Satec expertmeter EM720 User manual

POWER QUALITY AND REVENUE METER
EM720/EM720T
Operation Manual
BG0451 Rev. A3

2 EM720 Power Quality and Revenue Meter
LIMITED WARRANTY
The manufacturer offers the customer a 24-month functional warranty on the
instrument for faulty workmanship or parts from date of dispatch from the
distributor. In all cases, this warranty is valid for 36 months from the date of
production. This warranty is on a return to factory basis.
The manufacturer does not accept liability for any damage caused by
instrument malfunction. The manufacturer accepts no responsibility for the
suitability of the instrument to the application for which it was purchased.
Failure to install, set up or operate the instrument according to the instructions
herein will void the warranty.
Only a duly authorized representative of the manufacturer may open your
instrument. The unit should only be opened in a fully anti-static environment.
Failure to do so may damage the electronic components and will void the
warranty.
The greatest care has been taken to manufacture and calibrate your
instrument. However, these instructions do not cover all possible contingencies
that may arise during installation, operation or maintenance, and all details
and variations of this equipment are not covered by these instructions.
For additional information regarding installation, operation or maintenance of
this instrument, contact the manufacturer or your local representative or
distributor.
WARNING
Read the instructions in this manual before performing installation,
and take note of the following precautions:
Ensure that all incoming AC power and other power sources
are turned OFF before performing any work on the instrument.
Failure to do so may result in serious or even fatal injury
and/or equipment damage.
Before connecting the instrument to the power source, check
the labels on the back of the instrument to ensure that your
instrument is equipped with the appropriate power supply
voltage, input voltages and currents.
Under no circumstances should the instrument be
connected to a power source if it is damaged.
To prevent potential fire or shock hazard, do not expose the
instrument to rain or moisture.
The secondary of an external current transformer must never
be allowed to be open circuit when the primary is energized.
An open circuit can cause high voltages, possibly resulting in
equipment damage, fire and even serious or fatal injury.
Ensure that the current transformer wiring is secured using an
external strain relief to reduce mechanical strain on the screw
terminals, if necessary.
Only qualified personnel familiar with the instrument and its
associated electrical equipment must perform setup
procedures.
Do not open the instrument under any circumstances when it is
connected to a power source.

EM720 Power Quality and Revenue Meter 3
Do not use the instrument for primary protection functions
where failure of the device can cause fire, injury or death. The
instrument can only be used for secondary protection if
needed.
Read this manual thoroughly before connecting the device to
the current carrying circuits. During operation of the device,
hazardous voltages are present on input terminals. Failure to
observe precautions can result in serious or even fatal injury or
damage to equipment.
All trademarks are property of their respective owners
January 2011
Copyright 2008-2011 ©SATEC Ltd.

4 EM720 Power Quality and Revenue Meter
Table of Contents
Chapter 1 Introduction ............................................................... 8
Chapter 2 Operating the EM720................................................ 14
Controls and Indicators ........................................................................... 14
TEST Mode ............................................................................................... 15
Device Diagnostics................................................................................... 15
Meter Security.......................................................................................... 16
Meter Clock and Time Synchronization.................................................... 17
Monitoring Meter Batteries ...................................................................... 17
Billing and Energy Metering..................................................................... 18
Instrumentation Metering ....................................................................... 20
Instrument Transformer Correction ........................................................ 21
Power Transformer/Line Loss Compensation.......................................... 22
Operating Digital Inputs .......................................................................... 22
Operating Relay Outputs.......................................................................... 23
Operating the Logical Controller.............................................................. 24
Operating the Event Recorder.................................................................. 24
Operating the EN50160 Power Quality Recorder..................................... 24
Operating the Fast Transient Recorder.................................................... 25
Operating the Fault Recorder................................................................... 25
Communicating with the EM720.............................................................. 25
Auxiliary AC/DC Backup Power Supplies................................................. 29
Chapter 3 Using Front Display .................................................. 30
Display Operations................................................................................... 30
Navigation Buttons ................................................................................ 30
Navigating in Data Display Mode.............................................................. 31
Status Indicators ................................................................................... 32
Display Features.................................................................................... 33
Measurement Units................................................................................ 34
Data Displays........................................................................................... 35
TEST Mode Data Display......................................................................... 35
Billing Period Data Displays..................................................................... 35
Engineering Maximum Demand Data Display............................................. 39
Engineering Data Display........................................................................ 41
Setup Data Display ................................................................................ 42
Device Info Display................................................................................ 42
Device Diagnostics Display...................................................................... 43
Programming Mode ................................................................................. 45
Navigation Buttons ................................................................................ 45
Entering Numeric Values......................................................................... 45
Password Security ................................................................................. 45
Setup Menus and Access Rights............................................................... 46
Viewing and Changing Setup Options ....................................................... 46
Chapter 4 Using PAS Software.................................................. 48
Software Installation............................................................................... 48
Installing PAS........................................................................................ 48
Installing the USB Driver ........................................................................ 48
Creating a New Site for your Meter.......................................................... 51

