PMI 2SX Series User manual

2SX-Series Scanner User’s Manual
Power Monitors, Inc.
January 2002
1 Introduction
We founded Power Monitors Incorporated (PMI) to provide state-of-the-art,
easy-to-use, and affordable electronic test equipment to the power industry.
Our products have been developed by working directly with electric utilities to
determine their specific needs. The 2SX-Series Voltage Scanners have also been
developed by following these same principles. The 2SX-Series Scanner combines
the powerful, high technology voltage analysis capabilities of our larger Voltage
Scanners with precisely targeted end use specifically by plugging directly in to the
meterbase at a service entrance.
The 2SX-Series Voltage Scanner was developed for diagnosing electric
power problems at the revenue meter. The unit plugs into any standard 2S meter
socket, to detect outages, sags, swells, and flicker. Detectable voltage range is 0 to
290 volts, allowing the measurement and recording of severe voltage variations on
120VAC single-phase lines. Inside its lightweight, rugged enclosure, state-of-the-art
electronics measure and record true RMS line to neutral voltage and load currents.
Each unit has been individually calibrated to ensure high accuracy and
stability. With its voltage and current measurement and digital processing
circuitry based on the established Voltage Scanner line, the 2SX-Series Scanner
provides a voltage measurement, processing, and reporting system with a proven
performance history.
In summary, the 2SX-Series Scanner Voltage was created with your needs
in mind. It is perfect for analyzing voltage disturbances at the consumer level. After
looking through this manual and using the 2SX-Series Scanner Voltage, please
contact us if you have any questions about its operation, ideas for new features, or
ideas for additional products. We want you to be happy with this product, and
would appreciate any input that could help us develop products to meet your future
needs.

2 SAFETY ISSUES
2Safety Issues
Please read before installing the 2SX-Series Scanner.
The 2SX-Series Scanner Voltage contains dangerous voltage levels during
operation. Do not disassemble the Scanner. THERE ARE NO USER
SERVICEABLE PARTS INSIDE.
Do not install or operate near open bodies of water.
The 2SX-Series Scanner is intended for use with a standard 2S meterbase, with an
appropriate revenue meter plugged into it.
Wear protective gloves and safety glasses at all times during installation and
operation of the Voltage Scanner.
If possible, disconnect power during installation.
If the green ground clip is damaged or detached, call PMI for a replacement.
Do not install the 2SX-Series Scanner if the ground clip cannot be attached to earth
ground.
When removing an installed Scanner, always completely remove the revenue meter
before attempting to remove the Scanner from the meter socket.
The RJ-11 serial port is optically isolated from the 120VAC line. However, to
insure user safety and prevent damage to the unit, only the supplied 2SX-Series
Scanner serial cable should be plugged into this jack. The other end of the serial
cable should only be plugged into an RS-232 serial port.
The 2SX-Series Scanner contains a lithium battery. This battery is not user
replaceable. If the battery ride-through option is present, the Scanner also
contains a nickel metal-hydride battery. This battery is not user replaceable.
Follow all applicable regulations concerning disposal of batteries if the 2SX-Series
Scanner is discarded, or return the unit to the factory for disposal.
Although the 2SX-Series Scanner Voltage has been designed and built to be as safe
as possible, great care should be exercised at all times during operation and
installation. The National Electric Code should be followed at all times.

3Getting Started with the 2SX-Series Scanner
The 2SX-Series Scanner is an electronic recording device which plugs into a
standard single-phase 2S meter base. The unit measures and records voltages
from line to neutral on each single-phase line. The 2SX-Series Scanner powers
itself from the 120V line. After data has been recorded, the unit is connected
to a PC with a special serial cable. Winscan, the PC data analysis software,
is used to extract the data from the 2SX-Series Scanner. With Winscan, data
may be graphed, turned into reports, and exported to spreadsheets.
3.1 Contents of the 2SX-Series Scanner Package
The 2SX-Series Scanner is packaged with the following items:
•The 2SX-Series Scanner
•CD-ROM containing Winscan and all documentation
•Serial communications cable
•Wall adapter to power the unit in the office
•Locking ring to attach the Scanner to a meterbase.
If any of these items are missing, please call PMI immediately. The CD-
ROM includes the latest version of Winscan, example data files, and documentation
for Winscan and all Scanners in Adobe Acrobat format, Acrobat reader,
and the latest firmware for all Voltage Scanners.
3.2 Installing the PC software (Winscan)
Insert the CD-ROM into your CD drive. If the installation program doesn’t
start automatically, run setup.exe from the CD. The installation program will
guide you through the rest of the process.
3.3 2SX-Series Scanner Operation
Using the 2SX-Series Scanner consists of initialization, installation, recording,
downloading, and analyzing. First, the 2SX-Series Scanner is initialized with
parameters appropriate for the recording session. These parameters include
voltage thresholds, flicker limits, and a stripchart time interval, among others.
These parameters are set using Winscan. After sending the initialization to the
2SX-Series Scanner, it is ready for installation in a meterbase. When plugged in, the
2SX-Series Scanner begins a 60-second countdown. After the countdown, the 2SX-
Series Scanner starts recording. Later, after the desired data is recorded, the data
from the 2SX-Series Scanner is downloaded into Winscan. Winscan is then used to
analyze and save the data. The 2SX-Series Scanner may be reinitialized

