WT310/WT310HC/WT330
Digital Power Meter
Getting Started Guide
IM WT310-02EN
1st Edition
Product Registration
Thank you for purchasing YOKOGAWA products.
YOKOGAWA provides registered users with a variety of information and
services.
Please allow us to serve you best by completing the product registration
form accessible from our homepage.
http://tmi.yokogawa.com/
PIM 103-03E
Thank you for purchasing the WT310, WT310HC, or WT330 Digital Power Meter (hereinafter, “WT310/
WT310HC/WT330” will refer to all of these products). The WT310/WT310HC/WT330 is a power
measurement instrument that can measure parameters such as voltage, current, and power.
This getting started guide primarily explains the handling precautions and basic operations of the
WT310/WT310HC/WT330. To ensure correct use, please read this manual thoroughly before
beginning operation.
Keep this manual in a safe place for quick reference in the event that a question arises.
This manual is one of three WT310/WT310HC/WT330 manuals. Please read all manuals.
Manual TitleManual No.Description
WT310/WT310HC/WT330 Digital
Power Meter User’s Manual
WT310/WT310HC/WT330 Digital
Power Meter Getting Started Guide
WT310/WT310HC/WT330 Digital
Power Meter Communication
Interface User’s Manual
IM WT310-01EN The manual explains all the WT310/WT310HC/WT330
features, except for the communication interface
features, and how to use them.
IM WT310-02EN This guide. Provided as a printed manual. The manual
explains the handling precautions and basic operations
of the WT310/WT310HC/WT330 and provides an
overview of its features.
IM WT310-17EN This manual explains the WT310/WT310HC/WT330
communication interface features and how to use them.
PDF files of all the manuals above are included in the accompanying CD.
Notes
• The contents of this manual are subject to change without prior notice as a result of continuing
improvements to the instrument’s performance and functionality. The figures given in this manual
may differ from those that actually appear on your screen.
•
Every effort has been made in the preparation of this manual t
contents. However, should you have any questions or find any errors, please contact your nearest
YOKOGAWA dealer.
• Copying or reproducing all or any part of the contents of this manual without the permission of
YOKOGA
• The TCP/IP
WA is strictly prohibited.
software of this product and the documents concerning it have been developed/created
by YOKOGAWA based on the BSD Networking Software, Release 1 that has been licensed from
the Regents of the University of California.
o ensure the accuracy of its
Trademarks
• Microsoft, Internet Explorer, MS-DOS, Windows, Windows NT, Windows XP, Windows Vista, and
Windows 7 are either registered trademarks or trademarks of Microsoft Corporation in the United
States and/or other countries.
•
Adobe and Acrobat are either registered trademarks or tradem
• In this manual, the TM and
® symbols do not accompany their respective registered trademark or
trademark names.
• Other company and product names are registered trademarks or trademarks of their respective
holders.
Unpack the box and check the contents before operating the instrument. If the wrong items have been
delivered, if items are missing, or if there is a problem with the appearance of the items, contact your
nearest YOKOGAWA dealer.
WT310/WT310HC/WT330
Check that the product that you received is what you ordered by referring to the model name and suffix
code given on the name plate on the left side panel.
The WT330 includes the WT332 and WT333.
ModelSuffix CodeDescription
WT310WT310 Digital Power Meter
One input element model
WT310HCWT310 Digital Power Meter
One input element/large current model
WT332WT330 Digital Power Meter
Two input element model
WT333WT330 Digital Power Meter
Power cord
Communication interface-C1GP-IB interface
(The instrument is equipped
with one of these.)
Options/C7Ethernet Communication
1
-DUL/CSA Standard power cord (Part No.: A1006WD)
-FVDE Standard power cord (Part No.: A1009WD)
-QBS Standard power cord (Part No.: A1054WD)
-RAS Standard power cord (Part No.: A1024WD)
-HGB Standard power cord (Part No.: A1064WD)
-NNBR Standard power cord (Part No.: A1088WD)
-C2RS-232 interface
/EX1
/EX2
/G5Harmonic measurement
/DA4DA output (4CH); for the WT310 or WT310HC
/DA12DA output (12CH); for the WT332 or WT333
1 Make sure that the attached power cord meets the designated standards of the country and area
that you are using it in.