EM720 Power Quality and Revenue Meter 5
Setting up Communications..................................................................... 52
Communicating through a Serial Port ....................................................... 52
Communicating through the Internet ....................................................... 53
Communicating through a GSM/GPRS Modem ........................................... 54
Communicating through a USB................................................................ 56
Setting Up the Meter................................................................................ 57
Downloading Setups to the Meter ............................................................ 58
Uploading Setups from the Meter............................................................. 58
Authorization and Security ...................................................................... 59
Chapter 5 Configuring the EM720............................................. 60
Configuring Communications................................................................... 60
Setting Up Serial Communication Ports..................................................... 60
Setting Up the Ethernet.......................................................................... 62
Setting-Up Dial-Up GPRS Network ........................................................... 63
Setting-Up SNTP Client........................................................................... 64
Setting-Up eXpertPower Client ................................................................ 65
Setting-Up TCP Notification Client............................................................ 66
General Meter Setup ................................................................................ 68
Basic Meter Setup.................................................................................. 68
Device Options and Mode Control ............................................................ 70
Instrument Transformer Correction Setup................................................. 73
Transformer/Line Loss Compensation Setup.............................................. 74
Local Settings........................................................................................ 76
Display Setup........................................................................................ 80
Configuring Digital Inputs ....................................................................... 82
Configuring Relay Outputs ...................................................................... 84
Using Counters...................................................................................... 86
Using Periodic Timers............................................................................. 87
Using Control Setpoints .......................................................................... 88
Configuring Billing/TOU........................................................................... 93
Configuring Billing/Tariff Registers ........................................................... 94
Configuring the Daily Tariff Schedule........................................................ 95
Configuring the Season Tariff and DST Schedule........................................ 96
Configuring Recorders ............................................................................. 98
Configuring Meter Memory...................................................................... 98
Configuring the Event Recorder ..............................................................101
Configuring the Data Recorder................................................................101
Configuring the Waveform Recorder........................................................106
Configuring the Fault Recorder ...............................................................110
Configuring the EN50160 Recorders...................................................... 113
Basic Device Settings ............................................................................113
EN50160 Log Files ................................................................................113
EN50160 Evaluation Limits and Options...................................................114
EN50160 PQ Recorder Setup..................................................................114
EN50160 Harmonics Limits Setup ...........................................................117
EN50160 Advanced Setup......................................................................118
Clearing EN50160 Evaluation Counters....................................................119
Configuring Communication Protocols................................................... 120
Configuring Modbus ..............................................................................120
Configuring DNP3 .................................................................................121
Configuring Meter Passwords................................................................ 127
Chapter 6 Device Control and Upgrading................................ 129
Updating the Meter Clock....................................................................... 129