4 4 USING THE 2SX-SERIES SCANNER
for the next recording session at this time, or it may be initialized later. The
following sections describe these processes in detail.
4Using the 2SX-Series Scanner
4.1 Initialization
The 2SX-Series Scanner must be initialized before recording data. This is done
by connecting the 2SX-Series Scanner to your PC with the 2SX-Series Scanner
serial cable, and running Winscan. See the section “PC Communications with the
2SX-Series Scanner” for information on how to connect the 2SX-Series Scanner to
the PC. See the Winscan documentation for details on how to initialize a Voltage
Scanner.
4.2 Installation
Please read the safety section before installation. Always exercise extreme
caution when installing an 2SX-Series Scanner. Interrupt the electrical service
to the point of connection whenever possible. Always wear gloves and safety
goggles. Do not install the Scanner unless you are qualified by your utility to
install and remove revenue meters.
Remove the revenue meter at the installation site using normal safety pre-
cautions. Make whatever notations your procedures require about the status
and identification of the meter at the time of removal.
Attach the ground clip (exiting the rear of the Scanner) to earth ground,
or the ground from the service drop. Install the 2SX-Series Scanner in the meter
socket by sliding the blades of the Scanner into the receptacles in the socket.
The top of the unit is marked with a sticker inside the front face.
If the ground clip is damaged, call PMI for a replacement cable. The ground clip
MUST be connected for proper Scanner operation.
Use the locking ring supplied with the Scanner to secure the revenue meter
to the Scanner. The L-shaped brackets on the locking ring should slide into
locking position inside the meter socket as the bolts are tightened (rotated
clockwise).
Reinstall the revenue meter using the front of the Scanner as the meter
socket. Attach the clamp or locking ring you would normally use to install
a meter. The Scanner socket should accommodate the existing hardware.
Attach your utility’s standard meter seal and make any notations your procedures
require about the status and identification of the meter at the time of
installation.

5 4.3 Battery Ride-Through
When the revenue meter is re-installed on the Scanner, the LED on the
side of the Scanner will start blinking. This indicates that the one-minute
countdown to recording is in progress.
In addition to the blinking LED, the countdown will be displayed on the
LDU, if one is connected. The display will indicate one minute (1:00) and
count down to zero. Some Scanner options can be changed during the count-
down period. See the section on the Local Display Unit, or Palm PDA for
instructions on making these changes.
At the end of the countdown, the Scanner will begin recording information.
The LED will blink once every six seconds to indicate that the countdown is
complete and the unit is recording.
Note: If you have interrupted power to the meter socket during installation,
the countdown will not begin until the power is reapplied.
4.3 Battery Ride-Through
If the 2SX-Series Scanner has the Battery option installed, it will continue to
record during an outage for about 30 minutes. If the battery is full discharged,
it will take about 14 hours for the battery to be fully charged. Charging is
automatically performed by the 2SX-Series Scanner when it is plugged in. The
2SX-Series Scanner can detect that it has been unplugged from a meter base,
and will not continue to record under battery power if it is removed from
service (as opposed to an outage where it is still connected). No special setup
is needed for the battery option to function.
4.4 Downloading Data
After the 2SX-Series Scanner has recorded the desired data, it is downloaded into
Winscan or a Palm PDA. The 2SX-Series Scanner may be downloaded in the field
by connecting the serial cable into a laptop (see PC Communications with the2SX-
Series Scanner) or Palm PDA (see PDA Communications with the 2SX-
SeriesScanner). The 2SX-Series Scanner stops recording when a PC is connected to
the serial port and “Identify” is selected in WinScan. The data is then downloaded
into Winscan or the PDA. If the serial cable is unplugged from the 2SX-Series
Scanner, the 2SX-Series Scanner will continue recording, appending data to the
existing recording session. If the 2SX-Series Scanner is re-initialized, it will start a
60-second countdown. The Palm PDA can also download a 2SX-Series Scanner via
the infrared port–no cable is needed. PDA operation is the same regardless of the
connection type. The 2SX-Series Scanner also may be downloaded later. Simply
remove the unit from the meter base and take it back to the office. The 2SX-Series
Scanner

