion from AC to DC. Developing a
DC metering solution is a complex challenge that could delay the successful transition to electricautomobiles.
By using DCBM 400/600 product family, developers and installers of electric charging points
can easily prove their compliance with legislation while reducing the time required to design the
charging system.

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3.2. DCBM in EV charging systems
LEM Direct Current Billing Meters with 400 A and 600 A ratings, are connected DC energy meters,
referred to as "DCBM" in this document. They are dedicated to energy metering in the field of
DC applications such as fast and ultra-fast charging station for Electric Vehicles (covered by IEC
61851-23). Typical applications of the DCBM 400/600 product family are 50 kW up to 350 kW
Electric Vehicle charging systems.
The following figure illustrates typical integration of the device, and lists equipment and protagonists
as they are referred to in hereby document.

Power converters

DC

AC grid

Charge post 1

Charge post 2

Charge post 3

DCbackendCharger
controller

DCBM

To the

DCBM

DC

DCBM

End userACEV

DC link 1
DC link 2
DC link 3

Communication interface
EVSE/Charging station, operated by the Charge point operator

Figure 3: Namings designating equipment and protagonists

The DCBM comes with the following highlights:
Advantages•
Split meter concept easy to integrate into systems•

Flexible integration with bus bars or wires•

OCMF readouts compliant with S.A.F.E•

Compliant for energy billing or parking time billing•

System monitoring: Current, Voltage, Power, Temperature

Applications•
Electric Vehicle Charging infrastructures•

Data centers•

DC grids & Energy Monitoring•

Energy storage, Renewables

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Features•
Range of operation 150…1000 V DC•

Two sizes: Imax 400 A and 600 A,•

Wide current terminals, compliant with bus bars•

Bi-directional energy metering (V2G)•

Accuracy Class B, -40°C to 85°C•

Compatible with 4 wire measurement•

Cable loss compensation•

Ethernet communication with HTTP/HTTPS•

Signed data readouts in OCMF or LEM format•

Monitoring data (current / voltage / temperature / energy)•

Transaction mechanisms with start & stop tags and client identification•

Auxiliary power supply range +12 ... +48 V DC•

DIN rail 35mm and screw mounting•

Length of Datalink cable from 30 cm up to 3.5 m•

Integrated display with backlight•

Reinforced insulation at 1000 V DC, OVC II•

Sealing of terminals and interfaces

The DCBM is split into two elements linked via a cable (delivered with the DCBM): the Sensor Unit
and the Meter Unit. Figure hereunder depicts product construction.

Meter Unit

Sensor Unit

The device stores,
displays, communicatesand authenticatesmeasurement data. The
Meter Unit delivers
power supply to the
Sensor Unit.

The device isconnected to busbars
or wired systems, andsenses accurately
current and voltage tomeasure energy
continuously. Data issecurely transferredto the Meter Unit.

The Meter Unit offers
communication with the
charging station through
Ethernet /REST APIs.

Data link cable
Delivered with the product, this cableconnects Meter Unit to Sensor Unit, bothterminals can be sealed.

Figure 4: Product construction

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Sensor Unit has four terminals: two terminals to measure current flow and two terminals to measure
the DC link voltage. An arrow printed on the Sensor Unit indicates the default current flow used tomeasure imported energy.
The DC meter DCBM is designed in a hardware-based split and consists of the Sensor Unit, theMeter Unit and a datalink cable between the two units.
Two current rating Sensor Units are available. The possible installation variants of the sensor
types are listed in this manual The Sensor Unit and the Meter Unit are paired together. If another
Sensor Unit is connected to the Meter Unit a specific error flag is raised.
DCBM 400/600 operate from an auxiliary power supply (12... 48 V DC).
To cover the different power ratings of charging systems, the DCBM is available for 2 current
ratings:
Imax = 400 A or Imax = 600 A. Two additional variants of Sensor Unit offer measurement with current

measurement in the opposite direction.

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3.3. DCBM 400/600 in EVSE
This part describes the integration of LEM DCBM into different kind of Electric Vehicle Supply
Equipment (EVSE). Two examples are given: a 50 kW power class system, and a 350 kW powerclass system.

3.3.1. DCBM in 50 kW EVSE
The following figure presents the typical structure used in 50 kW power class charging systems.
These systems use to offer multiple output cable connectors (i.e. Combined Charged System and
CHAdeMO). Several AC to DC converters deliver power to either one or the other output cable.
Power relays select the output cable.
Charge Post
Communica�on & Control

Three phase Low voltage
AC Grid

CCS

Power stacks
AC
DC

Power stacks

SwitchingmatrixCHAdeMO

Figure 5: Typical 50 kW architecture

Specifications of a typical 50 kW EVSE•

Current range: 125 A DC•

Voltage range: 150 V DC – 920 V DC•

AC/DC converters and connection in a single cabinet•

Internal power connections made with cables

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In such application, the DCBM is integrated before the power relays. This integration is preferredbecause it optimizes space in the existing 50 kW charging station. Only one output cable can besupplied at the same time.

Charge Post
Communica�on & Control

CCS

DCBM
Power stacks
AC
DC

Grid
CHAdeMO

Power stacks
Figure 6: DCBM in a typical 50 kW EVSE

3.3.2. DCBM in 350 kW EVSE
To reduce charging time, high power charging is used. Specific power electronic techniques (e.g.
liquid-cooled cables) are used. Currents up to 600 A are applied during charging, with a maximum
system voltage of 1000 V DC.
To optimize system performance, central AC/DC converters are used instead of dedicatedconverters in the charge posts (the cabinet to connect the EV). Several DC buses link the central
converters to the charge posts.
Charge Post

Charge Post

175kW Module

Liquidcooledcable
CHAdeMOAC

175kW Module

Liquidcooled
cable

AC
DC

DC

CCS

CHAdeMOCCS

AC grid
DC BusDC BusFigure 7: Typical 350 kW EVSE system

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Specifications of a typical 350 kW EVSE:•

500 A DC•

Voltage range: 150 V DC – 920 V DC•

AC/DC converters separated from the charge posts•

Internal power connections made with bus bars•

Liquid-cooled cable between charge post and EV

The DCBM is integrated in the charge post. Figure hereunder gives an example of integration.
Charge Post

Charge Post
175kW Module

CHAdeMO

AC

AC
DC

DC

DCBM

DCBM

Liquidcooledcable

175kW Module

CCS

CHAdeMO

Liquidcooledcable
CCS

AC grid
DC BusDC BusFigure 8: DCBM in a typical 350 kW EVSEThe DCBM has to be integrated using bus bars and connections in a hazardous area, usually
separated from low voltage areas. Moreover, the operating temperature of bus bars can exceed+100 °C while charging at high power.
In such compact and space-limited environment, the specific split construction of the DCBM makes
it easy to integrate, just as other electrotechnical components like power relays, power diodes or
DC link fuses.

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3.4. Certification and compliance3.4.1. Standards
The DCBM complies with the following standards.
•

EN 50470-1: 2006, EN 50470-3: 2006•

PTB 50.7•

CISPR32 Class-B emission•

EN 62052-31: 2015•

IEC 62052-11: 2003•

IEC 61000-6-2: 2016•

IEC 61000-6-3: 2016•

UL94-V0•

Designed according to VDE-AR-E-2418-3-100.

3.4.2. Certification
The corresponding certificate for the DCBM is available in Appendix 1.

3.5. Product designation
Tables below summarize the product references depending on the possibles variants:•

Maximum current rating•

Current flow direction for default energy registering (i.e. imported energy direction)•

Compensation factor

Direction ofcurrent flow

Dynamic compensation
factorFix compensation factor

NormalDCBM_N0D_4000_0000

DCBM_N1D_4000_0000 ... DCBM_N4D_4000_0000

Reverse

DCBM_N0D_4010_0000

DCBM_N1D_4010_0000 ... DCBM_N4D_4010_0000

Figure 9: Simplified list of references for 400 A current rating

Direction ofcurrent flow

Dynamic compensation
factorFix compensation factor

NormalDCBM_N0D_6000_0000

DCBM_N1D_6000_0000 ... DCBM_N4D_6000_0000

Reverse

DCBM_N0D_6010_0000

DCBM_N1D_6010_0000 ... DCBM_N4D_6010_0000

Figure 10: Simplified list of references for 600 A current rating

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Complete list of references is designated as follows.

D C B M _ N 0 D _ 4 0 0 0 _ 0 0 0 0
Meter family
DCBM : Direct Current Billing Meter
Time source
N : Time synchroniza�on NTP
Cable loss compensa�on
0 : Dynamic 0 - 14 mΩ (2 mΩ steps)
1 : No compensa�on
2 : 2 mΩ3 : 4 mΩ4 : 6 mΩCer�ﬁca�on
0 : without cer�ﬁca�on
D : cer�ﬁed
Sensor Unit family
40 : 400 A version
60 : 600 A versionCoun�ng direc�on
00 : direct (I1 -> I2)
10 : reverse (I2 -> I1)
Reserved ﬁeld 10000 : default

Figure 11: Full list of references for the DCBM 400/600 product family

The complete type designation of the whole DCBM is marked as relevant designation on the nameplate of the Meter Unit.

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4. Device description and mechanical integration
4.1. Package content
The package is composed of:
A

D

C

F

B

G

E

i
!

A

1 Sensor Unit

D

1 Meter Unit

B

2 nuts with captive washer(already mounted on the
product)

E

1 Data link cableC

1 Protection coverF

1 Installation manualG

FerriteBefore any operation, read section "4.6.1. Manufacturer seals".
The Meter Unit and Sensor Unit included in the package are paired and cannot be swapped withanother set.
Protection cover C shall be mounted to ensure IP20 rating on the terminal areas.

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4.1.1. Meter Unit description
A

B
I

C
D

H

A

Public key
numberB

andserialG

F

E

E

Connection coverTop button

F

Status LED

C

Bottom button

G

DisplayD

Test LED

H

Verification marking

I

IR optical interface

4.1.2. Sensor Unit description
Please refer to section 3.2.2.

4.2. Mounting and unmounting
4.2.1. Meter Unit
4.2.1.1. Mounting

1

2

Click!

To mount the Meter Unit, place it onto the DIN rail and rotate it backwards, until hearing the ‘click’.