2 A single instrument cannot have both the /EX1 and /EX2 optio
Three input element model
Maximum rated voltage: 125 V
Maximum rated voltage: 250 V
Maximum rated voltage: 250 V
Maximum rated voltage: 250 V
Maximum rated voltage: 250 V
Maximum rated voltage: 250 V
2
2.5 V/5 V/10 V external input
2
50 mV/100 mV/200 mV/500 mV/1 V/2 V external input
ns.
No. (Instrument number)
When contacting the dealer from which you purchased the instrument, please give them the instrument
number.
Standard Accessories
D/A cable
3
B9879SX
Current input protection
cover
4
B8212BX
Current input protection
cover
5
B8212FX
Rubber feet
A9088ZM
One set of manuals
6
Safety terminal adapter set
2
758931
UL/CSA Standard
A1006WD
VDE Standard
A1009WD
BS Standard
A1054WD
AS Standard
A1024WD
D
F
Q
R
Power cord (one cord that matches the suffix code is included)
1
GB Standard
A1064WD
H
NBR Standard
A1088WD
N
The instrument is shipped with the following accessories. Make sure that all accessories are present
and undamaged.
Checking the Contents of the Package
1 Make sure that the attached power cord meets the designated standards of the country and area
that you are using it in.
2 Same number of sets as the number of installed input elements
WT310: One set with one hexagonal socket wrench
WT310HC: One set with one hexagonal socket wrench
WT332: Two sets with one hexagonal socket wrench
WT333: Three sets with one hexagonal socket wrench
3
Included with models that have D/A output and remote control (/DA4 or /DA12)
4 For the WT310/WT310HC
5 For the WT332/WT333
6 For information on the types of printed manuals and manuals on the CD that are provided, see
page i.
IM WT310-02EN
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iv
IM WT310-02EN
Checking the Contents of the Package
CD-R
The CD-R contains the data listed below. To view the PDF user’s manuals, you need Adobe Reader 5.0
or later.
PDFs of the WT310/WT310HC/WT330 User’s Manuals
These manuals are in the Manuals folder.
English
• WT310/WT310HC/WT330 Digital Power Meter User’s Manual
IM WT310-01EN
• WT310/WT310HC/WT330 Digital Power Meter Getting Started Guide
IM WT310-02EN
• WT310/WT310HC/WT330 Digital Power Meter Communication Interface User’s Manual
IM WT310-17EN
Japanese
• WT310/WT310HC/WT330 Digital Power Meter User’s Manual
IM WT310-01JA
• WT310/WT310HC/WT330 Digital Power Meter Getting Started Guide
IM WT310-02JA
• WT310/WT310HC/WT330 Digital Power Meter Communication Interface User’s Manual
IM WT310-17JA
Installer for the WTViewerFreePlus Application Software (For the
WT310/WT310HC/WT330)
• WTViewerFreePlus_Installer.exe
• WTViewerFreePlus (folder)
• YKMUSB (folder)
PDF of the Manual for the WTViewerFreePlus Application Software
These manuals are in the Manuals folder.
English
• Application Software WTViewerFreePlus for WT310/WT310HC/WT330 User’s Manual
IM 760121-02E
Japanese
• Application Software WTViewerFreePlus for WT310/WT310HC/WT330 User’s Manual
IM 760121-02
WARNING
Never play this CD-R on an audio CD player. Doing so may cause loss of hearing or speaker
damage due to the large sounds that may be produced.
Measurement
lead
758917
Alligator clip
adapter set
758922
Alligator clip
adapter set
758929
Fork terminal
adapter set
758921
Safety terminal
adapter set
758923
External sensor
cable
B9284LK
Safety terminal
adapter set
758931
Conversion adapter
758924
Checking the Contents of the Package
Optional Accessories (Sold separately)
The following optional accessories are available for purchase separately.
