YOKOGAWA WT200 User manual

Digital Power Meter
IM 253421-01E
1st Edition

i
IM 253421-01E
Thank you for purchasing the YOKOGAWA WT200 Digital Power Meter.
This User’s Manual contains useful information regarding the instrument’s functions
and operating procedures, as well as precautions that should be observed during use.
To ensure proper use of the instrument, please read this manual thoroughly before
operating it.
Keep the manual in a safe place for quick reference whenever a question arises.
Notes • The contents of this manual are subject to change without prior notice.
• Every effort has been made in the preparation of this manual to ensure the accuracy
of its contents. However, should you have any questions or find any errors, please
contact your dealer or YOKOGAWA sales office.
• Copying or reproduction of all or any part of the contents of this manual without
YOKOGAWA’s permission is strictly prohibited.
Trademarks Company and product names that are used in this manual are trademarks or registered
trademarks of their respective holders.
Revisions 1st Edition: April 2000
Disk No. BA36
1st Edition: April 2000(YK)
All Rights Reserved, Copyright © 2000 Yokogawa Electric Corporation

ii IM 253421-01E
Checking the Contents of the Package
Unpack the box and check the contents before operating the instrument. In case the
wrong instrument or accessories have been delivered, or if some accessories are not
present, or if they seem abnormal, contact the dealer from which you purchased them.
WT200 Main Unit Check that the model code and suffix code given on the name plate located at the right
side of the main body are according to your order.
WT200 (model code: 253421)
Made in Japan
SUFFIX
MODEL
NO.
Made in Japan
SUFFIX
MODEL
NO.
Model and Suffix codes
Model code Suffix code Specifications
253421.........................................WT200
Power cord -D ..................... UL,CSA Standard Power Cord (Part NO.: A1006WD)
[Maximum rated voltage: 125 V; Maximum rated current: 7 A]
-F...................... VDE Standard Power Cord (Part No.: A1009WD)
[Maximum rated voltage: 250 V; Maximum rated current: 10 A]
-R .....................SAA Standard Power Cord (Part No.: A1024WD)
[Maximum rated voltage: 240 V; Maximum rated current: 10 A]
-Q .....................BS Standard Power Cord (Part No.: A1054WD)
[Maximum rated voltage: 250 V; Maximum rated current: 10 A]
Options
Communication Interface /C1....... GP-IB interface
(Select either one) /C2....... RS-232-C interface
External sensor input function /EX1 .... 2.5/5/10 V range
(Select either one) /EX2 .... 50/100/200 mV range
Harmonic analysis function /HRM ... –
External input/output function /DA4 ... 4-channel D/A output
(Select either one) /CMP .. 4-channel comparator, 4-channel D/A output
Ex: GP-IB interface, with UL/CSA power cord, with external sensor input 50/100/200 mV range,
with harmonic analysis function, and 4 channels D/A output →253421-D/C1/EX2/HRM/DA4
NO. (instrument number)
When contacting the dealer from which you purchased the instrument, please quote the
instrument No.

iii
IM 253421-01E
Standard Accessories
The following standard accessories are supplied with the instrument. Make sure that
all items are present and undamaged.
Name Part No. Q’ty Remarks
1 Power cord see page ii 1 —
2 24-pin connector A1004JD 1 For remote, D/A output
(only provided with options /DA4 or /CMP)
3 Rubber feet A9088ZM 1 set
4 User’s Manual IM253421-01E 1 this manual
2. 3. 4.
D F R
Q
1. An appropriate power cord according to
the instrument's suffix code is supplied.
Note
We recommend you keep the packing box. The box is useful when you need to transport the
instrument.
Checking the Contents of the Package

iv IM 253421-01E
Safety Precautions
This instrument is a IEC safety class I instrument (provided with terminal for protective
grounding).
The following general safety precautions must be observed during all phases of
operation, service and repair of this instrument. If this instrument is used in a manner
not sepecified in this manual, the protection provided by this instrument may be
impaired.
Also,YOKOGAWA Electric Corporation assumes no liability for the customer’s failure to
comply with these requirements.
The following symbols are used on this instrument.
To avoid injury, death of personnel or damage to the instrument, the operator
must refer to an explanation in the User's Manual or Service Manual.
Danger, risk of electric shock
Alternating current
ON (power)
OFF (power)
In-position of a bistable push control
Out-position of a bistable push control
Ground