6 EM720 Power Quality and Revenue Meter
Clearing Device Diagnostics................................................................... 130
Resetting Accumulators and Log Files................................................... 130
Remote Relay Control ............................................................................ 132
Operating Event Flags............................................................................ 133
Upgrading Meter Firmware.................................................................... 135
Chapter 7 Monitoring Meters .................................................. 137
Viewing Real-time Data ......................................................................... 137
Viewing Real-time Min/Max Log............................................................ 140
Viewing Real-time Harmonic Spectrum................................................. 141
Viewing Real-time Waveforms............................................................... 141
Chapter 8 Retrieving and Storing Files ................................... 142
Uploading Files on Demand ................................................................... 142
Using the Upload Scheduler................................................................... 143
Retrieving EN50160 Statistics Files ....................................................... 145
Viewing Files On-line ............................................................................. 146
Retrieving Waveforms On-line on Events .............................................. 146
Exporting Files ....................................................................................... 146
Exporting Files in COMTRADE and PQDIF Formats.....................................146
Exporting Files in Excel Format...............................................................148
Archiving Files ....................................................................................... 149
Chapter 9 Viewing Files and Reports...................................... 150
Operations with Files............................................................................. 150
Viewing Options..................................................................................... 150
Customizing Views................................................................................150
Working with Tables..............................................................................151
Working with Graphic Windows...............................................................152
Viewing the Event Log ........................................................................... 155
Viewing the Power Quality Event Log.................................................... 157
Viewing the Fault Log ............................................................................ 160
Viewing the Data Log............................................................................. 162
Viewing Waveforms............................................................................... 163
Viewing a Waveform Graph....................................................................163
Viewing an RMS Plot .............................................................................164
Viewing a Frequency Plot.......................................................................165
Viewing a Spectrum Chart .....................................................................165
Viewing a Spectrum Table......................................................................167
Waveform Viewing Options ....................................................................168
Viewing Synchronized Waveforms...........................................................169
Viewing EN50160 Statistics Reports...................................................... 171
Viewing the EN50160 Compliance Report.................................................171
Viewing the EN50160 Online Statistics Report ..........................................174
Viewing the EN50160 Harmonics Survey Report .......................................174
Appendix A Parameters for Monitoring and Logging .............. 175
Appendix B Setpoint Parameters............................................ 194
Appendix C Billing and Load Profile Log Files ......................... 195
Appendix D EN50160 Statistics Log Files................................ 199
Appendix E EN50160 Evaluation and Recording..................... 205
EN50160 Background............................................................................205
Evaluation Techniques...........................................................................206
Methods of Evaluation ...........................................................................207

EM720 Power Quality and Revenue Meter 7
Appendix F Data Scales .......................................................... 215
Appendix G Device Diagnostic Codes...................................... 216
Appendix H OBIS Identification Codes ................................... 217

Chapter 1 Introduction
8 EM720 Power Quality and Revenue Meter
Chapter 1 Introduction
The eXpertmeter™EM720/EM720T
The EM720 is especially designed for utility, industrial and
commercial billing metering with high requirements to
reliability of power quality monitoring and availability of the
device.
The eXpertmeter™EM720 is an electronic revenue-
accuracy multi-rate polyphase static meter integrated with a
multi-function powermeter, an EN50160 power quality
recorder, a digital fault recorder and a programmable logical
controller, and provided with a wide range of digital I/O and
communication options.
A high-contrast graphical LCD display with backlight allows
easy local meter readings and servicing. Two serial
communication ports (infrared and RS232/RS485), a USB
port, Ethernet and a wireless GSM/GPRS modem allow local
and remote automatic meter readings and setup though the
supplemental communication software or user data
acquisition software
Meter Highlights
Internal Rechargeable Backup Battery
A high-capacity rechargeable auxiliary battery allows the
meter to continue uninterrupted operations for more than 3
hours with a NiMH battery and up to 7 hours with a Li-Ion
battery in the event of an extended power outage.
EN 50160 Power Quality Recorder
A full-featured programmable power quality recorder provides
EN 50160 compliance statistics and reports.