64 USING THE 2SX-SERIES SCANNER
automatically stops recording (even if the battery ride-through option is in-
stalled) when it is disconnected from a meter base. The recorded data is held
in non-volatile memory so no data is lost.
When the 2SX-Series Scanner is back in the office, connect it to a PC with
the serial cable, then plug the wall adapter into the power port in the face of
the Scanner. The red LED lights up steadily in this mode to indicate that it
is in communications mode, and ready for downloading.
The recorded data is still in the 2SX-Series Scanner and can be downloaded
again even after it has been re-initialized. The old data is not erased until the
end of the 60 second countdown of the next recording session.
4.5 Analyzing Data
See the Winscan documentation to learn about using Winscan to analyze
Voltage Scanner data. The documentation is located in the “Manuals” folder on the
WinScan CD-ROM.
4.6 PC Communications with the 2SX-Series Scanner
The 2SX-Series Scanner may communicate with Winscan running on a PC or
laptop to receive its initialization and to download data. Use the supplied S-
Series Scanner serial cable to connect the 2SX-Series Scanner to a PC. Plug the
DB9 connector into an available serial port (usually COM1 or COM2) on the
PC. Plug the other end of the serial cable (a 6-pin male connector)
into the jack on the side of the 2SX-Series Scanner. Then plug the wall adapter
into the 2SX-Series Scanner power jack in the face of the unit. The red LED
lights up steadily in this mode to indicate that it is in communications mode,
and ready for communications.
In Winscan, select the appropriate communications port (usually COM1
or COM2). The 2SX-Series Scanner and Winscan are now ready for
communications. For details on how to use Winscan to initialize and download a
Voltage Scanner, see the Winscan documentation located on the CD-ROM.
The 2SX-Series Scanner does not have a modem. References to modem
communications in the Winscan documentation do not apply to the 2SX-Series
Scanner.
4.6.1 Communications Troubleshooting
Failure to establish serial communications is usually a result of a faulty PC
setup. Follow these steps to isolate and correct the problem.

7 4.7 Using the LDU 7
Make sure the 2SX-Series Scanner is in communications mode. If the 2SX-Series
Scanner red LED is not lit steadily, the unit is not in communications mode,
and will not communicate through the serial port. Make sure the cable is
plugged firmly into the 6-pin female connector on the 2SX-Series Scanner. Also
check that the DB9 connector is plugged securely into the PC serial port. If the PC
is a laptop, the serial port may be disabled to save power. A disabled serial
port will often not appear as a valid serial port to the 2SX-Series Scanner.
If the 2SX-Series Scanner is in communications mode, the problem is probably
on the PC side. Make sure the comm port is operating properly by checking
the Device Manager (right click on “My Computer”, then select “Properties”).
Check the “Ports” category and make sure the desired communications port
doesn’t have any conflicts (indicated by a red X on the comm port icon). Also
check to see if a mouse or modem is using that comm port. The 2SX-Series
Scanner cannot share a comm port with a modem or mouse.
On some laptops, a comm port may be directed to an infrared port instead
of the regular DB9 connection. This must be re-directed to the standard
external DB9 connection. Due to changes in Windows 98, the infrared port
on laptops is not compatible with the infrared port on the 2SX-Series Scanner.
A serial cable must be used to communicate directly with a laptop.
4.7 Using the LDU
The LDU has an infrared port on the top for communications with newer S
Series Scanners, and an RJ-11 connector on the bottom for serial communications
with a computer or for communications with legacy S Series Scanners.
To use the infrared LDU, point the rectangular infrared window on the top
of the LDU at the infrared ports on the Scanner. The ports on the Scanner
are beside the red LED on the bottom of the Scanner. Turn on the LDU
using the push-button switch at the lower left of the keypad. Make sure the
LDU remains pointing at the Scanner to maintain communications. The LDU
will communicate with the Scanner from up to three feet away. The liquid
crystal display (LCD) on the LDU will open with the words “Power Monitors
Inc.” and will then say “Searching for a Scanner.” The LDU looks first for
a PC on the RJ-11 port, then for a Scanner through the infrared port, then
for a legacy Scanner on the RJ-11 port. The LCD will read, “Communicating
with Scanner” when it makes a link. If a PC is connected to the LDU, the
LCD will read, “PC is connected to LDU.” If you move the LDU too far from
the Scanner or point it away you will receive a message saying you have lost
communications with the Scanner. Turn the LDU off, point it at the Scanner,
and turn it back on.

84 USING THE 2SX-SERIES SCANNER
When the LDU finds a Scanner, it will display the RMS voltage and current
for Channel 1 on the LCD. You may then use the keys on the pad to view
data in various ways. Push the Ch2 key to read the voltage and current for
Channel 2, then Ch1 to return to the Channel 1 information. Hold down the
SET key and push the left arrow to make the LCD screen lighter. Hold down
the SET key and push the right arrow to make the LCD screen darker. The
blank BLUE key will take you to the menu screen, or will move you back one
step once you are in a menu. The first time you press the BLUE key you will
see four options on the LCD screen. Only the first, 4CH, and the fourth, SET,
are used at this point. The others are for future functions. Move among the
options using the left and right arrow keys. Move to the 4CH option, then
the RMS option, then press SET to bring up the default Channel 1 display.
Press the BLUE key to move back to the previous menu, or the CH2 key to
move to the Channel 2 display.
From the main menu, choose the SET option using the arrows, then press
the SET key. Of the options that appear, only the PAR for parameters and
DIA for diagnostics are used at this point. Move to the PAR option using
the arrow keys, then press the SET key to select it. The LCD will show you
the type of hookup (wye or delta), the recording interval, and the threshold
settings. Press the BLUE key to go back. Move to the DIA option using the
arrow keys and press SET to select it. The LCD will show you the type of
Scanner, an S Series, and the serial number of the Scanner. Press the right
arrow to bring up the next DIA screen. This one will show you the Scanner
firmware version and the Scanner battery voltage. Press the right arrow again
to bring up the next DIA screen. This one will show you the LDU firmware
version and the LDU battery voltage.
4.7.1 Using the LDU as an Infrared Interface to a PC
When the 2SX-Series Scanner has been recording long enough to measure the
condition you want to monitor, you can download the information for analysis
by hooking the Scanner and LDU to the serial port of a personal computer.
First, power on the LDU. Then press the DNL key for transparent mode.
The LCD will read, “Transparent mode PC to Scanner.” Now connect the
RJ-11 connector of your serial communication cable to the bottom of the
LDU and the other end to the serial port of your computer. Then point the
infrared window of the LDU at the infrared ports on the Scanner to establish
communications. The LDU transparently passes information from the Scanner
to the PC, as if the PC were connected directly to the Scanner. Winscan
must be set to 38400 baud in this mode! Run WinScan on the PC and follow
the instructions in the WinScan documentation. Download the information