v
IM 253421-01E
Make sure to comply with the following safety precautions. Not complying might
result in injury or death.
WARNING
Do not Operate in an Explosive Atmosphere
Do not operate the instrument in the presence of flammable liquids or vapors.
Operation of any electrical instrument in such an environment constitutes a
safety hazard.
Protective Grounding
Make sure to connect the protective grounding to prevent an electric shock
before turning ON the power.
Necessity of Protective Grounding
Never cut off the internal or external protective grounding wire or disconnect the
wiring of protective grounding terminal. Doing so poses a potential shock
hazard.
Defect of Protective Grounding
Do not operate the instrument when protective grounding or fuse might be
defective.
Power Cord and Plug
To prevent an electric shock or fire, be sure to use the power cord supplied by
YOKOGAWA. The main power plug must be plugged in an outlet with
protective grounding terminal. Do no invalidate protection by using an extension
cord without protective grounding.
Power Supply
Ensure the source voltage matches the voltage of the power supply before
turning ON the power.
External Connection
To ground securely, connect the protective grounding before connecting to
measurement or control unit.
Fuse
The power fuse of this instrument cannot be replaced by the user, because it is
located inside the case. If you believe the fuse inside the case is blown, contact
your nearest YOKOGAWA dealer as listed on the back cover of this manual.
Do not Remove any Covers
There are some areas with high voltage. Do not remove any cover if the power
supply is connected. The cover should be removed by qualified personnel only.
Safety Precautions

vi IM 253421-01E
Structure of this Manual
This User's Manual consists of the following 16 chapters and an index.
Chapter 1 Functional Overview and Digital Display
Describes the input signal flow, functional overview, digital numbers/characters,
initial menus that are displayed when a key is pressed, and other information..
Chapter 2 Names and Uses of Parts and the Overrange and Error Displays
Gives the name of each part and each key, and describes how to use it. This
chapter also gives the displays in case of overrange/error during measurement.
Chapter 3 Before Starting Measurements
Describes points to watch during use and describes how to install the instrument,
wire the measuring circuits, connect the power cord and switch the power ON/OFF.
Chapter 4 Setting Measurement Conditions and Measurement Range
Explains settings such as measurement mode, filter ON/OFF, measurement range,
scaling in case of external PT/CT or external sensor (such as shunt or clamp),
averaging and measurement conditions.
Chapter 5 Displaying the Results of the Measurement and Computation
Explains the procedures for displaying the voltage, current, active power, apparent
power, reactive power, power factor, phase angle, frequency, peak value, value
derived from four arithmetical operations, and crest factor.
Chapter 6 Integration
Explains the procedures for integration of active power and current.
Chapter 7 Using the Harmonic Analysis Function (Optional)
Explains the procedures when using the harmonic analysis function.
Chapter 8 Storing/Recalling Measured Data and Setting Parameters from the Internal
Memory
Explains the procedures when storing or recalling measured data or setting
parameters from the internal memory.
Chapter 9 Using External Input/Output
Explains the procedures for remote control, D/A output (option), external plotter/
printer output and comparator (option).
Chapter 10 Using the GP-IB Interface (Optional)
Explains the procedures for controlling the instrument by personal computer and
for sending measurement/computed data to a personal computer using the GP-IB
interface.
Chapter 11 Using the RS-232-C Interface (Optional)
Explains the procedures for controlling the instrument by personal computer/
controller and for sending measurement/computed data to a personal computer/
controller using the RS-232-C interface.
Chapter 12 Initializing Setup Parameters and Performing Zero Level Compensation
Explains the procedures such as backing up setting parameter and initializing
settings.
Chapter 13 Communication Commands 1 (System of Commands before the IEEE 488.2-
1987 Standard)
Describes communication commands and sample programs that follow the rules
that existed before the establishment of the IEEE 488.2-1987 Standard.
Chapter 14 Communication Commands 2 (System of Commands Complying to the IEEE
488.2-1987 Standard)
Describes communication commands and sample programs that comply with the
IEEE 488.2-1987 Standard.
Chapter 15 Adjustment, Calibration and Trouble-Shooting
Explains the procedures for calibration, adjustment, the way to verify trouble, the
contents of error messages and the way to replace the fuse.
Chapter 16 Specifications
Describes the specifications of the instrument.
Index Index of contents.

