Siemens 4720 Power Meter Operator's Manual

4720 Power Meter
Operator’s Manual
DANGER
Hazardous voltages and high-speed moving parts in electrical
devices communicating with the Power Meter.
Can cause death, serious injury or property damage.
See safety instruction contained herein. Restrict use to qualified
personnel.
The use of unauthorized parts in the repair of the equipment
or tampering by unqualified personnel will result in
dangerous conditions that can cause death, serious injury or
property damage.
IMPORTANT
The information contained herein is general in nature and not
intended for specific application purposes. It does not relieve
the user of responsibility to use sound practices in application, installation, operation, and maintenance of the
equipment purchased. Siemens reserves the right to make
changes at any time without notice or obligations. Should a
conflict arise between the general information contained in
this publication and the contents of drawings or supplementary material or both, the latter shall take precedence.
QUALIFIED PERSONNEL
For the purposes of this manual and product labels, "qualified
personnel" is one who is familiar with the installation,
construction, or operation of the equipment and the hazards
involved. In addition, s/he has the following qualifications:
(a) is trained and authorized to energize, de-energize, clear,
ground, and tag circuits and equipment in accordance
with established safety practices.
(b) is trained in the proper care and use of protective gear
equipment such as rubber gloves, hard hat, safety glasses
or face shields, flash clothing, etc., in accordance with
established safety procedures
(c) is trained in rendering first aid.
SUMMARY
These instructions do not purport to cover all details or variations in equipment, nor to provide for every
possible contingency to be met in connection with installation, operation, or maintenance. Should further information be desired or should particular problems arise which are not covered sufficiently for the purchaser’s
purposes, the matter should be referred to the local Siemens Energy & Automation, Inc. sales office.
THE CONTENTS OF THIS INSTRUCTION MANUAL SHALL NOT BECOME PART OF OR MODIFY ANY PRIOR OR
EXISTING AGREEMENT, COMMITMENT OR RELATIONSHIP. THE SALES CONTRACT CONTAINS ALL OBLIGATIONS OF SIEMENS ENERGY & AUTOMATION, INC. THE WARRANTY CONTAINED IN THE CONTRACT
BETWEEN THE PARTIES IS THE SOLE WARRANTY OF SIEMENS ENERGY & AUTOMATION, INC.
ACCESS, ISGS, Isolated Multi-Drop, S7-I/O, SBwin, SAMMS-LV, SAAMS-MV,SEAbus,SIEServe, Static Trip III,
Wisdom, and WinPM are trademark, Sensitrip and Sentron are registered trademarks of Siemens Energy &
Automation, Inc. SIEMENS is a registered trademark of Siemens AG. Windows is a trademark of Microsoft
Corporation. All other product names mentioned herein are used for identification purposes only and may be
the trademarks or registered trademarks of their respective companies.
Table of Contents
1
Introduction ...............................................1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
Communications Wiring .........................17
3.1
3.2
3.3
3.4
4
7
Start Up ......................................................... 25
Front Panel Operation ................................... 25
Importance of Power Quality Monitoring.......67
Waveform Capture.........................................67
Waveform Recording .....................................67
10 Logging Data .......................................... 71
10.1
10.2
10.3
10.4
10.5
Event Log.......................................................71
Minimum/Maximum Logs ..............................71
Programmable Snapshot Logs......................72
Retrieving Logged Data .................................74
Time Stamp Accuracy ...................................74
11 Communications .................................... 77
Configuring the Communications Card ......... 17
Terminal and LED Functions.......................... 18
RS-232 Connections ..................................... 18
RS-485 Connections ..................................... 19
Control Relay Connections............................ 21
Status Input Connections.............................. 22
Auxiliary Voltage Input ................................... 23
Auxiliary Current Output ................................ 23
Setpoint Operations.......................................59
Setpoint Types ...............................................59
Trigger Parameters ........................................60
Setpoint Actions ............................................63
Programming Setpoints.................................65
Power Outages ..............................................66
Using Waveforms ................................... 67
9.1
9.2
9.3
11.1
11.2
11.3
11.4
11.5
11.6
General ..........................................................77
RS-232 Communications ..............................77
RS-485 Communications ..............................77
Setting the Unit ID and Baud Rate ................77
Siemens WinPM Software .............................78
Third-Party System Compatibility..................78
12 Maintenance ........................................... 79
12.1
12.2
12.3
Operator Interface ..................................25
5.1
5.2
6
9
Optional Wiring........................................21
4.1
4.2
4.3
4.4
5
Location and Mounting ................................... 5
Power Wiring ................................................... 5
Power Supply Connections ............................. 5
Chassis Ground Connection ........................... 7
Phase Voltage and Current Input
Connections .................................................... 7
Using Setpoints ...................................... 59
8.1
8.2
8.3
8.4
8.5
8.6
Installation .................................................5
2.1
2.2
2.3
2.4
2.5
3
About the Power Meter ................................... 1
Inputs and Outputs.......................................... 1
Displays and Measurements ........................... 1
User Interface .................................................. 2
High-Speed Setpoint System.......................... 2
Power Quality Monitoring and Fault
Recording ........................................................ 3
Logging Capability........................................... 3
Network Communications ............................... 4
System Applications........................................ 4
8
Maintenance ..................................................79
Calibration .....................................................79
Field Service Considerations .........................79
13 Troubleshooting...................................... 80
Programming...........................................31
Appendixes
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
6.10
A
Technical Specifications ....................... 81
B
Dimensions ............................................ 83
C
Setpoint Parameter Form ..................... 84
D
Firmware Revisions............................... 85
E
Ordering Information ............................ 86
Programming Mode....................................... 31
Accessing and Modifying Parameters........... 32
Defining New Parameter Values .................... 32
Display Format .............................................. 32
Basic Settings................................................ 32
Control Relay Operation ................................ 35
Status Input Operation .................................. 36
Auxiliary Voltage Input Operation .................. 37
Auxiliary Current Output Operation ............... 37
Operating Parameter Descriptions ................ 38
Displaying Information ...........................51
Index
7.1
7.2
7.3
7.4
7.5
7.6
Warranty
High-Speed Triggers...................................... 51
Real-Time Measurements ............................. 51
Accumulated Measurements......................... 55
Resetting Energy Counters............................ 55
Power Reading Polarities .............................. 55
Status Information ......................................... 56
1996 Siemens Energy & Automation, Inc.
ACCESS, Isolated Multi-Drop, SEAbus, and WinPM are trademarks of Siemens Energy & Automation, Inc. Windows is a trademark and Microsoft is a registered
trademark of Microsoft Corporation. All other products, names, and services may be trademarks or registered trademarks of their respective companies.
Siemens Energy & Automation, Inc.
i
Table of Contents
ii
Siemens Energy & Automation, Inc.
1 Introduction
1 Introduction
1.1 About the Power Meter
The 4720 power meter is a microprocessor-based, digital
three-phase “smart” power meter designed for use in industrial, commercial, and utility power distribution switchboards
and substations. The 4720 power meter answers the everincreasing concern for “clean,” reliable power by integrating
the many critical aspects of power metering, analysis, and
control into one simple and economical instrument. It is a
state-of-the-art alternative to traditional analog electromechanical metering devices, replacing numerous individual
transducers and meters, and offering many features previously unavailable in power instrumentation.
The 4720 power meter offers the high accuracy, reliability,
and ruggedness of its companion products, the 4700 and
4300 power meters, while adding many new measurements
and advanced features. The 4720 power meter also matches
the 4700 power meter in its mounting dimensions and installation requirements, and in its straightforward, flexible user
interface. Figure 1.1 shows the 4720 power meter front and
rear views.
The unit is based on a 13.5 MHz, 16-bit microcontroller chip.
This provides very high computational throughput, allowing
the unit’s sophisticated software to process information in
real time. The meter’s readings and setup parameters are
maintained in nonvolatile memory.
The 4720 power meter is panel-mountable and provides
rear-mounted, utility approved terminal strips rated at 600 V.
The 4720 power meter is exceptionally rugged, with a high
tolerance to electrical disturbances and temperature
extremes. Many special design features guarantee performance in electrically harsh environments. The voltage, current, status (digital), relay, supply power, and
communications inputs are designed to withstand hipot,
C37.90A SWC, and fast transient tests. The 4720 power
meter transformer-coupled current inputs are fully isolated
with respect to the chassis of the unit, and provide 300 A
surge protection.
1.2 Inputs and Outputs
The 4720 power meter supports a variety of power distribution configurations, including 4-wire wye, 3-wire delta, and
single phase systems. Three-phase voltage and three-phase
current inputs are provided, as well as an additional current
input. In installations with non-linear loads, where odd harmonics can fail to cancel, significant currents in the neutral
conductor can be produced. The 4720 power meter fourth
current input can be used optionally for monitoring current in
the neutral conductor, or for ground current monitoring. Used
in conjunction with its high-speed setpoint system, the 4720
power meter can provide reliable ground fault protection.
Siemens Energy & Automation, Inc.
Intermediate transducers are not required on phase voltage
and current inputs. When equipped with the appropriate voltage input option, no voltage transformers (VTs) are required
for wye systems up to 347 VAC line-to-neutral/600 VAC lineto-line. For higher voltage wye systems, and all delta systems, VTs can be used. The transformer-coupled current
inputs accept current transformers (CTs) with 5 A full scale
outputs. Additionally, a 1 A input version is available. Overrange measurement options include 125% to 500%.
An auxiliary voltage input can be used to measure an external variable such as transformer temperature or battery voltage. Input range is 0 to 1 V (AC or DC). An auxiliary analog
current output can provide 0-20 or 4-20 mA proportional to
any measured parameter.
Four digital inputs can be used to monitor breaker status,
ground fault relay status, or any other external dry contact.
These can also be used as pulse counters to measure device
cycles, running hours, and so on. An internal 30 VDC supply
provides self-excitation for “volts free” contact sensing.
Outputs include three relays that can be automatically controlled by an extensive user-programmable setpoint system,
or manually operated by commands made via the communications port. Relays can perform operations ranging from
simple alarm activations to fully automated demand, power
factor, or load control. Relays can operate in a latched or
pulsed mode, and can also be programmed to provide kWH
(import/export), kVARH (import/export), or kVAH output pulsing. The basic 4720 power meter provides 10 A, Form C
electromechanical relays.
1.3 Displays and Measurements
The 4720 power meter offers many high accuracy, real-time,
three-phase measured parameters and status parameters.
All parameters are quickly accessible via the front panel display or through the meter’s communications port.
Real-time measurements include: Volts, Amps, Neutral/
Ground Current, kW, kVA, kVAR, Power Factor (PF), and Frequency. Power quality analysis capability offers total harmonic distortion, individual harmonic levels, and K-factor for
all eight voltage and current inputs (to the 15th harmonic).
Thermal, sliding window, and predicted sliding demands are
provided on all measurements. Minimum/maximum values
are also provided on all measurements.
Energy values include kWH, kVAH, and kVARH. All energy
readings provide bidirectional (import/export) indication. All
voltage, current, power and energy readings are true rms,
including harmonics.
Status information includes real-time conditions for the three
relays, four status/counter inputs, and seventeen user-programmable setpoints. The scaling for each pulse counter
reading is user-definable. Also included is internal self-diagnostic information.
1
1 Introduction
1.4 User Interface
1.5 High-Speed Setpoint System
The 4720 power meter front panel features a large, high-visibility, 20-character vacuum fluorescent display. Voltage, current, and power functions can all be displayed together for
the selected phase. Very large measured values with up to
nine significant digits (for example, kWH) are presented using
the entire display. Concurrent display of all three phases of
voltage and current readings is also possible.
The comprehensive setpoint system of the 4720 power
meter provides extensive control over the three relay outputs,
as well as triggering capabilities for the waveform capture,
waveform recorder, and snapshot logging features. Setpoints
can also be used to automatically clear status input
counters, or to reset Min/Max Logs.
Seventeen user-programmable setpoints are provided, six of
which offer high-speed (67 milliseconds/4 cycle) capabilities.
Setpoints can be activated by a wide variety of conditions,
including:
The 4720 power meter uses four long-life, stainless steel
membrane switches to access all measured parameters and
status information, and to program functions. Using the
Menu buttons, you can define convenient custom groupings
of important parameters for quick viewing.
You can program the basic setup parameters of the 4720
power meter quickly and easily from the front panel. Basic
parameters include voltage and current scales, voltage mode
such as wye or delta, baud rate, and so on.
Programming for many of the advanced features of the 4720
power meter must be performed via the communications
port using a portable or remotely located computer running
supervisory software such as Siemens WinPM™ software.
These parameters include setup for waveform, data logging,
and setpoint functions.
•
A user-defined level on any measured parameter
(for example, voltage, current, power, harmonic distortion (HD), demand, and so on)
•
Time-overcurrent characteristics
•
External equipment status (via the status inputs)
•
New hour, day, week, month, or year
An active setpoint condition can be used to trigger simultaneously up to two separate functions. For example, you may
wish to operate a relay and perform a waveform recording
when an overcurrent condition occurs. Using predicted
demand, you can apply setpoint control of the relays in effective demand management strategies.
Setup and other critical information is saved when the 4720
power meter power is turned off. All programming is password protected.
All setpoint activity is recorded automatically in the Event
Log.
TXD
R11 R12
RXD
Control Relays
GND
R13
R21 R22 R23
R31 R32
R33
V1
NOTE:
SG
RS-485
RS-232C
TXD
Voltage Inputs:
Power Supply:
Auxiliary IOut Output:
Auxiliary VAux Input:
Current Inputs:
Status Inputs:
Terminal Strip:
Maximum Wire:
This equipment complies with the requirements in part 15 of FCC rules for a
Class A computing device. Operation of this equipment in a residential area may
cause inacceptable interference to radio and TV reception requiring the operator
to take whatever steps are necessary to correct the interference.
Listed Ind.
Contr. Eq. 1T98
SIEMENS
ISOCOM
4720
R
L/+
Power
WARNING / AVERTISSEMENT
LR 57329
R
Siemens Energy & Automation, Inc.
Switchgear & Motor Control Division
Raleigh, NC • USA
Made in Canada
RTS
VREF N/-
Specifications below are standard.
For options refer to model number and
instruction book SG-6068.
Resistive: 10 Amp, 277 V AC/30 VDC
Inductive: 240 VAC, 3400 VA Make, 360 VA Break
Line to Neutral 120 VAC Nominal
85-264 VACC/0.2 Amp, 47-440 Hz
or 110-300 VDC/0.2 Amp
0 to 20 mA Output
1 Volt AC/DC Input, Class 2 only
5 Amp AC only, 25% Overrange, 30V Max.
Dry contact sensing. Do not apply voltage.
12 Lbs-inch (1.35Nm) Torque
12 AWG, 4 mm², 75°C Cu wire only
Control Relays:
Serial Number:
Software Version:
+
RXD
V3
Electrical Rating
4720 Power Meter
SHLD
-
V2
Voltage Inputs
Auxiliary
Current Inputs
IOut VAux
I11 I12
I21
Hazardous voltage.
Can cause death or
severe injury.
Haute tension
pouvant entrainer des
blessures mortelles.
More than one live
circuit. Disconnect all
power sources to deenergize before servicing.
See wiring diagram.
Plus d’un circuit sous-tension.
Déconnecter toutes les
sources de tensions avant
toute manipulation.
Voir schéma de cablage.
Status Inputs
I22
I31 I32
I41
I42
S1
S2
S3
S4 SCOM
Figure 1.1 Siemens 4720 Power Meter (Front and Rear View)
2
Siemens Energy & Automation, Inc.
1 Introduction
1.6 Power Quality Monitoring and Fault
Recording
In addition to harmonic distortion and K-factor measurements, the 4720 power meter is equipped with digital waveform sampling capabilities for power quality monitoring and
fault analysis. The 4720 power meter provides two powerful
methods for acquiring waveform data: waveform capture
and waveform recording.
1.6.1
Waveform Capture
Waveform capture allows you to perform high-speed (128
samples/cycle) sampling with any one of the eight voltage
and current inputs, providing high-resolution data which can
be used for detailed power quality analysis. Capture can be
triggered either through user-defined setpoint conditions or
commands via the meter’s communications port. Sampled
waveform data is stored in memory and can be read via the
communications port. WinPM software can be used to view
and display captured waveform data. WinPM software calculates total harmonic distortion for each waveform and a
breakdown of individual harmonic components (to the 63rd
harmonic) in graphical form.
1.6.2
Waveform Recording
Waveform recording allows you to analyze the conditions
occurring before, during, and after a power fluctuation or failure and is ideal for fault and surge analysis, and to aid in fault
location.
Waveform recording runs continuously at 16 samples/cycle
on all eight voltage and current inputs. A trigger by a userspecified setpoint condition or a command made via the
meter’s communications port freezes multiple cycles of each
waveform in memory along with a time stamp.
The user can configure the 4720 power meter to concurrently store up to three 12-cycle events, two 18-cycle events,
or one 36-cycle event for each input. A programmable trigger delay allows pre-event or post-event data to be
recorded.
The recorded data is saved until uploaded to a master station for analysis. WinPM software can be used to display the
waveforms together on the computer screen, presenting a
comprehensive picture of the power line conditions surrounding the disturbance.
1.7 Logging Capability
The 4720 power meter supports three types of data logs: the
Event Log, the Min/Max Log, and the Historical Log. Logged
data can be extremely useful in the study of growth patterns,
for scheduling loads, for cost allocation, for isolating problem
sources, or for analyzing a variety of power system operating
conditions.
1.7.1
Event Logging
The Event Log provides 100 date and time-stamped
records. Digital input changes are recorded with a resolution
of 1 millisecond typical and 10 milliseconds maximum, ideal
for sequence-of-event recording. The log also records all
relay operations, setpoint/alarm conditions, setup changes,
and self-diagnostic events (1 millisecond typical, 10 milliseconds maximum).
1.7.2
Min/Max Logging
A preset Min/Max Log records the extreme minimum and
maximum (min/max) values for all parameters measured by
the 4720 power meter, including all voltage, current, power,
frequency, power factor, harmonic distortion, and demand
values. Min/max values for each parameter are logged independently with date and time stamp with 1 second resolution.
You can also define up to 16 separate Min/Max Logs, each
containing up to 16 time-stamped parameters. Each log is
triggered by the first parameter in its list. When a new minimum or maximum value for the trigger parameter is
recorded, coincident real-time values for all other parameters
in the list are simultaneously stored. For example, you could
program a log to record all per-phase kW, kVAR, and PF
demand values when total kW demand peaks.
Reset functions for the preset and programmable Min/Max
Logs are performed either from the front panel or via communications.
1.7.3
Historical Logging
The 4720 power meter Snapshot Logs are historical or trend
logs. Up to 8 logs may be defined, each recording up to 12
channels of time-stamped data. The measured parameters
recorded by each log are user-programmable. Trigger functions are assigned independently for each log.
Each Snapshot Log can be triggered in one of three possible
ways, each described below:
Siemens Energy & Automation, Inc.
•
User-defined time interval
•
One-shot method
•
Gated method
3
1 Introduction
A user-defined time interval basis provides an interval range
from 1 second to 400 days. One log can be configured for
high-speed operation, recording at intervals as short as 2
cycles. The high-speed log can be useful for logging short
duration conditions such as motor start-ups.
1.9 System Applications
One-shot method allows any standard setpoint to automatically trigger a snapshot recording when an active condition
occurs. Setpoint conditions can include harmonic distortion
levels, status input changes, and more.
•
Utility Installations
•
Industrial Buildings
•
Office Buildings
A gated method allows readings to be recorded on a time
interval basis only during the time that a setpoint remains
active. This method is ideal for logging voltage and current
extremes following a breaker trip, for example.
•
Commercial Buildings
•
Hospitals
•
Airports
•
Telephone Exchanges
•
Factories
•
Pulp Mills
•
Saw Mills
WinPM software can be used to program all log setup
parameters and to display all logged data. Historical snapshot data can be displayed graphically.
•
Shopping Centers
•
Large Stores
1.8 Network Communications
•
Hotels
For integration into an energy management system, the
4720 power meter is equipped with a communications port
selectable as either RS-232 or RS-485. As part of the
ACCESS™ system, the 4720 power meter uses the open
SEAbus™ protocol for communications.
•
Substation Metering
•
Co-Generation Systems
•
Chemical Process Plants
•
Multi-user sites where allocation of electrical costs
is desirable
•
Any installation that uses significant amounts of
electrical energy
•
Any installation that is experiencing power quality
problems
•
Any location where remote power monitoring,
control, or analysis is needed
1.7.4
Access to Logged Data
Alarm conditions, events, min/max levels, and snapshot
interval readings are all automatically time-stamped and
logged into nonvolatile memory and are accessible via the
communications port. Preset Min/Max Log readings can also
be viewed via the front panel display by assigning them to
either Menu button.
4
The unique features of the 4720 power meter, including
measurement, storage, setpoint (load shedding) and display
characteristics, make it suitable for use in:
Siemens Energy & Automation, Inc.
2 Installation
2 Installation
The 4720 power meter model type is determined from the
phase voltage, phase current, power supply, and relay input
ratings. The rear panel of the 4720 power meter lists all
equipped options. Appendix A of this manual defines all
options and their associated ratings. This chapter provides
detailed installation instructions applicable to each hardware
option.
Figure 2.1 provides the mounting dimensions for the 4720
power meter. A five inch clearance behind the front panel is
required for access to wiring.
Note:
Most electrical codes prohibit extending
voltages greater than 240 VAC to the door
of the switchgear cabinet. If this is the
case, use a basic model (120 VAC input)
4720 power meter with VTs that are connected to provide 120 VAC line-to-neutral
input to the power meter (see section
2.5.1).
Refer to section 2.4 for information about chassis ground
connection.
2.2 Power Wiring
Connections to the 4720 power meter are made to three
terminal strips located on the rear of the unit. Figure 2.1
provides 4720 power meter terminal block dimensions.
Either 12 AWG or 14 AWG wire is recommended for all
connections except for communications connections. Ring
or spade terminals may be used to simplify connection.
Note:
All wiring must conform to applicable local
electrical codes.
2.3 Power Supply Connections
The basic model 4720 power meter can be powered by 85
to 264 VAC or 110 to 300 VDC at 0.2 A. An optional power
supply of 20 to 60 VDC at 10 W is also available. This option
is indicated by the catalog number 4720DRMC-3x-xx on the
rear of the unit.
The basic model can be powered from a dedicated fused
feed or from the voltage source which it is monitoring, as
long as it is within the supply range. The 20 to 60 VDC option
must be powered from a dedicated fused feed.
2.1 Location and Mounting
The 4720 power meter should be mounted in a dry, dirt-free
location away from heat sources and very high electric fields.
To operate properly and effectively, environmental conditions
should fall within the guidelines listed in Appendix A.
If an AC power supply is being used, connect the line supply
wire to the 4720 power meter L/+ terminal and the neutral
supply wire to the N/- terminal. If a DC power supply is being
used, connect the positive supply wire to the 4720 power
meter L/+ terminal and the negative (ground) supply wire to
the N/- terminal.
The enclosure in which the 4720 power meter is mounted
(typically a switchgear cabinet) should protect the device
from atmospheric contaminants such as oil, moisture, dust,
corrosive vapors, or other harmful airborne substances.
When choosing the enclosure size for the 4720 power meter,
allow extra space for all wiring, intermediate terminal strips,
shorting blocks, or any other required components. Position
the enclosure so the doors will open fully for convenient troubleshooting of wiring or related components.
Siemens Energy & Automation, Inc.
5
2 Installation
Panel Front
Panel Right Side
4 mounting studs #8-32
0.5" (12 mm) long
7.70"
(196 mm)
12.60
(320 mm)
4.60"
0.35"
(117 mm)
(9 mm) Behind Panel Depth
Panel Rear
1.00"
(25 mm)
1.40"
(36 mm)
TXD
R11 R12
RXD
Control Relays
GND
R13
Edge of
Front Bezel
R21 R22 R23
R31 R32
R33
V1
V2
V3
VREF N/-
Voltage Inputs
L/+
Power
4720 Power Meter
-
5.30"
(125 mm)
RS-485
SHLD
Serial Number:
Software Version:
+
RXD
TXD
SG
WARNING / AVERTISSEMENT
RS-232C
0.375"
(10 mm)
typ.
Listed Ind.
Contr. Eq. 1T98
LR 57329
RTS
SIEMENS
ISOCOM
4720
Auxiliary
Current Inputs
IOut VAux
I11 I12
I21
Status Inputs
I22
I31 I32
I41
I42
S1
S2
S3
S4 SCOM
0.60"
(15 mm)
0.45"
(11 mm)
2.44"
(62 mm)
0.45"
(11 mm)
typ.
4 mounting holes
3/16" (4.8 mm) diameter
Panel Cutout
5.30"
(125 mm)
0.80"
(20 mm)
6.90"
(175 mm)
11.20"
(284 mm)
11.90"
(302 mm)
0.35"
(9 mm)
Figure 2.1 Mounting Dimensions
6
Siemens Energy & Automation, Inc.
2 Installation
2.4 Chassis Ground Connection
The chassis of the 4720 power meter must be connected to
earth ground. A good, low impedance chassis ground
connection is essential for the 4720 power meter surge and
transient protection circuitry to function effectively. It should
be connected to the switchgear earth ground using a
dedicated 14 AWG (or larger) wire to a point where there will
be no voltage error due to distribution voltage drops. Do not
rely on metal door hinges as a ground path.
Ground wire connection to the chassis is made using the
ground lug supplied with the unit. For the basic model, this is
attached to one of the four mounting studs. Ensure that the
ground lug screw is tightened down securely onto the
ground wire and that the nut has been tightened down
securely onto the lug.
Note: For the noise and surge protection circuitry
to function correctly, the 4720 power meter
chassis ground lug must be connected to
the switchgear earth ground using a dedicated 14 AWG (or larger) wire. Failure to do
so will void the warranty.
2.5 Phase Voltage and Current Input
Connections
The following sections describe the requirements for connecting the 4720 power meter to the system being monitored. This includes selection and location of current and
voltage transformers.
2.5.1
277 VAC Option
This option provides 277 VAC full scale inputs that can
be used for direct connection (using fuses) to wye systems up to 277 VAC line-to-neutral/480 VAC line-to-line
or 277 VAC line-to-neutral/554 VAC line-to-line single
phase systems.
347 VAC Option
Models supplied with the 347 VAC option provide 347
VAC full scale inputs that can be used for direct connection (using fuses) to 347 VAC line-to-neutral/600 VAC
line-to-line wye or single phase systems up to 347 VAC
line-to-neutral/694 VAC line-to-line.
2.5.2
Phase Voltage Inputs: Using Voltage
Transformers
If wye system voltages are over 347 VAC line-to-neutral/600
VAC line-to-line or single phase system voltages are over 347
VAC line-to-neutral/694 VAC line-to-line, voltage transformers (VTs) are required.
Note: VTs are always required for delta systems.
VTs are used to scale down the line-to-neutral voltage of a
wye or single phase system, or the line-to-line voltage of a
delta system to the rated input scale of the 4720 power
meter. The inputs of the basic model can be used with VTs
that have secondaries rated at 120 VAC or less. This can
include 100/ 3 , 110/ 3 , 100, 110, or 120 VAC secondaries. Devices equipped with the 277 option can be used with
VTs that have secondaries rated to 277 VAC such as 220
VAC.