21January2021/Version 0
		

2
1

4 x2
3 x2

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5

1

2

Click!

4.2.1.2. Unmounting

5
2

4 x2
3 x2

1

•

The Meter Unit can be positioned on a DIN Rail TH 35-7.5 or TH 35-15 (IEC 60715: 2017)•

Possibility to fix the Meter Unit with 2x M4 screws (max), max torque 1.2 N⋅m.

4.2.2. Sensor Unit

≤ 4.5 mm

1

2•

The Sensor Unit can be positioned on a DIN Rail TH 35-7.5 or TH 35-15 (IEC 60715: 2017)•
The Sensor Unit shall be fixed with 4x M4 screws with washer. Screw head + washer ≤ 4.5 mm,
max torque 3.5 N⋅m.

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A

4.3. Product dimensions

B

4.3.1. Meter Unit

A

G

Drilling

I

B

A

B

C

G

H

J

I
E

F

G
G
C

H

I
J

D

Figure 12: Meter Unit dimensions
E
C

F
E

G

A

63.7 mmEH
4.6 mmB

126.2 mm (±0.2)F

3.9 mmC

F

81 mm (±0.2)

G

Max M4 screws(torque max 1.2 N⋅m)

D

117.5 mmH

94.8 mm

D

D

J

I

45 mm

J

45 mm

K

L

K

K
M

L

Figure 13: Meter Unit aperture for electrical cabinet
LK

64 mm (±0.2L

123 mm (±0.2)

M

M 67.2 mm: DIN rail TH 35-7.5
74.7 mm: DIN rail TH 35-15

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4.3.2. Sensor Unit
M
Drilling

M

I
A

B

H

G

C D

E

F

M
K

Figure 14: Sensor Unit dimensions

DCBM_SU40XX

M

L[1] Possible choice

DCBM_SU60XX

A

56.8 mm74.2 mm

B

23 mm

36 mm

C

54.6 mm

67 mm

D

50 mm

65 mm

E

143 mm

143 mmF

68 mm

86.3 mmG

5.5 mm

5.5 mmH

132 mm (±0.2)

132 mm (±0.2)

I

M8

M12

J

33.5 mm (±0.2)

51.6 mm (±0.2)

K11.2 mm (±0.2)

11.2 mm (±0.2)

L480mm (±0.2)

66 mm (±0.2)

M

M4

M4

21January2021/Version 0		M[1] [1]J

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4.4. Connectioni

To connect and disconnect the wires, use a screwdriver 3 x 0.5 mm (DIN 5264)
For detailed explanation of this graph, please refer to the below table "Table 1: Ports definition"and figure "Figure 16: Connection and wiring diagrams".

10 ... 11 mm
0.39 ... 0.43 in.

0,25 ... 1,5 mm²
23 ... 16 AWG

8 mm
0.31 in.

0,13 ... 1,5 mm²
24 ... 16 AWG

0.6 N.m max.

C

A
B

Click!

Click!

Click!

Figure 15: DCBM connection

A

Ethernet cable

21January2021/Version 0		BData Link cableC

Bus bars or lugs

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Port N°

Definition

1

Power Supply +2Power Supply −3

Reserved

4

Reserved

5

Reserved

6

Reserved

EthEthernet port

COM

Data link port

VP

Voltage measurement +VN

Voltage measurement −Table 1: Ports definition

Low side mounting

High side mounting

Reserved

3

Reserved

4 5 6
Supply

1

+

MU

-

Data
2

Eth

Com

V+
V-

3

MU
I2

VP

I1

VN ComMU

Supply

Data

1

SU

2

Eth

Com

V+
V-

SU

Direct current flow / Stromfluss Normal / Courant direct

SU
I1

SU

VP

I2

VN Com+MU-

Direct current flow / Stromfluss Normal / Courant direct

Reserved

Reserved

3 4 5 6

MU

Supply
1

4 5 6

Data
2

Eth

V+
V-

Com

+

3 4 5 6-

Supply

MU
I1

VP

I2

VN ComSU

SU

Reverse current flow / Stromfluss Revers / Courant indirect

1

MU

SU

Data
2

Eth

V+
V-

Com

I2

SU

+

VP

I1

VN ComMU-

Reverse current flow / Stromfluss Revers / Courant indirect

Figure 16: Connection and wiring diagrams

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You can connect the product with bus bars and lugs. F
The product is compatible for one lug per connection configuration with all lugs from standard:!

•

NF C 20-130: 2004•

DIN 46220: 1965•

DIN 46234: 1980•

DIN 46235: 1983

2 lugs can connect on each terminal, not all the lugs are compatible. Please check the dimensions.
A

A

B
H

H

E

G

C

F

D

Figure 17: Sensor Unit integration

DCBM_SU40XX

A

15 mm

15 mm

B

62 mm

62 mm

C

19 mm

27 mm

D

30 mm

40 mm

E

9 mm max. 1)

13 mm max. 1)

F

34.6 mm52.9 mm

G

13 mm

18 mm

H

15.9 mm15.9 mm

ReferenceFirehazardDCBM_SU60XX

Maximum thickness
for bus bar or lugs
1)

Nominal tightening
torque (N.m)

Size of stud

⌀ Drillinghole (mm)DCBM_SU40XX

10.4 ±0.5

M88.5

DCBM_SU60XX

36.4 ±0.5

M12

12.5

Table 2: Torque values for installation

21January2021/Version 0		Table 3: Bus bar drilling

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4.5. Cable management
1 To maintain the wires on the Sensor Unit use a tie (2.5 x 1 mm)
2 To maintain the Data link cable on the Sensor Unit use a tie (2.5 x 1 mm)
1

2

Figure 18: Cable management

4.6. Sealing
4.6.1. Manufacturer seals
Before any operation with the device, themanufacturer seals shall be checked.
Manufacturer seals are white tampering tapes
set on the two parts of the device.
A total of 4 seals shall be present, 2 for each partof the device.
Any alteration to the seals invalidate device’s
measurement capabilities.
Figure 19: Manufacturer seals

4.6.2. Installation seals
Installation seals can be set at the end of installation of the device. They prevent unnoticed
unmounting of the wiring and bus bars by unauthorized personnel.
Using installation seals is strongly recommended as unauthorized unmounting could lead to:•Electrical risks•

Malfunction of the device (unavailable power supply or communication link)•

Alteration to device configuration•

Any software attacks

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Once the product is installed1

Mount the protection cover2

Seal the Sensor Unit

3

Seal the Meter Unit
1

2 DCBM_SU400XX

2 DCBM_SU600XX

Click!

3!

The sealing wires are not provided by LEM.

Max diameter of the sealing wire ⌀ ≤ 2.2 mm

4.7. Disposing
The device packaging materials can be recycled. Please help protect the environment by recycling
them in appropriate containers. Thank you for your contribution to environmental protection.

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4.8. Marking
Meter Unit Marking Example – Without certification
DCBM N0D 4000 0000
Public Key

3

4

5

Meter Unit Marking Example - With PTB certification
DCBM N0D 4000 0000

-25°C / +70°C

Public Key

6

1

2

3

4

5

6

-25°C / +70°C

DE-M 20 0103
DE-20-M-PTB-0016

2020

2020

1202340856

1202340856

DCBM Series

DC Energy Meter

DCBM N0D 4000 0000

Power Supply:
12/48 VDC
400 mA (24 VDC)SUVN Com1
LEM INTERNATIONAL SA

2

3

4

5

6

DE-M 20 0103
2020

-

Eth
Ethernet port
COM Data link port
VP
Voltage measurement +VN
Voltage measurement I1Bus bar
I2
Bus bar

I1

+
SU
Com

DC Energy Meter

Eth

COM

V+
VReserved
Reserved
Reserved
Reserved

COM

Status3

41000 imp/kWh

Chemin des Aulx 8, 1228 Plan-les-Ouates, Switzerland

Made in Switzerland

LEM INTERNATIONAL SA

IP20

DCBM N0D 4000 0000

V+
V-

DCBM Serial Number

1
2
3
4
5
6

Data

MU

Eth
2
Supply1202340856

DCBM Series

Eth1

Reserved

3 4 5 6-25°C / +70°C

1000 imp/kWh
DE-20-M-PTB-0016

Chemin des Aulx 8, 1228 Plan-les-Ouates, Switzerland

VP

I2

Chemin des Aulx 8, 1228 Plan-les-Ouates, Switzerland

Public Key

Status1000 imp/kWh
MU

StatusDCBM Serial Number
Data Matrix

DCBM Type Designation

OCMF Public Key
Data Matrix

Eth

COM

mber
Calibration stickers

DCBM Type Designation

NumberChemin des Aulx 8, 1228 Pla

I1

I2

I2

If this seal is removed
or broken LEM does
not guarantee theproduct and data
integrity

Counting Direction

Ue: 1000V DC

Ie: 400A DC

4-80(400) A DC
150V...1000V
CI.B EN50470-40°C / +85°C IP10

VN

COM

1202340856

Sensor Unit Type Designation

21January2021/Version 0
		

I1

VP

DCBM SU 4000

Uimp: 8kV

Sensor Unit Serial Number
Data Matrix
DCBM Product Serial Number

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5. Electrical functions
5.1. Safety features
Reinforced insulation•

Reinforced insulation according to IEC 60664-1 is provided by the Sensor Unit.

•

Rated insulation RMS voltage: 1000V

Thermal consideration•

The DCBM features temperature measurements on its shunt.

•

Temperature can be read at any time using /livemeasure API (see "7.3.5. Other measurements")•
Furthermore, the Sensor Unit monitors those value. In case an over temperature is detected, a status
flag is raised, and traced in the on-going transaction (see "7.5.3. Current status")

5.2. Integration solutions
5.2.1. Overview
The DCBM 400/600 product family offers multiple solutions for integration of its Sensor Unit.
Choices can be made on:•

The current flow which is considered as regular counting direction•

The voltage side on which the DCBM is installed

Regardless of the Sensor Unit configuration, the Meter Unit connection is always the same.

!

The connection line for voltage measurement must include the supplied ferrite, ensuring
measurement reliability despite EMI interferences, as shown on Figure 21 and Figure 22.