vii
IM 253421-01E
Conventions Used in this Manual
Symbols Used
The following symbol marks are used throughout this manual to attract the operator’s
attention.
A symbol mark affixed to the instrument. Indicates danger to
personnel or instrument and the operator must see the User's
Manual. The symbol is used in the User's Manual to indicate the
reference.
WARNING Describes precautions that should be observed to prevent the
danger of serious injury or death to the user.
CAUTION Describes precautions that should be observed to prevent the
danger of minor or moderate injury to the user, or the damage to
the property.
Note
Provides information that is important for proper operation of the
instrument.
Displayed Characters on the 7-Segment LED
In order to display all numbers and alphabetic characters on the 7-segment LED, some
of them are displayed in a slightly altered format. For details, see section 1.3.

viii IM 253421-01E
Conventions Used in this Manual
Markings used for Descriptions of Operations
Keys Indicates the relevant panel keys and indicators to carry out the
operation.
Procedure The procedure is explained by a flow diagram. For the meaning of
each operation, see the example below. The operating procedures
are given with the assumption that you are not familiar with the
operation. Thus, it may not be necessary to carry out all the steps
when changing settings.
Explanation Describes settings and restrictions relating to the operation.
An example of an Operating Procedure
1.
SHIFT SETUP
OUTPUT
ENTER
3.
(Display C)
(Display C)
2.
ENTER
5.
4. End of
setting
The items in this figure are obtained by the following setting procedures. The blinking
part of the display can be set.
1. After pressing the SHIFT key and the SHIFT indicator is lit, press the SETUP
(OUTPUT) key. The output setting menu will appear on display C.
2. Select
rELAY using the up/down keys.
Pressing either key, 4 selectable items will be displayed consecutively.
3. Verify the setting by pressing the ENTER key.
The setting menu corresponding to the item selected at step 2 will appear at
display
C.
4. Select
oFF or on using the up/down keys.
Pressing either key, 6 selectable items will be displayed consecutively.
5. Verify the setting by pressing the ENTER key.

ix
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11
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13
14
15
16
Index
Contents
Checking the Contents of the Package ...........................................................................................ii
Safety Precautions .........................................................................................................................iv
Structure of this Manual .................................................................................................................vi
Conventions Used in this Manual..................................................................................................vii
Chapter 1 Functional Overview and Digital Display
1.1 System Configuration and Block Diagram ....................................................................... 1-1
1.2 Functions ......................................................................................................................... 1-2
1.3 Digital Numbers/Characters, and Initial Menus................................................................ 1-5
Chapter 2 Names and Uses of Parts and the Overrange and Error Displays
2.1 Front Panel, Rear Panel and Top View ............................................................................ 2-1
2.2 Operation Keys and Function Display.............................................................................. 2-2
2.3 Displays in case of Overrange/Error during Measurement .............................................. 2-3
Chapter 3 Before Starting Measurements
3.1 Usage Precautions........................................................................................................... 3-1
3.2 Installing the Instrument ................................................................................................... 3-2
3.3 Wiring Precautions........................................................................................................... 3-4
3.4 Improving the Measurement Accuracy............................................................................. 3-6
3.5 Connecting the Power Supply.......................................................................................... 3-7
3.6 Wiring the Measurement Circuit....................................................................................... 3-8
3.7 Wiring the Measurement Circuit when Using External PT/CT ......................................... 3-9
3.8 Wiring the Measurement Circuit when Using the External Sensor ................................ 3-10
3.9 Turning the Power ON/OFF, Opening Messages........................................................... 3-12
Chapter 4 Setting Measurement Conditions and Measurement Range
4.1 Selecting the Measurement Mode ................................................................................... 4-1
4.2 Selecting the Measurement Synchronization Source ...................................................... 4-3
4.3 Turning the Filter ON/OFF ............................................................................................... 4-4
4.4 Selecting the Measurement Range in case of Direct Input.............................................. 4-5
4.5 Setting the Scaling Constant when External PT/CT is Used ........................................... 4-8
4.6 Selecting the Measurement Range and Setting the Scaling Constant when External
Sensor is Used (option) ................................................................................................. 4-10
4.7 Using the Averaging Function ........................................................................................ 4-12
4.8 Using the MAX Hold Function ........................................................................................ 4-14
4.9 Using the Four Arithmetical Operation Function ............................................................ 4-15
4.10 Computing the Crest Factor........................................................................................... 4-18
4.11 Computing the Average Active Power during Integration............................................... 4-19
4.12 Selecting the Number of Displayed Digits...................................................................... 4-20
Chapter 5 Displaying the Results of the Measurement and Computation
5.1 Displaying Voltage, Current, and Active Power................................................................ 5-1
5.2 Displaying Apparent Power, Reactive Power, and Power Factor..................................... 5-3
5.3 Displaying the Phase Angle ............................................................................................. 5-4
5.4 Displaying the Frequency ................................................................................................ 5-5
5.5 Displaying Peak Value, Four Arithmetic Operation Value, and Crest Factor.................... 5-7