Phase Voltage Inputs: Direct Connection
The 4720 power meter uses the V1 input as the reference for
maintaining phase relationships for all power and energy
related measurements. For any system configuration, the V1
input must be connected to ensure accurate readings and
correct operation of the 4720 power meter.
Whether or not voltage transformers (VTs) are required
depends on the nature of the system being monitored, the
voltage levels to be monitored, and the input option of the
4720 power meter.
Note:
Most electrical codes prohibit extending
voltages greater than 240 VAC to the door
of the switchgear cabinet. If this is the
case, use a basic model (120 VAC input)
4720 power meter with VTs that are connected to provide 120 VAC line-to-neutral
input to the power meter.
Basic Model (120 VAC)
The basic model can be used for direct connection to
wye systems up to 120 VAC line-to-neutral/208 VAC
line-to-line or single phase systems up to 120 VAC lineto-neutral/240 VAC line-to-line.
Siemens Energy & Automation, Inc.
For proper monitoring, correct selection of VTs is critical. For
wye systems, the VT primary rating should equal the system
line-to-neutral voltage or nearest higher standard size. For
delta systems, the VT primary rating should equal the system
line-to-line voltage. For all system configurations, the VT secondary rating must be within the rated full scale range of the
4720 power meter voltage inputs.
VT quality directly affects system accuracy. The VTs must
provide good linearity and maintain the proper phase relationship between voltage and current in order for the voltage
and power readings to be valid.
2.5.3
Phase Current Inputs: Options
The 4720 power meter requires external CTs to sense the
current in each phase of the power feed and (optionally) in
the neutral or ground conductor. The selection of the CTs is
important because it directly affects accuracy.
The 4720 power meter offers various phase current input
options to match the type of CTs being used and the desired
overrange capability. The current input ratings of the three
phase inputs and the fourth current input (I4) are equivalent.
The fourth current input is typically used to measure the current flow in the neutral or ground conductor. The use of this
input is optional.
7
2 Installation
The basic model 4720 power meter is compatible with CTs
with 5 A secondaries. The 1AMP option provides compatibility with 1 A CT secondaries.
The basic model 4720 power meter provides 125% overrange capability which allows current readings to be accurately displayed up to 125% of full scale. For example, if the
AMPS SCALE has been set at 2000 A full scale, the 4720
power meter allows for readings up to 2500 A.
The 4720 power meter provides two additional current input
overrange options which include 200% and 500% of full
scale. Each overrange option also affects all current-related
measurement accuracies such as amperage (A) and kilowatt
(kW). Refer to Appendix A for detailed specifications on
each current input option.
Note: Refer to the rear panel catalog number to
determine the equipped current input
option(s). Applying current levels incompatible with the current input configuration will
permanently damage the device.
2.5.4
Phase Current Inputs: Current
Transformer Ratings
The CT secondary should have a burden capacity greater
than 3 VA.
The CT primary rating is normally selected to be equal to the
current rating of the power feed protection device. However,
if the peak anticipated load is much less than the rated system capacity, you can improve accuracy and resolution by
selecting a lower rated CT. In this case, the CT size should
be the maximum expected peak current +25% rounded up
to the nearest standard CT size.
Other factors may affect CT accuracy. The length of the CT
cabling should be minimized because long cabling contributes to inaccuracy. Also, the CT burden rating must exceed
the combined burden of the 4720 power meter plus cabling
plus any other connected devices. The burden is the amount
of load being fed by the CT measured in Volt-Amps. The
4720 power meter burden rating is given in Appendix A.
CT circuits that include a shorting block or test block to
facilitate the safe connection and disconnection of the CTs
are desirable.
Overall accuracy is dependent on the combined accuracies
of the 4720 power meter, the CTs, and the VTs (if used).
2.5.5
VT and CT Connections
Figure 2.2 to Figure 2.8 illustrate all required phase voltage
and phase current connections for various circuit configurations to ensure correct installation. Phasing and polarity of
the AC current and voltage inputs and their relationship is
critical to the correct operation of the unit.
All phase voltage sense leads should have overcurrent protection at their source. In cases where VTs are required, the
secondaries should be fused.
8
Siemens Energy & Automation, Inc.
2 Installation
2.5.6
Voltage Reference Connection
The voltage reference terminal (VREF) of the 4720 power
meter serves as the zero voltage reference for voltage readings. A good, low impedance VREF connection is essential
for accurate measurement. It should be made using a dedicated 14 AWG wire to a point where there will be no voltage
error due to distribution voltage drops.
The connection point for VREF is dependent on the system
configuration. Each of the following configurations is illustrated in Figure 2.2 through Figure 2.8:
•
If the system being monitored is 4-wire wye or single
phase, VREF must be connected to the neutral conductor
•
If the system is 3-wire grounded (delta), VREF must be
connected to the line transformer neutral
•
For 3-wire ungrounded (open delta) systems, and for
systems where VTs are being used, VREF must be connected to the VT common leads
2.5.7
The secondary rating of the CT connected to the I4 input
must be identical to that of the three phase current inputs.
This rating depends on the current input option installed in
the 4720 power meter.
Waveform Capture Connections
The 4720 power meter waveform capture feature allows
signals at each of its voltage inputs (V1, V2, V3, VAux) and
current inputs (I1, I2, I3, I4) to be digitally sampled. The 4720
power meter uses the V1 input as the triggering reference for
waveform capture, and to maintain phase relationships
between all sampled signals. The V1 input must be
connected for waveform capture to work. No other special
wiring considerations are necessary. The operation of the
waveform capture feature is described in detail in Chapter 9,
Using Waveforms.
The primary rating for the CT connected to the I4 input can
be different than for the three phase inputs, since the I4 input
scaling can be programmed independently.
Siemens Energy & Automation, Inc.
9
2 Installation
2.5.8
Three-Phase WYE (Star) Connection
Figure 2.2 through Figure 2.5 provide wiring diagrams for
4- and 3-wire wye system configurations.
For a 4-wire wye system, the 4720 power meter senses the
line-to-neutral (or ground) voltage of each phase and current
of each phase, making for an equivalent three-element
metering configuration.
If the power system to be monitored is a 120 VAC line-toneutral/208 VAC line-to-line system, the basic model with
120 VAC inputs can be used with direct sensing of each
phase, without the need for VTs. If the system is a 277 VAC
line-to-neutral/480 VAC line-to-line or 347 VAC line-to-neutral/600 VAC line-to-line system, models with the 277 or 347
input options (respectively) may be connected directly (using
fuses).
The wiring diagram for these voltage ranges is shown in Figure 2.2 below. VOLTS MODE should be set to 4W-WYE as
explained in Chapter 6, Programming.
Line
A
B
C
N
Supply Power
2A Fuses
VREF
N/-
V3
L/+
V2
V1
Chassis
Ground
Lug
Export
RS-232C RS-485 G
Control Relays
Import
Voltage Inputs
Power
SIEMENS
4720 Power Meter
Switchgear
Chassis
Ground
Auxiliary Current Inputs
Status Inputs
CT Shorting Switch
or Test Block
I11
I12
I21
I22
I31
I32
I41
I42
Neutral Current Input is Optional
CTs
Switchgear Chassis
Ground
Load
Volts mode is four wire wye. VOLTSMODE: WYE<4W>
Supported Models:
≤120VAC Line-to-Neutral/208VAC Line-to-Line Systems: Basic Model
≤277VAC Line-to-Neutral/480VAC Line-to-Line Systems: 277 Option
≤347VAC Line-to-Neutral/600VAC Line-to-Line Systems: 347 Option
Figure 2.2 Four-Wire Wye, Three-Element Direct Connection
10
Siemens Energy & Automation, Inc.
2 Installation
For wye system voltages over 347 VAC line-to-neutral/600
VAC line-to-line, VTs must be used. When VTs are used, both
the VT primary and secondary must be wired in a wye (star).
Voltage sense leads should have overcurrent protection at
their source. Wiring must be exactly as shown for correct
operation.
This configuration is shown in Figure 2.3 below. VOLTS
MODE should be set to 4W-WYE as explained in Chapter 6,
Programming.
Line
A
B
C
N
VREF
Fuses
VTs
2A Fuses
V3
Supply Power
N/-
V2
L/+
V1
Chassis
Ground
Lug
Export
RS-232C RS-485 G
Control Relays
Import
Voltage Inputs
Power
SIEMENS
4720 Power Meter
Switchgear
Chassis
Ground
Auxiliary Current Inputs
Status Inputs
CT Shorting Switch
or Test Block
I11
I12
I21
I22
I31
I32
I41
I42
Neutral Current Input is Optional
CTs
Switchgear Chassis
Ground
Load
Volts mode is four wire wye. VOLTSMODE: WYE<4W>
Supported Models:
≤120VAC Line-to-Neutral/208VAC Line-to-Line Systems: Basic Model
Figure 2.3 Four-Wire Wye, Three-Element Connection Using Three Voltage Transformers
Siemens Energy & Automation, Inc.
11
2 Installation
The 4720 power meter also supports a 2½-element
connection scheme which requires only two VTs. In this
mode, the phase B voltage displayed on the front panel is
derived from the available voltages.
Note:
VOLTS MODE = 3W-WYE only provides
accurate power measurement if the voltages are balanced. If the phase B voltage
is not equal to the phase A and C voltages, the power readings may not meet
the 4720 power meter accuracy specifications.
This configuration is shown in Figure 2.4. VOLTS MODE
should be set to 3W-WYE as explained in Chapter 6,
Programming.
Line
A
B
C
N
Supply Power
VREF
Fuses
VTs
2A Fuses
N/-
V3
L/+
V2
V1
Chassis
Ground
Lug
Export
RS-232C RS-485 G
Control Relays
Import
Voltage Inputs
Power
SIEMENS
4720 Power Meter
Switchgear
Chassis
Ground
Auxiliary Current Inputs
Status Inputs
CT Shorting Switch
or Test Block
I11
I12
I21
I22
I31
I32
I41
I42
Neutral Current Input is Optional
CTs
Switchgear Chassis
Ground
Load
Volts mode is three wire wye. VOLTSMODE: WYE<3W>
Supported Models:
≤120VAC Line-to-Neutral/208VAC Line-to-Line Systems: Basic Model
Figure 2.4 Four-Wire Wye, 2½-Element Connection Using Two Voltage Transformers
12
Siemens Energy & Automation, Inc.
2 Installation
When the common or star point of a 3-wire wye system is
grounded, the 4720 power meter may be connected directly
without the use of VTs (provided the voltages are within the
input range of the unit).
This configuration is shown in Figure 2.5. The VOLTS MODE
should be set to 4W-WYE as explained in Chapter 6,
Programming.
Line
N
A
B
Supply Power
C
VREF
2A Fuses
N/-
V3
L/+
V2
V1
Chassis
Ground
Lug
Export
RS-232C RS-485 G
Control Relays
Import
Voltage Inputs
Power
SIEMENS
4720 Power Meter
Switchgear
Chassis
Ground
Auxiliary Current Inputs
Status Inputs
CT Shorting Switch
or Test Block
I11
I12
I21
I22
I31
I32
I41
CTs
I42
Neutral Current Input is Optional
Switchgear Chassis
Ground
Load
Volts mode is four wire wye. VOLTSMODE: WYE<4W>
Supported Models:
≤120VAC Line-to-Neutral/208VAC Line-to-Line Systems: Basic Model
≤277VAC Line-to-Neutral/480VAC Line-to-Line Systems: 277 Option
≤347VAC Line-to-Neutral/600VAC Line-to-Line Systems: 347 Option
Figure 2.5 Three-Wire Wye, Three-Element Direct Connection
Siemens Energy & Automation, Inc.
13
2 Installation
2.5.9
Three-Phase Delta Connection
For ungrounded (floating) 3-wire delta systems, the 4720
power meter always requires VTs and senses the line-to-line
voltages between each of the phases.
The 4720 power meter may be connected in either of two
ways: using two or three CTs. Figure 2.6 below shows
ungrounded delta connection using three CTs. VOLTS MODE
should be set to DELTA as explained in Chapter 6, Programming.
Optional VT Polarity
Line
A
B
C
Supply Power
VREF
Fuses
VTs
2A Fuses
N/-
V3
L/+
V2
V1
Chassis
Ground
Lug
Export
RS-232C RS-485 G
Control Relays
Import
Voltage Inputs
Power
SIEMENS
4720 Power Meter
Switchgear
Chassis
Ground
Auxiliary Current Inputs
Status Inputs
CT Shorting Switch
or Test Block
I11
I12
I21
I22
I31
I32
I42
I41
CTs
Load
Switchgear Chassis
Ground
Switchgear Chassis
Ground
Volts mode is delta. VOLTSMODE: DELTA
Supported Models:
≤120VAC Line-to-Neutral/208VAC Line-to-Line Systems: Basic Model
Figure 2.6 Three-Wire Delta, 2½-Element Connection Using Two Voltage Transformers and Three Current Transformers
14
Siemens Energy & Automation, Inc.
2 Installation
Figure 2.7 below shows ungrounded delta connection using
two CTs. The VOLTS MODE parameter should be set to
DELTA as explained in Chapter 6, Programming.
Optional VT Polarity
Line
A
B
C
Supply Power
VREF
Fuses
VTs
2A Fuses
N/-
V3
L/+
V2
V1
Chassis
Ground
Lug
Export
RS-232C RS-485 G
Control Relays
Import
Voltage Inputs
Power
SIEMENS
4720 Power Meter
Switchgear
Chassis
Ground
Auxiliary Current Inputs
Status Inputs
CT Shorting Switch
or Test Block
I11
I12
I21
I22
I31
I32
I42
I41
CTs
Load
Switchgear Chassis
Ground
Switchgear Chassis
Ground
Volts mode is delta. VOLTSMODE: DELTA
Supported Models:
≤120VAC Line-to-Neutral/208VAC Line-to-Line Systems: Basic Model
Figure 2.7 Three-Wire Delta, Two-Element Connection Using Two Voltage Transformers and Two Current Transformers
Siemens Energy & Automation, Inc.
15
2 Installation
2.5.10 Single-Phase Connection
Wiring for single-phase systems is performed by connecting
the two voltage phases (each 180 degrees with respect to
the other) to the V1 and V2 inputs of the 4720 power meter,
and the outputs of the two corresponding current transformers to the I1 input pair and I2 input pair.
For single phase systems, the VOLTS MODE of the 4720
power meter should be set to SINGLE as explained in Chapter 6, Programming.
This is illustrated in Figure 2.8 below. Note that the V3 input
and I3 input pairs are unused and should all be grounded.
Line
A
B
N
Supply Power
VREF
N/-
V3
2A Fuses
L/+
V2
V1
Chassis
Ground
Lug
Switchgear
Chassis
Ground
Import
Control Relays
RS-232C RS-485 G
Export
Voltage Inputs
Power
SIEMENS
4720 Power Meter
Switchgear
Chassis
Ground
Auxiliary Current Inputs
Status Inputs
CT Shorting Switch
or Test Block
I11
I32
I12
I31
I21
I22
I41
I42
Switchgear
Chassis
Ground
Neutral Current Input is Optional
CTs
Switchgear Chassis
Ground
Load
Volts mode is sngle phase. VOLTSMODE: SINGLE
Supported Models:
≤120VAC Line-to-Neutral/208VAC Line-to-Line Systems: Basic Model
≤277VAC Line-to-Neutral/480VAC Line-to-Line Systems: 277 Option
≤347VAC Line-to-Neutral/600VAC Line-to-Line Systems: 347 Option
Figure 2.8 Three-Wire Single Phase, Two-Element Direct Connection
16
Siemens Energy & Automation, Inc.
3 Communications Wiring
3 Communications Wiring
To re-install the card:
The 4720 power meter is equipped with a communications
card. The card is field configurable to allow the 4720 power
meter to communicate using either the EIA/TIA-232 (RS-232)
or EIA/TIA-485 (RS-485) standard. Optical coupling provides
full isolation between the RS-232 or RS-485 communication
lines and the metering equipment. Protection circuitry provides protection from common mode voltages and incorrect
connection. All inputs pass the ANSI/IEEE C37.90A-1989
surge withstand and fast transient tests.
1.
Make sure that the power to the 4720 power meter is
off.
2.
Insert the communications card into the 4720 power
meter, ensuring that the circuit card is oriented such that
it will mate properly with the edge connector on the
main board inside the 4720 power meter.
Note: The card is polarized (keyed) to ensure it
may only be installed in the correct orientation.
Refer to Chapter 11 for information regarding communication setup parameters.
The communications card is shipped with a label affixed to
the mounting plate indicating the communications mode
(RS-485 or RS-232) set at the factory. If the mode is incorrect for your application, refer to the following section for
changing the configuration.
3.
Align the holes in the mounting plate of the card with the
mounting holes in the rear cover of the main chassis
while lowering the card toward its seating. A correct
alignment will allow the card edge to mate with the edge
connector inside the main chassis.
3.1 Configuring the Communications Card
4.
Once the board is resting in proper alignment on the
edge connector, carefully press down to plug the card
into the edge connector.
5.
Install the four mounting screws into the mounting plate
to secure the card.
This section describes how to change the communications
mode of the 4720 communications card. You can select
RS-232 or RS-485 lines by switching a jumper block on the
card. The currently selected communications mode may be
viewed from the power meter front panel, or by removing the
card and examining the position of the jumper block. (See
section 6.2 for instructions on how to use the power meter
front panel to display the communications mode.)
The card is now ready for use.
To remove the card for configuration:
1.
Turn off the power to the 4720 power meter.
2.
Remove the four machine screws holding the rectangular communications card mounting plate to the 4720
power meter case back cover.
3.
Carefully pull the plate away from the main chassis to
remove the card.
J1
RS232
RS485
To configure the card:
The circuit board of the communications card has a jumper
labelled J1. This jumper has two positions, labelled “RS485”
and “RS232,” which determine the communications mode.
Figure 3.1 illustrates the jumper position required for RS485 or RS-232 mode. Move the jumper to the correct position.
Jumper in RS-232 Position
Jumper in RS-485 Position
Figure 3.1 Communications Card Jumper Configuration
Siemens Energy & Automation, Inc.
17
3 Communications Wiring
3.2 Terminal and LED Functions
3.3 RS-232 Connections
The communications card provides a barrier-style terminal
strip as shown in Figure 3.2. Terminal functions include:
Figure 3.3 illustrates the wiring requirements for connection
of the 4720 power meter using RS-232 communication. This
can include a local direct connection to a computer or other
device, or a remote connection via modem.
Ground
GND
Chassis Ground
RS-485
SHLD
RS-485 Shield
(electrically connected to chassis
ground)
-
RS-485 Data Minus
+
RS-485 Data Plus
RXD
RS-232 Receive Data
(that is, receive data into device)
TXD
RS-232 Transmit Data
(that is, transmit data out of device)
SG
RS-232 Signal Ground
(isolated)
RTS
RS-232 Request To Send
(optional, see Chapter 11)
RS-232
Two LED indicators, TXD and RXD, show activity on the RS485 or RS-232 communication lines and can be used to verify correct communications operation. The TXD indicator
flashes when data is being sent out by the device. The RXD
indicator flashes when data is being received by the device.
Note:
For information on remote connections via
modem (telephone, fiber optic, radio, and
so on), contact Siemens for a detailed
application note.
The RS-232 standard allows only a single point-to-point
communication connection. Using this method, only one
RS-232 equipped device may be connected to the serial
port of the computer, modem, or other device.
The cable used between the computer and the modem (if
used) is a standard RS-232 communications cable with a
maximum length of 50 feet (15.2 meters). Refer to the installation manuals for each device for cable requirements.
The cable used between the computer or modem and the
4720 power meter is a custom RS-232 cable. One end is
equipped with a DB-25 or DB-9 plug (male) or socket
(female) connector. The connector required depends on the
mating computer or modem serial port connector. The other
end of the cable consists of discrete wires which connect to
the RS-232 terminals of the communications card of the
4720 power meter. Cable length is 50 feet (15.2 meters)
maximum.
4720 Power Meter
TXD
RXD
TX SG RX
GND
+
RS-485
SHLD
RXD
RS-232 (50 ft. maximum)
Personal Computer (DTE)
Computer
4720
Power Meter
TX
RX
Ground
RTS
CTS
DSR
DTR
RX
TX
SG
SG
RS-232-C
TXD
RTS
SIEMENS
ISOCOM
4720
Figure 3.2 Communications Card Terminal Block
18
Figure 3.3 RS-232 Communications Connections
Siemens Energy & Automation, Inc.
3 Communications Wiring
1
2
3
4
1 2 3 4 5 6 7 8 9 10 11 12 13
5
DB-25
DB-9
6
7
8
14 15 16 17 18 19 20 21 22 23 24 25
9
(Seen From Computer)
Pin
Computer (DTE)
1
2
3
4
5
6
7
8
9
RLSD
RX
TX
DTR
Ground
DSR
RTS
CTS
RI
(Seen From Computer)
Pin
Computer (DTE)
Isolated Multi-Drop
Converter
1
2
3
4
5
6
7
8
20
22
Ground
TX
RX
RTS
CTS
DSR
Ground
RLSD
DTR
RI
Ground
RX
TX
RTS
CTS
DSR
Ground
RLSD
DTR
RI
Figure 3.4 RS-232 Cable Wiring Specifications
Figure 3.3 and Figure 3.4 illustrate the RS-232 cable configurations and wiring connections.
If connected directly to a computer’s RS-232 port, the TXD
and RXD leads may need to be reversed at the remote
device, depending on whether the PC RS-232 port is configured as DCE or DTE.
Refer to Chapter 11 for information regarding the use of the
RTS line of the 4720 power meter.
3.4 RS-485 Connections
RS-485 communications allow multiple devices to be connected on the same bus (see Figure 3.5). Up to 32 devices
can be connected on a single RS-485 bus which consists of
a shielded twisted pair cable. The overall length of the RS485 cable connecting all devices cannot exceed 4000 feet
(1219 meters).
To connect an RS-485 communications bus to a computer
or other RS-232 equipped device, an RS-232 to RS-485
converter is required, such as the Siemens Isolated MultiDrop™ converter. The Isolated Multi-Drop converter offers
four RS-485 ports that can each support up to 32 devices.
RS-232
(50 ft. maximum)
Isolated Multi-Drop
Converter
Personal Computer (DTE)
Computer
Isolated
Multi-Drop
Converter
TX
RX
Ground
RTS
CTS
DSR
DTR
RLSD
RX
TX
Ground
RTS
CTS
DSR
DTR
RLSD
4720 Power Meter
RS-485 Cable
22 AWG shielded,
twisted pair
4000 ft. maximum
To Other
Devices
Figure 3.5 RS-485 Communications Connections
Siemens Energy & Automation, Inc.
19
3 Communications Wiring
Devices connected on the bus, including the 4720 power
meter converter(s), and other instrumentation, must be wired
as follows:
1.
Use a good quality shielded twisted pair cable for each
RS-485 bus. It is recommended that 22 AWG (0.6 mm)
or larger conductor size be used.
2.
Ensure that the polarity is correct when connecting to
the RS-485 port (+) and (-) terminals of each device.
3.
The shield of each segment of the RS-485 cable must
be connected to ground at one end only.
Note: Do not connect ground to the shield at both
ends of a segment. Doing so allows ground
loop currents to flow in the shield, inducing
noise in the communications cable.
4.
5.
It is recommended that an intermediate terminal strip be
used to connect each device to the bus. This allows the
easy removal of a device for servicing if necessary.
Cables should be isolated as much as possible from
sources of electrical noise.
Devices on an RS-485 bus are connected in a point-to-point
configuration with the (+) and (-) terminals of each device
connected to the associated terminals on the next device.
3.4.1
Topologies
While there are many topologies that can be used to connect
devices on an RS-485 communications bus, the two
recommended methods are the straight-line and the loop
topologies.
Straight-Line Topology
The straight-line wiring method is illustrated in Figure 3.5.
Note that connections are shown for one RS-485 port only.
The Isolated Multi-Drop converter supports four RS-485
buses simultaneously. The Isolated Multi-Drop converter can
exist at any position on the RS-485 bus, including an end
point.
Each end point of the straight-line bus must be terminated
with a 1/4 W resistor. These termination resistors reduce
signal reflections that may corrupt data on the bus.
Termination resistors are connected between the (+) and (-)
terminals of the device at each end of the bus. This device
can include either a converter or any other instrument. The
value of the resistor should match the line impedance of the
cable being used. For 22 AWG shielded twisted pair cable,
values between 150 and 300 are typical. Consult the cable
manufacturer’s documentation for the exact impedance of
your cable.
Loop Topology
The Isolated Multi-Drop converter can exist at any position
on the RS-485 bus when using a loop topology. The loop
topology does not require termination resistors at any point
on the bus.
One advantage of the loop topology is that a single open circuit fault condition anywhere on the loop will not result in the
loss of communication between the computer station and
any of the remote devices.
3.4.2
Calculating Overall Cable Length
When determining the overall length of an RS-485 communication straight-line or loop connection, it is important to
account for all cable segments. For example, when RS-485
connections to the device are made via an intermediate terminal block, the length of the cable between the device and
the terminal block must be added to the total cable distance.
Refer to the ACCESS Installation System (Manual No. SG6028-01) for detailed information on calculating the cable
length.
20
Siemens Energy & Automation, Inc.
4 Optional Wiring
4 Optional Wiring
4.1 Control Relay Connections
This section describes the wiring connection requirements
and applications of the 4720 power meter control relays.
Section 6.6 in Chapter 6 describes the operation of the
relays.
N
LOAD
Normally ON
120 VAC
10A FUSE
LOAD
N
Normally OFF
The basic 4720 power meter provides three Form C electromechanical control relays. Figure 4.1 illustrates the wiring
connection requirements for these relays. These relays are
rated for 277 VAC or 30 VDC at 10 A resistive load.
4.1.1
Relay Control
Enable/Disable
(shown enabled)
Relay Application Precautions
In applications where the relays are used to perform critical
equipment control operations (for example, breaker trip), the
important precautions described below should be followed.
2.
Connection to the external equipment should be made
via an intermediate mechanism such as a local/remote
switch allowing relay control to be completely disabled
for commissioning and servicing (see Figure 4.1).
Following initial power up, the 4720 power meter should
be programmed (see Chapter 6), including all required
setpoints for setpoint controlled relay operations (see
Chapter 8).
Control Relays
Voltage Inputs
Power
SIEMENS
RS-232C RS-485 G
1.
4720 Power Meter
Auxiliary Current Inputs
Status Inputs
4720 Power Meter
3.
4.
The relay outputs of the 4720 power meter should be
tested to ensure that setpoint or manual control condition(s) are occurring as expected.
Operational Block
Diagram
RX1
Once correct relay operation has been verified, relay
control of the external equipment can be enabled.
RX2
N/O
State:
Inactive
Active
Pulse
RX3
N/C
Rx1/Rx2
Open
Closed
Closed for
Duration of
Pulse
Rx2/Rx3
Closed
Open
Open for
Duration of
Pulse
Notes:
1. Relays are Form C dry contact rated at
277 VAC or 24 VDC at 10 Amps.
2. Only relevant 4720 power meter terminal
block connections are illustrated.
Figure 4.1 Control Relay Connections
Siemens Energy & Automation, Inc.