5.2.2. Counting direction
Two types of references are available, matched with different counting direction:
NamingCounting direction

References designation

Direct

I1

I2

DCBM_Nxx_xx00_xxxx

Reverse

I2

I1

DCBM_Nxx_xx10_xxxx

Table 4: Counting direction references

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The goal of this choice is to always have registers as follows:•

Energy coming from the electrical grid into the vehicle increments Import energy register.

•

Energy coming from the vehicle back to the grid increments Export energy register

Im

Ex

po

po

rt e

rt e n

nergy

ergy

Figure 20: Import and export energy registers matched with energy flow

5.2.3. Voltage side
Regardless of the product reference, one of the following mounting options must be chosen:•

Mounting the Sensor Unit on the negative side of the DC link, referred as "Low side mounting"•

Mounting the Sensor Unit on the positive side of the DC link, referred as "High side mounting"

These possibilities offer flexible integration in existing environments. Hence the choice depends
on existing architecture or foreseen integration. Decision influences how voltage inputs must beconnected, as described in next sections.

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5.2.4. Direct counting direction connection requirements

A

A
E

A

E

B

C

E

G

H

F

D
B

A

D

D

B

E

C

D

C

B
G

F

C

H

F
H
DC-

G

DC+

DC-

DC+

F

H
DC-

G

DC+

DC-

Low side mounting

DC+High side mounting

Figure 21: Connection for direct counting direction references (DCBM_NxD_x000_0000)

21January2021/Version 0		A

Meter Unit

E

Charging station bus bars

B

Ethernet CableF

Sensor UnitC

Data link cable

G

Voltage measurement cable +D

Current flow

H

Voltage measurement cable -Page 39/95
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5.2.5. Reverse counting direction connection requirements

A

A
E

A

E

D
B

E

B

H

C

B

E

G

D

C

D
F

H

C

A

D

B

G

C

F

F

H
DC-

DC-

DC+

G

DC+

F

H
DC-

DC-

DC+

Low side mounting

G

DC+High side mounting

Figure 22: Connection for reverse counting direction references (DCBM_NxD_x010_0000)

21January2021/Version 0		A

Meter Unit

E

Charging station bus bars

B

Ethernet CableF

Sensor UnitC

Data link cable

G

Voltage measurement cable +D

Current flow

H

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5.3. Energy registering
Conventional direction for current measurement fills the "import" energy register. This flow refers
to I1 and I2 indications on Sensor Unit marking (see below figure), and depends on productreference: see "Table 4: Counting direction references".
A current flow the other way around fills the export energy register.

I1

I2

I1

I2

If this seal is removed
or broken LEM does
not guarantee theproduct and data
integrity

Ie: 400A DC

VN

COM

1202340856

Ue: 1000V DC

4-80(400) A DC
150V...1000V
CI.B EN50470-40°C / +85°C IP10VP

DCBM SU 4000

Uimp: 8kV

VP and VN shall be connected to the positive and negative bus bars respectively. Voltage inversion
does not cause any damage to the DCBM but raises a status to indicate the wiring error (statusreversedVoltage, see "7.5.3. Current status").
The following graph shows how directions of current flow and voltage difference are registered by
the DCBM.
Voltage

Umax

Export energy

Import energy

Umin
-Imax

-Ist

Ist

Imax

Current

Figure 23: Counting quadrants for the DCBM

Anti-creep is performed on current and voltage measurements, as visible of above graph. Hence,no energy is accumulated in any of the following conditions:•

If voltage is below datasheet value "Minimum limit range of operation Umin"•

If current is between Ist and -Ist ("Starting current" as in datasheet)

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5.4. Handling energy losses
High power charging implies non-negligible power losses through components of the electricalcircuit. The DCBM offers solutions to avoid billing those losses to the end customer.
Two solutions are available:•
Achieve a compensation to subtract dissipated energy to the consumed energy; using cable loss
compensation•

Achieve the energy measurement as close to the EV as possible, using four-wire measurement

5.4.1. Cable loss compensation
The DCBM 400/600 product family features a unique solution to compensate energy dissipatedbetween the energy meter and the EV battery.
5.4.1.1. Principle
Below illustration gives an example of distribution of losses in an installation.

Power losses distribution
7%

2%

0%

4%
Cable
Fuse
Contactors
Cabling
Busbar connections

87%

Figure 24: Example of energy losses in an EVSE electrical circuit

If no compensation is performed on the measurement, the total resistance will bend the accuracy
characteristic of the metering system. This bending will be more significant at low system voltage.

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Figures hereunder depict an example of graph to compare system accuracy (standard offset andgain errors has been applied):•
Left hand figure displays a simulated accuracy graph with the 4-wire measurement technique (orperfect compensation of cable losses)•
Right hand figure displays the same results when cable losses are not compensated, and no 4-wiremeasurement is available.
With perfect cable loss compensation

5
4
3

Error (%)

2
Class B +1
0
-1

Class B 1

10

100

1000V
150V

-2
-3
-4
-5

Current (A)Without compensation
5
4
3

Error (%)

2
Class B +1
0
-1

Class B 1

10

100

1000V
150V

-2
-3
-4
-5

Current (A)Figure 25: Current accuracy graphs with and without cable loss compensation

When no compensation is implemented, the metering system does not subtract the losses ofelectrical circuit; therefore the measurement energy is too high.

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5.4.1.2. Compensation mechanism
In standard installations, the voltage measurement terminals of the DCBM are connected directly
to the bus bars inside the charging station. The voltage sense wires can be connected after the
power relay if necessary.
In this case, the cable loss compensation mechanism must be used. Figure hereunder describes
the possible integration.
Only resistive losses can be compensated. Notably, power diodes losses cannot be compensated(i.e. right-hand solution cannot be used).

ab

le

Vc

VrelaycablesHigh current relays

le

ab

EV

Vc

Vc

ab

Vmeas

VrelayHigh current relays

Vc

ab

le

cablesHigh current relays

leVrelayVccablesleabEV

VrelayVc

VrelayleabEV

Vrelayi

Diode module

DC link from power
converters

DC-

Idc

Idc

Sensor Unit

DC+

DC-

DC+

Idc

Sensor Unit

Imeas

DC link from power
converters

DC-

Sensor Unit

Diode module

Idc

Imeas

Vmeas

DC+

Imeas

Idc

Idc

Vmeas

DC link from power
converters

Figure 26: Integration examples using cable loss compensation

Cable loss compensation consists in subtracting estimated energy losses to actually measured
energy. To do so, the DCBM uses a resistance value, which estimates the dissipation resistanceof the circuit. This resistance value is referred to as RP. The compensated energy is integration ofcompensated power, calculated as follows:

With:

Pcompensated & VcompensatedCompensated power & voltage

Imeasured & Vmeasured

Measured current & voltage

RP			Resistive compensation

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5.4.1.3. Setting the compensation level
5.4.1.4. Setting cableId value
The DCBM includes a list of preset RP table of 8 RP values. Parameter cableId allows selection
through the table.
Three types of DCBM references are available, with different preset tables:•

Dynamic compensation•

No compensation•

Fixed-value compensation

Product designation separates those types (see "3.5. Product designation"). Resistance values for
all products are distributed as follows:
14
12

Dynamic compensation

N1D

No compensation

N2D

Compensated @ 2 mΩ

N3DCompensated @ 4 mΩ

N4DCompensated @ 6 mΩ

10
RP (mΩ)

N0D

8

N0D
N1D
N2D

6

N3D
N4D

4
2
0

0

1

2

3

cableId

4

5

6

7

Figure 27: Distribution of RP values depending on product designation

For references with dynamic compensation, RP value to use is chosen at the start of each transaction
by the charger controller. It cannot change during transactions. After the transaction, the usedcompensation level is securely stored within the corresponding signed transaction data structure.

i

The following items are excluded from compensation:•

Exported energy is not compensated•Live voltage, current, power are never compensated•

Any energy outside transactions is not compensated

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5.4.2. Four-wire measurement
Product offers the possibility to use four-wire measurement to comply with the latest generation ofhigh power charging cables.
This mode requires a charge cable featuring specific voltage measurement wires, to allow VP and
VN to measure voltage directly onto the EV connector.
This mode is compatible with both high side and low side mounting, as described in "5.2.3. Voltageside".
Figure hereunder describes the connection and the system integration.

Meas_DC_N
EV

Meas_DC_P

DC_P

DC_N

Vmeas
cablesHigh current relays

Ethernet
Power supply

Idc

Charging station

DC Fuse

Imeas

Meter Unit

DC-

DC+

Idc

Sensor Unit

DC link from power
converters

Figure 28: Integration example for four-wire measurement

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5.5. Performances
5.5.1. General
Parameter

Unit

Min

Supply voltage

V DC

+12

Supply current

mA

Supply bridging times

0.5

At +24 V DC

Voltage restoration (power up)s5

At +24 V DC

Rated conventional thermal current

A

400
600

DCBM-SU40xx
DCBM-SU60xx

Rated operational voltage

V

1000

Insertion loss in current pathW

10

Rated operational voltage

V

1000

Insertion loss in current path

W

10

kA

12
18

Rated short time withstand current

21January2021/Version 0		Symbol

ICW

Typ

Max

Comment+48±5 % tolerance

400

At +12 V DC

DCBM-SU40xx
DCBM-SU60xx
30 ms

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5.5.2. Accuracy
Parameter

SymbolUnit

DCBM 400

DCBM 600

B

B

Accuracy class
Meter type

Comment

Direct connected meter
Current specification (Uninterrupted duty)

Reference current

Iref

A

80

120

Minimum current

Imin

A

4

6

Transitional current

Itr

A

8

12

Maximum current

Imax

A

400

600

Starting current

Istart

mA

320

480

According to EN 50470-3
and EN 50470-1

Voltage specification
Range of operation

Un

V DC

150 - 1000

Maximum limit range of operation

Umax

V DC

1100

Minimum limit range of operation

Umin

V DC

130

Energy measurement bandwidth

DC

Cable loss compensationmΩ

0 - 14

By steps of 2 mΩ, imported
energy only. Selectableby charger controller or fix
value

Test Output LED

Imp/
kWh

1000

(see product designation)

Counting direction

Bidirectional

5.5.3. Insulation
Parameter

SymbolUnit

Insulation type
Rated insulation RMS voltage

UNm

V

Overvoltage category

Value

Comment

Reinforced insulation1)