9 4.8 Using a Palm PDA
by disconnecting the Scanner and returning it to your office or by taking a
portable or laptop computer to the site where the Scanner is operating.
4.8 Using a Palm PDA
Initialization: In order to initialize the scanner it must have power, either from
the line if the scanner is installed or from a 12-volt power adapter wall transformer.
Also, the PDA must be able to communicate with the scanner, either
through a serial cable or an infrared connection. Older scanners employed only the
serial cable, while newer VS-2SX scanners employ IR. An IR transmitter must
have a line-of-sight view of the receiver at a range of 12 inches or less. The
PDA emits a slight beep as long as communication is successful. To implement
a command in the Palm, touch or tap the screen surface with either a finger
or the supplied pointer. Tap Done at any point to return to the main menu.
Once the scanner is powered and the PDA is communicating with the
scanner, tap the PalmScan icon to reach the Main Menu, consisting of 3
commands: LDU, Comm, and Files.
4.8.1 LDU
This mode allows the user to scroll though a series of screens showing real-time
display of the measurements that have been enabled: voltage, current, power,
phase angle, power factor, displacement power factor, and harmonics are possible.
The “1 Chan” display option shows the measurements on fewer screens
than the “4 Chan” option, but both sequences show the same information.
•Tap More to scroll through the measurements.
•Tap Next to view other channels.
4.8.2 Comm
This mode allows the user to perform 6 functions, most importantly Download
and Initialize:
1) “Download” identifies the scanner in the heading, allows editing of the
identification, and leads to a download.
•Tap Done and OK to initiate the download. See “Downloading Data”
below.
2) “Identify” lists information about the individual scanner.
3) “Date/Time” allows the user to synchronize the scanner with the PDA.
•Tap Set Time to change the Date/Time of the PDA.

10 4 USING THE 2SX-SERIES SCANNER
4) “Initialize” allows the user to set parameters and choose options from a
series of screens similar to those in WinScan. By default, “Scanner Settings”
shows the recommended or usual quantities.
•Tap Edit to change the settings.
•Tap Previous or Next to scroll through the numbered screens.
•Tap Done and OK to accept the defaults or the user-selected settings.
5) “Retrieve Set” uploads the prior group of settings.
6) “Done” leads back to the Main Menu and accepts the chosen settings.
4.8.3 Downloading Data
When the Technician wishes to collect data from the scanners in the field, the
PDA serves as a storage medium to convey the data to the office PC. Depend-
ing on what records are enabled, the memory of the PDA holds downloads
from several scanners.
Connect the PDA to the scanner with the serial cable or position the PDA
fr infrared connection. To implement the download:
•Tap Comm, Download, and OK to initiate the transfer.
Depending on the size of the file, the process could take several minutes.
The download is complete when the Main Menu appears. Back at the office,
the PDA may be connected to the PC through the HotSync docking cradle:
•Connect the cradle to the PC according to the instructions for the Palm.
•Place the Palm in the cradle.
•Press the HotSync button, and the HotSync Progress screen
appears. HotSync places the .isf file in the folder you specify during the
installation program. The .isf file can now be opened and viewed as usual
with the WinScan software:
•Click on File, Open, and choose the file from the Open dialog box.
4.9 2SX-Series Scanner Options
The 2SX-Series Scanner is available with a number of options. All options are
installed internally inside the 2SX-Series Scanner housing. The most common
option is current. This allows the 2SX-Series Scanner to monitor two channels
of current. The measured current is the current flowing through each leg of
the single phase service. Load current is measured in the same manner as
voltage, with stripcharts, histograms, and daily profiles generated. Further