Chapter 1 Introduction
EM720 Power Quality and Revenue Meter 9
Fast Transient Recorder
An optional high-voltage fast transient recorder (EM720T)
detects impulsive and low frequency oscillatory transient
overvoltages with peaks up to 2kV and durations from 20
microseconds.
Digital Fault Recorder
An embedded fault recorder is capable of recording fault
currents up to 50 amps.
Meter Features
Billing/TOU
• Class 0.2S IEC 62053-22 active energy and class 0.5
reactive energy polyphase static meter
• Time-of-Use, 10 billing energy and maximum demand
registers, 8 tariff rates, 4 seasons x 4 types of days, 8
tariff changes per day
• One-time easy programmable tariff calendar schedule
(embedded Hebrew holidays till 2039 for Israeli
customers), one-time programmable or calendar
scheduled daylight savings switch dates
• Tariff switching options: automatic via a tariff calendar
schedule, external via communications or digital inputs
• Configurable triggering an end of billing period:
automatic monthly, local from the front display,
remote via communications
• Automatic recording billing energy, maximum demand
and cumulative maximum demand registers for last 24
billing periods
• Automatic 120–day daily energy and maximum
demand profile
• Automatic 120-day/15-minute or 240-day/30-minute
energy load profile
• Easy access to the three previous billing period data
via the front display
• Dynamic instrument transformer correction; up to 8
test points for both ratio and phase angle error
correction for external PTs and CTs
• Power transformer/line loss compensation
Multi-functional Power Meter
• High-accuracy 3-phase Power meter: true RMS volts
and amps, powers, power factors, unbalance, neutral
current, frequency
• Demand Meter: amps, volts, harmonic demands, block
and sliding power demands

Chapter 1 Introduction
10 EM720 Power Quality and Revenue Meter
• Harmonic Analyzer: up to 50th harmonic volts and
amps; fundamental volts, amps, power and power
factor, phasor, symmetrical components
Power Quality
• EN 50160 Power Quality (PQ) recorder: onboard power
quality analyzer; programmable limits; EN 50160
power quality event log, EN 50160 compliance
statistics; EN 50160 harmonics survey statistics
• Power frequency, voltage variations, rapid voltage
changes, IEC 61000-4-15 flicker, voltage dips,
interruptions, temporary overvoltages, transient
overvoltages, voltage unbalance, IEC 61000-4-7
harmonic and interharmonic voltage, mains signaling
voltage
• High-voltage fast transient recorder (EM720T);
impulsive and low frequency oscillatory transient
overvoltages with peaks up to 2kV and durations from
20 microseconds
• Ready-for-use compliance statistics reports with the
supplemental software
Fault Recorder
• Digital Fault recorder: three voltage and four current
channels, up to 8 external digital triggers for
monitoring circuit breakers and protection relays;
onboard overcurrent and undervoltage fault detector;
zero-sequence voltage and current, voltage and
current unbalance; programmable fault thresholds and
hysteresis
• Up to 50 Amp fault currents
• Ready-for-use fault reports with the supplementary
software - fault current magnitudes and duration,
coincident volt magnitude, fault waveforms and fast
RMS trace
Event Recorder
• Event recorder for logging internal diagnostics events,
setpoint and I/O operations
Waveform Recorders
• Three Waveform recorders: up to 7 channels
simultaneous recording of three voltage and four
current channels
• Fixed and event-controlled recording time
• Selectable sampling rate of 32, 64, 128 or 256
samples per cycle; 1-20 pre-fault cycles; 0-2048 post-
fault cycles in event-controlled mode; up to 3 min of
continuous recording at a rate of 32 samples per cycle
• Optional 4-channel transient voltage recording at 1024
samples per cycle (EM720T)