According to IEC 60664-1

1000
OV II

Impulse withstand voltage 1.2/50 μs

UNi

kV

8

RMS voltage for AC insulation test, 50/60 Hz, 1 min

Ud

V

4400

Pollution degree
Maximum altitude m 2000
Voltage sense terminals - rated insulation between
poles
Case material

Note:

PD2
m

2000

kV DC

1

Basic insulation, PD2

V0

According to UL 94

Reinforced insulation is provided by the Sensor Unit (DCBM-SU40xx/DCBM-SU60xx).
The DCBM Meter Unit operates in SELV only
1)

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5.5.4. Operating conditions
5.5.4.1. Sensor Unit
Parameter

Symbol

Unit

Min

Typ

Max

Ambient operating temperature

TA

°C

−40

+85

Ambient storage temperature

TA st

°C

−40

+85

Relative humidity

RH

%

Mass

m

g

SymbolUnit

Min

Ambient operating temperature

TA

°C

−25

+70

Ambient storage temperature

TA st

°C

−40

+85

Relative humidity

RH

%

95

Mass

m

g

200

Symbol

Unit

Min

TA

°C

−50

Comment

95
300

DCBM-SU40xx

415

DCBM-SU60xx

5.5.4.2. Meter Unit
Parameter

Typ

Max

Comment

5.5.4.3. Data link cableParameter
Ambient operating temperature
Nominal voltage

Max

kV

LengthmComment

+120

kV AC
kV DC

Test insulation voltage

21January2021/Version 0		Typ0.6/1 kV AC
0.9/1.5 kV DC
3.5
0.3

3.5

See product designation forcomplete product references

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6. Display and navigation
6.1. Quick startThis section describes how to validate measurements of the DCBM from the display.

6.1.1. STEP 1 - Power up the DCBM
On powering up the DCBM, the following screens will be displayed successively. In particular, thefollowing data allow metrological validation:•
The public key during the boot sequence, for further data authenticity check of LEM format(i.e. without OCMF RFC5480 header)•

The global energy registers (import and export), on the idle screen

Detail of data displayed can be found in section "6.3. Boot screens" and "6.4. Idle screen".

Figure 29: Sequence of screens on boot and during idle

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6.1.2. STEP 2 - Check transaction data
A transaction must be triggered. Sequences of screens are triggered by the beginning and end of
the transaction, which are illustrated below. Description of those screens is available in section"6.5. Transactions screens".

Figure 30: Sequence of screens for beginning of transactions

Figure 31: Sequences of screens for end of transactions

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In particular, the following data are of specific interest:•

The difference register for the current transaction, displayed at the bottom of every screen•

Total energy registers (import and export) at the beginning and end of the transaction•

Duration of the transaction, at the end of the transaction•

Public key for LEM format authenticity check (i.e. without OCMF RFC5480 header)

6.1.3. STEP 3 - Achieve further validation
Outside transactions, buttons give free access to data, which can help checking metrologicalstatus and registers. For instance, the following data can be of interest.
•

Transaction prerequisites: Status of Sensor Unit link and of time synchronization•

Metrological follow-up: Total energy registers•

Data authenticity: Public key (without OCMF RFC5480 header)

A
B

1/5

5/5

2/5

4/5

3/5
Figure 32: Maintenance screens which can help metrological validation

The full list of data is available in section "6.6. Maintenance state".

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6.2. General display concepts
The display of the DCBM primarily aims at
displaying data relevant to certified billing.
Screens are sequenced accordingly. The
display also provides data which can be usefulfor installation and maintenance.

Boot
screens

Timeout
or Buttons

The screens are sequenced according to theadjacent block-diagram.

Idle

Those states are described individually in below
sections.

Transaction
screens

Maintenancestate

Figure 33: Global state machine of the display

Two buttons are present on the front panel. Their effect depends on the current state and is
described along with states. Those buttons are referred to as follows:A

Identification
on figure

Naming in hereby
document

BA

Top button

B

Bottom button

Figure 34: Identification of buttonsi

Due to certification function of the display, a visual distinction appears between certification data
and user experience-oriented data. This distinction is illustrated on example of screen below.
Legally nonrelevant lines

On inverted dark
background

Legally
relevant lines

On regular lightbackgroundFigure 35: Visual distinction for legal relevance on the display
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6.3. Boot screens
6.3.1. Overview
Boot screens provide general information on the device. The sequence rolls on a regular basis
and can be overridden by a started transactions or a pressed button. The sequence ends with ascreen test sequence, allowing to visually check the proper functioning of the whole pixel matrix.

1/8
2/8
3/8
4/8
5/8
6/8
7/8
8/8

Screenindex

Solution

1/8

Company logo
Serial number of device

2/8

Identifiers of the versions of each firmware parts

3/8

Integrity checksums for legally relevant firmware parts

4/8

Public key of the device, for LEM format authenticity check (i.e. without OCMF RFC5480 header)

5-8/8

Screen test sequence

6.3.2. Effect of buttons
Buttons used in this state abort the sequence and lead to the maintenance state.

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6.4. Idle screen

6.4.1. Overview
The idle screen is the central screen, following the boot sequence, the transaction screens andthe maintenance state.

6.4.2. Available data
The data provided in the Idle screen are the following:•

Total import and export energy registers•

Current local date and time

6.4.3. Effect of buttons
Buttons used in this state give access to the maintenance screens.

6.5. Transactions screens
6.5.1. Layout of screens
All the transaction screens are built as follows:
Currentstate
symbolRollingdata

Transaction energy counter
Figure 36: Transaction screens layout

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6.5.2. State symbols
The transaction screens are spread into 3 categories. Each category is associated to a symbol,
displayed during the whole duration of the category.
Transac�on
beginning

In progressTransac�on
stop

Transac�on
end

Figure 37: State machine for transaction screens

6.5.3. Transaction energy register
During the whole sequence and until the return to the Idle screen, the transaction energy counteris displayed.
Before the end of the transaction, the counter increments according to measured energy. The
currently incrementing register is the one displayed: either import or export register.
Registers can be identified using an associated symbol.

Import energy
i.e. from the energy grid to the vehicle

Export energy
i.e. from the vehicle back to the energy grid

Figure 38: Transaction energy register

After the end of the transaction, the final definitive value of the energy register is displayed. If theimport energy register is displayed alone, it means the export energy register was not used andvice-versa (an unused register has an energy exactly equal to 0.000 kWh). In case both registers
were used, both are displayed successively.

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6.5.4. Rolling data
The rolling data pane features the following data.

1/4
2/4
3/4
4/4
Screenindex

Data on rolling pane

1/4

Total energy registers on the beginning of the transaction

2/4

Local date and time on the beginning of the transaction
Tariff input

3/4

Cable identifier input
EVSE identifier input

4/4

Client identifier input

Data on rolling pane
Tariff identifier
Elapsed time of the transaction
Live charge power (not to be used for billing purposes)

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1/4

4/4

2/4

3/4

Screenindex

Data on rolling pane

1/4

Total energy registers on the end of the transaction

2/4

Local date and time of the end of the transaction
Total definitive duration of the transaction

3/4

Status of the time synchronization for this transaction, featuring validity and mode of synchronization(not to be used for billing purposes)

4/4

Public key of the device, for LEM format authenticity check (i.e. without OCMF RFC5480 header)

6.5.5. Effect of buttons
Symbol oftransaction state

Effect of buttons
No effect

No effect

Browse screen faster and in chosen order

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6.6. Maintenance state
6.6.1. Overview
Maintenance state is available from the Idle screen and from the Boot screens, by using the
buttons. Its goal is to give access to some data that can ease installation and maintenance.
This state falls into several screens, split over 5 categories:•

STATUS•LIVE MEASURE•

DEVICE•FIRMWARE•

CLOCK

6.6.2. Layout of screens
The maintenance screens are built as follows:

Category
title
Data label

Indicatorof buttons
function

Symbols for
those data

Data
valuesFigure 39: Maintenance screens layout

6.6.3. Effect of buttons
Over those 5 categories, the effect of buttons is the following:
ActionEffectTop button pressed

Move on to next Maintenance state category

Bottom button pressed

Move on to next screen within the current
Maintenance state category

Button long-pressedor buttons pressed
simultaneously

Exit the Maintenance state

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6.6.4. Available data
Below are pictures of screens, sorted by category, and provided together with the featured data.
6.6.4.1. STATUS category

A
B

1/5

5/5

2/5

3/5

4/5

Screenindex

Included data

1/5

Status of the data link between the two parts
Current direction of the energy flow

2-5/5

Screen test, over 4 screens

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6.6.4.2. LIVE MEASURE category

A
B

1/5

5/5

2/5

4/5

3/5

Screenindex

Included data

1/5

Total import energy register

2/5

Total export energy register

3/5

Live voltage and current

4/5Live power

5/5

Live temperature of the two terminals of the Sensor Unit

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6.6.4.3. DEVICE category

A
B

1/2

Screenindex

2/2

Included data

1/2

Serial number and IP address of the device

2/2

Public key of the device, for LEM format authenticity check (i.e. without OCMF RFC5480 header)

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6.6.4.4. FIRMWARE category

A
B

1/3

3/3

2/3

Screenindex

Included data

1/3

Identifier and checksum for the legally relevant firmware part of the Meter Unit

2/3

Identifier and checksum for the firmware of the Sensor Unit
Note: This firmware is fully legally relevant

3/3

Identifier and checksum for the legally non-relevant firmware of the Meter Unit

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6.6.4.5. CLOCK category

A
B

1/5

5/5

2/5

4/5

3/5

Screenindex

Included data

1/5

Local date and time

2/5

Total deviation to UTC and UTC time

3/5

Offsets of local time versus UTC: time zone offset and daylight savings time offset

4/5

Status of time synchronization: current validity and synchronization mode

5/5Type of time management (info time or system time)

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6.7. Error screen
The error screen is displayed when at least one error is raised. It is triggered with no delay, fromany other screen.
Below figure is an example of the error screen.

The only data displayed on the error screen is the following:•

The current error code (see "7.5.5. Errors")

The rest of the screen is static.
Buttons allow access to the Maintenance screens, which could provide beneficial information
during troubleshooting.