xIM 253421-01E
Contents
Chapter 6 Integration
6.1 Integrator Functions ......................................................................................................... 6-1
6.2 Setting Integration Mode, Integration Type, and Integration Timer .................................. 6-4
6.3 Displaying Integrated Values ........................................................................................... 6-6
6.4 Precautions Regarding Use of Integrator Function .......................................................... 6-9
Chapter 7 Using the Harmonic Analysis Function (Optional)
7.1 Harmonic Analysis Function............................................................................................. 7-1
7.2 Setting the PLL Source and Harmonic Distortion Method................................................ 7-3
7.3 Switching the Harmonic Analysis Function ON/OFF........................................................ 7-5
7.4 Setting the Harmonic Order and Displaying the Results of Harmonic Analysis ............... 7-6
Chapter 8 Storing/Recalling Measured Data and Setting Parameters from the
Internal Memory
8.1 Storing/Recalling Measured Data .................................................................................... 8-1
8.2 Storing/Recalling Setting Parameters .............................................................................. 8-5
Chapter 9 Using External Input/Output
9.1 Remote Control and D/A Output Connector (optional)..................................................... 9-1
9.2 Remote Control (optional) ................................................................................................ 9-2
9.3 D/A Output (optional) ....................................................................................................... 9-3
9.4 Comparator Function (optional) ....................................................................................... 9-7
9.5 Setting the Comparator Mode (optional) ........................................................................ 9-10
9.6 Setting the Comparator Limit Values (optional).............................................................. 9-11
9.7 Comparator Display (optional) ....................................................................................... 9-15
9.8 Turning the Comparator Function ON/OFF (optional).................................................... 9-17
9.9 Outputting to an External Plotter or Printer .................................................................... 9-18
Chapter 10 Using the GP-IB Interface (Optional)
10.1 GP-IB Interface Functions and Specifications ............................................................... 10-1
10.2 Responses to Interface Messages................................................................................. 10-3
10.3 Status Byte Format (before the IEEE 488.2-1987 Standard)......................................... 10-4
10.4 Output Format ................................................................................................................ 10-5
10.5 Setting the Address/Addressable Mode....................................................................... 10-11
10.6 Setting the Output Items .............................................................................................. 10-13
10.7 System of Commands before the IEEE 488.2-1987 Standard .................................... 10-16
Chapter 11 Using the RS-232-C Interface (Optional)
11.1 RS-232-C Interface Functions and Specifications ......................................................... 11-1
11.2 Connecting the Interface Cable ..................................................................................... 11-3
11.3 Setting the Mode, Handshaking Method, Data Format and Baud Rate ......................... 11-6
11.4 Format and Commands of Output Data (before the IEEE 488.2-1987 Standard) ......... 11-9
Chapter 12 Initializing Setup Parameters and Performing Zero Level Compensation
12.1 Back-up of Setting Parameters ...................................................................................... 12-1
12.2 Initializing Setting Parameters ....................................................................................... 12-2
12.3 Performing Zero Level Compensation ........................................................................... 12-4