11 4.9 2SX-Series Scanner Options
recording is possible with the Power option. This allows the 2SX-Series Scanner
to compute and record real, reactive, and apparent power, as well as power
factor. Adding the Harmonics and Waveform Capture option gives the ability
to monitor voltage and current harmonics, as well as capture raw waveform
data. The Memory option doubles the available memory for longer recording
times. The Battery option lets the 2SX-Series Scanner continue recording during
an outage.
4.9.1 Current
The current option allows the 2SX-Series Scanner to measure and record the load
currents from the two single-phase legs. The currents are sampled just like the
voltage channels, 128 times per cycle. These samples are used to create one
cycle RMS values, and are recorded like the voltage channels. The 2SX-Series
Scanner with the current option contains two internal current transformers
to pick up the current signal–no external CTs or clamps are necessary. The
currents are measured through the lower two blades in the meter adapter
housing.
4.9.2 Power
The power option allows the 2SX-Series Scanner to compute and record the power
consumed by the loads on the service. Real power (watts), reactive power
(vars), apparent power (volt-amps), and power factor are computed for each
leg. These are computed using the voltages from line to neutral, and current
through each leg. The power option also includes extra memory so that all the
power quantities may be recorded without reducing the recording time. The
2SX-Series Scanner must have current measuring capability to compute power.
4.9.3 Harmonics and Waveform Capture
The Harmonics and Waveform Capture option give the 2SX-Series Scanner the
ability to measure and record voltage and current harmonics, as well as raw
waveform data. Stripcharts of selected voltage and current harmonics may be
recorded, up to the 31st, as well as daily profiles of total harmonic distortion. In
addition, raw voltage and current waveforms may be captured based on trigger
conditions set with Winscan. This option also includes extra memory so that
harmonic stripcharts may be recorded without lessening the total recording time.
The 2SX-Series Scanner must have the power option installed to measure
harmonics.

12 5 WHAT THE 2SX-SERIES SCANNER RECORDS
4.9.4 Memory
This option doubles the memory in the 2SX-Series Scanner, for twice the record-
ing time. This doubling occurs after any extra memory is added by the Power
and Harmonics options.
4.9.5 Battery Ride-Through
The Battery option lets the 2SX-Series Scanner keep recording through an out-
age. An internal battery powers the 2SX-Series Scanner for about 30
minutes. The 2SX-Series Scanner shuts down automatically when the battery
runs down. The battery is automatically charged when power returns, and is
trickle charged constantly while the 2SX-Series Scanner is line-powered so that
it will always be charged.
4.9.6 2SX-Series Scanner Model Numbering
The 2SX-Series Scanner model number indicates which options have been in-
stalled. The base model number is “VS-2SX”, which describes a voltage-only
unit. The addition of current creates an “iVS-2SX”. Adding power adds the
“P” suffix, giving an “iVS-2SP”. Adding Harmonics creates an “iVS-2SX/ PH”.
Memory adds an “M”, and the Battery option adds a “B” to the model. Thus, a fully
loaded 2SX-Series Scanner would be an “iVS-2SX/PHMB”. Since the power option
requires current, and the harmonics option requires power, there is no“VS-2X/SP”
or “iVS-2X/SH”.
5What the 2SX-Series Scanner Records
5.1 Introduction
The job of any power monitor is to record all interesting data, and leave
unrecorded the vast majority of boring, unremarkable data. The tricky part
for a monitor is deciding which events are important. This is a problem of data
reduction. A recorder that captured every 60 Hz waveform during a week’s
recording would never miss an event, but would present the user with millions
of useless cycles. Conversely, a recorder whose thresholds are set incorrectly
may not record anything. Staying somewhere between these two extremes
involves a balance of thresholds, settings, and record types. The monitor will
see an enormous amount of data on its voltage and current inputs–the 2SX-Series
Scanner sees over 1 billion samples per day! Ideally, all this data is reduced

13 5.1 Introduction
to a small report which just shows the important events and measurements.
The sifting of data into specific record types accomplishes this task.
5.1.1 Triggered Record Types
PMI Scanner records can be divided into two classes. The first is event driven.
These record types are triggered by a combination of triggering logic and adjustable
thresholds, usually voltage-based. If a trigger never happens, nothing
is recorded for that record type. As more triggers occur, more records are
collected for that record type. The advantage of this class is that nothing is
recorded unless something happens. In the ideal case, no problems occurred,
so nothing was recorded, and no data analysis is necessary. If a trigger did
occur, then the monitor logged the event for later analysis. This is a powerful
data-reduction tool, and can reduce huge amounts of data into a few small
records containing all the significant events. The disadvantage is that success
completely depends on good thresholds and settings. A threshold that is too
tight will cause the Scanner to log records that aren’t really worth analyzing.
These extraneous records often hide the (hopefully) few important ones. A
threshold that is too loose will cause the Scanner to ignore important distur-
bances. Although it is often possible to use regulatory limits or other known
standards to set thresholds, this can be a chicken-and-the-egg type problem:
sometimes you need to know something about the disturbance before you can
set proper thresholds to capture it. Despite these potential pitfalls, triggered
record types are powerful tools in powerline monitoring. They are most useful
for capturing voltage disturbances and power quality problems. The captured
events are usually presented in a text report. Triggered record types include
Power Outage, Abnormal Voltage, Event Change, Significant Change, and
Waveform Capture.
5.1.2 Non-triggered Record Types
The second class of record types is not event driven. These record types are
always logging data, regardless of how interesting or important the data is.
The classic example is a paper stripchart, which continuously logs data. There
are no thresholds to set, although there may be a parameter to determine how
often to collect data. The logged data is usually presented as a graph of data
points. Although there may be a large amount of data, using a graph lets the
eye pick out important data. Problems such as sags and swells are easy to see
in the Stripchart graphs. In addition to voltage quality studies, these record
types are used for finding daily trends in current or power values, measuring
power factor, etc. The advantage of not having thresholds to set is that there