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6.8. Index of symbols in screens
Below is the full list of symbols for the DCBM.
Tables match them with their label on HTTP/REST APIs and their OBIS code for data unicity.
Some symbols are rated as “informational”, meaning that they do not come with a data but informof a current state.

6.8.1. Transaction-specificSymbolMeaning

Corresponding HTTP label and OBIS code

Informational symbol: Transaction beginning. Whendisplayed, the transaction has started and is currently
on-going. This symbol is displayed along with the datanecessary at the beginning of the transaction

N/A

Informational symbol: Transaction running.
When displayed, the transaction is running, andtransaction beginning phase is over

N/A

Informational symbol: Transaction end.
When displayed, the transaction is over. This symbol isdisplayed along with the data necessary at the end of
the transaction

N/A

Data symbol: Import energy for current transactionenergyImport (/legal)
0.0.98.10.1.1

Data symbol: Export energy for current transactionenergyExport (/legal)
0.0.98.10.1.2

Data symbol: Elapsed time of transaction.
Corresponds to the difference between transaction
start timestamp and:•transaction stop timestamp (out of transaction)•or current timestamp (in-transaction)transactionDuration (/legal)
0.0.0.1.0.255

Data symbol: Currently active energy tariff

tariffId (/legal)
0.0.96.14.0.255

Data symbol: Client identifier for current transaction

clientId (/legal)
0.0.96.58.0.255

Data symbol: EVSE identifier for current transaction

evseId (/legal)
0.0.96.57.0.255

Data symbol: Cable identifier for current transaction

cableSp/cableSpId (/legal)
0.0.96.59.0.255

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6.8.2. Metrology
SymbolMeaning

Corresponding HTTP label and OBIS code

Data symbol: Total import energy counter

energyImportTotal - 1.0.1.8.0.255 (/livemeasure)energyImportTotalStart (/legal) or RD[0]/RV (/ocmf)
1.0.1.8.0.1
energyImportTotalStop (/legal) or RD[2]/RV (/ocmf)
1.0.1.8.0.2

Data symbol: Total export energy counter

energyExportTotal - 1.0.2.8.0.255 (/livemeasure)energyExportTotalStart (/legal) or RD[1]/RV (/ocmf)
1.0.2.8.0.1
energyExportTotalStop (/legal) or RD[3]/RV (/ocmf)
1.0.2.8.0.2

Data symbol: Voltage
Data is legally non-relevant

voltage (/livemeasure)
1.0.32.7.0.255

Data symbol: Current
Data is legally non-relevant

current (/livemeasure)
1.0.31.7.0.255

Data symbol: Power
Data is legally non-relevant

power (/livemeasure)
1.0.1.7.0.255

Data symbol: Temperature measured on side I1
Data is legally non-relevanttemperatureL (/livemeasure)
1.0.131.7.0.255

Data symbol: Temperature measured on side I2
Data is legally non-relevanttemperatureH (/livemeasure)
1.0.130.7.0.255

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6.8.3. Time management
SymbolMeaning
Data symbol: Current UTC time

Corresponding HTTP label and OBIS code
time/utc (/settings)
0.0.0.9.0.255

Data symbol:•

Current local date (Data is legally non-relevant)•

Date on transaction beginning•

Date on transaction end

time (/status)

Data symbol:•

Current local time (Data is legally non-relevant)•Time on transaction beginning•

Time on transaction end

time (/status)

6.8.4. Other data
SymbolMeaning

Corresponding HTTP label and OBIS code

Informational symbol: Fatal error
When displayed, the DCBM detected a fatal error

N/A

Data symbol: Fatal error code
When displayed, the transaction is running, andtransaction beginning phase is overerrors/value (/status)

Informational symbol: Informational area
Warns that the corresponding area contains legally
non-relevant data and values

N/A

Data symbol: DCBM serial number

meterId (/status, /settings, /logbook)
0.0.96.1.2.255

Data symbol: Public key

publicKey (/status) (without OCMF RFC5480 header)
0.0.98.10.2.1

Data symbol: Firmware version•

LR firmware•

LNR firmware•

Sensor Unit firmware

Data symbol: Firmware Checksum / Signature•

LR firmware•

LNR firmware•

Sensor Unit firmware

21January2021/Version 0		version/applicationFirmwareVersion - 0.0.0.2.2.255
version/legalFirmwareVersion - 1.0.0.2.2.255
version/sensorFirmwareVersion - 1.1.0.2.0.255(/status)
version/applicationFirmwareAuthTag - 1.1.0.2.8.255
version/legalFirmwareAuthTag - 1.0.0.2.8.255
version/sensorFirmwareCrc - 1.2.0.2.8.255(/status)

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7. Software concepts
7.1. Interfaces
Ethernet is the communication channel for the DCBM. It supports HTTP/REST communication toreceive requests and provide measurements and other data.
The REST-compatible API is an application programming interface that uses HTTP requests toobtain (GET), place (PUT) and publish (POST) data.
A RESTful API conforms to the Representational State Transfer or "REST" model.
This interface is using JSON format for the data payload.
URI with default IP

Methods

Description

192.168.1.2/v1/status

GET

Status of the DCBM

192.168.1.2/v1/settings

GET, PUT

Settings of the DCBM

192.168.1.2/v1/logbook

GET

Event logger of the DCBM

192.168.1.2/v1/livemeasure

GET

Live measurements

192.168.1.2/v1/legal

GET, PUT, POST

Transaction management (start & stop) andtransaction data structure, current or stored,
in LEM proprietary format

192.168.1.2/v1/ocmf

GET

Transaction data structure, current orstored, in certified, billable, OCMFcompliant format

192.168.1.2/v1/certificate

GET

HTTPS certificate of the DCBM

Table 5: REST API access and associated HTTP methods

The optical communication channel in the DCBM is disabled in the current
version.

i

I

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7.2. Transactions
7.2.1. Concept
To log the energy used during a charging cycle, the DCBM handles two specific requests: “starttransaction” and “stop transaction”.
When the “start transaction” command is received by the DCBM, the latter starts accumulatingenergy into a specific transaction. A transaction is made unique by its chosen transaction identifier,which can link it to the end user.
When the “stop transaction” command is received by the DCBM, the latter stops accumulatingenergy to the current transaction and sends a complete report in response. The data structure
contains all the transaction information, e.g. energy registers, status information, timestamps. The
whole data structure is authenticated by a signature mechanism.
The signature can be verified using product’s public key and a verification software, refer to section"7.4. Data authenticity".
Following figure illustrates the process of transaction.

Power

Transac�on

Energy

Time

DCBM

Stop

Read

Read

: ResponseStart: Request

Charger controller

Start command
Iden�ﬁers from Charger
controller
Acknowledgement of thestart command from DCBM-

Intermediate readings

Stop command[op�onal] Data structurefrom DCBM-

Acknowledgement of thestop command and full
data structure from DCBM

Figure 40: Transaction concept

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7.2.2. Conditions to start and input parameters
Prerequisites to a start command are:•(1) The Meter Unit and Sensor Unit are mounted as per LEM instructions•(2) There is no fatal error raised•(3) There is no running transaction•(4) Time synchronization is valid

In the device, this corresponds to the following values:
Above index

Parameter name

Value for readiness to new transaction(1)

suLinkStatusIsOk

True

(2)

muFatalErrorOccured

False

(3)

transactionIsOnGoing

False

(4)

timeSyncStatusIsOk

True

Table 6: Transaction preconditions in device implementation

If those conditions are met, a start request on /legal API (see §7.1) initiates a transaction.

!

Minimum duration for transactions is 2 minutes, to prevent potential memory storage weaknesses.
The start request shall include the following inputs:
Input nameType

Designates...

evseIdCharacter string, max 37 bytes-longthe EVSE in which the DCBM is locatedtransactionId

Character string, non-void and max 37 bytes-longthe transaction (from the backend)clientId

Character string, max 37 bytes-longthe end user

tariffId

Integer from 0 to 4

the tariff used

cableId

Integer from 0 to 7

the cable loss compensation level to use

userData

Character string, max 128 bytes-longa contract reference, or any other extra data

Table 7: Required inputs to a new transaction

Below is an example of request body to start a transaction.
{}
21January2021/Version 0		"evseId": "evse15674","transactionId": "transac5765","clientId": "client44678","tariffId": 2,"cableId": 1,"userData": "Test of a transaction"
Figure 41: Example of body for start request

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The transaction must be terminated using a stop request. The necessary input to stop the active
transaction is its transactionId. Response to the stop request contains the final data structure,in /legal format.

7.2.3. Transaction readouts
The last transaction and previous ones can be retrieved from the DCBM memory.
On the HTTP/REST interface, the DCBM supports two data formats for readouts:•

LEM proprietary format, in /legal API (see §7.1)•
Certified, billable, OCMF-compliant format in /ocmf API (see 7.1) (see "3.4. Certification andcompliance")!

For backend storage, OCMF format shall be preferred over LEM format. See "7.3.1. Energy
registering".
Four modes of access are available. All the readings of transactions are digitally signed.
Retrieval mode

HTTP target

DetailRetrieve the last transaction (or current)/v1/legal/v1/ocmf

If a transaction is on-going, this request
retrieves the current transaction.
Otherwise, the last one is retrieved.

Retrieve by transactionId(search limited to last 840 transactions)/v1/legal?transactionId=<xyz>/v1/ocmf?transactionId=<xyz>With <xyz> the transactionId of thetransaction to retrieve(search limited to last 840 transactions)

Retrieve by internal storage index/v1/legal/<index>/v1/ocmf/<index>

With <index> a positive number. See
below note. 1)
Internal index number is provided in the
response to a start transaction request.

/v1/legal/-<index>/v1/ocmf/-<index>

With <index> = -1 the past transaction
before the latest
With <index> = -20398 the oldest
transaction stored (once storage reachedfull capacity).

Retrieve by chronological storage index

Table 8: Solutions for retrieving past transactions
Note:

Chronological storage index is advised for retrieving all stored transactions.
Indeed, behavior of internal storage index is as follows:1)• Transaction storage is a circular buffer, allowing wrap-around (see "7.2.4. Memory depth"). Internal storage indexes
can span from 0 to 20425, with a buffer gap of 27 transactions.
• Hence, retrieving all transactions through internal storage index might throw back HTTP error “404 - Not found” forsome internal storage indexes.