For information about ordering accessories, contact your nearest YOKOGAWA dealer.
ItemModel/Min. Q’tyNote
Part No.
External sensor cableB9284LK1For connecting to the WT310/WT310HC/WT330’s
external current sensor input connector.
Length: 0.5 m.
Measurement lead7589171Two leads in one set. Used with the 758922 or
Safety terminal adapter set7589231Two pieces in one set. Rated voltage 600 V.*
7589311Two pieces in one set. Rated voltage 1000 V.*
Alligator clip adapter set7589221Two pieces in one set. For use with measurement
lead 758917.
Rated voltage 300 V.*
7589291Two pieces in one set. For use with measurement
lead 758917.
Rated voltage 1000 V.*
Fork terminal adapter set 7589211Two pieces in one set. For use with measurement
lead 758917.
Rated voltage 1000 V.* Rated current: 25 A.
Conversion adapter7589241BNC-4 mm socket adapter. Rated voltage: 500 V.*
* The actual voltage that can be used is the lowest voltage of the WT310/WT310HC/WT330 and
cable specifications.
IM WT310-02EN
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IM WT310-02EN
Safety Precautions
This instrument is an IEC safety class I instrument (provided with a terminal for protective earth
grounding).
The general safety precautions described herein must be observed during all phases of operation.
If the instrument is used in a manner not specified in this manual, the protection provided by the
instrument may be impaired. YOKOGAWA assumes no liability for the customer’s failure to comply
with these requirements.
The WT310/WT310HC/WT330 is a power measurement instrument that can measure parameters
such as voltage, current, and power. Do not use this instrument for anything other than its intended
purpose.
The following symbols are used on this instrument.
Warning: handle with care. Refer to the user’s manual or service manual. This symbol appears
on dangerous locations on the instrument which require special instructions for proper handling
or use. The same symbol appears in the corresponding place in the manual to identify those
instructions.
Electric shock, danger
Ground (earth) or functional ground terminal (do not use this terminal as a protective ground
terminal.)
Alternating current
Both direct and alternating current
ON (power)
OFF (power)
Power-on state
Power-off state
Safety Precautions
Failure to comply with the precautions below could lead to injury
or death.
WARNING
Use the Instrument Only for Its Intended Purpose
The WT310/WT310HC/WT330 is a power measurement instrument that can measure
parameters such as voltage, current, and power. Do not use this instrument for anything other
than as a power measurement instrument.
Check the Physical Appearance
Do not use the instrument if there is a problem with its physical appearance.
Use the Correct Power Supply
Make sure that the power supply voltage matches the instrument’s rated supply voltage and
that it does not exceed the maximum voltage range specified for the power cord.
Use the Correct Power Cord and Plug
To prevent the possibility of electric shock or fire, be sure to use the power cord supplied by
YOKOGAWA. The main power plug must be plugged into an outlet with a protective earth
terminal. Do not invalidate this protection by using an extension cord without protective earth
grounding.
Additionally, do not use the power cord supplied with this instrument with another instrument.
Connect the Protective Grounding Terminal
Make sure to connect the protective earth to prevent electric shock before turning on the
power. The power cord that comes with the instrument is a three-prong type power cord.
Connect the power cord to a properly grounded three-prong outlet.
Do Not Impair the Protective Grounding
Never cut off the internal or external protective earth wire or disconnect the wiring of the
protective earth terminal. Doing so may result in electric shock or damage to the instrument.
Do Not Operate with Defective Protective Grounding or Fuses
Do not operate the instrument if the protective earth or fuse might be defective. Check the
grounding and the fuse before operating the instrument.
Do Not Operate in an Explosive Atmosphere
Do not operate the instrument in the presence of flammable gasses or vapors. Doing so is
extremely dangerous.
Do Not Remove Covers
Only qualified YOKOGAWA personnel should remove the instrument’s covers. The inside of
the instrument is dangerous because parts of it have high voltages.