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9
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11
12
13
14
15
16
Index
Contents
Chapter 13 Communication Commands 1 (System of Commands before the
IEEE 488.2-1987 Standard)
13.1 Commands..................................................................................................................... 13-1
13.2 Sample Program .......................................................................................................... 13-13
13.3 For Users Using Communication Commands of Digital Power Meter 2533E.............. 13-21
Chapter 14 Communication Commands 2 (System of Commands Complying to
the IEEE 488.2-1987 Standard)
14.1 Overview of IEEE 488.2-1987........................................................................................ 14-1
14.2 Program Format ............................................................................................................. 14-3
14.2.1 Symbols Used in Syntax Descriptions ............................................................... 14-3
14.2.2 Messages........................................................................................................... 14-3
14.2.3 Commands......................................................................................................... 14-5
14.2.4 Responses ......................................................................................................... 14-7
14.2.5 Data ................................................................................................................... 14-7
14.2.6 Synchronization with the Controller ................................................................... 14-9
14.3 Commands................................................................................................................... 14-10
14.3.1 Command List .................................................................................................. 14-10
14.3.2 AOUTput Group ............................................................................................... 14-14
14.3.3 COMMunicate Group ....................................................................................... 14-15
14.3.4 CONFigure Group ............................................................................................ 14-17
14.3.5 DISPlay Group ................................................................................................. 14-21
14.3.6 HARMonics Group ........................................................................................... 14-22
14.3.7 INTEGrate Group ............................................................................................. 14-23
14.3.8 MATH ............................................................................................................... 14-24
14.3.9 MEASure Group............................................................................................... 14-25
14.3.10 RECall Group................................................................................................. 14-32
14.3.11 RELay Group ................................................................................................. 14-33
14.3.12 SAMPle Group ............................................................................................... 14-35
14.3.13 STATus Group................................................................................................ 14-36
14.3.14 STORe Group ................................................................................................ 14-37
14.3.15 Common Command Group............................................................................ 14-38
14.4 Status Report ............................................................................................................... 14-41
14.4.1 Overview of the Status Report ......................................................................... 14-41
14.4.2 Status Byte....................................................................................................... 14-42
14.4.3 Standard Event Register.................................................................................. 14-43
14.4.4 Extended Event Register ................................................................................. 14-44
14.4.5 Output Queue and Error Queue....................................................................... 14-45
14.5 Sample Program .......................................................................................................... 14-46
14.6 ASCII Character Codes ............................................................................................... 14-50
14.7 Communication-related Error Messages ..................................................................... 14-51
Chapter 15 Maintenance andTroubleshooting
15.1 Adjustments ................................................................................................................... 15-1
15.2 Calibration...................................................................................................................... 15-5
15.3 In Case of Malfunctioning ............................................................................................ 15-11
15.4 Error Codes and Corrective Actions............................................................................. 15-12
15.5 Replacing the Fuse ......................................................................................................15-14
15.6 Recommended Replacement Parts ............................................................................. 15-15

xii IM 253421-01E
Contents
Chapter 16 Specifications
16.1 Input ............................................................................................................................... 16-1
16.2 Measurement Functions ................................................................................................ 16-3
16.3 Frequency Measurement ............................................................................................... 16-5
16.4 Communication (optional) .............................................................................................. 16-5
16.5 Computing Functions ..................................................................................................... 16-5
16.6 Display Functions........................................................................................................... 16-6
16.7 Integrator Function ......................................................................................................... 16-6
16.8 Internal Memory Function .............................................................................................. 16-7
16.9 D/A Converter (optional) ................................................................................................ 16-7
16.10 External Input (optional)................................................................................................. 16-7
16.11 Comparator Output (optional) ........................................................................................ 16-7
16.12 External Contorol and Input Signals (in combination with the D/A converter and
comparator options) ....................................................................................................... 16-8
16.13 Total Harmonic Analysis Function (optional) .................................................................. 16-8
16.14 General Specifications ................................................................................................... 16-9
16.15 External Dimensions .................................................................................................... 16-10
Index