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7.2.4. Memory depth
The DCBM transaction storage is limited to 20399 transactions. Once this threshold is crossed,
oldest transactions are successively erased. This requires the charger controller to save thetransaction elsewhere in order to comply with national regulation.
Following sections offer solutions for the charger controller to periodically and safely retrieve pasttransactions.
7.2.4.1. Required action following a transaction
In order to prevent data loss, individual backup shall be observed:•

Achieve a transaction stop•

Read the data using /ocmf API•

Backup the response in the backend.

7.2.4.2. Fallback procedure for unavailable upload
In case individual backup is temporarily unavailable, transactions can be backed up subsequently.
The charger controller must count the number of transactions that could not be uploaded.
Once communication is back, all the unsaved transactions can be retrieved recursively (using
mode “Retrieve by chronogical storage index”, see "7.2.3. Transaction readouts")•
Retrieve last transaction
GET request on http://192.168.1.2/v1/ocmf•
2. Retrieve the one before
GET request on http://192.168.1.2/v1/ocmf/-1•
3. Retrieve the one before
GET request on http://192.168.1.2/v1/ocmf/-2•!

X. And so on until all unsaved transactions are successfully backed up.

If a total of 20399 were not saved, the charger controller shall prevent any new transactions until
upload is possible. Otherwise, the oldest transaction is deleted each time a new one is started.

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7.3. Measurements
7.3.1. Energy registering
As an energy meter, energy is the main output of the DCBM. Two types of energy registers areavailable:•

Total energy registers•

Transaction energy registers

As regard to certification of concerned product, the official registers to be used for billing are thefollowing:
Name

Description

transactionDuration

Transaction duration in seconds

energyImport

Import DC energy during the transactionenergyExport

Export DC energy during the transactionenergyImportTotal

Non-resettable register for import energy ("A+")energyExportTotal

Non-resettable register for import energy ("A-")

Table 9: Measurement results, metrologically relevant

7.3.2. Bidirectional current flow
Both sets of registers consist in two registers: Import energy and export energy (see "5.3. Energy
registering"). They are always displayed and stored together.

iA single transaction stores both import and export energy values.

7.3.3. Total energy registers
Total energy registers are available:•in the /livemeasure API (see §7.1)•

on Idle screen•

on dedicated maintenance screens (Livemeasure category)•in the transaction data structures (both /ocmf and /legal) and on transaction screens, as frozen
values corresponding to the start and end of the transaction

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7.3.4. Transaction energy registers
Transaction data in /legal API (see §7.1) include differential energy registers: import and exportenergy registers. Both of them are the difference of corresponding total energy register between
the beginning and the end of the transaction, as illustrated on below figure.
Total energy

End oftransaction
Beginning oftransaction

y

al

t
To

g
er

te

re

s
gi

r

Transactionenergy register
value

en

Time

Figure 42: "Transaction" vs "Total" energy registers (Import or Export)

Transaction energy registers are stored among the transaction
data. They can be retrieved by retrieving the transaction data.
Hence, transaction energy registers can be accessed through/legal and /ocmf APIs (see §7.1). They can also be seen
on most of the transaction screens.

7.3.5. Other measurements
The DCBM provides other measurements data:•

Voltage in V (with 3 fractional digits)•

Current in A (with 3 fractional digits)•

Power in kWh (with 3 fractional digits)•
Temperature measurement on both terminals of the Sensor Unit,
in °C (with 1 fractional digit)!

Those measurements are indicative and cannot be used for billing. They are provided as averageof the last 100 ms, updated every second, and therefore they cannot reflect surges or otherdynamic signals at any higher frequencies.
On HTTP/REST, those measurements are available only through /livemeasure API (see §7.1).
On the screen, they can be accessed on maintenance screens, in Livemeasure category. Poweris also available on transaction in progress screen.

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7.4. Data authenticity
7.4.1. Overview
In the context of metering, data are signed to ensure their authenticity (authentication and integrity).
Signatures secure the following sets of data:•/ocmf certified, billable transaction data structure•/legal LEM proprietary transaction data structure•/logbook buffer

A signature cannot be used alone. The following set of inputs is necessary as a whole:•

Content to be verified•

Signature for this content•

Associated public key

Once gathered, data authenticity can be verified with the following solutions:
Verifiable data
structure/ocmf API/legal API/logbook API

Description

Transaction data structure,in certified, billable, OCMFcompliant format

Transaction data structure, in
LEM proprietary format

Event logbook

Verification solution

OCMF official transparency
software

LEM DCBM verification software

Table 10: Solutions for signatures verification

Verification solutions are given as examples.

!

•

LEM DCBM verification software is available on LEM website or from LEM support•

OCMF transparency software is available at https://transparenz.software/

For /legal to be usable for billing in regards to certification, it shall be re-signed by the charger
controller. That is why /ocmf shall be preferred for external backup.

7.4.2. Keys specifics
Two unique public keys coexist in each DCBM, to be used according to the dataset to check.
Public key
Allows check of
Availability

publicKeyOcmf

publicKey/ocmf/legal, /logbook

In /status API
On the Meter Unit front face marking

In /status API
In /legal API
On the display (boot, end of transaction, maintenance screens)Figure 43: Keys specifics for signature checksipublicKeyOcmf is composed of an fix RFC5480 header and the publicKey

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7.5. Status and errors flags
7.5.1. Overview
The DCBM provides status and error flags allowing monitoring of its proper installation, its
readiness towards transactions, the fulfillness of its logbook, its internal operation, among others.
Those flags are available under various formats as follows:•

In /status API: current status and errors•

In /legal API: transaction status•

In /ocmf API: OCMF EF and ST fields

Additionally, /logbook API keeps track of raised statuses when a new event occurs.
Refer to "7.6. Event logbook".

7.5.2. Status/errors value field description
In /status API, status and error flags are available through two formats, as follows. In /legal
API (see §7.1), only value field format is used.
Format 1: value

Concatenation of flags as abinary value“status”: {“value”: 17,“bits”: {“suLinkStatusIsOk”: true,“muFatalErrorOccured”: false,“transactionIsOnGoing”: false,“tamperingIsDetected”: false,“timeSyncStatusIsOk”: true,“overTemperatureIsDetected”: false,“reversedVoltage”: false,“suMeasureFailureOccurred”: false}},

Format 2: bits

List of flags with explicit
name and unitary value“errors”: {“value”: 0,“bits”: {“muInitIsFailed”: false,“suStateIsInvalid”: false,“versionCheckIsFailed”: false,“muRngInitIsFailed”: false,“muDataIntegrityIsFailed”: false,“muFwIntegrityIsFailed”: false,“suIntegrityIsFailed”: false,“logbookIntegrityIsFailed”: false,“logbookIsFull”: false,“memoryAccessIsFailed”: false,“muStateIsFailed”: false}},

Figure 44: Description of the 2 formats of status and errors

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For both status and errors, the value field shall be used as follows:•

Flags are ordered in a binary word, from index 0.

•

Index 0 is the Least Significant Bit (LSB)•

true corresponds to value 1; false corresponds to value 0•

If all flags are false, value fields equals 0.

•

Any flag being true adds 2^(flag index) to the value.

See next figure.
d
te
ec
t
e
d
ng
d
Oc
sD sOk cte Goi ure k
e
I
r
e
e
I
e
n
c
O
lu
ag
ur
us
et
sO
Oc
Is
ai olt rat tat IsD onI ror tus
F
re
dV
pe
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ng
ti
Er
ta
su rse Tem Syn eri sac tal nkSa
Me eve ver ime amp ran uFa uLi
su
r
o
t
t
t
m
s
7
#
#6
#5
#4
#3
#2
#1
#0
d

0 1 0 0 0 1 0 0

LSB

re

r
cu

Figure 45: Illustration of using value field, example for status register

7.5.3. Current status
The current status is available in the /status API (see §7.1). It reflects the status of the DCBM
at any time. Associated conditions can raise the flags. Once the condition disappears, thecorresponding flag does too.

transactionOngoing
10

Status value

NominalTime
Figure 46: Status field persistence

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Flag reversedVoltage is an exception, it can only be turned off after a restart of the DCBM.

Event raising flag X

Restart!

1
0

Event raising flag reversedVoltage

10

Status value
Time

NominalFigure 47: Specific reversedVoltage status persistence

The list of flags is as follows:
Flag
index

Name

Figure 48:

Description

Criticality

0suLinkStatusIsOk

Data link cable is functional

Blocker

1

muFatalErrorOccured

At least an error is active

Blocker2transactionIsOnGoing

A transaction is on-going

Blocker3

tamperingIsDetected

Tampering is currently detected

Indicator

4

timeSyncStatusIsOk

Time synchronization is active

Blocker5

overTemperatureIsDetected

An over-temperature was detected by the Sensor Unit

Indicator

6

reversedVoltage

Reversed voltage is seen by the Sensor Unit

Indicator

7

suMeasureFailureOccurred

An error occurred in Sensor Unit ADC

Indicator

Table 11: List of status flags

Criticality levels are as follows:i•

Indicator: A transaction is still possible, event is logged.

•

Blocker: New transactions are rejected until status bit returns to nominal mode, event is logged.

17 is the status value corresponding to the nominal state of the DCBM, when ready for a transaction.

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7.5.4. transactionStatus fieldtransactionStatus keeps tracks of the status of the
DCBM during the whole transaction. This value is available
in the /legal API (stored with each transaction).
At the beginning of the transaction, the current statusvalue is copied to transactionStatus, regardless of
its value.

"transactionDuration": 7,"intermediateRead": false,"transactionStatus": 17,"sampleValue": {"energyUnit": "kWh",

During the transaction, any raised flag is tracked by increasing transactionStatus until theend of the transaction.

transactionOngoing
1
0

overTemperatureIsDetected

10Transaction status value

NominalTime
Figure 49: Transaction status field persistencei

17 is the transaction status corresponding to a transaction which finished successfully, and whichis therefore billable.