21
4 Optional Wiring
Primary Protection
An open contact registers as inactive; a closed contact registers as active.
The relays of the 4720 power meter should not be used for
primary protection functions. These include applications
where the device would be providing:
Overcurrent protection on circuit breakers.
•
Protection of people from injury. If failure of the device
can cause injury or death, the 4720 power meter should
not be used.
•
Control Relays
RS-232C RS-485 G
•
Energy limiting. If failure of the device will cause sufficient
energy to be released that a fire is likely, the 4720 power
meter should not be used. In electrical systems, energy
limiting is normally provided by circuit breakers or fuses.
Voltage Inputs
Power
SIEMENS
4720 Power Meter
Auxiliary Current Inputs
Status Inputs
Secondary Protection
The 4720 power meter can be used for secondary (that is,
backup) protection functions. Secondary protection includes:
1
2
•
•
Situations where the 4720 power meter is backing up a
primary protection device (shadow protection), such as
an overcurrent relay.
Situations where the 4720 power meter is protecting
equipment, not people. This typically includes applications such as over/under voltage, reverse power flow,
and so on.
3
4
External Dry Contacts
Contacts Open = Inactive
Contacts Closed = Active
4.2 Status Input Connections
4720 Power Meter
This section illustrates wiring connection methods and applications for the status inputs. Section 6.7 in Chapter 6
describes the operation of the status inputs.
Optically Coupled
Solid State Relays R
The 4720 power meter uses a current sensing technique to
monitor the status of an external dry contact. The 4720
power meter provides an internal 30 VDC supply for selfexcitation of the status inputs (see Figure 4.2). These can be
used for dry contact sensing applications, but not for voltage
sensing applications. Note that no ground or external voltage
connections are required.
R
R
R
+
Status Inputs
S1
S2
S3
S4
30 V
Internal
Supply
SCOM
Figure 4.2 Status Input Connections
Note: The 4720 power meter status inputs can
only be used for dry contact sensing applications. Connection of an external voltage
source to any of the status inputs of a
standard equipped 4720 power meter can
cause permanent damage to the 4720
power meter.
22
Siemens Energy & Automation, Inc.
4 Optional Wiring
4.3 Auxiliary Voltage Input
4.4 Auxiliary Current Output
Figure 4.3 illustrates several possible wiring connection
methods and applications for the VAux input. Section 6.8 in
Chapter 6 describes the operation of this input.
Figure 4.4 illustrates several possible wiring connection
methods and applications for the IOut output. Section 6.9
in Chapter 6 describes the operation of this output.
Note: VAux is a non-isolated input. If full isolation is
required, use an intermediate isolation
transducer.
Note: IOut is a non-isolated output. If full isolation
is required, use an intermediate isolation
transducer.
VAux Application: Temperature Sensing
Voltage Inputs
Power
Control Relays
SIEMENS
RS-232C RS-485 G
RS-232C RS-485 G
Control Relays
4720 Power Meter
Auxiliary Current Inputs
Temperature
Probe
IOut Application: Chart Recorder or RTU Input
Status Inputs
Voltage Inputs
Auxiliary Current Inputs
+
-
Temperature
Transducer
Power
SIEMENS
4720 Power Meter
Status Inputs
Chart Recorder
or
RTU Input
0–20 mA
or
4–20 mA
Input
Note:
250Ω maximum load
VAux Application: Battery Voltage Sensing
Voltage Inputs
IOut Application: Analog Meter
Power
SIEMENS
4720 Power Meter
Control Relays
Auxiliary Current Inputs
RS-232C RS-485 G
RS-232C RS-485 G
Control Relays
Status Inputs
Voltage Inputs
Power
SIEMENS
4720 Power Meter
Auxiliary Current Inputs
Status Inputs
+
2.3 kΩ
1W
Note:
Resistors selected to
give nominal 1V.
24 VDC
Generator
Start
Battery
100 Ω
1W
-
Figure 4.3 Auxiliary Voltage Input Connections
Siemens Energy & Automation, Inc.
0-20 mA
DC Meter
Figure 4.4 Auxiliary Current Output Connections
23
4 Optional Wiring
24
Siemens Energy & Automation, Inc.
5 Operator Interface
5 Operator Interface
5.2 Front Panel Operation
This chapter describes the following:
The 4720 power meter provides a unique and very flexible
user interface. One of its front panel features is the large,
high-visibility, 20-character vacuum fluorescent display. The
other feature is the row of four long-life, stainless steel membrane buttons for parameter selection and local programming functions. See Figure 5.2 for an illustration of the front
panel of the 4720 power meter.
•
Power-up procedure
•
Front panel operation
For a description of the 4720 power meter display mode and
a complete list of the meter’s measured parameters and status information available, refer to Chapter 7, Displaying
Information. Refer to Chapter 6, Programming, for a
description of programming mode and instructions on how
to program the meter.
Chapter 8 through Chapter 10 describe the setup and
operation of the advanced features of the 4720 power meter
including setpoint, waveform, and logging functions. Remote
communications setup and operation are described in
Chapter 11.
5.1 Start Up
After all installation wiring is complete and has been double
checked, the unit may be powered up by applying the
appropriate voltage to the power input terminals.
The 4720 power meter first enters its display mode, presenting Volts-Phase-Amps-Power Function. The power function
displayed on power up is kW average, totalled for all phases
(see Figure 5.1). The values initially appearing may not be
correct, since the unit has not been properly programmed
with the correct information. Refer to Chapter 6, Programming, for instructions on how to program the meter.
Power Functions
The display can present a wide variety of information in many
different formats. The user can customize the display by
defining which measured parameters can be accessed and
in what format they are displayed. The 4720 power meter
front panel can display readings of up to nine digits including
any floating point decimals. The type of information and formats that can be displayed are described below.
5.2.1
The front panel display (on power up) presents volts, amps
and power functions for the selected phase. The Phase button is used to advance through each phase in sequence,
while a selection of power functions can be accessed using
the Function button. The format of the phase labels and
numeric readings can be programmed to conform to international conventions (see section 6.4).
5.2.2
RMS
Phase
Amps
Full Width Display
Very large measured values (for example, kW hr) and parameters with large display labels are presented using the entire
display.
Note: While viewing a full-width display, press the
Phase button to return to the standard
Volts-Phase-Amps display.
5.2.3
Volts
Standard Phase Display
Three-Phase Displays
RMS
Standard Phase Display
Indicates 260 Volts, 1700 Amps, and 1241 kW for Phase A .
Concurrent display of readings for all three-phase voltages or
currents is possible. The Menu buttons can be programmed
to access these displays (see section 5.2.9).
5.2.4
Full Width Display
Indicates 29.4 MW for phase A, thermal demand, maximum.
Three Phase Display
Indicates 483 Volts, phase A, 485 Volts, phase B, and 479 Volts,
phase C.
Status Information
Status information includes the present condition of the three
relays, four digital (status) inputs, and seventeen setpoints.
The Menu buttons can be programmed to access all status
information (see section 5.2.9). For example, the two possible conditions of a setpoint-controlled relay could be displayed as “breaker normal” and “overcurrent trip.” Display
labels for relay and status input conditions are user-definable
via communications. Device programming is described in
Chapter 6.
Figure 5.3 lists the display labels used by the 4720 power
meter to identify various measurement modes and status
information. These labels are further described in Chapter 7.
A
B
Status Information (Two Examples)
"A" indicates that breaker 32 is open. (user defined display)
"B" indicates setpoint 5 has been activated.
Figure 5.1 Front Panel Display Modes
Siemens Energy & Automation, Inc.
25
5 Operator Interface
Phase indicator. Comma
indicates line-to-line values.
Four-digit Amps display
Five-digit plus three-character
power display
Four-digit Volts display
Display mode
button functions
Programming mode
button functions
Press and hold Menu1 and Menu2
to toggle between Programming and
Display modes.
Figure 5.2 4720 Front Panel Buttons
5.2.5
Parameter Formats
Special parameter name formats are used on the front panel
of the 4720 power meter. These labels are also used to identify parameter types selected by the user in programming
mode.
Most measured parameter readings are displayed in integer
format. The use of floating decimal points depends on the
parameter type. Harmonic distortion readings are displayed
with one decimal place. Frequency readings are presented
with two decimal places. Status Input Counter totals can be
displayed with between 0 and 3 decimal places depending
on the user-definable parameter setting (see section 6.4).
5.2.6
Timeout Feature
The life and brightness of the 4720 power meter vacuum fluorescent display can be significantly extended by reducing
the “on” time. The 4720 power meter provides a DISPLAY
TIMEOUT parameter that can be used to set a timeout interval of 1 to 999 minutes, after which the display automatically
switches to display saver mode. This interval starts counting
down from the last button press made on the front panel. A
timeout interval of 180 minutes (3 hours) or less is recommended. Setting the parameter to zero causes the display to
stay on indefinitely. While the display is in display saver
mode, pressing any button on the front panel turns on the
normal display again. Device programming is described in
Chapter 6.
26
5.2.7
Phase Button
The 4720 power meter uses four long-life, stainless steel
membrane buttons. The label above each button names a
Display Mode operation while the label below the button
refers to a Programming Mode operation (see Figure 5.2).
The buttons are used for parameter selection and local programming functions.
If you are viewing the standard display, the Phase button
advances through each phase. The sequence of phase readings depends on the device setup, including the volts mode
and phase rotation selected (device setup is described in
Chapter 6). The Phase field of the front panel display indicates the phase for which readings are being displayed.
Phase indicators displayed without a comma indicate line-toneutral values are being displayed for the indicated phase.
Phase indicators displayed with a comma indicate line-to-line
values are being displayed for the indicated phase. An asterisk (*) symbol indicates that the average for all line-to-neutral
or line-to-line phases is being displayed.
Siemens Energy & Automation, Inc.
5 Operator Interface
The following phases of readings are available in each mode:
Real Time
VOLTS MODE = 4W-WYE, 3W-WYE, or DEMO
For each of these modes, the Phase button advances
through:
Total Harmonic Distortion
•
line-to-neutral average of the three phases
•
line-to-neutral values for each phase
•
line-to-line average of the three phases
Individual Harmonic Distortion (3rd)
•
line-to-line values for each phase
Thermal Demand
VOLTS MODE = DELTA
The Phase button advances through:
Sliding Window Demand
•
line-to-line average of the three phases
Predicted Sliding Window Demand
•
line-to-line values for each phase
Minimum
VOLTS MODE = SINGLE
The Phase button advances through:
Total Even Harmonic Distortion
Total Odd Harmonic Distortion
Maximum
Imported Energy
Exported Energy
Net Energy
Total Energy
•
line-to-neutral average of the two phases
•
line-to-neutral values for each phase and the line-to-line
value
The Phase button also advances the display through each
relay (R1 to R3), digital status input (S1 to S4), or setpoint
(S01 to S11, H01 to H06) when status conditions are being
displayed.
High Speed Setpoint (6)
You can make the 4720 power meter automatically cycle the
display through each phase by holding down the Phase button for more than four seconds, then releasing. The display
advances through each phase at four second intervals, displaying the volts and amps for each phase. Pressing any button returns the display to the regular non-cycling viewing
mode.
Standard Setpoint (9)
5.2.8
Time Overcurrent Curve
A preset list of useful power function parameters is available
via the Function button. Press the Function button to
advance through each measured parameter.
Relay Output (3)
Status Input (4)
High Speed Snapshot Log
Figure 5.3 4720 Display Labels for Measured Parameters
and Status Information
Siemens Energy & Automation, Inc.
Function Button
For per-phase values displayed using the Function button,
the Phase button can be used to advance the display
through each phase.
27
5 Operator Interface
The following is the complete sequence of power function
parameters accessible using the Function button:
For per-phase parameters displayed using the Menu buttons, the Phase button can be used to advance the display
through each phase. For relay, status input, and setpoint
conditions, the Phase button can be used to advance
through each relay, status input or setpoint number. The
mode function can also be used to display additional related
parameters, if applicable. This feature is described in section 5.2.10.
•
kW per phase
•
kVAR per phase
•
kVA per phase
•
Power Factor per phase
•
Current I4
•
Frequency (phase A)
•
Voltage VAux
•
Three-phase Voltage line-to-neutral (if applicable)
•
kWH Import (total for all 3 phases)
•
Three-phase Voltage line-to-line
•
kWH Export (total for all 3 phases)
•
Three-phase Current
•
kVARH Import (total for all 3 phases)
•
Voltage line-to-neutral Maximum per phase (if applicable)
•
kVARH Export (total for all 3 phases)
•
Voltage line-to-line Maximum per phase
•
kVAH Net (total for all 3 phases)
•
Current Maximum per phase
•
kW Maximum per phase
•
kVAR Maximum per phase
•
Frequency Maximum (phase A)
•
Power Factor Minimum per phase
•
Power Factor Maximum per phase
•
Frequency Minimum (phase A)
•
Voltage line-to-neutral Minimum per phase
•
Voltage line-to-line Minimum per phase
•
Relay Condition (1 to 3)
•
Status Input Condition (1 to 4)
A full description of each parameter is provided in Chapter
7, Displaying Information.
You can make the 4720 power meter automatically cycle the
display through each power function on the front panel display. The power functions displayed are the group of parameters normally displayed using the Function button (kW,
kVAR, and so on). To start the cycling mode, hold down the
Function button for more than four seconds, then release.
The display will advance through each power function at four
second intervals. Pressing any button will return the display
to the regular non-cycling viewing mode.
5.2.9
Menu 1:
Menu Buttons
You can use the Menu 1 and Menu 2 buttons to display additional groups of measurements and status information. The
parameters accessible using each Menu button are userdefinable. Up to 18 parameters may be assigned to each
button. Similar to the Function button, each press of a Menu
button will advance the display through the list of items
assigned to that button.
The Menu buttons are ideal for creating convenient custom
groupings of important parameters for quick viewing. For
example, the user might wish to assign the third and fifth harmonic distortion values for each input to the Menu 1 button
and relay status information to the Menu 2 button. Any of the
measured and status parameters can be assigned to either
Menu button. Programming the Menu buttons must be performed via communications and WinPM software.
28
The following default parameters have been assigned to
each Menu button.
Menu 2:
•
Voltage THD (total harmonic distortion) per phase
•
Current THD per phase
•
Voltage THD Maximum per phase
•
Current THD Maximum per phase
•
Current 3rd HD (harmonic distortion) per phase
•
Current 5th HD per phase
•
Current 7th HD per phase
Siemens Energy & Automation, Inc.
5 Operator Interface
•
Current Sliding Window Demand Maximum average of
all phases
•
kW Sliding Window Demand Maximum total of all
phases
•
•
kVAR Sliding Window Demand Maximum total of all
phases
kVA Sliding Window Demand Maximum total of all
phases
The mode function can also be used to advance through all
bi-directional modes of an energy parameter. This can
include import, export, net, and total measurements.
The mode function is accessed using a special button combination on the front panel:
1.
Press the Function button and the Menu button that
includes the desired parameter at the same time.
2.
Repeat pressing the Function and the Menu button
simultaneously to scroll through the available modes.
A full description of each parameter is provided in Chapter
7, Displaying Information.
Note: If a particular parameter accessed using a
Menu button has not been programmed to
provide additional modes, the mode function has no effect.
5.2.10 Mode Function
As an added convenience feature, a special mode function
has been provided for use with parameters assigned to the
Menu 1 or Menu 2 button. The mode function is enabled
after the Menu buttons have been programmed (see section
5.2.9).
3.
To return the front panel buttons back to normal operation, press the Menu button only.
The mode function provides quick access to additional measurement modes for the parameter currently being displayed,
if applicable. For power and harmonic distortion parameters,
this can include demand and minimum/maximum values. For
example, if the front panel display is presenting a kW measurement, the mode function can be used to advance the
display through kW Min, kW Max, kW Thermal Demand, kW
Thermal Demand Min, and kW Thermal Demand Max. The
sequence of parameters displayed is definable by the user
via communications.
Siemens Energy & Automation, Inc.
29
5 Operator Interface
30
Siemens Energy & Automation, Inc.
6 Programming
6 Programming
6.1.1
Basic device programming can be performed quickly and
easily from the front panel (called local programming) or via
the communications port using a portable or remotely
located computer. Basic setup parameters include scaling
factors for the voltage and current inputs, voltage mode
(wye, delta, and so on), and communications settings.
In programming mode, the buttons of the front panel take on
new programming functions. The label below each button
indicates its alternate function.
The customization of the front panel display and the programming of the Menu buttons are only possible via the
communications port. The same applies to advanced features such as waveform capture, waveform recording, data
logging, and setpoint and relay control functions. WinPM
software fully supports 4720 power meter programming,
providing a number of parameter screens which make setup
quick and easy. (The open communications protocol of the
4720 power meter also allows free access to all programming parameters using any compatible third-party system.)
Cursor
Moves the cursor left one digit. The cursor position
wraps around to the right of the number if advanced
past the left-most digit.
Setup and other critical information are stored in nonvolatile
memory and are not lost if power to the unit is turned off. All
programming is password protected.
A complete list of all programmable setup parameters is provided in section 6.10.
This manual describes procedures for programming the
4720 power meter from its front panel only. For information
on programming via communications using WinPM software,
refer to the documentation for WinPM.
6.1 Programming Mode
To program the setup parameters of the 4720 power meter
from the front panel, you must first enter programming
mode. To enter programming mode, press the two Menu
buttons at the same time (see Figure 6.1). When programming mode is first entered, “PROGRAMMING MODE” is displayed.
You can return to display mode at any time by again pressing
the two Menu buttons at the same time.
Programming Button Functions
Parameter Select
Selects which parameter is displayed.
Increment
Increments the digit at the cursor, advances through a
number of preset values, or toggles a yes/no option.
Decrement
Decrements the digit at the cursor, advances through a
number of preset values in reverse order, or toggles a
yes/no option.
6.1.2
Entering the Password
At shipping, the 4720 power meter password is set to zero
(0). In programming mode, press the Parameter Select button until the PASSWORD parameter appears. Enter the
password using the Cursor and Increment buttons. You must
enter the password to change any parameter values,
although you can view them on the front display panel at any
time. You can also change the password as described in the
next section. If the password is lost or forgotten, contact Siemens customer service.
6.1.3
Changing the Password
To change the password, use the following procedure:
1.
Enter programming mode by pressing and holding
simultaneously the Menu 1 and Menu 2 buttons (see
Figure 6.1).
2.
Press Parameter Select until the PASSWORD parameter
appears. Enter the present password using the Cursor
and Increment buttons.
3.
Press the Parameter Select button repeatedly until the
PASSWORD parameter appears again.
4.
Enter the new password using the Cursor and Increment buttons.
5.
Return to display mode. The new password is now in
effect.
Figure 6.1 Entering Programming Mode
Siemens Energy & Automation, Inc.
31
6 Programming
6.2 Accessing and Modifying Parameters
6.4 Display Format
To support the extensive functionality and flexibility that the
4720 power meter offers, a large number of user-programmable parameters are provided. To make local programming
as efficient as possible, the parameters accessible via the
front panel have been organized into six groups:
The 4720 power meter front panel display can present
numeric information and phase labels in a number of different
formats which reflect various world and industrial standards.
Two programmable parameters are used to define the display format:
•
Basic System Setup
•
Auxiliary Setup
•
Clear Functions
FORMAT
This parameter allows you to select formats for numeric
information. The front panel display can present measured values using either of the two following numeric
formats:
•
Communications
•
Front Panel Display
•
Diagnostics
Each parameter group has an access parameter with the
default value NO. If the setting is not changed, the parameter
group will be skipped when pressing the Parameter Select
button. With the value set to YES, the Parameter Select button advances through each parameter within that group.
Advancing past all parameters within a group returns you to
the access parameter for that group with its value set to NO.
You can then skip to the next group by pressing Parameter
Select or gain access once more to the same group by setting the parameter to YES.
The entire parameter list wraps around. If a parameter group
is missed, the Parameter Select button may be pressed
repeatedly to return to the desired group.
6.3 Defining New Parameter Values
If the correct password was entered, you can modify any
setup parameter. As discussed in section 6.1.1, the Cursor,
Increment, and Decrement buttons can be used to change
individual digits or select from a preset list of options for that
parameter value. Section 6.10 lists all programmable
parameters and their range of possible values.
If you attempt to set a parameter to a value outside of its
allowed range, the display flashes the message “INVALID
ENTRY.” The message remains on the display until any button is pressed. The parameter is shown again with its previous value.
Parameter modifications are implemented immediately when
you advance to the next parameter.
Once all parameters have been set to their desired values,
pressing the two Menu buttons at the same time returns to
display mode.
Figure 6.2 and Figure 6.3 show a step-by-step example of
how to program the operating parameters from the front
panel. The example given shows how to set the VOLTS
MODE to DELTA, the VOLTS SCALE to 277, and the AMPS
SCALE to 2000.
32
1,234.5 This is the default. A comma is used for the
thousands delimiter (radix), and a decimal point is used
for the decimal delimiter.
1234,5 No thousands delimiter is used, and a comma
is used for the decimal delimiter.
PHASE LABELS
This parameter defines the three letters used for the
phase labels. The possible choices are ABC (default),
XYZ, RYB, and RST.
6.5 Basic Settings
This section details the minimum basic programming setup
required for proper operation of the 4720 power meter.
6.5.1
Volts Scale
The setting of the VOLTS SCALE parameter depends on the
voltage of the system being monitored and whether the 4720
power meter is connected directly to the lines, or if VTs are
used.
Note: VTs are required for connection to all delta
systems. Some electrical codes may prohibit extending voltages greater than 240
VAC to the door of the switchgear cabinet.
If this is the case, use a basic model (120
VAC input) 4720 power meter with VTs that
are connected to provide 120 VAC line-toneutral input to the power meter (see section 2.5.1 in Chapter 2).
The various phase voltage input options of the 4720 power
meter support direct connection (using fuses) to wye systems up to 347 VAC line-to-neutral/600 VAC line-to-line and
single phase systems up to 347 VAC line-to-neutral/694 VAC
line-to-line without the need for VTs.
For direct connection, the VOLTS SCALE parameter of the
4720 power meter must be set to the full scale rating of its
phase voltage inputs. The basic model provides 120 VAC
voltage inputs, which allow for direct connection (using fuses)
to wye systems up to 120 VAC line-to-neutral/208 VAC lineto-line and single phase systems up to 120 VAC line-to-neutral/240 VAC line-to-line. For the basic model, VOLTS SCALE
must be set to 120.
Siemens Energy & Automation, Inc.
6 Programming
Programming the 4720 Power Meter
Display reads:
Press these buttons:
1
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Press both Menu buttons at the same time to enter programming mode.
2
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Press the Parameter Select button once.
3
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Enter the password using the Cursor and Increment buttons.
To enter the default password, 0 (zero), press the Increment button once.
4
Press Parameter Select once.
5
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Press Increment once to allow access to this parameter group.
6
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Press Parameter Select to advance to the next parameter.
7
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Press Increment until the desired parameter value appears.
8
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Press Parameter Select to advance to the next parameter.
Figure 6.2 Step-by-Step Example Showing How to Program the 4720 Power Meter (Steps 1-8)
Siemens Energy & Automation, Inc.
33
6 Programming
Programming the 4720 Power Meter (continued)
Display reads:
Press these buttons:
9
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Enter a new value (277) for the Volt Scale parameter.
Set the rightmost digit to 7 by pressing the Increment button seven times.
10
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Press the Cursor button once to move the cursor one digit left.
11
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Set the digit under the cursor to 7 by pressing the Increment button seven times.
12
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Press the Cursor button twice to move to the leftmost digit.
13
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Press Decrement once to set the leftmost digit to 0 (zero).
14
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Press Parameter Select to advance to the next parameter.
15
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Enter a new value (2000) for the Amp Scale parameter.
Press Cursor three times to move the cursor to the leftmost character .
16
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Press Decrement three times to set the leftmost digit to 2.
17
Phase
Menu 1
Menu 2
Function
Decrement
Parameter
Select
Cursor
Increment
Press both Menu buttons at the same time to return to display mode.
Figure 6.3 Step-by-Step Example Showing How to Program the 4720 Power Meter (Steps 9-17)
34
Siemens Energy & Automation, Inc.
6 Programming
Similarly, a 4720 power meter equipped with the 277 option
must be set for a VOLTS SCALE of 277, while units with the
347 option must be set to a VOLTS SCALE of 347.
For system voltages between the ratings of the input options
provided by the 4720 power meter, the next highest input
option should be used. For example, to monitor a 220 VAC
line-to-neutral/381 VAC line-to-line wye system, a 4720
power meter equipped with the 277 option should be used.
In this case, the VOLTS SCALE must still be set to 277.
VTs must be used for wye systems above 347 VAC line-toneutral/600 VAC line-to-line, single phase systems above
347 VAC line-to-neutral/694 VAC line-to-line, and for all delta
systems.
When using VTs, the volts scale set for the 4720 power
meter is dependent on the primary and secondary ratings of
the VTs used.
For VTs that provide secondaries up to 120 VAC, use a basic
model 4720 power meter (120 VAC input). If the VTs have
secondaries rated at 120 VAC, set the VOLTS SCALE to the
primary rating of the VT. For example, for a 13.8 kV system,
120:1 ratio VTs with primary ratings of 14.4 kV are typically
used. For these VTs, set the VOLTS SCALE to 14400.
If the secondaries of the VTs are not rated at 120 VAC, use
the following formula to determine the required volts scale:
VOLTS SCALE =
VT Primary Rating
VT Secondary Rating
x 120
For VTs that provide secondaries with ratings between 120
and 277 VAC, such as 220 VAC, use a 4720 power meter
equipped with the 277 option. Use the following formula to
determine the required volts scale:
VOLTS SCALE =
6.5.2
VT Primary Rating
VT Secondary Rating
x 277
Amps Scale (Phases A, B, and C)
The basic model 4720 power meter provides 5 A phase current inputs. If the CTs used are rated for a 5 A full scale output, set AMPS SCALE to the primary rating of the A, B, and
C phase CTs being used.
The 4720 power meter also offers a 1AMP option for use
with CTs with 1 A full scale output.
If the CTs are not rated for a 5 A or 1 A full scale output, contact Siemens for more information.
Note: For the above parameter settings, VOLTS
SCALE x AMPS SCALE should be less than
999,999,999 for correct display of kW,
kVAR, and kVA readings which have a maximum range of 999.999K.
Siemens Energy & Automation, Inc.
6.5.3
Fourth Current Input (I4) Scale
The 4720 power meter has a fourth current input, designated
I4. This input uses connections I41 and I42 on the terminal
strip. Typically, this input is used to measure current in the
neutral conductor. In installations with non-linear loads, odd
harmonics can fail to cancel, producing significant currents in
the neutral conductor.
The ratings of this input are identical to the three-phase current inputs (5 A for the basic model, 1 A for the 1AMP
option).
The I4 SCALE parameter of the 4720 power meter specifies
the scaling for the fourth current input. The scaling can be
set to the CT’s primary rating independent from the other
phase current inputs. The CT used should be rated for a 5 A
full scale output. For other ratings contact Siemens.
6.5.4
Volts Mode
The VOLTS MODE parameter should be set according to the
system connection configuration (4W-WYE, 3W-WYE,
DELTA, SINGLE). Refer to Chapter 2 section 2.5 and Figure 2.2 through Figure 2.8 for more information.