Ground the Instrument before Making External Connections
Securely connect the protective grounding before connecting to the item under measurement
or to an external control unit. Before touching a circuit, turn off its power and check that it has
no voltage.
IM WT310-02EN
Measurement Category
This instrument is a measurement category II product. Do not use it for measurement category
III or IV measurements.
Install or Use the Instrument in Appropriate Locations
•
Do not install or use the instrument outdoors or in locations subject to rain or water.
• Install the instrument so that you can immediately remove the
dangerous condition occurs.
power cord if an abnormal or
vii
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IM WT310-02EN
Safety Precautions
Connect Cables Correctly
Power meters can measure large voltages and currents directly. If you use a voltage
transformer or a current transformer together with this power meter, you can measure even
larger voltages or currents. When you are measuring a large voltage or current, the power
capacity of the item under measurement becomes large. If you do not connect the cables
correctly, an overvoltage or overcurrent may be generated in the circuit under measurement.
This may lead to not only damage to the power meter and the item under measurement, but
electric shock and fire as well. Be careful when you connect the cables, and be sure to check
the following points.
Before you begin measuring (before you turn the item under measurement on), check that:
•
Cables have been connected to the power meter’s input terminals correctly.
Check that there are no voltage measurement cables that hav
current input terminals.
Check that there are no current measurement cables that have been connected to the
voltage input terminals.
If you are measuring multiphase power, check that there are no mistakes in the phase
wiring.
• Cables have been connected to the power supply and the item under measurement
correctly.
Check that there are no short circuits between terminals or between connected cables.
•
The cables are connected firmly to the current input terminals.
• There are no problems with the current input terminals and the crimping terminals, such as
the presence of foreign substances.
e been connected to the
During measurement (never touch the terminals and the connected cables when the item
under measurement is on), check that:
There no problems with the input terminals and the crimping terminals, such as the
•
presence of foreign substances.
• The input terminals are not abnormally hot.
• The cables are connected firmly to the input terminals.
The terminal connections may become loose over time. If this happens, heat may be
generated due to changes in contact resistance. If you are going to take measurements
using the same setup for a long time, periodically check that the cables are firmly
connected to the terminals. (Be sure to turn both the power meter and the item under
measurement off before you check the connections.)
After measuring (immediately after you turn the item under measurement of
After you measure a large voltage or current, power may rema
under measurement even after you turn it off. This remaining power may lead to electric
shock, so do not touch the input terminals immediately after you turn the item under
measurement off.
varies depending on the item.
The amount of time that power remains in the item under measurement
in for some time in the item
See below for operating environment limitations.
f):
CAUTION
This is a class A instrument designed for an industrial environment. Operation of this product
in a residential area may cause radio interference in which case the user will be required to
correct the interference.
Waste Electrical and Electronic Equipment
Waste Electrical and Electronic Equipment (WEEE), DIRECTIVE 2002/96/EC
(This directive is valid only in the EU.)
This product complies with the WEEE Directive (2002/96/EC) marking requirement. This
marking indicates that you must not discard this electrical/electronic product in domestic
household waste.
Product Category
With reference to the equipment
as a “Monitoring and control instruments” product.
Do not dispose in domestic household waste. When disposing products in the EU, contact your
local Yokogawa Europe B. V. office.
types in the WEEE directive Annex I, this product is classified
New EU Battery Directive
New EU Battery Directive, DIRECTIVE 2006/66/EC
(This directive is valid only in the EU.)
Batteries are included in this product. This marking indicates they shall be sorted out and
collected as ordained in ANNEX II in DIRECTIVE 2006/66/EC.
Battery type: Lithium battery
You ca
nnot replace batteries by yourself. When you need to replace batteries, contact your
The notes and cautions in this manual are categorized using the following symbols.
Improper handling or use can lead to injury to the user or damage to the
instrument. This symbol appears on the instrument to indicate that the user must
refer to the user’s manual for special instructions. The same symbol appears in
the corresponding place in the user’s manual to identify those instructions. In the
user’s manual, the symbol is used in conjunction with the word “WARNING” or
“CAUTION.”