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7.5.5. Errors"errors": {"value": 0,
DCBM errors caught are reported in the errors"bits": {section of the /status API. This section is"muInitIsFailed": false,
composed of a list of flags.
"suStateIsInvalid": false,"versionCheckIsFailed": false,
Any error has the following impact:"muRngInitIsFailed": false,•
Block new transactions"muDataIntegrityIsFailed": false,"muFwIntegrityIsFailed": false,•
Display the error(s) on screen"suIntegrityIsFailed": false,"logbookIntegrityIsFailed": false,
Any error remains until a power down. All errors"logbookIsFull": false,are cleared on a reboot, then raised again if"memoryAccessIsFailed": false,
errors still exist. The DCBM checks the presence"muStateIsFailed": falseof all errors within the first 10 seconds, most of}them are re-checked cyclically.
},i

0 is the error value corresponding to the nominal state of the DCBM. Any other value prevents newtransactions.

i

An on-going transaction is not interrupted by an error. But the error
invalidates the transaction through the transactionStatus.
All errors display the screen shown on adjacent figure (the FF#
value refers to value field)
Flag
index

Name

Check
frequency

Description

0

muInitIsFailed

Meter unit initialization failed

On startup

1

suStateIsInvalid

Sensor unit is in an invalid state

Any time2

versionCheckIsFailed

Firmware version of the Sensor Unit is not the one theMeter Unit expects

On startup

3

muRngInitIsFailed

Random Number Generation initialization failed

On startup

4

muDataIntegrityIsFailed

CRC error on the operation data of the Meter Unit

Every 30 minutes

5

muFwIntegrityIsFailed

CRC error on the Meter Unit firmware memory

Every 30 minutes

6

suIntegrityIsFailed

CRC error on the data or firmware memory of theSensor Unit

Any time

8

logbookIntegrityIsFailed

CRC error on logbook memory

Every 30 minutes

9

logbookIsFull

Logbook is fullAny time

10

memoryAccessIsFailed

Rejected access to memory

Any time

13

muStateIsFailed

Unexpected error in the Meter Unit

Every 30 minutes

Table 12: List of error flags
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7.5.6. OCMF error and status fields
In /ocmf API, in compliance with OCMF specification, statuses and errors are formatted differently.
They are simplified and scattered into EF and ST fields. In case more than one line of EF or ST
fields is active, only the letter with highest priority is displayed.
EF field value

Description

Status equivalent

Priorityblank

Nothing to report

None of the below

1

E

Energy issue

suLinkStatusIsOk = false

3tTime issue

timeSyncStatusIsOk = false

2

Table 13: OCMF EF field equivalents

ST fieldvalue

Description

Status equivalent

PriorityG

Nothing to report

None of the below

1

M

Manipulation detected

tamperingIsDetected = true

2

N

Sensor Unit link is broken

suLinkStatusIsOk = false

4TTime synchronization expired

timeSyncStatusIsOk = false

5E

Other error

At least one of the other statuses is raised(except transactionIsOnGoing)

3 for overTemperatureIsDetected
6 for others

Table 14: OCMF ST field equivalentsi

Statuses have direct equivalents, while errors are
muFatalErrorOccured, i.e. in OCMF ST field with value E.

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7.6. Event logbook
The DCBM features an event logbook,
tracing metrological events as well asother events linked to the application
software.

{

When an event occurs, it is permanently
stored into the DCBM logbook, alongwith the current status register and thecorresponding UTC timestamp.

!

Logbook entries cannot be erased.

i

The DCBM can store approximately
40 000 events.

In case the logbook reaches maximal
capacity, the DCBM is out of order (error
logbookIsFull is raised irrevocably,
preventing new transactions).

The content of the event logbook can be
retrieved using the /logbook API (see§7.1). When a large number of events isstored, retrieving the logbook can takeseveral minutes. The logbook cannot be}
retrieved partially.

"meterId": "1202531106","logbook": [{"timestamp": "2020-09-14T10:05:05Z","eventCode": "EV_COMMISSIONING","status": ["STATUS_SENSOR_LINK","STATUS_TAMPERING","STATUS_TIME_SYNC"]},{"timestamp": "2020-09-14T10:06:03Z","eventCode": "EV_POWER_SUPPLY_FAILURE","status": ["STATUS_SENSOR_LINK","STATUS_TIME_SYNC"]},{"timestamp": "2020-09-18T07:34:33Z","eventCode": "EV_TIME_SYNC_SUCCEEDED","status": ["STATUS_SENSOR_LINK","STATUS_TIME_SYNC"]}

The logbook is digitally signed to ensure
its authenticity (authentication and integrity). Refer to section "7.4. Data authenticity".

i

The list of events is available in the Communication Protocols manual.

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7.7. Connectivity settings
7.7.1. IP addressing
The DCBM IP address allows its registration onto a network.
To avoid collisions, the IP of the DCBM shall not be identical toanother device on the same network.
Two solutions exist for choosing the DCBM IP address•

Use a static address•

Get an address from a DHCP server

7.7.1.1. Static addressing
On simple networks, the easiest solution is to give a static IP address to the device.
The IP to set for the DCBM must be written through field ipAddress at the root of /settings
API (see §7.1).

!

Do not confuse with ipAddress in the dhcp section.
Once set, the new IP address is available for use immediately. The value can be seen on thedisplay, in the Maintenance screens.

iSubnet mask: The subnet mask is “0.0.0.0”. It cannot be changed. This value allows access fromany other IP address (i.e. no subnet mask restriction).

7.7.1.2. DHCP
When a Dynamic Host Configuration Protocol server is available on the network, the DCBM canbe set to request an IP address. The server responds with an available IP address, avoiding conflicts.
The DCBM can be turned into DHCP mode using field dhcp/activation in /settings API.
Other settings in section dhcp allow configuration of ports to use, for the client and for the server(respectively clientPort for the DCBM and serverPort for the server).
For advanced DHCP networks (e.g. multiple DHCP servers on a network), the IP address of the
DHCP server can be configured in the DCBM, using field dhcp/ipAddress.

!

ipAddress in dhcp section is the address of the DHCP server. In most situations, it is not
required and default value must be kept.

i

ipAddress at the root of /settings API will not be updated according to dynamic DHCP
address, as it is an input for static addressing.

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7.7.1.3. DNS
The DCBM can be reached using its DNS name, just like using its IP address.
The DCBM's DNS name is "lem-meter".

7.7.2. HTTP & TLS
7.7.2.1. HTTPSHTTP transports data on a clear channel, readable by any other device on the network. The
DCBM supports TLS, for HTTPS communication. Enabling it creates an encrypted channel forcommunications, which prevents undesired listening. It also authenticates the DCBM based on its
certificate.
The HTTPS certificate is available through the /certificate API. This API is read-only. It is
described in Communication Protocols manual.
HTTPS can be enabled for the DCBM through field http/tls_on in /settings API.
7.7.2.2. HTTP port
The DCBM allows configuration of its HTTP port to use. Port can be set using http/httpPort
in /settings API.

i!

Default port numbers as defined by IANA are:•80 for HTTP•

443 for HTTPS

Enabling HTTPS does not automatically change the port to use. Do not forget to set it to 443 if
needed.

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7.8. Time management
7.8.1. Time synchronization
7.8.1.1. Overview•

Proper synchronization is required for any new transaction•

Synchronization expires after 48 hours•

It cannot be achieved during transactions

7.8.1.2. General constraints
Time synchronization is a prerequisite to new transactions. At a given time, synchronization iseither valid or outdated.
A time synchronization remains valid for 48 hours. Any successful synchronization restarts thetimer for a new 48 hours span. No event can shorten or extend this duration, including powerdown.
No time synchronization can be achieved during transactions. This 48 hours expiration can happen
in any state of the DCBM, including during transactions and power down.

!

It is recommended to achieve time synchronization at least once a day (< 24 hours period),
considering 48 hours expiration.

i

The time management is “Info time”. The DCBM does not support “System time” in this version.

7.8.1.3. Synchronization solutions
Two time synchronization modes are available:•

Synchronization by NTP•

Synchronization by a command sent to the DCBM

/settings API offers a setting to switch from one mode to another: /ntp/activated in /settings API. Switching mode has no effect on status of synchronization or on the 48 hours
timeout.

!

In case NTP is used (ntpEnabled = true), achieving a time synchronization by command
automatically disables /ntp/activated boolean (i.e. sets ntpEnabled = false)

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7.8.1.4. Command time synchronization
Command time synchronization requires nothing more than a HTTP request, consisting in writing
a timestamp on field /time/utc in /settings API.
Timestamp shall be UTC time, and compliant with ISO-8601 format.

Here is an example of writable timestamp: “2020-01-01T14:00:00Z”
It is not necessary to specifically switch off NTP if used before triggering Command timesynchronization request, as it is done automatically.
7.8.1.5. NTP synchronization
Network Time Synchronization allows reliable and automatic synchronization. NTP allows using alarge amount of public and precise time references.
Use of NTP requires the following actions in /settings API:•
Configure at least one server, by entering an IP or URL in field ntp/servers/ipAddress, and therequired port in field ntp/servers/port•

Switch ntp/activated to “true”i

123 is the default IANA port for NTP.

!

No synchronization is allowed during a transaction
An attempt of NTP synchronization is achieved:•

As configured in field ntp/syncPeriod in /settings API•

On expiration of the synchronization•

Or at the end of the transaction, if synchronization expired during it•

On startup of the DCBM•

When switching to NTP mode

An attempt of NTP synchronization can end with the following outcomes:•
The synchronization succeeded. Time of valid synchronization is saved, and synchronization becomesvalid for the next 48 hours.
•
The synchronization failed. Synchronization status is not discarded; it stays valid until expiration (48hours after the last valid synchronization).

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If two different NTP servers are configured:•If only one server responds, its time is used•

If both servers respond, the time of the server 2 is used

NTP servers response time is limited to 30 seconds.

!

Starting a transaction aborts any on-going time synchronization, as transactions prevail oversynchronization.