The 4720 power meter also offers a demonstration mode
which generates dynamic readings for all real-time measurements based on the input scales you program. These readings can be viewed from the front panel or via
communications. To use this feature, set VOLTS MODE to
DEMO.
6.5.5
Standard Frequency
The STANDARD FREQ parameter should be set according
to the frequency of the power signal the 4720 power meter is
to be monitoring. Options include 50 or 60 Hz.
It is important that this parameter is set correctly, as the
accuracy of the power measurements can be seriously
affected by this setting.
6.6 Control Relay Operation
The 4720 power meter provides three control relays (R1 to
R3). Each relay can switch AC loads of up to 277 Volts at 10
A and DC loads of up to 30 Volts at 10 A. Chapter 2 provides wiring requirements for the relays.
The operation of each relay may be controlled in a number of
different ways for various applications:
1.
Setpoint control on selected measured parameters,
controlled by user-definable conditions. This is useful for
applications such as activation of alarms or tripping of
breakers for demand, power factor, or load control. Setpoint operation is described in detail in Chapter 8.
2.
kWH, kVARH, or kVAH pulse output.
3.
Manual forced control by the user through remote commands made via the communications port using WinPM
software.
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6 Programming
A group of programmable operating parameters are available
for assigning relay operations. The parameters allow each of
the three relays to be assigned to setpoints (in latch or pulse
mode), kWH pulsing, kVARH pulsing, or kVAH pulsing. These
parameters are accessible via communications only, and
WinPM software provides configuration screens for redefining the relay parameters.
If the relay is operating in latch mode (Rx VALUE = 0), it
behaves normally for forced operate, forced release, and
return-to-normal (return to setpoint control) commands.
6.6.1
For a relay assigned to setpoint operation (MODE = SETPOINT), the Event Log logs relay operations in one of two
ways, depending on whether the relay has been set to operate in latch or pulse mode:
Setpoint Relay Operation
For setpoint operation, the relays can provide latched or
pulsed operation. In latch mode, the relay is operated (that is,
normally open contacts are closed) for the duration that the
assigned setpoint is active. In pulsed mode, when the setpoint becomes active, the relay operates for a specified
pulse duration.
Set MODE to SETPOINT for setpoint operation. Set VALUE
to select latch mode (VALUE = 0), or set the pulse duration
for pulse mode operation (in seconds).
Note: While you are programming the 4720 power
meter via communications, no setpointcontrolled relay operations occur until you
complete the programming sequence. The
4720 power meter then assesses the status
of each setpoint and performs any required
operations.
6.6.2
kWH, kVARH, or kVAH Pulse Operation
Each relay can be configured for energy pulsing. Pulses can
be based on kWH Imported, kWH Exported, kWH Total,
kVARH Imported, kVARH Exported, kVARH Total, or kVAH.
The MODE parameter is used to set the type of pulsing. The
VALUE parameter is used to set the number of unit-hours
(kW, kVAR, or kVA) between pulses.
Note: A relay configured for energy pulsing will not
respond to an assigned setpoint that
becomes active.
Maximum pulse rate for the relays is 1 pulse
every 2 seconds (0.5 Hz).
6.6.3
Manual Forced Relay Operations
Only a setpoint relay (Rx MODE = SETPOINT) may be forced
operated or released using commands made via communications. Manual commands override current setpoint condition.
If the relay is operating in pulse mode (Rx VALUE > 0), a
forced operate command initiates a pulse of length equivalent to the value set by the Rx VALUE parameter for that
relay. This operation is logged in the Event Log and indicates
that the relay was pulsed. A forced release command has no
effect.
36
See section 6.6.5 for manual relay command special cases.
6.6.4
Relay Event Logging
Latch mode (VALUE = 0):
The Event Log records that the relay was operated (on)
when the setpoint became active and released (off)
when the setpoint returned to an inactive state.
Pulse mode (VALUE > 0):
The Event Log shows that the relay is pulsed when the
setpoint becomes active. When the setpoint returns to
its inactive state, the setpoint event is logged but does
not indicate the relay, since no pulse is generated.
If the relay is assigned to kWH, kVAH or kVAH pulse mode,
no relay operations are logged.
Manual forced relay commands are logged in the Event Log;
however, special cases exist which are described below.
6.6.5
Manual Relay Command Special Cases
If a manual forced operate command for a selected relay is
received while that relay is already in a forced operated state,
the relay command is ignored and is not logged. This is also
true for a forced release command to a relay already in a
forced released state. Manual relay commands made to
relays which are in a kWH, kVAH, or kVAH pulse mode will
also not be logged.
6.7 Status Input Operation
The 4720 power meter provides four digital status inputs (S1
to S4) which can each be used to sense the condition of an
external dry (volts free) contact. Chapter 2 provides wiring
diagrams illustrating various requirements and connection
methods for the status inputs.
Your local utility company uses one of two methods to count
pulses. One method counts one pulse when the contact
turns from on (closed) to off (open) to on (closed). Using the
second method, one pulse is counted when the contact
changes state–either on to off or off to on. Be sure to check
with your local utility company to determine which method
they use before indicating the multiplier used to count
pulses.
A minimum pulse width of 40 milliseconds is required for reliable sensing of status input changes. The status inputs may
only be used for external contact sensing. In this application,
a contact closure is sensed as active, and a contact opening
is sensed as inactive.
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6 Programming
6.7.1
Pulse Counting
6.8 Auxiliary Voltage Input Operation
The 4720 power meter maintains a counter for each of the
four status inputs. The maximum frequency the counter
accurately follows is 10 Hz. A number of programmable
parameters, accessible via communications, are provided to
allow each counter to be customized for specific applications.
The 4720 power meter has an auxiliary voltage input (VAux)
which allows an external voltage (1 VAC nominal, 1.25 VAC
max.) to be measured and displayed with user-programmable scaling.
RESOLUTION
The floating decimal point for each counter can be fixed
between 0 and 3. For example, a setting of 3 would display a total pulse count of 1234 as 1.234.
VAUX SCALE
This parameter defines what reading is displayed with a
1.000 V (AC or DC) rms input applied (that is, full scale
input). Range is 0 to 999,999.
SCALE FACTOR
This parameter allows the total pulse count to be scaled
by a factor of 0.001 to 1000 units per pulse. For example, a setting of 200 would display a total pulse count of
10 as 2,000.
VAUX ZERO
This parameter defines what reading is displayed with a
0.000 V (AC or DC) rms input applied. Range is
-999,999 to 999,999.
ROLLOVER
The maximum (scaled) reading that each counter can
achieve prior to rollover to zero (0) can be defined. The
default is 999,999,999. This is the maximum range of
the counters.
Example:
A transducer is used to measure the operating temperature
of a transformer’s windings. The output of the transducer is
connected to the VAux input of the 4720 power meter. A
transducer output of 1.000 VAC represents 100.0°C. A
transducer output of 0.000 VAC represents 30.0°C.
PRESET
You can preset each counter reading to a specific value.
This is a one-shot function only. If the counter rollover
value is reached, it rolls over to zero, not to the preset
value.
6.7.2
Resetting Status Input Counters
Status input counter values can be manually reset to zero (0)
using the CLEAR STATUS COUNT parameter from the front
panel in programming mode or via communications. Each
counter can be cleared individually, or all counters can be
cleared together. Counters can also be automatically reset
using setpoints. Status Input S4 can be used to provide
external demand interval synchronization for demand measurements. Refer to section 7.2.2 for more information.
6.7.3
Viewing Status Input Conditions
Two parameters must be set:
Set VAUX SCALE to 100. Set VAUX ZERO to 30.
In this example, a transducer output of 1.000 VAC produces
a reading of 100, while an output of 0.000 VAC produces a
reading of 30.
Note: The 4720 power meter does not display
VAux readings with floating point decimals
as significant digits; however, additional
significant integer digits can be obtained
by setting both scaling parameters to
larger values. For the example above, setting VAUX SCALE to 1000 and VAUX
ZERO to 300 provides one more significant
digit. In this case, remember to interpret
the least significant digit as a decimal place
(for example, a reading of 850 is equivalent
to 85.0).
The condition of the status inputs and status input counter
totals can be viewed from the front panel using the Menu
buttons or via communications. Chapter 7, Displaying
Information, lists all available status parameters.
The 4720 power meter’s low input impedance of 10 K will
determine the resistor size required on the input.
6.7.4
6.9 Auxiliary Current Output Operation
Logging Status Input Conditions
Status input changes can also be logged in the Event Log of
the 4720 power meter which is accessible via the communications port. Logging of status input changes can be
enabled or disabled via communications.
6.7.5
The 4720 power meter is equipped with an analog current
output (IOut) that may be programmed to deliver a current
proportional to a measured parameter. The maximum load
on the current output is 250 resistive. Four parameters
must be set:
Status Input Setpoints
Status input conditions can be used for setpoints. This
allows relay control functions to be performed based on status input conditions. Refer to Chapter 8, Using Setpoints,
for more information.
Siemens Energy & Automation, Inc.
IOUT SCALE
This parameter defines the value of the associated measured parameter corresponding to full scale current output. If IOUT KEY = FREQUENCY, IOUT SCALE should
be set to the desired parameter value x 100 for which
the current output is 20.0 mA. Range is 0 to 999,999.
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6 Programming
IOUT ZERO
This parameter defines the value of the associated measured
parameter corresponding to zero scale current output (the
zero offset). For an IOut range value of 0-20 mA, IOUT ZERO
should be set to the desired parameter value for which the
current output is 0.0 mA. For an IOut range value of 4-20
mA, IOUT ZERO should be set to the parameter value for
which the current output is 4.0 mA. IOUT ZERO can be positive or negative. Range is -999,999 to 999,999.
IOUT KEY
This defines the measured parameter to which the current output is proportional. Table 6.2 in Chapter 6 provides a list of measured parameters that may be used.
IOUT RANGE
This defines the maximum current output range.
Choices are 0-20 mA or 4-20 mA.
Example:
The IOut current output must be proportional to the phase A
current reading. The maximum phase A current expected is
approximately 2000 A. The minimum phase A current
expected is approximately 500 A. The IOut output is being
used to provide input to a chart recorder with an input range
of 4 to 20 mA.
IOut output to analog meter
20mA
4mA
Values assigned internally by the meter
Actual Power Factor value
0.0
0.50
Lagging
1.00
0.50
Leading
0.0
Figure 6.4 Power Factor Scale Representation
6.10 Operating Parameter Descriptions
Table 6.1 through Table 6.4 provide a brief description of
each operating parameter that may be programmed from the
front panel. Table 6.5 through Table 6.12 list all additional
operating parameters which are only accessible via communications.
More detailed descriptions of each operating parameter are
provided throughout this manual where operational features
are described.
Set IOUT KEY to CURRENT A. Set IOUT RANGE to 4 to 20
mA to match the full input range of the chart recorder. To
produce the maximum chart recorder range of deflection, set
IOUT SCALE to 2000 and IOUT ZERO to 500.
In this example, a phase A current input reading of 500 produces 4 mA at the IOut output (minimum scale deflection of
the chart recorder). A phase A current reading of 2000 produces an output of 20 mA (maximum scale deflection of the
chart recorder).
IOUT POWER FACTOR
Since the scale for Power Factor is essentially two
0.0-1.0 scales (one for leading and one for lagging), the
meter must combine these into one scale. To do this,
the meter represents the entire Power Factor scale as
0-200, where 0 is 0.0 lagging and 200 is 0.0 leading
(see Figure 6.4).
The 4720 power meter allows the IOut scale to be customized so that the bottom end (4mA or 0mA) and the
top end (20mA) can be programmed to any value on the
0-200 scale. In Figure 6.4, 4mA is set to 50 (which is
0.50 lagging), and 20mA is set to 100 (which is 1.00, or
unity).
38
Siemens Energy & Automation, Inc.
6 Programming
Table 6.1 Operating Parameters Programmable from the Front Panel
Parameter
Description
Range/Options
PROGRAMMING
MODE
PASSWORD
Initial display upon entering programming mode. Press Parameter Select to advance through each parameter.
not applicable
Correct password must be entered to allow setup parameters
to be modified or clear (reset) functions to be executed. Also
used to redefine password. See section 6.1.3.
0 to 9999
SYSTEM SETUP
Allows access to this group of parameters. Selecting NO
(default) will advance to the next group.
NO, YES
VOLTS MODE
Defines the power system configuration.
4W-WYE, DELTA, SINGLE, DEMO,
3W-WYE
VOLTS SCALE
Defines the full-scale input reading (in Volts) for the phase A, B,
and C voltage inputs. This should match the VT primary rating,
or if connected directly, the system line-to-neutral rating.
0 to 999,999
AMPS SCALE
Defines the full-scale input reading (in Amps) for the phase A, B,
and C current inputs. This should match the CT primary current
rating.
0 to 30,000
I4 SCALE
Defines the full-scale input reading (in Amps) for the I4 (neutral/
ground) current input. This should match the CT primary current
rating.
0 to 9,999
STANDARD FREQ
Defines the line frequency the 4720 power meter is to monitor
(in Hertz).
50 or 60
PHASE ROTATION
Defines the normal phase sequence used for power factor
polarity detection in delta mode, and for the phase reversal
detection setpoint. See Chapter 8 for setpoint operation.
POS (=ABC),
NEG (=ACB)
DEMAND
PERIOD
DEMAND SYNC
Defines the length of the demand period (in minutes) used in
calculating sliding window demand values. See section 7.2.2.
0 to 99
Defines the method of demand synchronization. INTERNAL
synchronizes to the memory clock. EXTERNAL synchronizes to
the S4 pulse.
INTERNAL,
EXTERNAL
THERMAL
PERIOD
NUM DEMAND
PERIOD
PREDICT DMD
BASE
Sets the time (in minutes) it takes the demand to reach 90% of
the thermal constant for thermal demand measurements.
2 to 99,
0 or 1 = off
Defines the number of demand periods to be averaged in calculating all sliding window demands.
1 to 15
Defines the base (in percentage of demand period) for predicted
demand. Lower percentage gives faster prediction.
1 to 99% (default = 5%)
Basic System Setup Group
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6 Programming
Table 6.2 Operating Parameters Programmable from the Front Panel (continued)
Parameter
Description
Range/Options
AUXILIARY
SETUP
VAUX SCALE
Allows access to this group of parameters. Selecting NO
(default) will advance to the next group.
NO, YES
Defines the reading for a full-scale (1.000V AC or DC) auxiliary
voltage input. See section 6.8.
0 to 999,999
VAUX ZERO
Defines the reading for a zero-scale (0.000V AC or DC) auxiliary
voltage input. To define a negative number, toggle the 7th (the
most significant) digit with the Increment button.
-999,999 to 999,999
IOUT SCALE
Defines the reading of the associated parameter corresponding
to a full-scale auxiliary current output. See section 6.9.
0 to 999,999
Auxiliary Setup Group
Note: Frequency values must be entered x100.
Example: 60Hz = 6000
IOUT ZERO
Defines the reading of the associated parameter corresponding
to a zero-scale auxiliary current output. To define a negative
number, toggle the 7th (the most significant) digit with the Increment button.
-999,999 to 999,999
IOUT KEY
Defines the measured parameter to which the current output will
be proportional.
VOLTAGE A, VOLTAGE B, VOLTAGE C,
VOLTAGE AV,
Note: SD PARAMETER # 1 and SD PARAMETER #2
are the first two in the list of sliding window
demand parameters defined by the user.
CURRENT A, CURRENT B, CURRENT C,
CURRENT AV, CURRENT I4,
kW A, kW B, kW C, kVAR A, kVAR B,
kVAR C, kVA A, kVA B, kVA C, kW TOTAL,
kVAR TOTAL, kVA TOTAL, PF TOTAL,
SD PARAMETER #1,
SD PARAMETER #2,
FREQUENCY, VAUX
IOUT RANGE
40
Defines the output range for the auxiliary current output.
0-20mA, 4-20mA
Siemens Energy & Automation, Inc.
6 Programming
Table 6.3 Operating Parameters Programmable from the Front Panel (continued)
Parameter
Description
Range/Options
Allows access to this group of parameters. Selecting NO
(default) will advance to the next group.
NO, YES
Selecting YES resets the preset and programmable max/min
logs when Parameter Select is pressed.
NO, YES
Clear Functions Group
CLEAR FUNCTIONS
CLEAR MAX/
MIN?
Note: Logs can be reset individually via communications. See “Resetting Min/Max Parameters” in
section 7.2.2 for instructions.
CLEAR HOURS?
Selecting YES resets kWH, kVARH, and kVAH counters to zero
when Parameter Select is pressed.
NO, YES
Note: Time-of-use energy registers are not affected.
CLEAR STAT
COUNT
Selected status input counter total(s) are cleared when Parameter Select is pressed.
0 (none), 1, 2, 3, 4, ALL
COMMUNICATIONS
UNIT ID
Allows access to this group of parameters. Selecting NO
(default) will advance to the next group.
NO, YES
Defines the SEAbus communications address for the 4720
power meter.
1 to 256
BAUD RATE
COMM MODE
RTS ACTIVE LVL
Defines the baud rate.
300, 1200, 2400, 4800, 9600, or 19,200
Displays the communications mode. Not programmable.
RS-232 or RS-485
Sets the active logic level asserted by the RTS line when using
RS-232 communications. See Chapter 11.
LOW, HIGH
PASSWORD PROTECT
TRANSMIT
DELAY
Provides password protection for all configurations and relay
operations. The default is NO.
NO, YES
Sets the delay between asserting RTS and the transmission of
the first bit.
0 to 999 ms
Communications Group
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41
6 Programming
Table 6.4 Operating Parameters Programmable from the Front Panel (continued)
Parameter
Description
Range/Options
DISPLAY
Allows access to this group of parameters. Selecting NO
(default) will advance to the next group.
NO, YES
DISPLAY TIMEOUT
FORMAT
PHASE LABEL
RESTORE DISPLAY
Duration (in minutes) between last button press and display turn
off.
0 (always on), 1 to 999
Defines numeric format. 1,234.5 is the default.
1,234.5 or 1234,5
Defines the phase label format.
ABC, XYZ, RYB, RST
Used to restore front panel display brightness. Selecting YES
lights all segments of display upon exit from programming
mode. See section 12.1.2.
NO, YES
DIAGNOSTICS
Allows access to this group of parameters. Selecting NO
(default) returns to PASSWORD.
NO, YES
FIRMWARE VER
Firmware version currently installed.
WWW X.X.X.X
Front Panel Display Group
Diagnostics Group
WWW = standard (V) or custom
X.X.X.X = version number
EXTENDED
42
NO, YES
Allows access to an extended group of diagnostic parameters
using a special button combination from display mode. See
section 7.6.2 for instructions and a list of extended parameters.
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6 Programming
Table 6.5 Operating Parameters Programmable via Communications only
Parameter
Description
Range/Options
Configures storage for the waveform recorder. Option format =
(number of events) x (cycles per event).
3x12, 2x18, 1x36
Waveform Recorder Setup
WFR CONFIGURATION
Sliding Window Demand Setup
Note: Only the additional demand setup parameters not available from the front panel of the 4720 power meter are listed here.
SWD PARAMETER
PARAMETER
TYPE
Selects one of ten sliding window demand measured parameters to configure.
1 to 10
Defines the type of measured parameter. NOT USED disables
the selected parameter.
NOT USED,
VOLTAGE LN, VOLTAGE LL, CURRENT,
kW, kVA, kVAR, PF, FREQUENCY,
THD, HD ODD, HD EVEN, HDxx (xx = 02
to 15), K-FACTOR
INPUT
Selects the phase or input for the selected parameter type, if
applicable.
A, B, C, AVG, TOT, I4, VAUX
STD SETPOINT
Selects one of the eleven standard setpoints to be programmed.
1 to 11
PARAMETER
TYPE
Defines the type of parameter the selected setpoint is to monitor. A setting of NOT USED disables the setpoint. See Chapter
8 for setpoint type descriptions.
NOT USED,
Standard Setpoints Setup
OVER VOLTAGE LN, OVER VOLTAGE LL,
UNDER VOLTAGE LN, UNDER VOLTAGE
LL, VOLTAGE UNBALANCE,
OVER CURRENT, UNDER CURRENT,
CURRENT UNBALANCE, PHASE REVERSAL,
OVER kW IMP, OVER kW EXP, OVER
kVAR IMP, OVER kVAR EXP, OVER kVA,
OVER kWD, OVER kVAD, OVER FREQ,
UNDER FREQ, UNDER PF LAG, UNDER
PF LEAD,
STATUS x INACTIVE (x = 1 to 4), STATUS x
ACTIVE (x = 1 to 4), ANY STATUS INACTIVE, ANY STATUS ACTIVE,
OVER Sx COUNTER (x = 1 to 4),
OVER THD, OVER HD ODD, OVER HD
EVEN, OVER HDxx (xx = 02 to 15), K-FACTOR,
NEW HOUR, NEW DAY, NEW WEEK,
NEW MONTH, NEW YEAR
INPUT
Selects the phase or input for the selected parameter type, if
applicable.
Siemens Energy & Automation, Inc.
A, B, C, AVG, TOT, I4, VAUX
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6 Programming
Table 6.6 Operating Parameters Programmable via Communications only (continued)
Parameter
Description
Range/Options
Standard Setpoints Setup (continued)
HIGH LIMIT
MEASUREMENT
MODE
Defines the high limit for the selected setpoint.
-999,999 to 999,999
Defines the variation of measurement for the selected
parameter type, if applicable.
RT, RT MIN, RT MAX, (RT = real-time)
TD, TD MIN, TD MAX, (TD = thermal
demand)
SD, SD MIN, SD MAX, (SD = sliding window demand)
PD, PD MIN, PD MAX (PD = predicted
demand)
LOW LIMIT
TIME DELAY
OPERATE
TIME DELAY
RELEASE
ACTION 1
Defines the low limit for the selected setpoint.
-999,999 to 999,999
Defines the time delay to operate (in seconds) for the
selected setpoint.
0 to 32,000
Defines the time delay to release (in seconds) for the selected
setpoint.
0 to 32,000
Defines the first of two possible actions triggered when the
selected setpoint becomes active.
NOT USED,
RELAY 1, RELAY 2, RELAY 3,
Note: ACTION 1 is always executed first. See
Chapter 8.
WAVE CAPTURExx (xx = V1, V2, V3, I1, I2,
I3, I4, VX), WAVE RECORDER,
SNAPSHOTx (X = 1 to 8),
CLEAR PRESET RT MIN/MAX LOGS,
CLEAR PRESET TD MIN/MAX LOGS,
CLEAR PRESET SD MIN/MAX LOGS,
CLEAR PRESET PD MIN/MAX LOGS,
CLEAR PRESET HARM.DIST. MIN/MAX,
CLEAR PRESET HARM.DIST. TD MIN/
MAX,
CLEAR PROGRAMMABLE MIN/MAX x
(x = 1 to 8),
CLEAR ALL MIN/MAX LOGS (preset and
programmable),
CLEAR Sx COUNTER (x = 1 to 4, ALL)
ACTION 2
Defines the second of two possible setpoint actions.
Same as ACTION 1
Note: ACTION 2 is always executed following any
specified ACTION 1. See Chapter 8.
44
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6 Programming
Table 6.7 Operating Parameters Programmable via Communications only (continued)
Parameter
Description
Range/Options
Selects one of the six high-speed setpoints to be programmed.
1 to 6
Defines the type of parameter the selected setpoint is to monitor. A setting of NOT USED disables the setpoint. Curve characteristics for time-overcurrent (option TOC) must be
programmed separately. See Table 6.8.
NOT USED,
High-Speed Setpoints Setup
HIGH SPD SETPOINT
PARAMETER TYPE
OVER VOLTAGE, UNDER VOLTAGE,
VOLTAGE UNBALANCE,
OVER CURRENT, UNDER CURRENT,
CURRENT UNBALANCE, OVER I4,
PHASE REVERSAL,
OVER kW IMP, OVER kW EXP, OVER kVA,
OVER FREQUENCY, UNDER FREQUENCY, TOC (time-overcurrent),
STATUS x INACTIVE (x = 1 to 4), STATUS x
ACTIVE (x = 1 to 4), ANY STATUS INACTIVE, ANY STATUS ACTIVE,
OVER Sx COUNTER (x = 1 to 4)
INPUT
Selects the phase for the selected parameter type, if applicable.
A, B, C, AVERAGE, TOTAL
HIGH LIMIT
LOW LIMIT
TIME DELAY
OPERATE
TIME DELAY
RELEASE
ACTION 1
Defines the high limit for the selected setpoint.
0 to 999,999
Defines the low limit for the selected setpoint.
0 to 999,999
Defines the time delay to operate (in cycles) for the selected
setpoint.
0 to 32,000
Defines the time delay to release (in cycles) for the selected
setpoint.
0 to 32,000
Defines the first of two possible actions triggered when the
selected high-speed setpoint becomes active.
NOT USED,
RELAY 1, RELAY, 2, RELAY 3,
WAVE CAPTURExx (xx = V1, V2, V3, I1, I2,
I3, I4, VX), WAVE RECORDER,
SNAPSHOT 8 (high-speed snapshot log),
CLEAR Sx COUNTER (x = 1 to 4, ALL)
ACTION 2
Defines the second of two possible actions triggered when
the selected high-speed setpoint becomes active.
Siemens Energy & Automation, Inc.
Same as ACTION 1
45
6 Programming
Table 6.8 Operating Parameters Programmable via Communications only (continued)
Parameter
Description
Range/Options
Specifies the active high speed feature: Time-Overcurrent
Curve (TOC), or High-Speed Snapshot (HSS) Log. Default is
TOC.
TOC, HSS
Time-Overcurrent Curve Setup
HIGH SPEED FEATURE
Note: The parameters listed below are for programming the time-overcurrent curve.
MAX CURRENT
Defines the maximum (pickup) current for the time-overcurrent
curve.
1 to 30,000
DATA PTS
Selects one of the eight data points on the curve characteristic to be defined.
0 to 8
xCURRENT
Defines the X (current) coordinate for the selected curve point.
Specified in multiples of MAX CURRENT parameter value.
1.00 to 110.00
TIME
Defines the Y (time) coordinate for the selected curve point (in
milliseconds).
33 to 10,000
RELAY CONTROL
MODE
Selects one of the three relays to be programmed.
1 to 3
Defines the type of operation the selected relay is to perform.
See section 6.6.
SETPOINT, kWH IMP, kWH EXP, kWH
TOT, kVARH IMP, kVARH EXP, kVARH
TOT, kVAH
VALUE
For Rx MODE = SETPOINT, specifies latch mode or sets
pulse mode duration (in seconds).
0 = latch mode or disable pulsing
Relay Setup
For Rx MODE = kWH, kVARH, or kVAH pulsing, disables pulsing or defines number of unit-hours (kW, kVAR, or kVA)
between pulses.
1 to 65,535 = pulse duration or unithours (kW, kVAR, or kVA)
Status Input Counter Setup
STATUS COUNTER
RESOLUTION
Selects the status input counter to be programmed.
1 to 4
Fixes the floating decimal point for the selected counter.
Default is 0. See section 6.7.1.
0 to 3
SCALE FACTOR
Specifies the value represented by one pulse on the selected
counter input (in units/pulse). Default is 1.
0.001 to 1000
ROLLOVER
Specifies the maximum range before the selected counter
rolls over to zero (0). Default is 999,999,999.