WARNING
CAUTION
Calls attention to information that is important for the proper operation of the
Note
Calls attention to actions or conditions that could cause serious or fatal injury to
the user, and precautions that can be taken to prevent such occurrences.
Calls attention to actions or conditions that could cause light injury to the user
or cause damage to the instrument or user’s data, and precautions that can be
taken to prevent such occurrences.
software.
Characters That Appear on the 7-Segment LED
Because this instrument uses a 7-segment LED display, numbers, letters, and mathematical symbols
are displayed using special characters. For details, see section 1.3, “Digital Numbers and Characters.”
6.
4.
2.
(Display C)
Configure the storage feature.
(Display B)
1.
3.
5.
Confirm
the setting.
Close menu.
Conventions Used in This Manual
Symbols and Conventions Used in Procedural Explanations
The contents of the procedural explanations are indicated using the following symbols.
This mark appears on the right side of the page to indicate features and settings that can be
operated and configured using the WTViewerFreePlus application software, which comes with the
instrument.
Procedure
Operations are explained using flowcharts. See the example below for an
explanation of how various operations are indicated. All procedures are written
under the assumption that you are starting operation at the beginning of the
procedure, so you may not need to carry out all the steps in a procedure when
you are changing the settings.
Example: Operations for turning the storage feature on and off
The above flow chart indicates the following operations.
You can configure items that are blinking.
Press the SHIFT key so that it illuminates, and then press SETUP (UTILITY).
1.
A menu appears in display B.
Use ▲ or ▼ to select StorE.
2.
Pressing either key cycles through 9 menu items.
Press SET to confirm the selection of StorE.
3.
The StorE function menu that you selected in step 2 appears in display C.
Use ▲ or ▼ to select oFF or on.
4.
Pressing either key cycles through 3 menu items.
Press SET to confirm the selection of oFF.
5.
The selected or set item is confirmed when you press SET.
A menu appears in display B.
Press HOLD (ESC) to return the menu display to the measurement data display.
6.
• When you are making a number positive (no sign) or negative (–) or setting a number, when the
digit in the display that the input will be added to is blank, an underscore flashes at the position of
the digit.
• While you are performing menu operations, to leave the menu display, press HOLD (ESC). All
setting changes that you have confirmed by pressing the SET
Explanation
This section describes the setup items and the limitations regarding the
key will be reflected in the settings.
procedures. It may not give a detailed explanation of the feature. For a detailed
IM WT310-02EN
explanation of the feature, see chapter 1 in the User’s Manual, IM WT310-01EN.
xi
Workflow
Getting Started Guide
Section 2.2
Sections 2.3 and 2.4
Section 2.8
Sections 2.9 to 2.11
Installation and Circuit Wiring
Install the WT310/WT310HC/WT330.
Connect the power supply, and turn the power on.
Select the measurement method.
Wire the circuit under measurement.
Getting Started Guide
Sections 3.1 and 3.2
Section 3.3
Voltage, current, and active power
Apparent power, reactive power, and power factor
Phase angle and frequency
Peak value
Crest factor, etc.
Integrated power (watt hour)
Harmonic measurement
User’s Manual
Chapter 7
Section 8.4 and chapter 5 of the
Getting Started Guide
Communication Interface
User’s Manual
Acquire Data
Store data to internal memory.
Transmit data using D/A output (option).
Transmit data through the USB, GP-IB,
RS-232, or Ethernet interface.
Read the precautions in sections 2.5 and 2.7 thoroughly before connecting the wires.
Also, if necessary, assemble the input terminal adapter that connects to the voltage
input terminal (see section 2.6) before connecting the wires.