Chapter 1 Introduction
EM720 Power Quality and Revenue Meter 11
• Synchronized waveforms from multiple devices in a
single plot
• Exporting waveforms in COMTRADE and PQDIF file
formats
Data Recorders
• Sixteen Data recorders
• Programmable data logs on a periodic basis and on
any internal and external trigger; triggering from the
Fault recorder, PQ recorder or control setpoints;
exporting data trends in PQDIF file format
• Fast fault and PQ data profiling (trending) triggered
from the Fault and PQ recorders: 1/2-cycle to 10-min
RMS envelopes; up to 20 pre-fault and post-fault
cycles
Programmable Logical Controller
• Embedded Programmable Controller: 16 control
setpoints
• OR/AND logic, extensive triggers, programmable
thresholds and delays, relay control, event-driven data
recording
• 8 digital counters for counting pulses from external
sources and internal events
• 4 programmable timers from 1 cycle to 24 hours for
periodic recording and triggering operations on a time
basis.
Time and Clock
• High-accuracy real-time clock with a lithium backup
battery
• 1-ms satellite-synchronized clock option (IRIG-B time-
code input)
• SNTP clock synchronization option
• 1PPM or 1PPS clock synchronization option via a fast
digital input
• One-time programmable or calendar scheduled
daylight saving time (DST) switch dates; configurable
DST start and end time
Extended Security
• 3-level password security for protecting meter setups
and accumulated data from unauthorized changes
Display
• Easy to read high contrast graphical 128x32 pixel LCD
display with backlight
• Multi-page data display with auto-scroll; time, billing,
instrumentation and service data

Chapter 1 Introduction
12 EM720 Power Quality and Revenue Meter
• Menu-driven setups
Digital I/O
• Four embedded digital inputs with 1 ms scan time
• Replaceable 2DI/2DO expansion I/O modules with 1/2
cycle scan/update time
Memory
• 8 or 16 Mbyte flash memory for long-term billing,
event, waveform and data recording
Communications
• Front Infrared IEC 62056-21 serial communication port
(IEC 62056-21, Modbus RTU/ASCII and DNP3
protocols)
• Plug-in serial RS232/RS485 communication port
(Modbus RTU/ASCII and DNP3 protocols)
• Plug-in full speed USB 1.1 port (Modbus RTU protocol)
• Plug-in Ethernet port (Modbus/TCP and DNP3/TCP
protocols, IEC 61850 – future releases), up to 5
simultaneous connections
• Plug-in wireless GSM/GPRS modem (Modbus/TCP and
DNP3/TCP protocols)
Expansion I/O and Communication slots
• 3 expansion slots for plug-in I/O and communication
modules
Backup Power Supplies
• Rechargeable auxiliary battery (more than 3 hours
operation time with a NiMH battery, up to 7 hours
operation with a Li-Ion battery)
• Auxiliary 24VDC backup power supply module
• Auxiliary 85-265VAC/90-290VDC backup power supply
module
Upgradeable Firmware
• New features can be easily added to your meter by
simply replacing firmware through any communication
port.
Software Support
• PAS – free meter configuration and data acquisition
tool
• eXpertPowerTM – SATEC proprietary Internet services

Chapter 1 Introduction
EM720 Power Quality and Revenue Meter 13
EM720 Models
The EM720 meter series includes two models:
• EM720 – basic model - offers all the EM720 billing,
instrumentation, control, power quality and fault
recording capabilities
• EM720T – fast transient model - adds to above a fast
transient recorder with a capability of detecting
transient overvoltages with peaks up to 2kV and
durations of less than 20 microseconds
See the EM720 Installation Manual for technical specifications
and ordering options.
Supplemental Documents
BG0450 EM720 Installation Manual
BG0457 EM720 Modbus Reference Guide
BG0458 EM720 DNP3 Reference Guide
BG0460 EM720 IEC 62056-21 Reference Guide
BG0459 EM720 IEC 61850 Reference Guide
BG0337 PAS Getting Started Guide
Meter Nameplate
Watt-hour meter constant
Volta
g
e input
Rated current
MAC address Meter serial number

Chapter 2 Operating the EM720 Controls and Indicators
14 EM720 Power Quality and Revenue Meter
Chapter 2 Operating the EM720
Controls and Indicators
Push Buttons
The EM720 provides two sealable push buttons that do not
have labels. They allow you to scroll through the multi-page
display screens for local meter reading, to inspect or change
meter setup parameters, and to control display operations.
See Navigation Buttons in Chapter 3 for buttons location and
functionality.
Graphical Display Indicators
The EM720 graphical display is used both for displaying billing
and instrumentation data, and for indication of the present
tariff rate and important diagnostic information. See Status
Indicators in Chapter 3 for information on graphical status
indicators.
Energy Pulse LED Indicators
The EM720 is provided with two red LED indicators labeled as
“kWh” and “kvarh” that flash when a load is applied to the
meter.
The LED pulse rate in NORMAL mode is indicated on the
meter nameplate. The standard LED pulse rates are listed in
the following table. All indicated rates are in secondary units.