7.8.2. Local time
UTC is the reference time for the DCBM, timestamping logbook entries and getting updated fromtime synchronizations.
Though, the DCBM supports local time as an applicative, legally non-relevant feature. It offers
more user-friendly information, for display and billing data notably.

iLegal non-relevance of local time is due to unlocked settings configuring local time. Actually a local
time timestamp can allow billing if it includes offset to UTC, such as in /legal timestamps.
Local time consists in an offset to UTC. Two features create this offset:•

Time zone offset•

DST offset

7.8.2.1. Time zone
Time zone configures the DCBM according to a geographical area. It consists in an offset of hours
and minutes, which is added to the UTC.
Time zone is configured using field time/tz (/settings API). It can be either a positive or
negative offset; hours can be set from -11 to +14 hours and minutes shall be picked between 00,
15, 30 and 45.
7.8.2.2. Daylight Saving Time
Daylight Saving Time is an offset of time to be added to time zone offset, usually half of the year.
It is configurable in field time/dst (/settings API). Boolean activated allows using it or not.
Field offset is the offset in minutes to use, during the part of year when DST is on. Fields startand end configure the boundaries within which DST offset shall be added to time zone offset. Outof this range, the offset value is not used, allowing configuration of DST once and for all (DST
does not have to be manually activated and deactivated).

!

The hour subfields (in fields start and end) shall be expressed in local time.

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8. Troubleshooting!

For troubleshoot investigations and in support communications, make sure to save and provide
status and error value fields rather than just active errors, to provide thorough information.

8.1. Wrong statuses
Status field behavior is described is section "7.5.3. Current status" and "7.5.4. transactionStatus
field".

i"Status flag #" is followed by the flag index number, as described in "7.5.1. Overview"

Status flag #0 - suLinkStatusIsOk
Value

Description

True

NominalFalse

The Meter Unit
is somehow
disconnected from theSensor Unit

Solution
N/A
1. Check that connectors are inserted properly, both on Meter Unit side and Sensor Unit side
2. Make sure the Sensor Unit - Meter Unit couple is correct (marking on them can help)
3. Check absence of dirt or fluid, on connectors of the Meter Unit, Sensor Unit and the cable.
Check the sanity of the cable, look for cuts or mark of excessive mechanical effort. Try to replace
the cable

Status flag #1 - muFatalErrorOccured
Value

Description

Solution

False

Nominal

N/A

True

At least one error isactiveRefer to errors troubleshooting: "8.2. Raised errors"

Status flag #2 - transactionIsOnGoing
Value

Description

False

NominalTrue

A transaction is ongoing

Solution
N/A
1. This status is informative and does not reflect an issue
2. To start a new transaction, the on-going one shall be stopped first. Refer to section "5.2.2.
Conditions and inputs"

Status flag #3 - tamperingIsDetected
Value

Description

False

NominalTrue

Tampering is currently
detected

21January2021/Version 0		Solution
N/A
1. The device might have received unauthorized manipulation
2. Check the integrity of the device: manufacturer seals, front panel of the Meter Unit, Meter Unit
housing forced open

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Status flag #4 - timeSyncStatusIsOk
Value

Description

True

NominalFalse

Time synchronization
expired: last valid
synchronization isolder than 48 hours

Solution
N/A
1. In command synchronization mode, achieve a new synchronization
2. In NTP synchronization mode, check the settings, as well as network access to the NTP
servers
3. Refer to section "5.8.1. Time synchronization"

Status flag #5 - overTemperatureIsDetected
Value

Description

Solution

False

Nominal

N/A

True

Over-temperature was
detected by the Sensor
Unit

1. Temperature shall be lowered with no delay, risking damage to the device and the infrastructure
2. Check cabling issues, loosened bolts, over-confined architecture, insufficient ventilation...

Status flag #6 - reverseVoltage
Value

Description

Solution

False

Nominal

N/A

True

Reversed voltage isseen by the Sensor
Unit

1. The Sensor Unit sees voltage with a wrong sign. Voltage input wires shall be inverted and the
DCBM restarted
2. Refer to section "5.2. Integration solutions"

Status flag #7 - suMeasureFailureOccurred
Value

Description

False

NominalTrue

An error occurred in
Sensor Unit ADC

21January2021/Version 0		Solution
N/A
1. EMC surge may have occurred. Make sure to use a ferrite as recommended (refer to "5.2.
Integration solutions"), check for other possible EMC interferences and limit them
2. Restart the DCBM

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8.2. Raised errors!
iErrors correspond to protective behavior against malfunction, data corruption and data loss. In
case below suggestions are not sufficient, it means that the DCBM reached a protective lock state.
In this case the product is no longer usable and must be replaced.
Error field behavior is described in section "7.5.5. Errors".
Indexes are not contiguous. Make sure to use the right index.

FF# 1 - Error flag #0 - muInitIsFailed
Value

False

True

Description

NominalMeter Unit initialization
failedSolution

N/A
1. Various initialization processes can cause this error, both hardware and software processes.
The latter might be reverted on a reboot
2. Try to reboot the DCBM.
3. If not sufficient, reboot again a few more times.

FF# 2 - Error flag #1 - suStateIsInvalid
Value

Description

False

Nominal

N/A

True

Sensor Unit is in an
invalid state

1. Try to reboot the DCBM
2. If not sufficient, reboot again a few more times

FF# 4 - Error flag #2 - versionCheckIsFailed
Value

Solution

Description

Solution

False

NominalN/A

Firmware version of
the Sensor Unit is not
the one the Meter Unit
expects

1. Make sure the Sensor Unit - Meter Unit couple is correct (marking on them can help)

True

2. Try to reboot the DCBM to force a new check
3. If not sufficient, a memory corruption occurredFF# 8 - Error flag #3 - muRngInitIsFailed
Value

Description

False

NominalTrue

Random Number
Generation
initialization failed

N/A
1. Try to reboot the DCBM
2. If not sufficient, reboot again a few more times
3. If not sufficient, the issue is probably hardware-related

FF# 16 - Error flag #4 - muDataIntegrityIsFailed
Value

Solution

Description

Solution

False

Nominal

N/A

True

CRC error on theoperation data of theMeter Unit

1. Try to reboot the DCBM to force a new check right away or wait for next check cycle (30minutes)

21January2021/Version 0		

2. If not sufficient, then the memory is corrupted (global energy registers might be jeopardized)
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FF# 32 - Error flag #5 - muFwIntegrityIsFailed
Value

Description

Solution

False

Nominal

N/A

True

CRC error on theMeter Unit firmware
memory1. Try to reboot the DCBM to force a new check right away or wait for next check cycle (30minutes)
2. If not sufficient, then the memory is corrupted

FF# 64 - Error flag #6 - suIntegrityIsFailed
Value

Description

Solution

False

Nominal

N/A

True

CRC error on the dateor firmware memory of
the Sensor Unit

1. Try to reboot the DCBM to force a new check right away or wait for next check cycle (30minutes)
2. If not sufficient, then the memory is corrupted

FF# 256 - Error flag #8 - logbookIntegrityIsFailed
Value

False

True

Description

Nominal
CRC error on logbook
memorySolution

N/A
1. Try to reboot the DCBM to force a new check right away or wait for next check cycle (30minutes)
2. If not sufficient, reboot a few more times
3. If not sufficient, then the memory is corrupted

FF# 512 - Error flag #9 - logbookIsFull
Value

Description

Solution

False

Nominal

N/A

True

Logbook is full

1. Once the logbook is full (approximately 40 000 events logged), no fix is possible (refer to "7.6.
Event logbook")

FF# 1024 - Error flag #10 - memoryAccessIsFailed
Value

Description

Solution

False

Nominal

N/A

True

Rejected access tomemory1. Check for tampering marks, the DCBM code memory might have been altered
2. Reboot the product, the issue could come from a unknown software issue

FF# 8192 - Error flag #13 - muStateIsFailed
Value

Description

False

NominalTrue

Unexpected error in
the Meter Unit

21January2021/Version 0		Solution

N/A
1. Try to reboot the DCBM to force a new check right away or wait for next check cycle (30minutes)
2. If not sufficient, reboot again a few more times or wait for a couple of hours

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8.3. Other software issues
Lost connection on Ethernet
Issue description

Solution
1. Make sure the right IP address is used when trying to contact the DCBM. The IP address can be seen on
Maintenance screen, category “Device” (see "6.6.4.3. DEVICE category")

It looks like the DCBM
is unresponsive on the
Ethernet port

2. Make sure to use the right port when trying to communicate. Port to use (customizable) is written in /settings API, http section (see "7.7.2. HTTP & TLS")
3. Check the sanity of the cable, look for cuts or mark of excessive mechanical effort. In case of any doubt, try
with another cable
4. There might be a software issue with the Ethernet interface. Try to reboot the DCBM
5. The issue might be hardware-related

IP address is 0.0.0.0 / DHCP enabled unintentinally
Issue description

Solution

The IP address can be seen on Maintenance screen, category "Device" (see "4.6.4.3. DEVICE
category screens")
In case IP address is "0.0.0.0", it likely means that DCHP was enabled but no DHCP server wasavailable ("0.0.0.0" is fallback address for this case)This address is not reachable by any device, hence there is no solution to revert the DCBM to
static IP

1. The only solution is to provide a DHCP
server, so the DCBM can be reverted toa regular IP address. LEM support can
provide a walkthrough guide to do so.

Time does not sync
Issue description

Solution
1. Tip: Rebooting the DCBM forces a NTP synchronization attempt
2. Make sure to Ethernet connection is functional

It looks like NTP
synchronization does not
happen3. Make sure at least one time server is configured properly. Check IP address or URI, and check that the port
set in the DCBM matches the port the server listens onto (see "7.8.1. Time synchronization")
4. Make sure the network architecture gives functional access from the DCBM up to the time server. Make sureused ports are not filtered by any firewall
5. The time server might be down temporarily. Try with another one
6. To get rid of potential network issues, a local NTP server can be set up to validate the DCBM operation
7. If the issue cannot be fixed, command time synchronization can be a workaround

Wrong signature
Issue description

Solution
1. Check your data: Make sure the input is entered properly, according to instructions of the checker software
2. Check the public key: Make sure the public key used is the right one: make sure the public key, the data tocheck and the signature come from the same DCBM. Do not mix classical public key and OCMF public key(refer to "7.4. Data authenticity")

A signature check fails

3. Check the signature: Make sure the signature corresponds to the data to check (from same device; one
signature for one set of data to check)
4. Make sure no characters are missing or added in public key, signature and data to check
5. A wrong signature can come from weak memory area.
Check for presence of "Error #4 - muDataIntegrityIsFailed" and "Error #8 - logbookIntegrityIsFailed"

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9. Appendix - PTB type-examination certificate for DCBM

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