The figure below is provided to familiarize the first-time user with the workflow of WT310/WT310HC/
WT330 operation. For a description of an item, see the relevant section or chapter. In addition to
the sections and chapters that are referenced in the figure below, this manual also contains safety
precautions for handling and wiring the instrument. Be sure to observe the precautions.
xii
IM WT310-02EN
1
2
3
4
5
6
7
App
Contents
Checking the Contents of the Package.............................................................................................ii
Lights when the harmonic measurement display is on
Key protection indicator (KEY PROTECT)
Lights when the keys are locked
7-segment LED display
Displays the measured data for the function that you select using the function key
and displays menus when you are using menus to configure the settings
Function and unit indicators
Indicates the type of function and unit that are being shown on the
7-segment LED display
WT310/WT310HC
Component Names and Functions
IM WT310-02EN
1-5
1-6
IM WT310-02EN
Auto range monitor (CHECK RANGE)
Lights when an input signal meets the conditions for auto range switching
Measurement mode indicator (MODE)
Indicates the voltage and current measurement modes
Data update indicator (UPDATE)
Blinks when measurement data is being updated.
MAX HOLD indicator (MAX HOLD)
Lights when MAX HOLD is enabled
Scaling indicator (SCALING)
Lights when scaling is enabled
Averaging indicator (AVG)
Lights when averaging is enabled
Line filter indicator (FILTER-LINE)
Lights when the line filter is enabled
Frequency filter indicator (FILTER-FREQ)
Lights when the frequency filter is enabled
Storage indicator (STORE)
When you start storage, this indicator blinks at the pace at which storage is taking place.
Remote indicator (REMOTE)
Lights when the WT310/WT310HC/WT330 is in remote mode
Lights when the harmonic measurement display is on
Key protection indicator (KEY PROTECT)
Lights when the keys are locked
7-segment LED display
Displays the measured data for the function that you select using the function key and
displays menus when you are using menus to configure the settings
Function and unit indicators
Indicates the type of function and unit that are being shown on the
7-segment LED display
Wiring method indicator
Indicates the wiring method
1.2 Displayed Items
WT330
1
1.3 Digital Numbers and Characters
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
Lowercase c
Lowercase h
U
V
W
X
Y
Z
+
–
×
÷
^ (exponentiation)
Because this instrument uses a 7-segment LED display, numbers, letters, and mathematical symbols
are displayed using special characters in the manner shown below. Some of the characters shown
below are not used by this instrument.
Component Names and Functions
IM WT310-02EN
1-7
1-8
IM WT310-02EN
1.4 Keys
WT310/WT310HCWT330
Switching the Display
FUNCTION Key
Choose which function to display.
ELEMENT Key (Only on the WT330)
Choose which input element to display. The indicator of the selected element lights.
Measurement Range and Mode
VOLTAGE Key
Displays the voltage range setting menu. The AUTO indicator lights when the range is set to AUTO.
CURRENT Key
Displays the current range setting menu. The AUTO indicator lights when the range is set to AUTO.
SHIFT+VOLTAGE (MODE) Key
Switches the measurement mode.
Wiring System
WIRING Key (Only on the WT330)
Select the wiring system that corresponds to the wiring system you are using to connect to the voltage
and current terminals on the rear panel.
1
Display Hold/MAX Hold
SHIFT+CURRENT (MAX HOLD) Key
Turns the MAX hold feature on and off. When the MAX hold feature is on, the MAX HOLD indicator
lights.
HOLD Key
Switches from updating the display after each data update interval to stopping the series of display
operations and holding the display of the numeric data. The HOLD key lights. If you press HOLD
again, the data starts getting updated again, and the HOLD key light turns off.
SHIFT + HOLD Key
While the numeric data is held, press SINGLE to measure data only once at the set data update
interval and then update and hold the displayed values.
General-Purpose Keys
▲ and ▼ Keys
Select features and set values.
SHIFT+▼ (►) Key
Moves the digit that is being set in a value to the right (or from the farthest right position back to the
farthest left position)
1.4 Keys
Component Names and Functions
SHIFT+▲ (.) Key
Moves the decimal point to the right (or from the farthest right position back to the farthest left position)
SET Key
Confirms the specified range, feature, or value
Zero-Level Compensation
SHIFT+SET Key (CAL)
Executes zero-level compensation. When zero-level compensation is executed, the WT310/WT310HC/
WT330 creates a zero input condition in its internal circuitry and sets the zero level to the level at that
point.