Chapter 2 Operating the EM720 TEST Mode
EM720 Power Quality and Revenue Meter 15
Rated Voltage,
V Secondary Current, A Pulse Rate, imp/kWh
57-120 1 20,000
57-120 5 4,000
120-277 1 12,500
120-277 5 2,500
The LED pulse rate in TEST mode is user-programmable. The
factory set defaults and available ranges are shown in the
following table.
Rated
Voltage, V Secondary Current, A Default Pulse Rate,
imp/kWh (Wh/imp) Range, imp/kWh (Wh/imp)
57-120 1 20,000 (0.05) 20,000-100,000 (0.01-0.05)
57-120 5 10,000 (0.10) 4,000-100,000 (0.01-0.25)
120-277 1 20,000 (0.05) 12,500-100,000 (0.01-0.08)
120-277 5 10,000 (0.10) 2,500-100,000 (0.01-0.40)
See Device Options and Mode Control in Chapter 5 on how to
change the LED pulse rate in your meter.
TEST Mode
The EM720 can run in NORMAL or in TEST mode.
TEST mode is intended for testing the device energy
measurement accuracy without affecting the billing energy
and demand data. All instrumentation data is still available in
TEST mode.
The front pulse LED indicators flash at a programmable rate
in TEST mode, and the billing data display shows separate
test kWh and kvarh energy readings with an extended 0.001
kWh resolution.
See Device Options and Mode Control in Chapter 5 on how to
put your meter in TEST mode and to change the test LED
pulse rate. See TEST Mode Data Display for more information
on the TEST mode display.
NOTE
In TEST mode the following features are not operational:
• setpoints
• power quality recorder
• fault recorder
• relay outputs
• instrument transformer correction
• transformer/line loss compensation
Device Diagnostics
Device diagnostic messages may appear as a result of the
EM720 built-in diagnostic tests performed during start-up and
device operation.
A blinking diagnostics indicator is shown on the display
whenever there are diagnostic messages. See Status

Chapter 2 Operating the EM720 Meter Security
16 EM720 Power Quality and Revenue Meter
Indicators in Chapter 3 for information on diagnostics
indicators. See Device Diagnostics Display in Chapter 3 on
how to inspect the meter diagnostics messages from the
display.
The device diagnostics status is stored in a non-volatile
register, which may be inspected and cleared from the meter
display, via the supplemental PAS software, or from a user
application. See Viewing and Clearing Device Diagnostics in
Chapter 6 on how to clear the device diagnostics status in
your meter.
All diagnostic events with time stamps are also recorded in
the meter Event log and can be inspected via PAS (see
Retrieving Recorded Files in Chapter 7).
In the event of a device fault, check the fault reason and
clear the device diagnostics. See Device Diagnostic Codes in
Appendix G for the list of diagnostic messages and their
meanings. In the event of a time fault, update the device
clock. In the event of a configuration reset, check the setup
affected by the fault via the device Event log, and then verify
the setup data.
Hardware failures are normally non-critical recoverable faults
that do not cause a system failure but may cause data loss.
Hardware failures are often caused by excessive electrical
noise in the region of the device. If the device continuously
resets itself, contact your local distributor.
Device Fault Alarm
The EM720 provides a global "DEVICE FAULT" event flag that
is asserted all the time while one of the diagnostic events
exists. It can be monitored via a setpoint (see Using Control
Setpoints in Chapter 5) to give a fault indication through a
relay output. If the alarm relay is programmed for failsafe
mode using inverting polarity, then its normally closed
contacts will be open if either the meter looses power or a
device fault occurs.
Meter Security
The EM720 provides 3-level password security for protecting
meter setups and accumulated data from unauthorized
changes. Meter readings are not software protected.
Access to particular setup and control items is granted
depending on the security level of the password you entered.
The passwords can be 1 to 8 digits long.
The following table shows the meter security levels and user
access rights.
Password Security Level Access Rights
Password 1 Low Reset of billing and engineering maximum
demands, and device diagnostics.
Meter clock update.
Display setup.