0 to 999,999,999
PRESET
Presets the counter reading to a specific value.
0 to 999,999,999
Note: Counter will rollover to zero (0), not to the
preset value.
Event Log Setup
LOG STATUS
CHANGES?
46
Selects whether status input events will be logged. Default is
YES. User must select for each individual status input.
YES, NO
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6 Programming
Table 6.9 Operating Parameters Programmable via Communications only (continued)
Parameter
Description
Range/Options
Standard Snapshot Logs Setup
SNAPSHOT LOG
MEMORY ALLOCATION
TRIGGER TYPE
Selects one of eight snapshot logs to configure.
1 to 8
Defines the triggering method for the selected log. See section 10.3.1 for information on memory requirements.
0 to 100%
Defines the triggering method for the selected log. If SETPOINT is defined, the desired setpoint must be programmed
to trigger the selected log. See Standard Setpoints Setup in
Table 6.5 and Table 6.6.
INTERVAL, SETPOINT
INTERVAL
Defines the time interval between snapshots. If TRIGGER
TYPE = INTERVAL, logging will run continuously at specified
intervals. If TRIGGER TYPE = SETPOINT, logging will occur at
specified intervals only while the setpoint is active.
DAYS: 1 to 399
HOURS: 1 to 23
MINUTES: 1 to 59
SECONDS: 1 to 59
PARAMETER
NUMBER
PARAMETER
TYPE
Selects one of twelve possible measured parameters for the
selected log to be defined.
1 to 12
Defines the type of measured parameter.
VOLTAGE LN, VOLTAGE LL, VOLTAGE
UNBAL,
CURRENT, CURRENT UNBAL, PHASE
REVERSAL,
kW, kVAR, kVA, kWH, kVARH, kVAH, PF,
FREQ,
THD, HD EVEN, HD ODD, HDxx (xx = 2 to
15), K-FACTOR,
DATE/TIME,
RELAY OUTPUT, STATUS CONDITION,
STATUS COUNT, SETPOINT CONDITION
INPUT
Selects the phase, input, output, register, or setpoint number
for the selected parameter type, if applicable.
A, B, C, AVG, TOT, I4, VAUX,
1, 2, 3,
R1, R2, R3, S1, S2, S3, S4,
SPxx (xx = 1 to 11),
HSxx (xx = 1 to 6)
MEASUREMENT
MODE
Defines the variation of measurement for the selected parameter type, if applicable.
RT, RT MIN, RT MAX,
TD, TD MIN, TD MAX,
SD, SD MIN, SD MAX,
PD, PD MIN, PD MAX,
IMP, EXP, NET, TOT
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47
6 Programming
Table 6.10 Operating Parameters Programmable via Communications only (continued)
Parameter
Description
Range/Options
High-Speed Snapshot Log Setup
MEMORY ALLOCATION
Defines the memory allocated in snapshot memory for the
high-speed log. See section 10.3.1 for information on memory requirements.
0 to 100%
TRIGGER TYPE
Defines the triggering method. MANUAL requires a trigger
command received via communications. If SETPOINT is
defined, the setpoint must be programmed to trigger the highspeed log. See High-Speed Setpoints Setup in Table 6.7.
MANUAL, SETPOINT
Note: Only one setpoint trigger is possible prior to
re-arming the high-speed log.
STOP CONDITION
Defines the condition following a trigger that will stop the highspeed logging function.
LOG FULL = Stop when allocated memory
is used up.
TIMED OUT = Stop when DURATION has
passed.
SETPT OFF = Stop when setpoint returns
to inactive.
DURATION
If STOP CONDITION = TIMED OUT, specifies number of
cycles until logging is stopped, in increments of two cycles.
0 to 130,000
INTERVAL
Defines the time interval between snapshots in increments of
two cycles. Logging will run continuously at specified intervals
until stop condition is reached. See section 10.3.3 for configuring a one-shot mode.
0 to 130,000
PARAMETER
NUMBER
PARAMETER
TYPE
Selects one of the twelve possible measured parameters for
the high-speed log to be defined.
1 to 12
Defines the type of measured parameter.
VOLTAGE HS (LN or LL dependent on voltage mode), VOLTAGE UNBAL HS,
CURRENT HS, PHASE REVERSAL HS,
kW, kVA,
STATUS CONDITION, STATUS COUNT
INPUT
Selects the phase or input for the selected parameter type, if
applicable.
A, B, C, AVG, TOT, I4,
S1, S2, S3, S4
48
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6 Programming
Table 6.11 Operating Parameters Programmable via Communications only (continued)
Parameter
Description
Range/Options
Selects which Menu button to configure.
1 or 2
Selects the measured parameter to be defined.
1 to 18
Defines the type of measured parameter.
VOLTAGE LN, VOLTAGE LL, VOLTAGE
UNBAL,
Menu Buttons Setup
MENU BUTTON
PARAMETER
NUMBER
PARAMETER
TYPE
CURRENT, CURRENT UNBAL,
kW, kVAR, kVA, kWH, kVAH, PF, FREQ,
THD, HD EVEN, HD ODD, HDxx (xx = 2 to
15), K-FACTOR,
DATE/TIME,
RELAY OUTPUT, STATUS CONDITION,
STATUS COUNT, SETPOINT CONDITION
PHASE BUTTON
Defines the sequence of phases, inputs, setpoint numbers, or
harmonic numbers accessible using the Phase button. List of
available options is dependent on the PARAMETER TYPE
defined above.
Any phase sequence, any three-phase display, any relay or status input sequence,
any setpoint sequence, any combination of
other measured or status parameters.
MODE FUNCTION
Defines the sequence of measurement variations accessible
using the mode function, if applicable. Options listing only a single mode will effectively disable the mode function, since no
additional modes will be available to the user.
Any combination of modes, including: RT,
TD, SD, MIN, MAX, IMP, EXP, NET, TOT
Programmable Minimum/Maximum Logs Setup
MIN/MAX LOG
PARAMETER
NUMBER
Selects one of the minimum/maximum logs to configure.
1 to 16
Selects the minimum/maximum trigger or one of the 15 possible
coincident parameters for the selected log to be defined.
PARAMETER 1 is the trigger parameter.
1 to 16
PARAMETER
TYPE
Defines the type of measured parameter. *
VOLTAGE LN, VOLTAGE LL, VOLTAGE
UNBAL,
CURRENT, CURRENT UNBAL, PHASE
REVERSAL,
kW, kVAR, kVA, kWH*, KVARH*, kVAH*,
PF, FREQ,
THD, HD EVEN, HD ODD, HDxx (xx = 2 to
15), K-FACTOR,
DATE/TIME*,
RELAY OUTPUT*, STATUS CONDITION*
STATUS COUNT*, SETPOINT CONDITION*
INPUT
Selects the phase or input for the selected parameter type, if
applicable.
A, B, C, AVERAGE, TOT, I4, VAUX
MEASUREMENT
MODE
Defines the variation of measurement for the selected parameter
type, if applicable.
RT, TD, SD, MIN*, MAX*, IMP*, EXP*,
NET*, TOT*
* These parameter types or modes cannot be used as the minimum/maximum trigger but can be defined as coincident parameters.
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49
6 Programming
Table 6.12 Operating Parameters Programmable via Communications only (continued)
Parameter
Description
Range/Options
Status Input and Relay Labels Setup
STATUSx INACTIVE
STATUSx ACTIVE
RELAYx INACTIVE
RELAYx ACTIVE
50
Defines the label for the inactive state of status input x (x = 1 to
4).
20 character label
Defines the label for the active state of status input x (x = 1 to 4).
20 character label
Defines the label for the inactive state (released) of relay x (x = 1
to 4).
20 character label
Defines the label for the active state (operated) of relay x (x = 1
to 4).
20 character label
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7 Displaying Information
7 Displaying Information
7.1 High-Speed Triggers
This chapter provides detailed descriptions of each measured parameter and all status information provided by the
4720 power meter. All measurements, measurement modes
(including user-defined sliding window demands), and status
parameters are continuously monitored or calculated internally by the 4720 power meter.
A set of high-speed measured parameters are calculated by
the 4720 power meter which are true rms, including harmonics, and are updated every two cycles. These parameters are
used exclusively as user-definable triggers for the six highspeed setpoints (see Chapter 8) and as parameter options
for high-speed snapshot logging. These parameters include:
The parameters discussed in this chapter are categorized as
follows:
•
Voltage line-to-neutral
Each phase
Three-phase average
•
Voltage line-to-line
Each phase
Three-phase average
•
Voltage unbalance (%)
•
Current
Each phase
Three-phase average
•
I4 (neutral or ground current)
•
Frequency (phase A)
•
kW (signed value indicates import/export)
Each phase
Total of all phases
•
kVA
Each phase
Total of all phases
The following sections of this chapter provide complete listings of all measured parameters, their associated display
labels, and detailed information on each parameter type.
Parameter names that require a large number of characters
will be presented using the entire display.
•
Phase reversal
•
Status input condition (S1 to S4, or any)
•
Status input counter (S1 to S4)
A complete list of accuracies, display resolutions, and range
of readings for all measurements can be found in Appendix
A. Refer to Chapter 5, Operator Interface, for instructions
on using the buttons on the front panel of the 4720 power
meter to access a specific parameter.
•
Time-overcurrent curve
One selected current phase
1.
High-Speed Triggers
2.
Real-Time Measurements
•
Power Parameters
Voltage
Current
Real, Reactive, and Apparent Power
Power Factor
Frequency
•
Harmonic Distortion
Total, Even, Odd, and Individual Harmonics
K-Factor
3.
4.
Accumulated Measurements
•
Real, Reactive, and Apparent Energy
Status Information
•
Control Relay Conditions, Status Input Conditions,
Status Input Counter Totals, and Setpoint Conditions
•
Self-Diagnostic Information
Note: The complete selection of measured parameters and status information is always
accessible via remote communications
(Chapter 11).
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These parameters are all accessible via communications.
Note that most high-speed parameters, except the timeovercurrent curve, are also calculated as real-time (one second update) parameters.
7.2 Real-Time Measurements
Real-time measurements include power parameters and harmonic distortion measurements. The following sections list
the base (primary) parameters provided and the additional
measurement modes available for each. Table 7.1 lists all
measurements, their associated phases or inputs, and display labels.
51
7 Displaying Information
Table 7.1 Real-Time Measurements and Display Labels
Measurement
Display Labels
Type
Phase or Input
Voltage
Current
Description
A
B
C
Average
Voltage line-toneutral (VLN)
A
B
C
*
Voltage line-to-line
(VLL)
A,
B,
C,
*,
Voltage unbalance
(%)
V UNB
Current
A
A UNB
B
C
*
KW A
KVR A
KVA A
PF A
KW B
KVR B
KVA B
PF B
KW C
KVR C
KVA C
PF C
Current unbalance
(%)
Power
Real power
Reactive power
Apparent power
Power
Factor
Power factor
Frequency
Frequency (phase
A)
HZ
Harmonic
Distortion
(in percent
of fundamental)
Total harmonic
distortion (2nd +
3rd + ... 15th)
THD V1
THD I1
TEHD
V1
TEHD I1
TOHD
V1
TOHD I1
HDx V1
THD V2
THD I2
TEHD
V2
TEHD I2
TOHD
V2
TOHD I2
HDx V2
THD V3
THD I3
TEHD
V3
TEHD I3
TOHD
V3
TOHD I3
HDx V3
HDx I1
KF V1
KF I1
HDx I2
KF V2
KF I2
HDx I3
KF V3
KF I3
Total even
harmonic distortion
(2nd + 4th + ...
14th)
Total odd harmonic
distortion (3rd + 5th
+ ... 15th)
Individual harmonic
distortion x = 2 to
15
K-Factor
52
K-factor
Total
I4
VAux
VX
I4
KW*
KVR*
KVA*
PF*
THD I4
THD VX
TEHD I4 TEHD
VX
TOHD I4 TOHD
VX
HDx I4
HDx VX
KF I4
KF VX
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7 Displaying Information
7.2.1
Standard Measurements
The following sections are the base measurements displayed
by the 4720 power meter.
Power-Related Parameters
These parameters include all voltage, current, power, power
factor, and frequency measurements. For phase dependent
measurements, this includes per phase readings, and averages or totals for all phases. The I4 (neutral/ground current)
and VAux (auxiliary voltage) inputs are also included. All measurements are true rms and are updated approximately each
second. Table 7.1 lists all measurements and their associated phases or inputs. A comma indicates a line-to-line voltage measurement, an asterisk represents average of all
phases or total for power measurements.
Reverse kW or kVAR readings are indicated as a negative
value (minus sign).
Power factor readings are displayed as leading (PF LD) or
lagging (PF LG). See section 7.5 for polarity conventions.
Harmonic Distortion and K-Factor
The 4720 power meter calculates harmonic distortion as a
percentage of the fundamental for each of the three phase
voltage inputs, the three phase current input channels, the I4
(neutral/ground current) input, and the VAux (auxiliary voltage) input. For each input, the following parameters are calculated:
•
Percent total harmonic distortion (THD) up to the 15th
harmonic
•
Total even harmonic distortion (TEHD)
•
Total odd harmonic distortion (TOHD)
•
Harmonic distortion for individual harmonics (HD2 to
HD15)
K-factor (KF) is also calculated using the first 15 harmonics
for all seven voltage and current inputs. K-factor can be useful in the selection of properly rated transformers for application in systems with high harmonic content.
The update rate for each harmonic distortion and K-factor
parameter is between 5 and 30 seconds. Setpoints programmed to trigger on harmonic distortion parameters can
have response times of over 30 seconds. Setpoints are
described in detail in Chapter 8.
7.2.2
Additional Measurement Modes
Additional measurement modes available for real-time
parameters include thermal demand, sliding window
demand, and predicted sliding window demand. Minimum
and maximum values are also available for all base and
demand parameters. Table 7.2 illustrates the modes available to all base parameters, the display labels used to identify them, and examples of combined display labels.
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Table 7.2 Measurement Mode Parameter Display Labels
Real-Time
Measurement Mode
Display Labels
Mode
Minimum
Maximum
Standard
Measurement
*
MN
MX
Thermal Demand
TD
SD
TD.MN TD.MX
SD.MN SD.MX
PD
PD.MN PD.MX
Sliding Window
Demand
Predicted Sliding
Window Demand
For parameters that have been assigned to the front panel
Menu buttons, additional measurement modes can be
accessed using the mode function described in section
5.2.10 in Chapter 5, Operator Interface. The sequence of
modes available using the mode function are user-definable
and dependent on the parameter type.
Power utilities generally bill commercial customers based on
both their energy consumption (in kWH) and their peak
usage levels called peak demand (in kW). Demand is a measure of average power consumption over a fixed time period,
typically 30 minutes. Peak (or maximum) demand is the highest demand level recorded over the billing period.
Demand measurement methods and intervals vary between
power utilities. Some common methods include thermal
averaging, sliding window, and fixed interval techniques. The
4720 power meter can perform demand calculations using
both the thermal averaging and sliding window demand
techniques. Beyond these methods, the 4720 power meter
can also calculate predicted values on all sliding window
demand measurements.
Thermal Demand
Thermal demand values are calculated automatically for all
base real-time parameters. The 4720 power meter uses a
method which is equivalent to thermal averaging. For thermal
averaging, the traditional demand indicator responds to
heating of a thermal element in a Watt-Hour meter. The thermal demand period is determined by the thermal time constant of the element, typically 15 to 30 minutes. The demand
period is the period of time it would take the demand to ramp
up to approximately 90% of the steady-state value (see Figure 7.1).
For thermal demand, the programmable demand period is
set by the THERMAL PERIOD parameter.
This allows you to match the power utility’s demand calculation technique. Each thermal demand measurement also has
associated minimum/maximum parameters available.
On the front panel display, thermal demand parameters are
indicated using the label “TD.” See Table 7.2.
53
7 Displaying Information
Parameter
and
Parameter Demand
Load
100%
90%
Demand
Time
0%
Demand Period
Figure 7.1 Thermal Demand Calculation
Sliding Window Demand
The 4720 power meter can provide up to ten sliding window
demand measurements. Their parameters can be programmed via communications. The first four sliding window
demand parameters have been preprogrammed at the factory, but they may be changed as needed. These are:
•
Current, average of all phases
•
kW, total of all phases
•
kVAR, total of all phases
•
kVA, total of all phases
To compute sliding window demand values, the 4720 power
meter uses the sliding window averaging (or rolling interval)
technique, which divides the demand interval into subperiods. The demand is measured electronically based on the
average load level over the most recent set of subperiods.
This method has the effect of improving the response time as
compared to the fixed interval method.
The DEMAND PERIOD and NUM DEMAND PERIOD parameters allow you to match the power utility’s demand calculation technique. For sliding window measurements, DEMAND
PERIOD represents the length of the utility’s demand subperiod, while NUM DEMAND PERIOD represents the number of
subperiods that make up the total demand interval. For
example, with a 6 x 5 minute (30 minutes total) sliding window method, demand is the average power consumption
over the last six 5-minute periods. This allows you to match
virtually any type of sliding window measurement method
used by the utilities (for example, 2 x 15 minutes, 6 x 5 minutes, 1 x 30 minutes).
Each sliding window demand measurement also offers minimum/maximum parameters.
Using the sliding window method, the 4720 power meter
readings will always be as high or slightly higher than the utility readings.
54
On the front panel display, sliding window demand parameters are indicated using the label “SD.” See Table 7.2.
Predicted Sliding Window Demand
The 4720 power meter automatically predicts the value that
each sliding window demand parameter will attain when
updated at the start of the next sliding demand interval.
Additional predicted demand peak values can be provided
by the Preset and Programmable Min/Max Logs.
The 4720 power meter predicts changes in demand as they
occur. With predicted demand, the 4720 power meter can
be easily applied in energy management strategies. All
demand results are available as setpoint triggers that can be
used to control any of the relays (R1 to R3) for load shedding, backup generator control, and so on.
The setup parameters DEMAND PERIOD and NUM
DEMAND PERIOD used by the sliding window demand calculations are the same for predicted demand. An additional
predicted demand base parameter sets the sensitivity of the
demand prediction, allowing the instrument’s response to be
carefully tuned to demand variations in the power system.
Smaller values provide faster response. The default value is
5%. A value between 1% and 25% is recommended. Setting
to zero disables prediction and returns values of zero (0) for
all predicted sliding window demand parameters.
On the front panel display, predicted sliding window demand
parameters are indicated using the label “PD.” See Table
7.2.
External Demand Synchronization
When the DEMAND SYN parameter is set to EXTERNAL, the
4720 power meter looks for a pulse (INACTIVE to ACTIVE
transition) on status input S4 to indicate the start of the subsequent demand interval. This allows you to synchronize the
4720 power meter demand calculations to the utility’s
demand period. The NUM DEMAND PERIOD parameter is
still operational in this mode and can be used to set the number of subperiods that make up the total demand interval.
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7 Displaying Information
Resetting Demand Parameters
The accumulated demand, minimum demand, and maximum (peak) demand measurements are all cleared at the
same time when the CLEAR MIN/MAX? parameter is set to
YES in programming mode or via communications. However,
all demand measurements are always cleared when any
4720 power meter operating parameter is changed either
from the front panel or via communications.
It is important that any reset of the demand values be performed near the beginning of a demand subperiod (synchronized with the utility’s subperiod). Resets performed in the
middle or near the end of a demand subperiod cause erroneous predicted sliding window demand readings. These occur
only for the first one or two subperiods following the reset.
Lower settings for the user-definable predicted demand base
(for example, < 25%) allow for faster recovery of the predicted demand readings under these circumstances.
Minimum/Maximum Parameters
The 4720 power meter maintains all min/max values in its
Preset Min/Max Log. This log records the extreme values for
all real-time, harmonic distortion, and demand parameters.
This includes all user-defined and predicted sliding window
demands.
On the front panel display, minimum and maximum values
are indicated using the labels “MN” and “MX,” respectively.
See Table 7.2.
Resetting Min/Max Parameters
All min/max values in the Preset Min/Max Log can be cleared
using the CLEAR MIN/MAX? parameter from the front panel
in programming mode. This also clears the 16 Programmable Min/Max Logs. Individual logs can be cleared via communications as described in more detail in Chapter 11.
each energy parameter and the display labels used to identify them.
Imported
Imported energy represents energy in the positive or forward direction (that is, energy consumed). Readings for
imported energy use the label “IM.”
Exported
Exported energy represents energy in the negative or
reverse direction (that is, energy generated or fed back
to the utility). Readings for exported energy use the label
“EX.”
Net
Net measurements represent the difference between
energy imported and exported for all three phases. A
net export of energy is displayed as a negatively signed
number. Net readings are indicated by an “NT” label.
Total
Total measurements represent the sum of (the absolute
values of) the energy imported and exported for all three
phases. In other words, a total energy counter increments whether energy is being imported or exported.
Total readings do not use any additional mode labels to
identify them.
Conventions used in regards to energy import/export are
described in section 7.5.
Table 7.3 Energy Parameter Display Labels
Accumulated
Measurement
kWH (real
energy)
7.3 Accumulated Measurements
The following sections describe the standard energy measurements of the 4720 power meter.
Energy parameters are accumulating values. The base
energy parameters include:
•
Real energy, or kW hours (kWH)
•
Reactive energy, or kVAR hours (kVARH)
•
Apparent energy, or kVA hours (kVAH)
All energy parameters represent the total for all three phases.
kVARH (reactive energy)
kVAH (apparent energy)
Imported
Exported
Net
Total
KWH*
IM
KVAR
H*IM
KWH*
EX
KVAR
H*EX
KWH*
NT
KVAR
H*NT
KVAH
* NT
KWH*
KVAR
H*
KVAH
*
*Measurements represent the total of all phases.
7.4 Resetting Energy Counters
You can reset all kWH, kVARH and kVAH counters to zero (0)
using the CLEAR HOURS? parameter from the front panel in
programming mode, or via communications. This action
clears the import, export, net, and total counters for each
parameter.
Energy readings are true rms and are updated approximately
once each second. Maximum range of energy readings is 0
to 999,999,999. Beyond this value, readings roll over to zero
(0).
7.5 Power Reading Polarities
kWH and kVARH energy parameters provide four measurement modes that indicate bi-directional power flow:
imported, exported, net, and total. The kVAH energy parameter provides only a net and a total reading, which produce
the same result. Table 7.3 describes the modes available to
The polarity of energy import/export readings can be
reversed by reversing the polarity of the CTs connected to
the 4720 power meter.
Siemens Energy & Automation, Inc.
Figure 7.2 illustrates how the 4720 power meter interprets
and displays signed values for power, energy import/export
indication, and power factor leading/lagging indication.
55
7 Displaying Information
Line
Load
Export
Reverse
Negative
Import
Forward
Positive
Ø=90°, +kVAR,
kVARh Imported,
Power Factor = 0
Ø=90 to 180°
Power Factor Lead
Ø=0 to 90°
Power Factor Lag
Phase Angle Ø
Ø=180°, -kW,
kWh Exported,
Power Factor = 1
Ø=180 to 270°
Power Factor Lag
Ø=0°, +kW,
kWh Imported,
Power Factor = 1
Ø=270 to 360°
Power Factor Lead
Ø=270°, -kVAR,
kVARh Exported,
Power Factor = 0
Figure 7.2 Power Reading Polarities
7.6 Status Information
Status information includes the present conditions of the
three relays, four digital (binary) status inputs, four status
input counters, and seventeen user-programmable setpoints.
Also included under this category is self-diagnostic information.
This section discusses only the display formats for all status
information. Relay and status input operations are described
in detail in Chapter 5. Setpoint operation is described in
Chapter 8.
7.6.1
Relays, Status Inputs, and Setpoints
Table 7.4 lists examples of the display label formats used for
relay, status input, counter, and setpoint conditions. The
4720 power meter displays relay and status input conditions
using the set of default display labels shown. Display labels
for the active and inactive condition of each relay and status
input can be redefined via communications. Labels are limited to 20 alphanumeric characters. Both upper and lower
case letters can be defined. Most punctuation can be displayed. Note that all punctuation and spaces are counted as
56
single characters. Delimiters (decimals, brackets, equal sign,
and so on) may be defined as part of the label.
Examples:
BREAKER 82B = TRIP
GENERATOR = ON
Siemens WinPM software provides configuration screens for
redefining display labels for the 4720 power meter. Labels
defined by the system operator are displayed at the computer.
Display labels for status input counters and setpoints are not
user-definable.
7.6.2
Diagnostics Parameters
These parameters are non-programmable and are used to
indicate various internal status conditions of the 4720 power
meter. Diagnostic parameters can be accessed in programming mode by setting the DIAGNOSTICS parameter to YES.
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7 Displaying Information
Diagnostic Firmware Version
This indicates the current firmware version installed in
the 4720 power meter. Table 6.4 in Chapter 6
describes the format of firmware version numbers.
As a policy of ongoing product development, Siemens will
offer firmware upgrades when additional features or expansion of existing functionality becomes available.
To access the extended diagnostics parameters, use the following procedure:
1.
Enter programming mode and set the EXTENDED
parameter (under DIAGNOSTICS) to YES.
2.
Return to display mode.
3.
Access the extended parameters by pressing the Phase
and Function buttons at the same time. The first group
that appears is COMMUNICATIONS.
4.
Use the Phase button to advance through each parameter in the group. The list wraps around.
5.
Press the Phase and Function buttons at the same time
to advance to the next group. The list wraps around.
6.
Press the Function button to return to normal display
mode.
The 4720 power meter provides three groups of extended
diagnostics parameters. Table 7.5 lists all extended parameters. These parameters can be used as follows:
Group 1: COMMUNICATIONS
This group of parameters can be useful to third-party
developers requiring real-time remote communications
diagnostics information. Refer to the 4720 power meter
Communications Protocol document for more detailed
descriptions of these parameters.
Group 2: BATTERIES
These parameters indicate the current condition of the
two backup batteries. Low levels indicate that remaining
battery life is limited and that one or both of the batteries
should be replaced.
You can continue to access the extended parameters as
described above if the EXTENDED parameter remains set to
YES.
Group 3: METER TIME
This parameter can be used to view the current date
and time indicated by the meter’s clock. Date and time
can be reset via communications only.
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7 Displaying Information
Table 7.4 Status Information Display Labels
Information
Source
Condition
Display Label
Relay Output
Relay x, x = 1, 2, or 3
Released (Inactive)
RELAY x INACTIVE1*
RELAY x ACTIVE1*
STATUS x
INACTIVE1*
STATUS x ACTIVE1*
Sx COUNT =
123456789
STD Sxx INACTIVE
STD Sxx ACTIVE
Hx INACTIVE
Hx ACTIVE
Operated (Active)
Status Input
Status Input x, x = 1, 2, 3, or 4
Inactive
Active
Status Input Counter
Status Counter x, x = 1, 2, 3, or 4
Accumulated Pulse Count
Standard Setpoint
Standard Setpoint xx, xx = 1 to 11
Inactive
Active
High-Speed Setpoint
High-Speed Setpoint x, x = 1 to 6
Inactive
Active
*The inactive and active state labels for status inputs and relays are user-definable via communications.