14 5 WHAT THE 2SX-SERIES SCANNER RECORDS
is no question about what data will be recorded. The disadvantage is that
sometimes there is no question that a lot of data will be recorded, most of
it unimportant. For non-power quality data such as power factor measure-
ment, there is no disadvantage. These record types include Stripcharts, Daily
Profiles, Histograms, and Energy Usage.
5.1.3 Using the Scanner
The PMI Scanner can record every available record type simultaneously. Each
record type has its own fixed memory allocation, so there is no danger of
one errant record type filling the Scanner memory to the exclusion of other
record types (for example, Event Capture can never overflow into Stripchart
memory). Thus the choice usually isn’t what to record types to record, but
what record types to examine. In order to answer that question, a good
understanding of each record type is required. The details of each record
type, and potential uses, are described in the following subsections.
5.2 Stripcharts
The Stripchart is one of the most useful record types. In a single Stripchart
graph, you can see power quality events such as single-cycle voltage sags and
current surges, as well as long term voltage trends. With the graph, an entire
recording session can be examined at a glance.
5.2.1 What’s Recorded
The only setting for the Stripchart is the Stripchart Interval. This Interval,
which can be as small as one second to as large as four hours, determines
how often the Scanner takes a Stripchart data point. Every Stripchart the
Scanner is recording uses the same Interval setting. During the Interval period,
the Scanner keeps a history of the largest and smallest one-cycle values for
each Stripchart, as well as a running average. At the end of the Interval,
the max, min, and average values for that time period are recorded as a
Stripchart data point. For example, if the Stripchart Interval is set to one
minute (a typical setting), at the end of each minute, the Voltage Stripchart
will record the average RMS voltage, the minimum one-cycle RMS voltage,
and the maximum one-cycle RMS voltage, all during that minute. All of the
3600 60Hz cycles during that minute are used to calculate the average, and
for max/min detection.
These values are presented to the user as three traces on a graph: a maxi-
mum, a minimum, and an average. The average trace roughly corresponds to

15 5.2 Stripcharts
a graph from a paper stripchart recorder. The maximum and minimum graphs
are unique, however. Each gives the worst case value for every Interval, with
single-cycle measurement resolution.
Each Scanner has at least enough memory to record Stripcharts for a week
with a one minute Interval. When the Stripchart data fills the Stripchart mem-
ory, the Scanner has two options: it can either stop recording Stripcharts, or go
into “wrap-around” mode. In “wrap-around” mode, the oldest Stripchart data
points are erased to make room for the new ones as they are collected, which
allows the Scanner to always have the latest data. This choice is made by the
user during the Initialization. If the “Enable Stripchart Wraparound” box is
checked, the Scanner will go into “wrap-around” mode as needed, otherwise it
will stop Stripchart recording when memory is full. This does not affect other
record types. For example, if there is memory for one week of Stripcharts, and
the Scanner was left in the field for three weeks, it would either have the first
or the last week’s Stripchart data, depending on the wrap-around setting.
Every Scanner can record a Stripchart of voltage. Some Scanners can also
record a Stripchart of current. With the power option, the 2SX-Series Scanner
can also record Stripcharts for real, reactive, and apparent power, and power
factor. With the harmonics option, the 2SX-Series Scanner can record stripcharts
of harmonic magnitudes. Typically, only a few stripcharts are needed at one
time. All the Stripcharts share the same memory, so enabling more Stripcharts
reduces the total Stripchart recording time.
When creating a Stripchart graph or report, any “gaps” in the data due
to a power outage are filled with zeroes. This happens when the Scanner loses
power, and its rechargeable battery (if present) runs down.
5.2.2 Typical Settings and Suggested Uses
There are three settings for the Stripchart record types. The primary setting is
the Stripchart Interval. This time setting determines how often the Stripchart
data is recorded. Since the Stripcharts always give worst case one-cycle max
and min values, the Interval can be set to any time value without a loss of
measurement resolution. For example, even if the Interval is set to 15 minutes,
the maximum and minimum one-cycle RMS values for each 15 minute period
are recorded. What is lost by setting the Interval to larger values is time
information. If there is a voltage minimum of 90 volts RMS during a Stripchart
interval, with the Interval set to 15 minutes, you are sure that voltage dipped
that low for at least a cycle, but you don’t know when or how often or how
long during that 15 minutes it happened. A smaller Interval, such as one
minute, provides a finer time resolution. The smallest Interval, one second,
gives excellent time resolution, but consumes memory 60 times faster than a