Chapter 2 Operating the EM720 Meter Clock and Time Synchronization
EM720 Power Quality and Revenue Meter 17
Password Security Level Access Rights
Password 2 Medium TEST mode.
Reset of meter and battery operation time
counters, failure counters and pulse counters.
Communications setup.
I/O operation setup and control.
Memory and recorders setup.
Billing/TOU system setup.
Password 3 High
(Administration
level)
Meter passwords setup.
Basic device setup.
Device energy and power options setup.
Reset of conventional log files.
The meter is primarily shipped with all passwords preset to 9
at the factory. It is highly recommended that you change the
factory set passwords as fast as possible. See Configuring
Meter Passwords in Chapter 5 on how to change passwords in
your meter.
Password-tampering events are automatically recorded to the
Event log file after every three unsuccessful login attempts in
5 minutes.
Meter Clock and Time Synchronization
Time synchronization provides a common time basis for the
meter billing and tariff system, and for the power quality and
fault recorders so that events and disturbances can be
compared to one another.
The EM720 can receive time synchronization signal either
from a GPS satellite clock that has an IRIG-B time code
output, or from another device that can provide minute-
aligned time synchronization pulses through relay contacts.
The EM720 IRIG-B port uses unmodulated (pulse-width
coded) time code signal (unbalanced 5V level). The red
IRIGB LED is blinking when the IRIG-B port receives a GPS
clock signal.
The EM720 also provides an SNTP client that can receive
precise time from an available SNTP server via the Internet.
See Setting-Up SNTP Client in Chapter 5 on how to configure
the SNTP client.
See Time Synchronization Source in Local Settings setup for
more information on how to select an external time
synchronization source in your meter.
Monitoring Meter Batteries
The EM720 is provided with a rechargeable auxiliary battery
that can supply power in the event of long outages without
the need of an external power supply.
A second backup lithium battery keeps the meter clock
running when the meter goes to standby after the auxiliary
battery is discharged.

Chapter 2 Operating the EM720 Billing and Energy Metering
18 EM720 Power Quality and Revenue Meter
You can monitor the status of batteries from the front display
on the Device Info pages (see Device Info Display in Chapter
3) and via the device diagnostics.
The auxiliary battery voltage is about 8.2 volts at full charge
(for at least 20 hours). If it falls below, then the battery
should be checked.
When the lithium battery voltage drops below the minimum
allowed level, it is indicated by the blinking “Battery Low”
icon on the display and via the device diagnostics. In this
event, the battery should be checked and replaced if
required.
NOTE
Always clear the battery operation time counters after
replacing a battery. See Resetting Accumulators and Clearing
Log Files in Chapter 6 for information on how to clear the
operation counters in your meter.
Billing and Energy Metering
The EM720 provides true four-quadrant energy
measurements with Class 0.2S IEC 62053-22 accuracy. The
following energy quantities are available for instrumentation
and billing:
• kWh import (Q1+Q4)
• kWh export (Q2+Q3)
• kWh net (Q1+Q4)-(Q2+Q3) - instrumentation
• kvarh import (Q1+Q2)
• kvarh export (Q3+Q4)
• kvarh net (Q1+Q2)-(Q3+Q4) - instrumentation
• kvarh Q1, Q2, Q3, Q4 quadrants
• kVAh import (Q1+Q4)
• kVAh export (Q2+Q3)
• kVAh total (Q1+Q2+Q3+Q4)
Energy Measurement Channels
The EM720 uses two independent current channels for high-
accuracy energy measurements and for conventional high-
range instrumentation. They have different gain and
measurement ranges as necessary for billing accuracy energy
metering and for power quality and fault monitoring.
1-second currents and powers provided by the meter and the
corresponding engineering display readings are taken from
the energy measurement channel. They begin measurements
from 5 mA starting currents and up to 10 A RMS with 5 A
secondaries, while instrumentation currents provide
measurements up to 50 A RMS.