Table 7.5 Diagnostic Parameters
Display Label
Description
Value
RX FRAME
TX FRAME
NO RESPONSE
BAD CHECKSUM
INCOMPLETE
WATCHDOG
Number of SEAbus packets detected on the bus
Total increments by 1
Packets transmitted
Total increments by 1
Application layer not ready
If true, total increments by 1
Bad CRC-16
If true, total increments by 1
Reserved for future use
If true, total increments by 1
No SEAbus packets detected on the bus for a period exceeding
five minutes
If true, total increments by 1
BYTE ERROR
OVERRUN
Framing errors (indicates data collisions)
Total increments by 1
Data received at too high a rate
If true, total increments by 1
Real-time clock battery life remaining (percent of maximum)
0 to 100
NVRAM battery life remaining (percent of maximum)
0 to 100
Real-time clock date and time
WWW = MON, TUE, WED, THU, FRI, SAT,
SUN
Group 1: Communications
Group 2: Batteries
RTC
RAM
Group 3: Meter Time
WWW MMM DD
HH:MM:SS
MMM = JAN, FEB, MAR, APR, MAY, JUN,
JUL, AUG, SEP, OCT, NOV, DEC
DD = 1 to 31
HH = 0 to 23
MM = 0 to 59
SS = 0 to 59
58
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7 Displaying Information
Siemens Energy & Automation, Inc.
59
7 Displaying Information
60
Siemens Energy & Automation, Inc.
8 Using Setpoints
8 Using Setpoints
8.1.2
The 4720 power meter user-programmable setpoints provide a host of control, protection, and analysis tools. Setpoints provide extensive control over the three relay outputs,
as well as triggering capabilities for the waveform capture,
waveform recording and snapshot logging features. Seventeen individual setpoints are provided, six of which offer highspeed capabilities.
All setpoint activation and deactivation conditions are automatically recorded in the Event Log. This information
includes any setpoints that become activated but are not
programmed to perform any subsequent setpoint actions
such as relay control.
Setpoint-controlled relays can be used to perform such functions as automated demand, power factor, or voltage control. Setpoints can also enhance system reliability and safety
by protecting against such conditions as neutral current or
transformer heating, and ground current leakage. Upon the
detection of a fault condition, the relays can be used to activate external alarms or to provide shadow protection on critical breakers. Fault conditions can be analyzed in detail to
determine their source(s) using sampled waveform data or
logged data triggered by user-defined setpoint levels.
8.1 Setpoint Operations
A group of programmable parameters specify how a setpoint
is to operate. These parameters are programmable via communications only:
•
The trigger parameter defines the parameter a setpoint
is to monitor. This can be a measured parameter, status
input condition, and so on.
•
Two setpoint limits are provided (high limit, low limit).
One of these limits defines the value of the trigger
parameter which will activate the setpoint. The other
limit defines the value of the trigger parameter which will
deactivate the setpoint.
•
•
Setpoint actions define the operations that each setpoint can be used to control. When a setpoint becomes
active it can be used to trigger relay control, waveform
capture, waveform recording, snapshot logging, or a
number of different register clearing operations (for
example, Min/Max Log, status input counters). Each
setpoint can control up to two independent actions
simultaneously. If you only want to log a setpoint condition when it occurs, the setpoint can be programmed to
perform no subsequent actions.
Two programmable time delays are provided: time delay
to operate and time delay to release. The function of
these time delays is described in section 8.2.1.
8.1.1
Setpoint Programming
Setpoint programming facilitates a wide range of alarm, control, and analysis applications. Each of the seventeen setpoints can be programmed to concurrently monitor a
separate parameter. A single active setpoint can trigger up to
two independent actions (relay control, logging, and so on).
For multi-level control, more than one setpoint can monitor
the same parameter. Multiple setpoints can also be assigned
to trigger the same action (that is, the “or” function).
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Setpoint Recording
Event Log entries include the date and time stamp for when
the setpoint event occurred, and the value of the trigger
parameter. Any subsequent setpoint action is displayed in
the log, along with a date and time stamp. The Event Log is
described in more detail in Chapter 10.
8.1.3
Setpoint Monitoring
Monitoring of all setpoint conditions is performed continuously by the 4720 power meter, uninterrupted by the execution of other measurement, control or logging operations.
This means that critical setpoint-related events of short duration are always captured.
The following sections describe setpoint operation and programming in detail.
8.2 Setpoint Types
The 4720 power meter offers six high-speed setpoints and
eleven standard setpoints. Both setpoint types are similar in
their operation and programmability; however, response
times for each differ significantly. The characteristic response
of each setpoint type makes each ideal for specific ranges of
applications.
8.2.1
Setpoint Response Times
Due to the difference in response characteristics between
high-speed and standard setpoints, the response times and
programmable delays for each are specified using different
units. High-speed setpoint times are specified in number of
cycles (where a cycle = 16.6 ms for a 60 Hz input, or 20 ms
for a 50 Hz input). Standard setpoint times are specified in
number of seconds.
Under normal operating conditions, the response time of setpoint functions is defined as the time lapse between a setpoint event occurring and an associated setpoint action
being executed. Response times are as follows:
High-Speed Setpoint
Three cycles (typical), four cycles (maximum).
Standard Setpoints
One second (typical), two seconds (maximum). This
does not include harmonic distortion parameters (see
the following note).
Note: The update rate for each harmonic distortion parameter is between five and 30 seconds. Setpoints programmed to trigger on
harmonic distortion parameters can have
response times over 30 seconds.
61
8 Using Setpoints
The 4720 power meter relays have a response time of
eight milliseconds (typical), and 15 milliseconds (maximum). This does not include any additional contact
bounce which may occur. This response must be added
to setpoint response times when using setpoints to trigger relay control actions.
Power-Up Response
For both high-speed and standard setpoints, response
time could be up to five seconds after any meter powerup (for example, initial power or subsequent power-ups
following any system power failures). The 4720 power
meter should not be used for protective functions that
require faster operation. A battery-backed DC power
supply should be considered for 4720 power meter
devices whose setpoints are being used to perform protective functions in which response time is important.
8.2.2
High-Speed Setpoints
The six high-speed setpoints are numbered H01 to H06.
High-speed setpoints are ideally suited for conditions in
which fast response is essential such as overcurrent, overvoltage, reverse power, or ground faults on high impedance
ground systems.
Note: The 4720 power meter is not intended for
use as a primary overcurrent protection
device. Setpoint relay control capabilities
are designed to execute a variety of less
critical functions, or to perform shadow
(backup) protection on critical breakers.
The setpoint trigger parameters that can be used with the
high-speed setpoints are listed in Table 8.1. The measured
parameters associated with these trigger parameters are the
internal high-speed parameters described in Chapter 7.
8.2.3
Standard Setpoints
The eleven standard setpoints are numbered S01 to S11.
Standard setpoints are ideally suited for a wide range of
operations ranging from simple alarm activations to fully
automated demand, power factor, or load control.
The setpoint trigger parameters that can be used with the
standard setpoints are listed in Table 8.2. The measured
parameters associated with these trigger parameters are the
real-time and harmonics parameters described in Chapter
7.
8.3 Trigger Parameters
8.3.1
Over and Under Setpoints With Time
Delays
Many trigger parameters can function either as an over setpoint such as for overcurrent, or as an under setpoint such
as for undervoltage.
Over Setpoint
Figure 8.1 illustrates the operation of an OVER setpoint.
An OVER setpoint becomes active when the parameter
that is being monitored exceeds and remains over the
value of the programmable high limit parameter for a
time greater than the value of the TIME DELAY OPERATE parameter. An OVER setpoint becomes inactive
when the trigger parameter that is being monitored falls
below the value of the low limit parameter for a time
greater than the value of the TIME DELAY RELEASE
parameter. The difference between the high and low limits effectively produces a programmable level of operational hysteresis (or deadband).
Under Setpoint
Figure 8.2 illustrates the operation of an UNDER setpoint. An UNDER setpoint differs from an OVER setpoint
only in that the meanings of high limit and low limit are
reversed. The setpoint becomes active when the trigger
parameter falls below the value of the low limit parameter for a time greater than the value of the TIME DELAY
OPERATE parameter. The UNDER setpoint becomes
inactive when the parameter exceeds and remains over
the value of the high limit parameter for a time greater
than the value of the TIME DELAY RELEASE parameter.
Similar to over setpoint operation, the difference
between the high and low limits produces an area of
hysteresis.
8.3.2
On/Off and Counter Setpoints
Some trigger parameters provide a simple on or off condition
such as phase reversal, or status input conditions. For status
input types, setpoints can monitor the condition of individual
inputs such as S1 active, S2 normal, and so on, or monitor
all four status inputs together (for example, sx active). This
second method effectively operates as an “or” function. For
all ON/OFF trigger parameters, the setpoint will become
active when the defined condition becomes true. These trigger parameters do not use the high or low limit parameters.
Setpoints can also monitor status input counter totals. The
setpoint will become active when the associated counter
exceeds the total defined by the high limit parameter. These
trigger parameters do not use the low limit parameter.
This section describes the characteristics of various types of
trigger parameters. Table 8.1 and Table 8.2 list all trigger
parameters, including parameters that can only be used with
the six high-speed setpoints and parameters that can be
used with the eleven standard setpoints.
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8 Using Setpoints
Table 8.1 Setpoint Trigger Parameters (High-Speed)
High-Speed Setpoint Trigger Parameters
Table 8.2 Setpoint Trigger Parameters (Standard)
Parameter
Description
Standard Setpoint Trigger Parameters
NOT USED
Disables the setpoint.
Parameter
Active if measured voltage exceeds specified value, for selected phase or phase
average.
NOT USED
OVER V
1
UNDER V 1
Active if measured voltage falls below
specified value, for selected phase or
phase average.
V IMBAL
Active if measured value for any voltage
phase differs from the measured phase
average by the specified percent (%)
value.
OVER AMP
Active if measured current exceeds specified value, for selected phase or phase
average.
UNDER AMP
Active if measured current exceeds specified value, for selected phase or phase
average.
OVER <parameter>
Description
Disables the setpoint.
4
Active if measured value for the
selected parameter exceeds specified value. Parameter options include
all real-time, harmonics, demand,
and min/max measurements for all
applicable phases, phase averages,
phase totals, I4 or VAux inputs. A
total of over 700 parameter options
are provided.
UNDER <parameter>4
Active if measured value for the
selected parameter falls below specified value. Parameters options are the
same as in OVER setpoint described
above.
V IMBAL
Active if measured value for any voltage phase differs from the measured
phase average by the specified percent (%) value.
A IMBAL
Active if measured value for any current phase differs from the measured
phase average by the specified percent (%) value.
PHASE REVERSAL 3
Active if the actual phase rotation
does not match the programmable
PHASE ROTATION parameter.
STATUS x OFF
Active if status input Sx becomes
inactive (x = 1 to 4).
STATUS x ON
Active if status input Sx becomes
active (x = 1 to 4).
ANY STATUS OFF
Active if any status input becomes
inactive.
OVER I4
Active if measured I4 (neutral) current
exceeds specified value.
OVER KW IMP 2
Active if measured kW imported exceeds
specified value, for selected phase or
phase total.
OVER KW EXP 2
Active if measured kW exported exceeds
specified value, for selected phase or
phase total.
OVER KVA 2
Active if measured kW exported exceeds
specified value, for selected phase or
phase total.
OVER FREQUENCY
Active if measured frequency exceeds
specified value.
UNDER FREQUENCY
Active if measured frequency falls below
specified value.
ANY STATUS ON
TOC
Response based on user-programmable
time-overcurrent curve, for selected
phase or phase average (see section
8.3.3).
Active if any status input becomes
active.
Sx COUNTER
Active if status input Sx counter total
exceeds the specified limit (x = 1 to
4).
PHASE REVERSAL 3
Active if the actual phase rotation does
not match the programmable PHASE
ROTATION parameter.
NEW xxxx
STATUS x OFF
Active if status input Sx becomes inactive
(x = 1 to 4).
Momentarily active when real-time
clock advances to a new hour, day,
week, month, or year (xxxx = HOUR,
DAY, WEEK, MONTH, or YEAR).
STATUS x ON
Active if status input Sx becomes active (x
= 1 to 4).
ANY STATUS
OFF
Active if any status input becomes inactive.
2.
Per phase measurements are not available for OVER KW IMP,
OVER KW EXP, or OVER KVA if VOLTS MODE = DELTA.
ANY STATUS ON
Active if any status input becomes active.
3.
Not functional if VOLTS MODE = SINGLE or 3W-WYE.
Sx COUNTER
Active if status input Sx counter total
exceeds specified limit (x = 1 to 4).
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Notes for Table 8.1 and Table 8.2
1. Volts line-to-line is not functional if VOLTS MODE = WYE. Volts
line-to-neutral is not functional if VOLTS MODE = DELTA.
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8 Using Setpoints
4.
64
Volts line-to-neutral is not functional if VOLTS MODE = DELTA. Per phase kW, kVAR, and kVA options are not available if VOLTS MODE =
DELTA.
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8 Using Setpoints
Setpoint Alarm Active
ss
me
o
Time less
than time
delay to
release
Time
delay to
operate
Setpoint alarm activated
Setp
Figure 8.1 Over Setpoint Operation
Setpoint Alarm Active
ss
me
o
Time
delay to
operate
Time less
than time
delay to
release
Setpoint alarm activated
Setpo
Figure 8.2 Under Setpoint Operation
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8 Using Setpoints
8.3.3
Time-Overcurrent Curve
Note: The Time-Overcurrent Curve (TOC) cannot
be used concurrently with the High-Speed
Snapshot Log (HSS) feature. You must
select which feature to enable by setting
the HIGH SPEED FEATURE parameter via
communications. To enable the Time-Overcurrent Curve, set it to TOC.
The 4720 power meter offers additional overcurrent protection capabilities using a programmable inverse time characteristic. Only the six high-speed setpoints can use this
setpoint type. Virtually any time-current characteristic can be
defined to match a wide range of applications.
The time-overcurrent curve represents a boundary for safe
current operation of a feeder. The curve is represented by
current on the x-axis and time on the y-axis. The curve’s
shape is such that as the current increases, the time necessary to trip the setpoint is reduced. The amount of time
required to trip the setpoint is configurable through selection
of the proper data points.
Note:
For accurate time-overcurrent response
times, the meter must provide adequate
current overrange capability to measure
the expected peak current. To provide
this, the meter must be equipped with the
correct overrange option (for example,
Basic, 200%, or 500%). See Chapter 2
section 2.5.3 and section 2.5.4, and
Appendix A.
Setpoint Active Condition
The time-overcurrent setpoint operates similar to all other
setpoints. If the 4720 power meter measures a current that is
maintained for a period of time longer than is specified on the
characteristic curve, the setpoint becomes active. This curve
is based on time versus xcurrent multiplied by the max current (or pickup current).
Note: Time-overcurrent calculations are based on
the high-speed setpoint system which provides responses times in increments of two
cycles. Refer to section 8.2.1 for minimum
response times.
Setpoint Inactive Condition
An inverse version of the time-overcurrent curve is used to
determine when the setpoint becomes inactive. This curve is
based on time versus the max current divided by the xcurrent.
Additional Time Delays
The programmable time delay to operate and release delays
are still operational for this setpoint type; however, it is not
recommended that they be used. Required delays should be
implemented using the characteristic time delays of the timeovercurrent curve. Using the TIME DELAY OPERATE and
66
TIME DELAY RELEASE parameters to provide additional
delays could produce unexpected results.
Programming
You can program response curve parameters via the communications port. Siemens WinPM software provides a setup
screen for the time-overcurrent curve. Specify the MAX CURRENT parameter, then define the eight data points on the
curve using the y-axis coordinate xCURRENT and the x-axis
coordinate TIME parameters. Once the curve has been calculated and displayed, it can be sent to the 4720 power
meter via communications and stored. To define a highspeed setpoint as a time-overcurrent type, set its type
parameter to TOC.
8.4 Setpoint Actions
An active setpoint condition can be used to simultaneously
trigger up to two separate actions. Each setpoint has two
programmable parameters which allow you to define each
action. These are named ACTION 1 and ACTION 2.
Note: If ACTION 1 and ACTION 2 are both configured for a setpoint, ACTION 1 is always performed first.
For each setpoint action, many action types are available.
The eleven standard setpoints can be used to trigger:
•
Relay Control
•
Waveform Capture
•
Waveform Recording
•
Snapshot Logging (standard only)
•
Clearing Functions:
Clearing the Min/Max Logs (Preset and/or Programmable)
Clearing the Status Counters (One or All)
The six high-speed setpoints can trigger:
•
Relay Control
•
Waveform Capture
•
Waveform Recording
•
Snapshot Logging (High-Speed Only)
•
Clearing Functions:
Clearing the Status Counters (One or All)
ACTION 1 and ACTION 2 for each setpoint are both programmable via communications. The following sections
describe each setpoint action in detail.
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8 Using Setpoints
8.4.1
Relay Control
Any of the three relays of the 4720 power meter can be automatically controlled by a high-speed or standard setpoint.
Setpoint-controlled relays can perform a wide range of operations, including:
•
Tripping a breaker
•
Activating an alarm buzzer or light
•
Controlling an external piece of equipment
Note:
Refer to section 8.2.1 for information
regarding setpoint and relay response times
and other considerations.
A relay assigned to a setpoint is automatically operated when
the setpoint becomes active, and released when the setpoint
returns to its inactive state.
To configure a setpoint for relay control, you must program
the parameters for both the setpoint and for the assigned
relay:
1.
Set the ACTION 1 or ACTION 2 parameter to the
desired relay.
2.
The MODE parameter for the assigned relay must be
defined as SETPOINT.
The programmable time delay to operate delay can be used
to delay a setpoint from becoming active, thus delaying the
assigned relay operation. The programmable time delay to
release delay can be used to delay when the setpoint returns
to its inactive state, thus delaying when the assigned relay is
released.
As described in Chapter 6, section 6.6.2, relays may also
be used for kWH, kVARH, or kVAH pulsing. Be sure that a
relay configured for pulsing is not also assigned to setpoint
operation. Pulsing operations always override setpoint control.
The 4720 power meter setpoint system allows for multi-level
and multi-function relay control operations. The following
examples illustrate this flexibility.
Examples:
1.
By assigning the same relay number to more than one
setpoint, multiple setpoints can be channelled to a single relay. This feature can effectively produce a logical
“or” function. This also allows a single relay to perform
multiple functions; however, as mentioned above, care
must be taken to avoid operational conflicts.
2.
You want to configure a two-level relay protection
scheme. First assign two setpoints to monitor the same
trigger parameter (for example, OVER CURRENT). Set
each setpoint to trigger on a different parameter limit,
one higher than the other (for example, H01 HI LIMIT =
500, H02 HI LIMIT = 750). Configure each setpoint to
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control a different relay (for example, H01 ACTION 1 =
RELAY1, H02 ACTION 1 = RELAY2). Each relay could
control a different external protection device. As the
value of the measured parameter increases, each relay
will activate in sequence.
A relay configured for setpoint control (MODE = SETPOINT)
may be forced operated or released using commands issued
via communications. Manual commands override any
present setpoint-controlled relay operations. Once a command to return to normal is issued via communications, the
affected relay is immediately returned to setpoint control.
8.4.2
Waveform Capture Triggering
Any of the standard or high-speed setpoints can be used to
trigger the waveform capture functions. Setpoint triggered
waveform capture allows the 4720 power meter to automatically perform a high-resolution capture of one cycle of a single selected input. Input options include any one of the six
phase voltage and current inputs, I4 (neutral) input, or VAux
input. This data can be uploaded to WinPM software to facilitate analysis of the harmonic content that existed at the
same time of the fault condition defined by the setpoint. This
is described in more detail in Chapter 9, section 9.2.
To configure a setpoint condition to trigger waveform capture, the user must program one of the setpoint’s two
ACTION parameters as WAVE CAPTURExx, where xx represents the specific input to be captured (V1, I1, and so on).
The programmable TIME DELAY OPERATE parameter can
be used to provide a delay interval between when the setpoint becomes active and when waveform capture is triggered. The TIME DELAY RELEASE parameter has no effect.
A waveform capture trigger command received via communications overrides any setpoint-controlled waveform capture
action. Once the capture data is uploaded via communications, the recorder automatically re-arms and returns to setpoint control.
8.4.3
Waveform Recorder Triggering
Any of the standard or high-speed setpoints can be used to
trigger the waveform recording function. Waveform recording
can provide a detailed 12 to 36-cycle record of all input signals before, during, and after the occurrence of a fault. Inputs
include all six phase voltage and current inputs, plus the I4
(neutral) and VAux inputs.
The recorder can be configured to store three 12-cycle
events, two 18-cycle events, or one 36-cycle event for all
inputs. The waveform recorder runs continuously until it is
triggered either by a setpoint event or manually by a command issued via communications. At that time, the waveform
data is captured and stored in memory. This is described in
more detail in Chapter 9, section 9.3.
To configure a setpoint condition to trigger waveform recording, you must program one of the setpoint’s two ACTION
parameters to WFR.
The programmable time delay to operate can be used to
delay a setpoint from becoming active, thus delaying the trig67
8 Using Setpoints
gering of the waveform recorder. This is described in detail in
Chapter 9, section 9.3. The TIME DELAY RELEASE parameter can be used to delay when the setpoint becomes inactive, but this has no effect on waveform recorder triggering.
A waveform recorder trigger command received via communications overrides any setpoint-controlled waveform
recorder action. Once the recorded data is uploaded via
communications, the recorder automatically re-arms and
returns to setpoint control.
8.4.4
defined parameters with a time stamp. This can provide
detailed operations information to aid in isolating problem
sources.
Any of the eleven standard setpoints can be programmed to
trigger any of the eight standard Snapshot Logs. Only highspeed setpoints can be programmed to trigger a high-speed
Snapshot Log, if one has been configured.
Snapshot Logs can be triggered by setpoints in one of two
ways:
Snapshot Log Triggering
Triggering of Snapshot Logs using setpoints allows you to
define groups of important measured parameters or status
information whose values or conditions are logged when a
setpoint becomes active. The Snapshot Log records all user-
One Shot
If the Snapshot Log’s programmable INTERVAL parameter is set to zero seconds, the log records once when
the setpoint condition initially occurs.
Gated
If the programmable INTERVAL parameter is set to a non-zero time interval, the Snapshot Log records once when the setpoint condition initially occurs, and continues to record at the specified intervals the entire time the setpoint remains in an
active condition.
Note that a high-speed Snapshot Log operates differently than a standard log, using an additional user-defined stop condition.
This is described in more detail in Chapter 10.
Setpoint parameters related to snapshot logging are not accessible via the front panel of the 4720 power meter. To configure a
setpoint condition to trigger a Snapshot Log, you must program the setpoint via communications. One of the setpoint’s two
ACTION parameters (ACTION 1 or ACTION 2) must be set to one of the standard Snapshot Log numbers 1 to 8 (see Table 6.6
in Chapter 6); or to SNAPSHOT 8 if the high-speed Snapshot Log is configured (see Table 6.7 in Chapter 6).
The programmable TIME DELAY OPERATE parameter can be used to delay a setpoint from becoming active, thus delaying the
triggering of the Snapshot Log. The TIME DELAY RELEASE parameter can be used to delay when the setpoint becomes inactive, but this has no effect on Snapshot Log triggering.
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8 Using Setpoints
Example:
Setpoint triggered snapshot logging is ideal for saving critical
information prior to the clearing of registers or logs. Suppose
a standard setpoint is configured to trigger on NEW HOUR,
NEW DAY, NEW MONTH, or NEW YEAR. To save the current
values of the MIN/MAX parameters, assign those parameters
of interest to a standard Snapshot Log, then configure the
log to be one-shot triggered by the setpoint. The first action
of the setpoint would be to trigger the log. The second action
would be to clear the Min/Max Log. Each time a new month
occurs, the current data is saved, and the parameters are
reset. See section 8.4.5 and Table 6.3 in Chapter 6 for
information on clearing registers and logs.
Note: As mentioned above, ACTION 1 of any setpoint is always performed before ACTION
2. Therefore, it is very important that
ACTION 1 performs the Snapshot Log trigger while ACTION 2 performs the subsequent clearing function. Otherwise the
present data will always be lost.
8.4.5
Clearing Functions
Preset and programmable Min/Max Logs and counters can
be cleared automatically using setpoints. Refer to Table 6.3
in Chapter 6 for a detailed list of the clearing functions you
can assign to a setpoint-triggered action.
8.5 Programming Setpoints
It is recommended that setpoint utilization be planned using
a Setpoint Parameter Form. Appendix C provides a blank
Setpoint Parameter Form for this purpose. This form contains the setpoint information that the user programs into the
4720 power meter. A copy of this information should be kept
with the meter.
Figure 8.3 provides an example of a Setpoint Parameter
Form used to plan setpoint usage. The form contains all the
parameter values required to program the 4720 power meter
to perform the operations described in the following examples:
1.
Setpoints S01 to S02 are used to sense loads that are
over 70% of the breaker rating. This includes overcurrent and overvoltage conditions. Setpoints S03 to S04
are used to sense excessive power factor lead or lag.
Setpoint S05 is used to sense a voltage unbalance condition. For all these conditions, Relay 2 is triggered to
operate as an alarm relay, with its output connected to a
buzzer. Setpoint S01 is also used to trigger Snapshot
Log #1 to record the real-time readings of measured
parameters associated with the overcurrent condition.
2.
Relay 3 is used by setpoint S06 as a kW demand control relay, and is connected to a sheddable load or
backup generator.
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8 Using Setpoints
3.
Setpoints H01 to H02 are used to sense over and under
voltage conditions. Both setpoints are triggering Relay 1
to operate as a trip relay, which is connected to a
breaker shunt trip input. Setpoint H01 is also used to
trigger the waveform recorder if an overvoltage condition occurs.
During the programming of a setpoint via communications,
any relay currently assigned to that setpoint is temporarily
forced into its released state (normally-open contacts forced
open). The 4720 power meter then re-evaluates setpoint
conditions based on the new parameter settings and performs any required relay operation.
8.6 Power Outages
When the power control to the 4720 power meter is interrupted, even momentarily, the output relays release. When
power is restored, the 4720 power meter allows a three second settling time. After this interval, the setpoint conditions
are re-evaluated and, if appropriate, the relays operate after
the programmed time delays.
If any relay has been forced operated or forced released
using commands issued via the communications port prior
to the power outage, the relay is released when the outage
occurs. When power is restored, the 4720 power meter
resumes normal setpoint operation as described above.
Relays will not automatically return to a forced operated or
forced released condition following a power outage.
Setpoint Parameter Form
Setpoint
Trigger
Parameter
High Limit
TD Operate
Low Limit
TD Release
Action 1
Action 2
S01
Overcurrent
2100
10
2000
1
Relay2, Alarm
Snapshot1
S02
Overvoltage
300
10
290
1
Relay2, Alarm
S03
Under PF Lag
90
10
85
10
Relay2, Alarm
S04
Under PF Lead
90
10
85
10
Relay2, Alarm
S05
Volts
Unbalance
30%
5
10%
1
Relay2, Trip
S06
Over KWD
1200
10
900
10
Relay3, DmdCntl
S07
Not Used
S08
Not Used
S09
Not Used
S10
Not Used
S11
Not Used
H01
Overvoltage
332
5
290
1
Relay1, Trip
H02
Undervoltage
270
5
220
1
Relay1, Trip
H03
Not Used
H04
Not Used
H05
Not Used
H06
Not Used
WaveRecord
Figure 8.3 Example Setpoint Parameter Form
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9 Using Waveforms
9 Using Waveforms
The 4720 power meter is equipped with digital waveform
sampling capabilities. The 4720 power meter provides two
powerful methods for acquiring waveform data: waveform
capture and waveform recording. Waveform capture can be
used for detailed power quality analysis beyond that offered
by the harmonics measurements. Waveform recording can
assist in analyzing short duration events such as faults,
surges, and so on.