IM WT310-02EN
1-9
1-10
IM WT310-02EN
1.4 Keys
Integrated Power (Watt hour)
START Key
Starts integration
STOP Key
Stops integration
SHIFT+START (INTEG SET) Key
Displays a menu for setting the integration mode, timer, and rated integration time
SHIFT+STOP Key (RESET)
Resets the integrated value and the elapsed integration time.
Communication Interface
INTERFACE Key
Displays the communication interface setting menu and connection information
Key Lock
SHIFT+INTERFACE (KEY PROTECT) Key
Turns key protection on and off.
The key protection indicator lights, and the front panel keys are locked. Press this key combination
again to unlock the keys.
1
Other Features
SETUP Key
Set the measurement synchronization source, input filter, scaling, external sensor input, averaging,
computation, data update interval, etc.
SAVE/LOAD Key
Save or load setup data.
SHIFT+SETUP (UTILITY) Key
Displays a menu for displaying system information (model information, suffix code, instrument number,
and firmware version), initializing settings, setting the number of displayed digits, performing self-tests,
and configuring crest factor, storage, network, and D/A output settings.
SHIFT+SAVE/LOAD (HARMONICS) Key
Displays a setting menu for turning the harmonic measurement display on and off, setting the PLL
source, etc.
SHIFT Key
When you press the SHIFT key once, an indicator illuminates, and you can access the features that
are written in purple below each key. Pressing the key again disables the shifted state. Holding the key
for at least two seconds enables SHIFT lock.
SHIFT (LOCAL) Key
Press this key to switch from remote mode (in which the REMOTE indicator is illuminated) to local
mode (in which front panel key operations are valid). This key is disabled when the WT310/WT310HC/
WT330 is in local lockout mode.
1.4 Keys
Component Names and Functions
ESC Key
Pressing this key when a setup menu is showing returns the screen to the waveform data display.
IM WT310-02EN
1-11
1-12
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1.5 Auto Range, Overrange, and Error Indications
WT310/WT310HCWT330
During Measurement
Overrange Indication
The measured voltage and rated current values are determined to be overrange when they exceed
140% of their rated range.* When auto range is enabled, the range is automatically increased, but
if a values exceeds 140% of its maximum range, it is determined to be overrange, and the following
indication appears.
* On the WT310HC, the current is determined to be overrange when it exceeds 110% of the
maximum current range (40 A range).
Computation Overflow Indication
If a computed value cannot be displayed using the specified decimal place or unit, the following
indication appears.
Auto Range Monitor Indications
When an input signal meets the conditions for auto range switching, an indicator lights.
Colors and Meanings of Auto Range Monitor Indicators
ColorDescription
RedPeak overrange
MagentaGreater than 140% of the rated range (overrange)
YellowGreater than 130% of the rated range and not more than 140% (condition for raising the auto range)
Cyan30% or less of the rated range (condition for reducing the auto range)
If the range is already at the minimum measurement range, this indicator will not light even when
values are 30% or less of the rated range.
1 On the WT310HC, the current is determined to be overrange when it exceeds 110% of the maximum current
range (40 A range).
2 On the WT310HC, the current is determined to be overrange when it exceeds 100% of the maximum current
range (40 A range).
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Indications When the Measured Value Is Too Small
When the measured voltage or current is 0.5% or less of the rated range (1% or less when the
crest factor is set to 6), the following indications appear. These indications only appear when the
measurement mode is RMS or VOTLAGE MEAN.
FunctionIndication
Voltage, current, apparent power, or reactive powerA zero appears.
Power factor or phase angle
Measurement Suspension/No Data Indication (Dashes)
When the measurement range, function, or element is switched and the displayed contents change or
when there is no data to display, the following dashes are displayed temporarily.
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1.5 Auto Range, Overrange, and Error Indications During Measurement
Error
Displayed in cases such as when a measured value is outside of its determined range.