Chapter 2 Operating the EM720 Billing and Energy Metering
EM720 Power Quality and Revenue Meter 19
Energy Counters
The EM720 provides instrumentation energy and billing
energy metering. Both use the same energy measurement
circuitry as a source input for accumulation energies but
operate independently.
Energy counters have a nine-digit kWh resolution with one
decimal place by default. You can set the energy counters to
have fewer digits by changing the default energy roll value in
your meter (see Device Options and Mode Control in Chapter
5).
Billing energy registers have the same resolution as
instrumentation energy counters.
Billing Energy Registers
The EM720 has 10 fully programmable billing energy
registers that can be linked to any internal energy source or
to any external pulse source that delivers pulses through the
device digital inputs.
Any of energy registers can provide either a single-tariff
energy accumulation or be individually linked to the TOU
system providing both total and multi-tariff energy billing.
See Configuring Billing/TOU in Chapter 5 on how to configure
the meter billing registers and tariff schedule for your
application.
Maximum Demand Registers
Any of billing energy registers can be individually linked to
the maximum demand and cumulative maximum demand
registers providing the same demand tariff structure as you
selected for energy registers.
Tariff Rates
The EM720 provides three options for switching tariff rates:
• automatic via a programmable TOU calendar schedule
• external via communications by direct writing a tariff
number to the meter tariff register
• external via digital inputs by providing a tariff number
code on the meter tariff inputs
See Device Options and Mode Control in Chapter 5 on how to
program the tariff control mode and select tariff inputs in
your meter.
The meter tariff structure supports 8 different tariff rates
using an arbitrary tariff schedule.
The EM720 TOU calendar provides a season tariff schedule
and an option for scheduled daylight savings switch dates. A
total of 4 types of days and 4 seasons are supported with up
to eight tariff changes per day. See Configuring Billing/TOU
for more information on programming the tariff calendar
schedule in your meter.

Chapter 2 Operating the EM720 Instrumentation Metering
20 EM720 Power Quality and Revenue Meter
The present tariff rate is indicated on the EM720 display. If
required, tariff-switching pulses with a programmable
duration can be output via the meter relays.
End of Billing
The EM720 can be configured to trigger a reset of billing
maximum demands and an end of billing period automatically
on a monthly schedule, manually from the front display and
remotely via communications. It can also be done via control
setpoints using any programmable internal or external
trigger, like a specific time schedule or an external pulse.
You can select the reset sources via the Device Options setup
(see Device Options and Mode Control in Chapter 5).
The EM720 uses a one-day protection lockout time to avoid
multiple consecutive resets of the billing maximum demands.
Billing Data Recording and Load Profiling
The EM720 provides automatic recording of the billing data to
flash files:
• Monthly billing period data for the last 24 billing
periods
• Daily energy and maximum demand profile for the last
120 days
• 15-min energy load profile for 120 days or 30-min
profile for 240 days.
Maximum demand profiling for monthly and daily billing data
profiles can be individually configured for every register.
See Factory Preset Data Log Files in Chapter 5 and Billing and
Load Profile Log Files in Appendix C for more information on
the file layout and contents.
Billing Data Display
The EM720 display indicates billing energy, maximum
demand and cumulative maximum demand registers for the
present billing period and for three previous billing periods.
The display is automatically configured for your set of billing
registers and your tariff schedule. See Billing Period Data
Displays in Chapter 3 for the display layout.
Instrumentation Metering
Instrumentation metering provides real-time measurements
and time-integration for local and remote power monitoring
and control, and a source for power quality evaluation and
triggering the logical controller and Fault recorder.
See Parameters for Monitoring and Logging in Appendix A for
a full list of the electricity and status measurements provided
by the EM720.
All RMS quantities are based on 1/2-cycle true RMS
measurements as per IEC 61000-4-30.