16 5 WHAT THE 2SX-SERIES SCANNER RECORDS
one minute setting. Often, the exact time of a voltage dip is not as important
as the size–for this case, any reasonable Interval setting is fine.
The most common setting is one minute. This is a good balance between
frequent data collection and long recording time. Since most loads that start
and stop usually run for longer than a minute, the start and stop effects (such
as inrush current) are easily spotted in the Stripchart. An example is an air
conditioner load: a forty minute period of cycling on and off is obvious in the
Stripchart graph as twenty data points at one load current, then twenty data
points at low current, all connected by straight lines on the graph. The first
interval of the high current period will probably have a much larger current
maximum than the rest due to the starting current of the air conditioner. The
voltage interval will probably have a dip at the same time.
The most frequent reason to use an Interval smaller than one minute is
for large loads that cycle on and off more frequently than one minute. For
example, if an elevator is causing power quality problems, and it only takes 10
or 20 seconds to start at one floor and stop at another, a one second Interval
is probably necessary, otherwise the entire elevator travel will occur during a
single Stripchart Interval. In this case, the Scanner should not be left to record
for days, since it would only hold the last few hours of Stripchart data. The
best use in this case is to set the Stripchart to one second, then cycle the load
(such as the elevator) for a while, in an attempt to reproduce the problem,
then download the Scanner. In general, the Interval should be smaller than
the quickest cycling time of a problem load.
The most frequent reason to use an Interval larger than one minute is to
increase the recording time. Setting the Interval to two minutes doubles the
recording time, without a serious loss of time resolution. Other common set-
tings are five and fifteen minutes, used to match metering or billing increments
or regulatory time periods.
The second Stripchart setting is the “Stripchart Wrap-Around” mode. The
best setting for this depends on how the Scanner will be used. Some users
leave a Scanner at a problem site until the customer calls with a power quality
complaint. The Scanner is set to a small Interval such as one minute or thirty
seconds, and Wrap-Around is enabled. Because Wrap-Around is enabled, the
Stripcharts always have the latest few days of data in memory, by discarding
the old data. The Scanner is downloaded, and has the most recent days
of Stripchart data in memory, no matter how long it was recording. This
recent data will have the voltage disturbance in it. Other users will disable
Wrap-Around, and leave a Scanner at a problem site where the power quality
problem will definitely occur soon. The Scanner will record the first week or
so of Stripchart data, then stop Stripchart recording. The Scanner can be

17 5.3 Daily Profiles
downloaded at any time later, knowing that the beginning of the recording
session is locked in memory, and will not be overwritten. Other users always
download the Scanner before it fills up Stripchart memory, which make the
Wrap-Around setting irrelevant. The choice depends on how the Scanner will
be used. The factory default setting is for Wrap-Around to be enabled.
The third Stripchart setting is which Stripcharts are enabled. For voltage-
only Scanners, there is no choice: a voltage Stripchart is always recorded. For
Scanners that can record current, the current Stripchart can be turned off to
extend the recording time of the voltage Stripchart. It is usually better to
increase the Interval time instead of disabling current to get more recording
time. For the ViP Scanner, there are many more Stripcharts to enable or
disable. The choice depends on what information is needed. If a power factor
study is being performed, for example, turn on power factor, and possibly
apparent power and displacement power factor. If a power quality problem
is present, only voltage and current may be necessary, although adding Total
Harmonic Distortion (THD) may be useful to see if harmonics are present.
The total recording time is shown by Winscan as Stripcharts are enabled and
disabled during the Scanner setup. Another method to increase Stripchart
memory is to reduce the number of recorded channels. If only three channels
are needed on the ViP, changing the number of channels from four to three
gives 25% more recording time.
For quantities such as power factor, phase angle, THD, etc. often the
average is much more important than the one-cycle max and mins. The max
and min traces on the graph may be turned off so that they don’t obscure the
average trace.
5.3 Daily Profiles
The Daily Profiles are used to spot daily trends in voltage, current, power
factor, etc. The entire recording session is combined to form the “average”
24-hour day, which is plotted on a graph like a stripchart. Power quality issues
are usually not addressed with Daily Profiles (except perhaps consistently low
or high line voltage or harmonic distortion). Rather, average line conditions
such as regulation voltage, load current, etc. are profiled.
5.3.1 What’s Recorded
Each measured quantity has only one Daily Profile per channel in a recording
session. For example, there are two voltage Daily Profiles in a recording
session, one per channel. The Profile is averaged over the entire recording
session. This average is created by dividing the 24-hour day into 96 time

18 5 WHAT THE 2SX-SERIES SCANNER RECORDS
periods, each 15 minutes long. During each 15 minute period, the Scanner
computes the average value for that Profile (voltage, current, etc.). This 15
minute average is then averaged with all the previous days’ averages of that
15 minute period. For example, the first Voltage Daily Profile data point is
the average voltage during the 15 minute period from 12:00am to 12:15am,
averaged again over the entire recording time. If a Scanner is recording for a
week, then this 12:00-12:15am period is averaged seven times over the entire
week.
There are no settings for Daily Profiles. All available Daily Profiles in a
Scanner are always enabled, regardless of the settings for any other record
types. Memory does not run out for a Daily Profile; it just keeps averaging as
long as the recording session lasts (there is a practical limit of about a year).
Some Scanners record just a voltage Profile, others voltage and current. The S-
Series Scanner with power and harmonics options records a Profile for voltage,
current, real, reactive and apparent power, power factor, voltage and current
THD, and phase angle.
5.3.2 Suggested Uses
Daily Profiles are typically used to profile or characterize a parameter, such as
average load current or power factor. Since the Profile is supposed to reflect
average line conditions, the more loads included in the recording, the better
the average. Monitoring a single small load such as a small office building
would not create a very good profile of distribution line conditions (such as
distribution line power factor), since the building would be a small part of the
total distribution load. Voltage is somewhat of an exception in that anywhere
can be good place to create a profile: every other load (at least those nearby)
will see the same distribution line voltage. The ideal location for creating
power factor profiles is where a PFC would be placed to correct power factor.
The voltage Daily Profile is normally used to identify voltage regulation
problems, or other steady-state low/high voltage issues. The current Profile
can be used to identify daily trends in load current. This is also possible
with the apparent power Profile. Power factor and reactive power Profiles can
be used to set PFC timers to correct for power factor only when necessary
during the day. The voltage and current THD Profiles show when harmonic
distortion is present during the day.
The more days the Scanner records, the better the average created by the
Profile. A recording session that just lasts a single day doesn’t incorporate
any daily averaging at all. Since a Profile starts with all zeros, a recording
session that doesn’t even last 24 hours will include some 15 minute blocks with
the data still zeroed. A recording session that doesn’t even last 15 minutes