Waveform capture and recording are independent functions
and can be used concurrently. Each function can be independently triggered by a user-defined setpoint condition or
by a command issued via communications.
9.1 Importance of Power Quality Monitoring
Power quality has become a foremost concern for power
utilities and their customers due to an increasing presence of
induced harmonic voltages and currents in industrial, commercial, and residential electrical supplies. Harmonics are
typically generated within a power distribution system by
non-linear loads (variable frequency drives, UPS systems,
HVAC and lighting systems, computers, and so on).
Poor power quality can have serious and potentially damaging consequences, including equipment malfunctions or failures, reduced efficiency and mechanical vibration in motors,
or incorrect tripping and/or failure of circuit breakers. Harmonic currents from individual phases can also add in the
neutral line, sometimes producing dangerously high neutral
currents.
As harmonic sources become more prevalent, it is important
to have the analytical tools necessary to identify potential
problem sources and help in determining the preventive or
corrective measures necessary to improve power quality in
electrical distribution systems.
9.2 Waveform Capture
Waveform capture allows you to perform high-speed sampling of the V1, V2, V3, VAux, I1, I2, I3, or I4 (neutral current)
inputs. One full cycle of the signal at a single selected input is
sampled at a rate of 128 samples per cycle. All samples are
taken synchronously to the line frequency and within one
input cycle.
Sampled waveform data is stored in memory and can be
read via the communications port. The high sampling rate
used by the 4720 power meter produces high-resolution
data which allows analysis of frequency components to the
63rd harmonic.
Siemens WinPM software can be used to upload captured
waveform data from the 4720 power meter to a master computer station and display the waveforms on the computer
screen. WinPM software automatically performs a Fast Fourier Transformation on each waveform, and provides an indication of total harmonic distortion and a breakdown of
individual frequency components both in graphical and tabular form to the 63rd harmonic. This wide variety of data formats can help you quickly pinpoint the source and severity of
Siemens Energy & Automation, Inc.
harmonics, evaluate which sources must be minimized, and
develop corrective strategies.
9.2.1
Triggering From a Setpoint
Triggering waveform capture from a setpoint allows you to
analyze the harmonic character of any single selected voltage or current input that existed coincidental with the userdefined setpoint condition. An example might be a power line
fault condition that is being produced by high harmonic content.
Triggering can be performed by either a high-speed or standard type setpoint. The user must set the programmable
ACTION 1 or ACTION 2 parameter for the selected setpoint
to WAVE CAPTURE. This parameter option must be programmed via communications. You must also select the
input that is to be captured (V1, V2, V3, VAux, I1, I2, I3, I4).
The TIME DELAY OPERATE parameter can be used to provide an additional delay before the setpoint becomes active,
thus delaying when waveform capture is triggered. The TIME
DELAY RELEASE parameter has no effect.
When the setpoint becomes active (following any programmed time delay), waveform capture is automatically initiated on the selected input and the data is held in memory.
No subsequent capture actions are allowed until the currently stored data is read via communications and waveform
capture has been re-armed.
WinPM software’s waveform capture screen can be used to
retrieve one or more captured waveforms and display them
graphically with the time stamp and an indication of the trigger source.
9.2.2
Triggering Manually via Communications
You can manually initiate waveform capture from the master
station. Manual trigger commands override any currently
active setpoint-triggered waveform capture.
With Siemens WinPM software, you can perform a waveform
capture for each of the eight possible inputs individually. A
command from the computer immediately initiates capture at
the 4720 power meter. The computer automatically uploads
and displays the waveform on the screen. The waveforms
captured in turn for each of the eight inputs can be displayed
on the screen at the same time, presented with correct
phase relationships.
9.3 Waveform Recording
Power line faults, surges, sags, or other disturbances can
cause expensive service interruptions. The 4720 power
meter waveform recording feature is ideal for fault and surge
analysis and to aid in fault location. It provides a powerful
method for analyzing the conditions occurring before, during,
and after a power fluctuation or failure. For example, fault
recording can be performed by triggering on a status input
setpoint that is monitoring a breaker trip. Other applications
include the recording of voltage or current transients, transformer inrush currents, or motor start-up currents.
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9 Using Waveforms
Waveform recording allows for simultaneous 12, 18, or 36cycle sampling of all eight voltage and current inputs at a rate
of 16 samples per cycle. The recorder runs continuously until
triggered by a user-specified setpoint condition or by a manual command made via communications. You can also set a
programmable trigger delay which allows you to define the
amount of pre-event and post-event waveform data to be
captured.
Siemens WinPM software can be used to display one or
more of the eight recorded waveforms on the computer
screen. The waveforms for single inputs or groups of inputs
can be displayed together, presenting a comprehensive picture of the power line conditions surrounding the disturbance.
9.3.1
Configuring the Recorder
The memory of the 4720 power meter can store a total of 36
cycles of waveform data for each input. This memory space
can be configured to store single or multiple events. Choices
are:
•
Three 12-cycle events (3x12)
•
Two 18-cycle events (2x18)
•
One 36-cycle event (1x36)
You must program the WFR CONFIGURATION parameter via
communications to select one of the options above.
Choosing either the 3x12 or 2x18 multiple waveform configuration allows the 4720 power meter to record many events
that may be close together in time. In the case of the 3x12
option, up to three events could be stored until uploaded to
the computer.
The 1x36 configuration is ideal for recording events of longer
duration; however, it is recommended that this option not be
used if events are expected to be close together. For example, a recloser activation may generate multiple, closely
spaced contact closures.
The waveform recorder is automatically re-armed so that
successive recordings can occur until all of the recorder
memory has been filled. This would occur after the third
recording of 12 cycles for the 3x12 configuration, or after the
second recording for the 2x18 configuration. The memory is
always filled after the single recording for the 1x36 cycle configuration.
Note:
To avoid duplication of waveform data,
recorder triggers must be at least two
cycles apart. Following the initial trigger, all
subsequent triggers within a two-cycle
period will be ignored.
Once the recorder memory is filled, the recorder is disarmed.
All subsequent setpoint triggers are ignored until the currently stored data is read via communications. Manual trigger
commands can override this (see section 9.3.4). The
recorder is re-armed automatically following transfer of the
waveform recorder data.
Using WinPM software, the master station automatically
identifies if the waveform recorder is currently storing one or
more recorded events. If so, all recorded events for all inputs
are uploaded to the computer along with their time stamp,
and archived to the hard disk.
WinPM software’s waveform recorder screen can be used to
retrieve one or more channels of each recorder event from
the hard disk and graphically display them.
9.3.3
Adjusting the Trigger Point Pre-Event and
Post-Event Data
Using high-speed setpoints to trigger the waveform recorder,
you can acquire both pre-event data and post-event data. If
the programmable TIME DELAY OPERATE parameter is set
at zero (the default), the time that the setpoint event occurred
will exist within the window of cycles recorded by the waveform recorder (see Figure 9.1, Example 1).
Triggering can be performed by either a high-speed or standard type setpoint. You must set the programmable ACTION
1 or ACTION 2 parameter for the selected setpoint to WFR.
This parameter option must be programmed via communications.
The recorder exhibits an inherent trigger delay of up to two
cycles between when the external or internal setpoint event
occurs and the setpoint has been fully evaluated. The best
case for this delay is one cycle. At this point, the setpoint
performs the action of freezing the waveform recorder. This
process exhibits an additional stop delay of up to two cycles.
In total, this can provide up to four cycles of post-event data,
without the addition of a user-programmable delay.
As described in section 9.3.3, the programmable TIME
DELAY OPERATE parameter can be used to delay a setpoint
from becoming active, thus delaying the triggering of the
waveform recorder. The TIME DELAY RELEASE parameter
can be used to delay when the setpoint becomes inactive,
but this has no effect on waveform recorder triggering.
Using standard setpoints to trigger the waveform recorder
provides a much slower response. This slower response
allows the waveform recorder to provide only post-event
data. The time that the event occurred could exist one to two
seconds prior to the start of the window of cycles recorded
by the waveform recorder.
9.3.2
Triggering From a Setpoint
The waveform recorder runs continuously until it is triggered
by the setpoint event. When the setpoint becomes active,
the waveform recorder is triggered (following any programmed time delay) and the window of cycles (either 12,
18, or 36) of each input are captured and stored in memory
along with a time stamp.
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Note:
When using high-speed or standard setpoints to trigger the waveform recorder, the
actual trigger point depends on the type of
setpoint parameter being monitored (for
example, under voltage or status input
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9 Using Waveforms
change) and the additional programmable
delay that you define.
The TIME DELAY OPERATE parameter can be used to vary
the amount of pre-event and post-event data recorded by
the waveform recorder.
If a high-speed setpoint is being used to trigger the waveform recorder, the TIME DELAY OPERATE parameter can be
used to provide additional cycles of post-event data. The
setpoint event time will effectively be moved earlier within the
window of recorded cycles, reducing the amount of preevent data and increasing the amount of post-event data.
9.3.4
Triggering Manually via Communications
You can manually trigger waveform recording via the communications port. Using Siemens WinPM software, you can
manually initiate waveform recording from the master station.
A command from the computer immediately initiates capture
at the 4720 power meter, and the data is subsequently
uploaded. The TIME DELAY OPERATE parameter has no
effect on manual triggering.
Manual trigger commands override any currently active setpoint triggered waveform recording.
Figure 9.1, Example 2 shows how setting TIME DELAY
OPERATE = 2 (cycles) can cause the trigger point to be displaced by two cycles later in time, making the location of the
setpoint event two cycles earlier in the window of recorded
cycles. Note that the time delay to operate is added to the
four cycle (worst case) total inherent trigger and stop delay of
the recorder.
Note: As mentioned in section 9.3.2, for a setpoint to become active, the active condition
must exist for a period greater than the
value of the TIME DELAY OPERATE parameter. Therefore, no additional programmable delays should be applied when using
the waveform recorder to capture events of
short duration (two to six cycles). Otherwise, the recorder may fail to trigger.
Adding a large delay causes the setpoint event time to exist
outside of the window of recorded cycles, causing the
recorder to provide only post-event data.
As mentioned previously, if a standard setpoint is being used
to trigger the waveform recorder, the cycles recorded will
always be post-event data. The TIME DELAY OPERATE
parameter can be used to shift this window later in time, in
increments of seconds.
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9 Using Waveforms
Example 1
High-Speed Setpoint
12 Cycles Recorded
Time Delay to Operate = 0 Cycles
Pre-Event Data
Post-Event Data
Time
1
2
3
4
5
6
7
8
9
10
Maximum
Inherent Delay
two cycles
Setpoint
Event
11
12
Maximum
Stop Delay
two cycles
Trigger
Point
Recorder
Frozen
Example 2
High-Speed Setpoint
12 Cycles Recorded
Time Delay to Operate = 2 Cycles
Pre-Event Data
Post-Event Data
Time
1
2
3
4
5
6
7
Maximum
Inherent Delay
two cycles
Setpoint
Event
8
9
10
User-Defined
Time Delay to
Operate
two cycles
11
12
Maximum
Stop Delay
two cycles
Trigger
Point
Recorder
Frozen
Figure 9.1 Waveform Recorder High-Speed Trigger Point Adjustment
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10 Logging Data
10 Logging Data
Each event record stored in the Event Log includes:
Data logging can be extremely useful in the study of growth
patterns, for scheduling loads and cost allocation, for isolating problem sources, or for analyzing a variety of power system operating conditions.
Cause
This identifies the condition that activated or deactivated
a setpoint, a user action (such as device programming),
or any other event type that occurred.
The 4720 power meter supports three types of data logs:
(Cause) Value
If the event was a setpoint being activated or deactivated, the value of the measured parameter that triggered the setpoint is recorded. If a setpoint action is
being logged, the new state of the setpoint is recorded.
•
Event Log
•
Minimum/Maximum Logs
1 Preset (Master)
16 Programmable
•
Programmable Snapshot Logs
8 Standard, one of which can be assigned as
High-Speed
All logged data is stored in internal nonvolatile memory and is
accessible via the communications port. Measured values
from the Preset Min/Max Log are also accessible from the
front panel of the 4720 power meter. These parameters must
be assigned to the Menu buttons as described in section
5.2.9 in Chapter 5.
10.1 Event Log
The Event Log records automatically the 100 most recent
events. A wide variety of event types are recorded by this
log:
•
Power-up and power-down activity
•
Setpoint (alarm) conditions
•
Relay activity. This includes operate/release actions triggered by setpoints or manually via communications
•
Status input activity. If desired, the logging of status
input activity can be enabled via communications
•
Triggering of the waveform capture, waveform recorder,
and snapshot logging features. This includes waveform
functions and snapshot logging functions triggered by
setpoints
•
Changes made to the user-programmable parameters
from the front panel or via communications
•
Self-diagnostic events
The Event Log can be used to record a complete sequenceof-events record for breaker and transfer switch operations,
alarm conditions, and equipment starts and stops.
Note that when a setpoint is programmed to trigger an action
such as relay control or waveform recording, the setpoint
activation and the subsequent setpoint action are logged
separately.
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Effect
If the event was a setpoint being activated or deactivated, the setpoint is identified. If a setpoint action is
being logged, the action taken is identified. If any other
type of event occurred, it is described.
(Effect) Value
If the event was a setpoint being activated or deactivated, the new state of the setpoint is recorded.
Date and Time
The event is date and time-stamped. The date provides
the year, month, and day. Event times are recorded in
hours, minutes, seconds, and milliseconds. Logged
time stamps are provided with millisecond resolution;
however, time accuracies vary depending on the type of
parameter being logged and other factors. Refer to section 10.5 for more information.
10.2 Minimum/Maximum Logs
The 4700 power meter provides for both preset and programmable Minimum and Maximum (Min/Max) Logs. They
are described below.
10.2.1 Preset Min/Max Log
The Preset Min/Max Log is a non-programmable log that
automatically records the extreme values for all parameters
measured by the 4720 power meter. This includes all voltage, current, power, frequency, power factor, harmonic distortion, and auxiliary input parameters. Minimum and
maximum values are also provided for all demand measurement modes, including both thermal and user-defined sliding
window parameters.
The 4720 power meter Preset Min/Max Log can be used to
determine such values as the highest loading on a plant or
feeder, peak demand, voltage operating ranges, worst case
power factor, highest VAR loading for capacitor sizing, and
so on.
Minimum and maximum values for each parameter are
logged independently with date and time stamp. Each value
in the Preset Min/Max Log can be accessed from the front
panel of the 4720 power meter by assigning the MIN or MAX
measurement mode for the desired parameter to one of the
Menu buttons as described in section 5.2.9 in Chapter 5.
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10 Logging Data
10.2.2 Programmable Min/Max Logs
The 4720 power meter provides 16 Programmable Min/Max
Logs. For each log, you can define up to 16 time-stamped
parameters.
The following section describes the configuration and operation of standard and high-speed Snapshot Logs. All configuration must be performed via communications.
10.3.1 Memory Allocation
Each log is triggered by the first parameter in its list which is
named the trigger parameter. When a new minimum for the
trigger parameter is reached, the log simultaneously records:
The large capacity of memory allocated to Snapshot Logs
allows the partitioning of each individual Snapshot Log for
programming.
•
The trigger parameter’s minimum value
•
The date and time the minimum occurred
•
All coincident real-time values for all other parameters in
the list
The amount of memory space each Snapshot Log requires
depends on the number of parameters (channels) being
logged, the type of parameter being logged (some parameters are not compressible), the maximum number of snapshot records stored, and whether the log is triggered by time
interval or setpoint. Triggering is described in the following
sections. Setpoint-triggered snapshots require somewhat
more memory than interval-triggered snapshots.
Similarly, when a new maximum for the trigger parameter is
recorded, the values for all other parameters are stored. This
provides two lists of coincident values, one for the trigger
parameter’s minimum and one for its maximum.
The Programmable Min/Max Logs are ideal for analyzing
overall power system characteristics on the occurrence of a
specific load limit or fault condition. For example, you could
program a log to record all per-phase kW, kVAR, and PF
demand values when total kW demand peaks.
The Programmable Min/Max Logs may only be programmed
via communications. Siemens WinPM software provides
setup screens for programming all logs.
10.2.3 Resetting the Min/Max Logs
The minimum and maximum values in both the Preset and
Programmable Min/Max Logs can be reset at the same time
from either the front panel of the 4720 power meter or individually via communications. The logs can also be cleared
automatically using setpoints (see Chapter 8, Using Setpoints).
From the front panel, set the CLEAR MIN/MAX? parameter
to YES in programming mode. All values are reset when you
advance to the next parameter or return to display mode.
10.3 Programmable Snapshot Logs
Snapshot Logs in the 4720 power meter are historical or
trend logs. Up to eight standard logs may be defined. Snapshot Log 8 can be alternatively configured as a high-speed
log. Each standard or high-speed log can record up to 12
channels of data. Each snapshot record is stored with a date
and time-stamp to aid in isolating problem sources.
Each Snapshot Log can be independently triggered either on
a user-defined time interval basis or from a setpoint.
Snapshot Logs can be used to replace traditional strip chart
recorders. Data collected by the logs can be used to produce daily/weekly/monthly load profile graphs for power,
demand, power factor, and so on. Data can also be used for
time-of-use or billing calculations.
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The number of Snapshot Logs, number of parameters per
log, triggering method, time intervals (if interval-triggered) and
total number of records per log can be set to make best use
of the available memory for the specific application(s). Table
10.1 illustrates this with a number of possible log assignments. All logs in the example are interval-triggered.
The parameters that cannot be compressed include kWH,
kVAH, kVAR, time values, various status registers and scalable status input counters. All other parameters can be compressed. If the parameters you wish to log are compressible,
you will be able to store more records. Note that compression is not used for the high-speed log.
10.3.2 Standard Snapshot Logs
Up to eight standard Snapshot Logs can be defined. Note
that the high-speed feature parameter must be set to TOC
for Snapshot Log 8 to be configured as a standard log. See
section 10.3.3 for more information.
Logged Parameters
The parameter recorded by each channel of a log is userprogrammable. The values of any real-time parameter,
energy parameter, or status parameter can be logged.
Chapter 7, Displaying Information, lists these parameters. High-speed parameters can only be logged by a highspeed log (see section 10.3.3).
Time Interval Triggering
Time interval triggering allows a Snapshot Log to run continuously, automatically recording all channels of data at userdefined time intervals. To set a log for interval triggering, the
programmable TRIGGER TYPE parameter must be set to
INTERVAL. The user-defined time interval is set using the
INTERVAL parameter. For a standard Snapshot Log, this can
be set to a range between 1 second and 400 days.
This method of triggering a log is ideal for analyzing power
usage trends for the study of growth patterns, or for scheduling loads. Historical data recorded using a time-interval triggered Snapshot Log can be graphically viewed in WinPM
software using the Snapshot Viewer feature.
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10 Logging Data
Table 10.1 Snapshot Log Capacity Examples
Number of Logs
Parameters/Log
Parameter Type
Interval
Capacity
Single Log Example
#1
1 Log
3
Non-compressible
15 minutes
30 days
Single Log Example
#2
1 Log
3
Compressible
15 minutes
48 days
Single Log Example
#3
1 Log
12
Compressible
15 minutes
17 days
Single Log Example
#4
1 Log
3
1 Non-compressible
2 Compressible
15 minutes
40 days
Setpoint Triggering
Standard Snapshot Logs may also be triggered by any of the
eleven standard setpoints. This method of triggering a log is
ideal for analyzing system conditions that occur periodically
due to faults, power fluctuations, or other events (breaker
trip, and so on). Setpoint conditions can include harmonic
distortion levels, status input changes, and more (see Chapter 8, Using Setpoints). High-speed setpoints cannot be
used for this purpose.
To set a log for setpoint triggering, the programmable TRIGGER TYPE parameter must be set to SETPOINT. The
ACTION 1 or ACTION 2 parameter used for the standard
setpoint must be configured as SNAPSHOTx (where x = 1 to
8).
Logs can be triggered by setpoints in one of two ways:
One Shot
If the programmable INTERVAL parameter is set to zero
seconds, the Snapshot Log records once when the setpoint condition initially occurs.
Gated
If the programmable INTERVAL parameter is set to a
non-zero time interval, the Snapshot Log records once
when the setpoint condition initially occurs, and continues to record at the specified intervals during the entire
time that the setpoint remains in an active condition.
This effectively produces a window of snapshot records.
Subsequent triggers cause successive windows of
snapshot records to be stored. This method makes very
efficient use of the snapshot memory, since logging
occurs only during periods of interest.
Wrap-Around Storage Method
For both interval and setpoint triggering, the internal logging
function for a standard Snapshot Log fills all the available
memory allocated for the log, then wraps around by writing
new snapshot records over the earliest records in the memory.
Siemens Energy & Automation, Inc.
10.3.3 High-Speed Snapshot Log
Snapshot Log 8 of the 4720 power meter can be configured
as a high-speed log. The log can record two-cycle (or
greater) intervals and is controlled by an additional userdefined STOP CONDITION. This log is ideal for analyzing
short-term conditions such as motor start-up, system stability, or load switching response.
The High-Speed Snapshot Log (HSS) cannot be used concurrently with the Time-Overcurrent Curve (TOC) feature.
Select which feature to enable by setting the HIGH SPEED
FEATURE parameter via communications. This parameter
must be set to HSS to enable the High-Speed Snapshot
Log.
Logged Parameters
The parameter recorded by each channel of a log is userprogrammable. The values of any high-speed measured or
status parameter can be logged. See Chapter 7, Displaying Information, for a list of these parameters.
For the high-speed log, if the meter is configured in delta
mode, all high-speed phase voltage line-to-neutral parameters produce line-to-line values. Conversely, line-to-line values produce line-to-neutral values when operating in wye
mode.
Manual Triggering
To enable manual triggering, the TRIGGER TYPE parameter
must be set to MANUAL. If the log has been set to SETPOINT, manual triggering is not possible.
Logging can be performed in one of two ways:
Interval
The INTERVAL parameter should be set to any non-zero
number. Interval values between two and 130,000
cycles (approx. 36 minutes) in two-cycle increments are
possible. Following the manual trigger command, logging is performed at the specified intervals until the
defined stop condition is encountered. LOG FULL or
TIME OUT stop conditions must be used (see “Stop
Condition” in this section).
DRAFT 11/19/99
77
10 Logging Data
Note: The high-speed log will not run continuously.
A stop condition must be defined.
One Shot
This mode causes the Snapshot Log to record once
when the manual trigger command initially occurs. This
mode can be programmed in two ways.
1. Set the STOP CONDITION to TIMED OUT. Set the
INTERVAL parameter to a value greater than the time
out period.
2. Set the STOP CONDITION to TIMED OUT or LOG
FULL. Set the INTERVAL parameter to zero (0).
Setpoint Triggering
The log can also be triggered by a high-speed setpoint.
Standard setpoints cannot be used.
To enable setpoint triggering, the TRIGGER TYPE parameter
must be set to SETPOINT. The ACTION 1 or ACTION 2
parameter for the high-speed setpoint used must be configured as SNAPSHOT 8 (high-speed log).
Logging can be performed in one of three ways:
Timed Out
Logging is stopped after a user-specified duration (in
cycles) has passed. This stop condition can be used
with manual or setpoint triggering. The DURATION
parameter is used to set the time out duration.
Setpoint Off
If the log is being triggered by a setpoint, logging is
stopped when the setpoint goes inactive. This stop condition can be used only with setpoint triggering.
When the stop condition occurs, the log is frozen until the
data is uploaded via communications. The system uploads
all data and re-arms the log. In all cases, downloading cannot occur while the log is running.
Wrap-Around Recording
There are only two cases when high-speed snapshot logging
wraps around by writing new snapshot records over the earliest records in the memory. These are as follows:
1.
If triggering is manual or setpoint, interval logging is
used, the stop condition is timed out, and the duration is
set higher than the time needed to fill the memory.
2.
Triggering is set to SETPOINT, gated logging is used by
setting the STOP CONDITION to SETPT OFF, and the
setpoint remains active for a duration longer than the
time needed to fill the memory. Alternatively, repetitive
setpoint triggers cause the log to wrap around prior to
the data being uploaded.
Interval
Operation is similar to the interval mode described for
manual triggering, except that an active setpoint condition triggers the log. LOG FULL or TIMED OUT stop
conditions must be used (see below).
One Shot
Operation is similar to the one-shot mode described for
manual triggering, except that an active setpoint condition triggers the log.
Gated
The programmable INTERVAL parameter must be set to
a non-zero time interval. If the STOP CONDITION is set
to SETPT OFF, the Snapshot Log records once when
the setpoint condition initially occurs, and continues to
record at the specified intervals during the entire time
the setpoint remains in an active condition. Similar to
gated logging with standard Snapshot Logs, this effectively produces a window of snapshot records. Subsequent triggers cause successive windows of snapshot
records to be stored. If the data is not uploaded via
communications, logging wraps around, writing new
snapshot records over the earliest windows of records
in the memory. Once uploaded, all previous data is
cleared and the log is re-armed.
Stop Condition
One of the following stop conditions must always be specified for manual or setpoint-triggered high-speed Snapshot
Logging:
Log Full
Logging is stopped when all memory space designated
for the log has been filled up. This stop condition can be
used with manual or setpoint triggering.
78
The LOG FULL stop condition does not allow wrap-around
to occur.
Ensure that critical data is not overwritten by wrap-around by
selecting an appropriate stop condition for the application.
10.4 Retrieving Logged Data
The Event, Min/Max, and Snapshot Logs of the 4720 power
meter are stored in nonvolatile memory and are accessible
via communications. WinPM software can be used to read
this data.
10.5 Time Stamp Accuracy
Time stamps for 4720 power meter logged parameters have
an internal resolution of one microsecond. When using
WinPM software to upload and display logged data, log
records are displayed with time stamps of millisecond resolution.
The actual accuracy of the time stamp depends on the type
of parameter being logged:
•
Relay, Status Input, Waveform Capture, and Waveform
Recorder Activity
These items are logged with a time stamp accuracy of ±1
millisecond. The fast sensing and accurate time stamping of
the status inputs make them ideal for sequence-of-event
recording using the Event Log.
Siemens Energy & Automation, Inc.
10 Logging Data
Real-Time Measured Parameters
These measurements are updated once each second
and therefore have a logged time stamp accuracy of ±
1 second.
High-Speed Setpoints
These use the internal high-speed measured parameters as trigger parameters, and therefore provide a time
stamp accuracy of ± 2 cycles.
Standard Setpoints
These use the one second update measured parameters as trigger parameters, and therefore have a logged
time accuracy of ± 1 second.
Meter-to-Meter Time Sync
Using the global time sync broadcast capability of
WinPM software, the clocks of all 4720 power meter
devices connected on the same RS-485 bus are time
synchronized to a typical accuracy of ±1 millisecond
(max. ±10 ms). This allows for one millisecond time
stamp accuracy on waveform capture and recorder
data, and status input or relay activity in the Event Log.