19 5.4 Cycle Histograms
will have all zeroes for a Daily Profile.
A Stripchart can also be used for profiling tasks, but is not ideal. The
stripchart interval is usually set to an interval faster than 15 minutes; a fast
interval can show too much information, making it hard to form a good aver-
age Profile. Often the stripchart only has enough memory for a week or two,
limiting the averaging time; the Daily Profiles have no such limit. Most im-
portantly, the stripchart does not divide the data into an averaged day period,
so it can difficult to spot daily trends in the graph.
5.4 Cycle Histograms
The cycle histograms contain valuable power quality information as well as
information for distribution line profiling. Questions such as “what were the
absolute highest and lowest RMS voltage?”, “how many cycles was the voltage
below 80 volts?”, and “what are the most common load currents?” are easily
answered. The histograms also contain the raw data necessary to answer more
complicated statistical questions such as “what is the probability of a voltage
sag below 100 volts?” and “what high and low limits does the line voltage
meet 99.99% of the time?”. Where the Daily Profiles give average current,
power factor, etc. for distribution profiling, the histograms show what values
are the most common–the “mode” in statistical terms.
5.4.1 What’s Recorded
A Histogram divides a measurement range into many bins. For example, in
the Vip, the voltage Histogram divides the 290V voltage range into 290 bins,
each one volt wide, giving a bin for zero volts, a bin for one volt, two volts,
all the way to 600 volts. After each 60Hz cycle is measured, the voltage is
rounded to the nearest volt and “put” in the appropriate bin. The bins are
really counters that count how many cycles were at that voltage. If the 108
volt bin has a count of 45, then there have been 45 cycles with an RMS voltage
of exactly 108 volts, sometime during the recording session. The Histogram
throws away time information: those 45 cycles could have occurred anytime
during the recording session. They may have been 45 cycles in a row, or
three 15-cycle sags, or 45 isolated sags spread out during the entire recording
session. (To recover the time information, use the Stripchart or an event-based
report.)
Every Stripchart max and min value will have a non-zero count in the
corresponding Histogram. For example, if the voltage Stripchart shows six
sags to 108 volts sometime during the recording session, there should be a

20 5 WHAT THE 2SX-SERIES SCANNER RECORDS
count of at least six in the Histogram at 108 volts. The count will probably
be somewhat larger, unless each sag was only one cycle long.
There are no settings for Histograms. All available Histograms in a Scan-
ner are always enabled, regardless of the settings for any other record types.
Memory does not run out for a Histogram; it just keeps classifying measure-
ments into the bins (by incrementing the bin counters) as long as the recording
session lasts.
The neutral to ground voltage channel on the 2SX-Series Scanner records a
histogram with tenth-volt increments, from 0.0 to 90.0 volts.
5.4.2 Suggested Uses
The power of the Histogram is that every cycle is included in the report. Every
cycle during the recording session is reflected in the count of one of the bins.
If all the counts in a Histogram are totaled, the result is how many cycles the
recording session lasted (minus any time under a power outage).
Histograms are presented as a bar graph and a report. The report is in
some ways easier to read than the graph. The absolute highest and lowest
voltages during the recording session are found by finding the highest and
lowest bins with a non-zero count. At that point you also know how many
cycles the voltage was at those extremes, and by glancing at the nearby bins,
you know how many cycles the voltage was near those extremes. For example,
if all the bins below 110 volts are zero, then you immediately know that there
was not even a single cycle of voltage below 110 volts anytime during the
recording session. If the count at 111 volts is 1,352,200, then the voltage was
at 111 volts for over 6 hours (1; 352; 200=(60 ‡ 60 ‡ 60)). By totaling the
counts for all the bins in a voltage range (for example, 0 to 90 volts), you find
how many cycles the voltage was in that range.
More complicated power quality questions can be answered by exporting
the histogram data to a spreadsheet. By dividing each count by the total of
all the counts, the histogram data is normalized, and can represent a sample
probability distribution function. If a normal, or bell-shaped probability dis-
tribution is fit to this data, a standard deviation is created that can be used
to answer “what high and low limits does the line voltage meet 99.99% of the
time?”. A cumulative sum over the data will convert the distribution function
into a sample cumulative probability function. Correlations between channels
can be performed by comparing the probability functions of channels.
For the voltage histogram, most of the time the user is interested in the
few cycles that are outside certain limits, not the vast majority of cycles that
are perfectly normal. These few cycles usually represent power quality issues.
The current, power, and power factor histograms are useful for distribution