Note: Mechanical relay delay is not included in the
above specification. As described in Chapter 8, section 8.2.1, this additional delay is
typically between eight and fifteen milliseconds.
The clock of the 4720 power meter is battery-backed,
allowing the clock to continue to run even in the event of
a power failure.
Siemens Energy & Automation, Inc.
79
10 Logging Data
80
Siemens Energy & Automation, Inc.
11 Communications
11 Communications
11.1 General
The 4720 power meter is equipped with a communications
port that allows the 4720 power meter to be integrated
within large energy monitoring networks. The communications port is optically isolated and transient protected. It is
field-configurable for EIA/TIA-232 (RS-232) or EIA/TIA-485
(RS-485) standards and can operate at data rates up to
19,200 baud.
The communications port provides you with access to the
advanced features of the 4720 power meter not available
from the device’s front panel. These include waveform capture and recording, data logging, and many of the setup
parameters for the setpoint system and other features.
The 4720 power meter is fully compatible with Siemens
WinPM software. WinPM software can display all measured
parameters and status information, waveform data, and data
logs provided by the 4720 power meter. WinPM software
can also be used to remotely program the setup parameters
for all basic and advanced features.
The open communications protocol of the 4720 power meter
allows access to all data and setup parameters by third-party
systems.
This chapter provides additional information regarding
remote communications connections, programming, and
general operation.
11.2 RS-232 Communications
RS-232 is commonly used for short distance, point-to-point
communications. Connection between a host computer (or
PLC) and a single remote device must be less than 50 feet.
Figure 3.3 and Figure 3.4 in Chapter 3 provide wiring diagrams for direct RS-232 connection and the required wiring
for the RS-232 interconnect cable(s).
Connection using modems via dedicated or dial-up telephone lines is also possible (see Figure 11.1).
When using a modem, it is important that the computer-tomodem and modem-to-4720 power meter cable connections illustrated in Figure 3.4 in Chapter 3 are used.
The RS-232 port RTS line is operational and can be used if
required by any hardware device connected to the 4720
power meter. Siemens WinPM software does not require the
use of the RTS line for direct RS-232 connections; however,
some types of modems (for example, radio modems) may
require its operation.
The RTS signal is asserted before the beginning of a transmission and remains asserted throughout the transmission.
The time delay between the assertion of the RTS and the
start of the transmission is controlled by the TRANSMIT
DELAY parameter, which can be set from the front panel. The
range is 0 to 999 milliseconds (with 0 (zero) as default).
Siemens Energy & Automation, Inc.
The programmable RTS ACTIVE LVL parameter selects
whether the RTS line is asserted HIGH or LOW during transmission.
11.3 RS-485 Communications
RS-485 is used when multiple devices are installed at a
remote site. RS-485 communications can be used to concurrently connect up to thirty-two remote devices on a single
communications loop. Each device is given a unique unit ID
(identification number). In this way, each remote device may
be monitored and controlled from one location by a single
supervisory device.
The total distance limitation on a single RS-485 communications network is 4000 feet (1200 meters) using 22 AWG
twisted pair shielded cable. Figure 3.5 in Chapter 3 provides a wiring diagram for RS-485 network connection.
Communication methods between the remote RS-485 site
and the supervisory device can include a direct RS-485 connection, telephone lines with modems, fiber-optic and/or
radio links. An RS-232 to RS-485 converter, such as the Isolated Multi-Drop converter, is required between the RS-232
port of the computer or modem and the RS-485 network as
illustrated in Figure 3.5 in Chapter 3.
11.4 Setting the Unit ID and Baud Rate
Before communication with the host computer/PLC is possible, ensure that the 4720 power meter, and all other connected devices, are configured for the required
communications standard (RS-232 or RS-485). Instructions
for the 4720 power meter communications card configuration are provided in Figure 3.1 in Chapter 3.
The next step is to program the communication parameters
of the 4720 power meter and all other connected devices.
The UNIT ID and BAUD RATE parameters of the 4720 power
meter can be programmed via the front panel. The unit ID
must be set to a unique value between 1 and 254. The baud
rate of each device on the network must be set to correspond with the baud rate selected for the computer. Options
include 300, 1200, 2400, 4800, 9600 or 19,200 baud.
When using a modem interface between the host computer
and any remote device(s), ensure that the host computer is
not used to set the BAUD RATE parameter of any selected
device outside the working range of the modem. Doing so
will cause that meter to cease communicating. Re-establishing communications with that meter is then only possible
through the following steps:
1.
Reset the baud rate of the remote device from its front
panel to a value within the working range of the modem.
2.
Set the computer to communicate at the baud rate at
which the remote device has been set to communicate.
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11 Communications
11.5 Siemens WinPM Software
11.6 Third-Party System Compatibility
WinPM Electrical Distribution Communication software operates in the Microsoft® Windows™ 3.1 operating environment on a personal computer (PC). Through
communications drivers, WinPM software collects and displays real-time data from Siemens ACCESS field devices,
Siemens protective relays, and other field devices. WinPM
software displays information and adds the capabilities of
programming, monitoring alarms, and logging system
events. WinPM software also monitors and displays historical
data, minimum and maximum data, and waveform data. In
addition, WinPM software can deliver its data to other compatible Windows applications, in real-time, through dynamic
data exchange (DDE), a method of sharing information that is
supported by Windows applications.
4720 power meter communications uses an advanced
object and register based open protocol which supports an
efficient exception reporting methodology. This allows the
4720 power meter to be easily adapted to third-party PLC,
DCS, EMS, and SCADA systems.
All data and configuration registers are accessible via communications. All configuration and control operations have
embedded password protection.
Contact Siemens for complete documentation on the 4720
power meter SEAbus communications protocol or to discuss
a specific application.
Your computer running WinPM software can be connected
to intelligent field devices directly, or through a modem to the
ACCESS system’s SEAbus communications bus.
RS-485 4000ft maximum, up to 32 devices
Personal Computer
Isolated
Multi-Drop
Converter
Modem
Fiber Optic Link,
Phone Line
or Dedicated Cable
Modem
Personal Computer
RS-485 4000ft maximum, up to 32 devices
Isolated
Multi-Drop
Converter
Radio Link
Personal Computer
Radio
Modem
Radio Modem
RS-485 4000ft maximum, up to 32 devices
Figure 11.1 Remote Communications Methods
82
Siemens Energy & Automation, Inc.
12 Maintenance
12 Maintenance
12.1 Maintenance
The following two circumstances describe the only regular
maintenance that the 4720 power meter may require.
12.1.1 Battery Replacement
The 4720 power meter nonvolatile memory (NVRAM) and
real-time clock (RTC) circuit contain integrated battery
backup systems.
The rated life of the NVRAM battery is seventy years at
122°F (50°C), 28 years at 140°F (60°C), and 11 years at
158°F (70°C). If the unit operates at less than 122°F (50°C)
for 60% of the time, less than 140°F (60°C) for 90% of the
time, and less than 158°F (70°C) for 100% of the time, the
expected life of the NVRAM battery is 35 years. If the meter
is operating in an environment where the temperatures regularly exceed 140°F (60°C), the NVRAM battery should be
replaced every ten years.
12.1.2 Restore Display
The 4720 power meter front panel display is a vacuum-fluorescent type which exhibits high visibility due to its exceptional brightness. A natural buildup of internal residues may
reduce the brightness of individual segments over extended
periods when the display is not in use, such as when the display timeout feature is used.
The brightness and consistency of all display segments can
be restored as follows:
1.
Enter programming mode and set the RESTORE DISPLAY parameter (under DISPLAY) to YES.
2.
Return to display mode. All segments of all characters in
the display are lit.
3.
Leave the display in this mode for an extended period of
time. Twenty-four to 48 hours are recommended.
4.
Press any button on the front panel to return to normal
display mode.
The battery system for the RTC may exhibit a somewhat
shorter lifespan than the NVRAM backup because it remains
active (that is, the clock continues to run) when the meter is
off.
12.2 Calibration
The present condition of the NVRAM and real-time clock batteries can be checked from the front panel of the 4720
power meter by viewing the extended diagnostics parameters. See section 7.6.2 in Chapter 7 for instructions. If
remaining battery life is 10% or less, the NVRAM should be
replaced.
For information regarding the required calibration procedure,
contact your local Siemens sales representative.
Contact your local Siemens sales representative for information on replacement procedures.
Note: When the NVRAM is replaced, historic data
may be lost. We recommend backing up
critical logged data to the hard drive of a
computer prior to servicing. Setup parameters and calibration of the unit are not
affected.
Siemens Energy & Automation, Inc.
The calibration interval for the 4720 power meter depends
on your accuracy requirements. The rated accuracy drift is
0.1% per year.
12.3 Field Service Considerations
In the unlikely event that the 4720 power meter unit should
fail, servicing requires disconnection and removal of the unit
from its mounting for the purpose of repair, or for exchange
with a replacement unit. The initial installation should be done
in a way which makes this as convenient as possible:
1.
All power to the 4720 power meter should be removed
and connections grounded.
2.
Current transformer secondary leads should be shortcircuited at the CT shorting block. Check to be sure that
protective relaying is not affected.
3.
All wiring should be routed to allow easy removal of the
connections to the 4720 power meter terminal strips,
the 4720 power meter rear cover, and the 4720 power
meter itself.
4.
If the control relays are used, a bypass mechanism
should be installed (see section 4.1 in Chapter 4).
83
13 Troubleshooting
13 Troubleshooting
A number of problems can cause the 4720 power meter not
to function properly. This section lists possible problems and
explains how to correct them.
1.
If the display does not operate:
a. check that there are at least 110 VAC available to the
power supply (L and N connections on the terminal
strip).
b. confirm that the Chassis Ground Lug terminal is connected directly to ground.
c. turn the power off for ten seconds, then turn it back
on and check the display.
If the above steps do not solve the problem, perform the
following:
a. As a diagnostic test, turn the unit off (disconnect
power) for at least ten seconds. Apply power again
and check if the unit powers up correctly.
b. Contact Siemens and report the problem and results
of the test.
2.
If the voltage or current readings are incorrect:
4.
If RS-232-C or RS-485 communication does not work:
a. check that the baud rate of the host computer/PLC is
the same as that of the 4720 power meter.
b. check that the communications mode (RS-232 or
RS-485) set by the jumper on the communications
card is correct for the type of standard being used
(see Chapter 3, section 3.1).
c. check all communications wiring (see Chapter 3,
Figure 3.3 through Figure 3.4).
d. check that the number of data bits is set to 8, with
one stop bit and no parity.
If the above steps do not solve the problem, perform the following:
a. As a diagnostic test, turn both the 4720 power meter
and the computer off (disconnect power) for at least
ten seconds. Apply power again and check if the
communications operate successfully.
b. Contact Siemens and report the problem and results
of the test.
If the problem persists after performing the specified steps,
or if the problem is not listed above, contact Siemens.
a. check that the voltage mode is properly set for the
given wiring.
b. check that the voltage and current scales are properly set.
c. make sure the Chassis Ground Lug terminal is properly grounded.
d. check the quality of the CTs and VTs being used.
e. make the following voltage tests:
•
•
3.
V1, V2, V3 to VREF should be 120 VAC for the
standard voltage input option. This depends
on whether or not the voltage input option is
installed (either -277 or -347).
Chassis Ground Lug to switchgear earth
ground should be 0 V.
If the kW or Power Factor readings are incorrect but
voltage and current readings are correct:
make sure that the phase relationship between voltage
and current inputs is correct by comparing the wiring
with the appropriate wiring diagram.
84
Siemens Energy & Automation, Inc.
Appendix A: Technical Specifications
A Technical Specifications
Parameter
Accuracy (% of full scale)
Front Panel Display
Basic Model
200%
500%
Resolution
Range
Current
0.2 %
0.3 %
0.8 %
0.1 %
0 - 30,000
Current Unbalance
1.0 %
1.0 %
2.0 %
1.0 %
0 - 100%
kW
0.4 %
0.5 %
1.0 %
0.1 %
0 - 999,999 (2)
kVAR
0.4 %
0.5 %
1.0 %
0
0 - 999,999 (2)
kVA
0.4 %
0.5 %
1.0 %
0.1 %
0 - 999,999 (2)
kWH
0.4 %
0.5 %
1.0 %
1 kWH
0 - 999,999,999
kVARH
0.4 %
0.5 %
1.0 %
1 kVARH
0 - 999,999,999
kVAH
0.4 %
0.5 %
1.0 %
1 kVAH
0 - 999,999,999
Voltage
0.2 %
0.1 %
0 - 999,999 (1)
Voltage Unbalance
1.0 %
1.0 %
0 - 100 %
Power Factor
1.0 %
1.0 %
-0.6 to 1.0 to +0.6
0.01 Hz
20.00 to 75.00 Hz
Frequency
0.05 Hz
Harmonic Distortion
1.0 %
0.1 %
0.0 to 1000.0 %
K-Factor
10.0 %
0.1
1.0 to 9999.9
I4
0.2 %
0.1%
0 - 9,999
VAux
0.25 %
0.1 %
0 - 999,999
(1) Reads in kV for voltages over 9,999
(2) Reads in MVA, MW, MVAR for readings over 9,999k
Current Overrange Options
Option
Accuracy
Amps
Power
Waveform Capture and Recording
Current Input Overrange
% Full
Scale
Amps
Waveform Capture
Sampling Rate: approximately 128 times per cycle
Basic
1 AMP
Sampling Accuracy: 2% of full scale
Basic
0.2 %
0.4 %
125%
6.25
1.25
Resolution: 10 bits (0.1 %)
200%
0.3 %
0.5 %
200%
10.00
2.00
Waveform Recording
500%
0.8 %
1.0 %
500%
25.00
5.00
Sampling Rate: approximately 16 times per cycle
Sampling Accuracy: 2% of full scale
Resolution: 10 bits (0.1 %)
Siemens Energy & Automation, Inc.
85
Appendix A: Technical Specifications
Technical Specifications
Input and Output Ratings
Voltage Inputs:
Current Inputs:
Aux. Voltage Input:
Basic Model:
120 VAC nominal full scale input
277 Option:
277 VAC nominal full scale input
347 Option:
347 VAC nominal full scale input
Overload withstand for all options:
1500 VAC continuous, 2500 VAC for 1 second
Input impedance for all options:
2M
Basic Model:
5.000 A AC nominal full scale
1 AMP Option:
1.000 A AC nominal full scale
Overload withstand for all options:
15 A continuous, 300 A for 1 second
Input impedance:
0.002
, Burden:
0.05 VA
1.0 VAC/VDC nominal full scale input (1.25 VAC /VDC max.)
Overload withstand: 120 VAC/VDC continuous, 1000 VAC/VDC for 1 second
Input impedance: 10 K
Control Relays:
Basic Model:
Form C dry contact. 277 VAC / 30 VDC
@ 10 A resistive
load. Accuracy: 2%
Aux. Current Output:
0 to 20 mA into max. 250
Status Inputs:
+30 VDC differential SCOM output to S1, S2, S3, or S4 input
Min. Pulse Width: 40 ms
Power Supply:
Basic Model:
85 to 264 VAC / 47 to 440 Hz or
110 to 300 VDC @ 0.2 A
Operating Temperature:
20-60 VDC Power Supply Option:
20 to 60 VDC @ 10 W
Basic Model:
32°F to 122°F (0°C to 50°C) ambient air
Extended Temperature Range Option:
-4°F to +158°F (-20°C to +70°C)
Storage Temperature:
-22°F to +158°F (-30°C to +70°C)
Humidity:
5 to 95%, non-condensing
Shipping:
Weight: 8lbs. 10 oz. (3.9 kg)
Carton: 15” x 9.8” x 7.1” (38 x 25 x 18 cm)
Voltage, Current, Status, Relay and Power inputs all pass the
ANSI/IEEE C37.90A-1989 surge withstand and fast transient tests.
86
Siemens Energy & Automation, Inc.
Appendix B: Dimensions
B Dimensions
Panel Front
Panel Right Side
7.70"
(196 mm)
12.60
(320 mm)
Siemens Energy & Automation, Inc.
4.60"
0.35"
(117 mm)
(9 mm) Behind Panel Depth
87
Appendix C: Setpoint Parameter Form
C Setpoint Parameter Form
Standard Setpoints
Setpoint
Trigger
Parameter
High Limit
TD Operate
Low Limit
TD Release
Action 1
Action 2
High Limit
TD Operate
Low Limit
TD Release
Action 1
Action 2
S01
S02
S03
S04
S05
S06
S07
S08
S09
S10
S11
High-Speed Setpoints
Setpoint
Trigger
Parameter
H01
H02
H03
H04
H05
H06
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Siemens Energy & Automation, Inc.
Appendix D: Firmware Revisions
D Firmware Revisions
The following table lists each firmware version release for the
4720 power meter and the new features or performance
enhancements added with each release.
The version number can be viewed from the front panel in
Programming Mode. If your 4720 power meter is currently
using a firmware version older than the most recent version
listed in the table below, you may upgrade the firmware in
that unit by contacting Siemens.
The Siemens representative will need to know the serial
number of the 4720 power meter and the firmware version
number indicated on the rear cover label.
Most upgrades to the 4720 power meter require a simple
replacement of the EPROM (integrated circuit chip) inside the
unit which contains the operating firmware. Complete
instructions for this procedure are provided with the replacement EPROM.
V1.3.x.x
December 1994
Siemens Energy & Automation, Inc.
Initial Release
89
Appendix E: Ordering Information
E Ordering Information
4720DRMC–
–
–
Basic Display Unit
with Communications
Power Supply
85–264 VAC/110–300 VDC
20–60 VDC
Input Voltage
120 VAC
277 VAC
347 VAC
Rated Input Current
1A
5A
Overrange on Current Input
125% full scale current
200%
500%
Extended Temperature Range
(Standard Model, no suffix)
-22°F to +158°F (-30C to + 70C)
90
1
3
1
2
3
1
5
1
2
3
T
Siemens Energy & Automation, Inc.
Index
A
ACTION parameters, 67, 68, 73, 74
defined, 45
setpoint actions, 63–66
AMPS SCALE parameter, 35, 39
auxiliary current output (IOut), 23
connections for (illustration), 23
operation, 37
specifications, 84
auxiliary voltage input (VAux), 23
connections for (illustration), 23
operation, 37
specifications, 84
B
battery,
clock, 75
diagnostics, 57
replacing, 79
baud rate, 41, 77
C
calibration (of device), 79
chassis ground, 7
Clear Functions parameter group, 41
CLEAR HOURS? parameter, 55
CLEAR MIN/MAX? parameter, 55, 72
clock (internal), 75
communications card, 17–18
communications, 77–78
parameters for, 41
programmable parameters, 43–50
retrieving log data via, 74
RS-232 to RS-485 converter, 77
troubleshooting, 81
connection,
auxiliary current output, 23
auxiliary voltage input, 23
chassis ground, 7
control relays, 21
power supply, 5
power wiring, 5
RS-232, 18
RS-485, 19
status inputs, 22
VOLTS MODE parameter, 35
VREF terminal, 9
Siemens Energy & Automation, Inc.
control relays,
and power outages, 66
applications, 21
connections for (illustration), 21
connections for, 21
define display labels, 50, 58
in event log, 71
operation of, 35–36
parameters for, 46
pulse rate of, 36
setpoint-controlled, 64
specifications, 84
current transformers,
and AMPS SCALE, 35
connecting, 7
ratings, 8
current,
incorrect reading, 81
Cursor button, 31
D
data logs, 71–75
date and time stamp,
accuracy, 74
event log, 71
min/max logs, 72
Decrement button, 31
demand measurement methods, 53
demand,
defined, 53
parameters for setup, 43
resetting demand parameters, 55
sliding window demand, 54
synchronize to utility, 54
thermal demand, 53
device specifications, 83–84
diagnostics,
batteries, 57, 79
communications, 57
extended diagnostics parameters (illustration), 58
extended diagnostics parameters, 57
meter time, 57
parameters for, 42
self-diagnostics in event log, 71
troubleshooting, 81
DISPLAY TIMEOUT parameter, 26
I- i
Index
display,
changing numbers format, 32
changing phase labels format, 32
labels used for real-time measurements, 52
labels used, (illustration), 25
modes available, 25
parameters for modifying, 42
reading the display, 25–29
restoring the display, 79
return to display mode, 31
troubleshooting, 81
K
k-factor,
calculation, 53
kVAR,
reverse kVAR reading, 53
kW,
incorrect reading, 81
reverse kW reading, 53
L
E
energy parameters, 55
event log, 71
control relay log entries, 36
parameters, 46
setpoint log entries, 59
F-G
firmware, 87
FORMAT parameter, 32
fourth current input. See I4.
Function button, 25, 27
H
harmonic distortion,
and setpoints, 59
calculation, 53
I-J
I4 (fourth current input), 7, 39
I4 SCALE parameter, 35, 39
Increment button, 31
installation, 5–16
field service considerations, 79
INTERVAL parameter,
and snapshot logs, 65, 72
setpoint triggering, 73
INVALID ENTRY message, 32
IOUT KEY parameter, 38, 40
IOUT RANGE parameter, 38, 40
IOUT SCALE parameter, 37, 40
IOUT ZERO parameter, 38, 40
IOut. See auxiliary current output.
I-ii
logs. See data logs.
M-N
maintenance, 79
measurements,
demand, 53
displayed, 52, 53
memory available,
snapshot logs, 73
waveform data, 68
Menu buttons, 28–29
and additional measurement modes, 53
and the mode function, 29
assigning parameters for data logs, 71
parameters for setup, 49
min/max logs, 71
preset, 55, 71
programmable, 72
parameters for setup, 49
resetting, 55, 72
mode function, 29
and additional measurement modes, 53
MODE parameter, 36
modem,
and RS-232 connections, 18
connections, 77
mounting the device, 5
dimensions for (illustration), 6, 85
O
over setpoint, 60
P-Q
Parameter Select button, 31
Siemens Energy & Automation, Inc.
Index
parameters, 38–50
auxiliary setup group, 40
basic system setup group, 39
clear functions parameter group, 41
communications group, 41
control relay labels, 50
control relay setup, 46
default settings, 32
demand setup, 43
diagnostics group, 42
event log setup, 46
front panel display group, 42
high-speed setpoints, 45
high-speed snapshot logs setup, 48
Menu buttons setup, 49
min/max logs (programmable), 49
programmable from front panel, 39–42
programmable via communications only, 43–50
standard setpoints, 43
standard snapshot logs setup, 47
status input counter setup, 46
status input labels, 50
time-overcurrent curve setup, 46
waveform recorder, 43
PASSWORD parameter, 31
peak, defined, 53
Phase button, 25–27
PHASE LABELS parameter, 32
polarity, 55
power factor, 53
incorrect reading, 81
power supply, 5
specifications, 84
predicted sliding window demand, 54
programming,
entering programming mode, 31
minimum requirements, 32–35
setpoints, 59–66
using the front panel, 25–29
with WinPM, 78
protocol, 78
pulse operation,
of control relays, 36
R
real-time measurements, 51, 52
response times, setpoints, 59
RS-232. See also communications.
cable wiring for (illustration), 19
communications, 77
connections for (illustration), 18
connections for, 18
selecting this communications mode, 17
Siemens Energy & Automation, Inc.
RS-485. See also communications.
communications, 77
connections for (illustration), 19
connections for, 19
selecting this communications mode, 17
RTS ACTIVE LVL parameter, 77
S
SEAbus, 78
setpoint relay,
forced operated, 36
forced released, 36
setpoints, 59–66
high-speed, 60
parameters for high-speed triggers, 51
parameters for, 45
triggering snapshot log, 74
triggering waveform capture, 67
triggering waveform recording, 68
in event log, 59, 71
over setpoint (illustration), 62
over setpoint, 60
parameter form, 86
response times, 59
setpoint-controlled relay operation, 36
standard, 60
parameters for, 43
triggering snapshot logs, 73
triggering waveform capture, 67
triggering waveform recording, 68
under setpoint (illustration), 62
under setpoint, 60
sliding window demand, 54
snapshot logs, 71
defined, 72
high-speed, 73–74
parameters for setup, 48
memory available, 72, 73
standard, 72–73
parameters for setup, 47
triggering by setpoints, 65
STANDARD FREQ parameter, 35
status inputs, 36
connections for (illustration), 22
connections for, 22
counter setup parameters, 46
define display labels, 50, 58
in event log, 71
pulse counting, 37
setpoint-controlled, 60
specifications, 84
I- iii
Index
T
thermal demand, 53
time-overcurrent curve (TOC), 63
and high-speed snapshot log, 73
parameters for, 46
TOC. See time-overcurrent curve (TOC).
transformers,
current. See current transformers.
voltage. See voltage transformers.
trigger parameters, 59
and min/max logs, 72
for setpoints, 60–61
TRIGGER TYPE parameter, 72, 73
troubleshooting, 25, 81
when resetting demand values, 55
WinPM software, 78
and control relays, 35
and logged data, 74
and programmable min/max logs, 72
and programming Menu buttons, 28
and waveform data, 67–70
wiring. See also installation.
communications wiring, 17–19
control relays, 21
power wiring, 5
status inputs, 22
U
under setpoint, 60
UNIT ID, 41, 77
V
VALUE parameter, 36
VAUX SCALE parameter, 37, 40
VAUX ZERO parameter, 37, 40
VAUX. See auxiliary voltage input.
voltage transformers,
and VOLTS SCALE, 32
connecting, 7
requirements for, 7
voltage,
incorrect reading, 81
VOLTS MODE parameter, 35, 39
VOLTS SCALE parameter, 32, 39
VREF terminal, 9
W-Z
waveform data, 67–70
connections for waveform capture, 9
in event log, 71
parameter for, 43
specifications, 83
waveform capture defined, 67
setpoint-triggered capture, 64
waveform recording defined, 67
setpoint-triggered recorder, 64
I-iv
Siemens Energy & Automation, Inc.
Warranty
Siemens Energy & Automation, Inc. warrants that all equipment purchased hereunder is warranted on a "RETURN TO
FACTORY" basis against all defects in workmanship and materials under normal and proper use and service in its unmodified condition for a period of one (1) year from the date of initial shipment. Siemens Energy & Automation, Inc.'s sole obligation under this warranty shall be limited to furnishing parts and labor to remedy such defects; either, at the option of
Siemens Energy & Automation, Inc., by replacing or repairing any defective parts which are returned to Siemens Energy &
Automation, Inc. factory or by making available at a Purchaser designated facility a repaired or replaced part. All replaced
equipment shall become the property of Siemens Energy & Automation, Inc. The cost of freight to and from Siemens
Energy & Automation, Inc. Siemens Energy & Automation, Inc. will be borne by the Purchaser. If Siemens Energy & Automation, Inc. determines that the equipment returned to it for warranty correction is not defective, as herein defined, Purchaser shall pay Siemens Energy & Automation, Inc., all costs of service, parts, handling and transportation.
Product Return Procedure
Contact Siemens Energy & Automation Customer Service at 800-427-2256 for information on the product return procedure.
Siemens Energy & Automation, Inc.
Siemens Energy & Automation, Inc.
Power Distribution Solutions
3333 Old Milton Parkway
Alpharetta, GA 30005
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Order No. XXOM-00101-1199
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