1-1
IM 253421-01E
Functional Overview and Digital Display
1
1.1 System Configuration and Block Diagram
System Configuration
Equipment
under
test
Voltage
input
Current
input
PT
CT
Ext.
sensor
Analog output
GP-IB or
RS-232-C
Recorder
Personal
Computer
Ext. printer
or plotter
Contact / relay output
Input
either
one
Input
either
one
WT200
(253421)
Block Diagram
VOLTAGE INPUT
CURRENT INPUT
LPF
LPF
A/D
A/D
Zero Cross
Detector
Zero Cross
Detector
ISO
ISO Lead/Lag
Detector
EEPROM
SAMPLING
CLOCK
CPU
FREQUENCY
PLL
HARMONICS
DMAC
RAM
COMPARATOR
EEPROM
D/A OUTPUT
RS-232-C
GP-IB
CONTROLLER
KEY&DISPLAY
ROM
RAM
or
DSP
INPUT
A/D
interface
Bus
Arbiter
Bus
Arbiter
(Option)
(Option)
(Option)
CPU
COUNTER × 2
CLOCK
This instrument consists of various sections: input (voltage input and current input
circuits), DSP, CPU, display and interface section.
In the voltage input circuit, the input voltage is formalized by a voltage divider and
operational amplifier, then sent to the A/D converter.
In the current input circuit, the input current passes through a shunt resistor that forms
a closed circuit. The voltage across shunt resistor is amplified and normalized and
then input to the A/D converter. This method enables switching of the current range
without opening the current measurement circuit, so the current range can be switched
while electricitiy is supplied to the circuit. This also enables remote control via
communications outputs.
The output from the A/D converter in the current input and voltage input circuits is sent
to the DSP (Digital Signal Processor) via a photo-isolator, which is used to provide
insulation between the current input circuit (or voltage circuit) and the DSP. One DSP
is provided for each input element (current/voltage). For example, a total of 3 DSP’s
are used for the three-phase, four-wire model. The DSP performs averaging of
voltage, current and active power for each sampled data sent from the A/D converter.
After processing of a certain number of sets of data has been completed, computation
of apparent power, reactive power, power factor and phase angle starts.
Computation results are then sent from the DSP to the CPU, where computation such
as range conversion, and scaling is carried out. Control of display and outputs is also
performed by the CPU.
Chapter 1 Functional Overview and Digital Display

1-2 IM 253421-01E
1.2 Functions
Input Functions Voltage and Current Input Sections
A voltage or current supplied to each input terminal is normalized then sent to the A/D
converter, where the voltage or current is converted into digital signals. The digital
signals are then sent via photo-isolator to a 16-bits high-speed DSP (Digital Signal
Processor) or CPU, where computation of the measured value is carried out.
Frequency Measuring Range
Measurement of DC voltage, current and power as well as AC voltage and current in
the frequency range 10 Hz to 50 kHz.
Filter
This instrument carries out various measurements after synchronizing the frequency of
the input signals. Therefore, correct measurements are necessary. Thus, a filter is
being applied to the frequency measurement circuit to eliminate noise of waveforms,
such as inverted and distortion waveforms.
Wiring Method
The wiring method indicates the circuit configuration used to measure the voltage,
current, and power. The WT200 uses a single-phase, two-wire (1φ2W) wiring method.
Display Functions This function enables display of measured/computed values using three red high-
intensity 7-segment LED displays. A total of three values can be displayed at once.
Peak Measurement Function
This function measures the peak values of the voltage and current. This value is used
to compute the crest factor.
MAX Hold FunctionThis function holds the maximum values of the voltage, current, active power, apparent
power, reactive power, voltage peak, and current peak. It holds the maximum value
that exists while the MAX hold function is enabled.
Computing Functions
Apparent Power, Reactive Power, Power Factor and Phase Angle
Based on the measurement values of voltage, current and active power, the values of
apparent power, reactive power, power factor and phase angle can be computed.
Scaling
When performing voltage or current measurements with an external PT, CT, shunt,
external sensor (clamp) or such connected, you can set a scaling factor to the primary/
secondary ratio. This is called scaling. This function enables display of the measured
values of voltage, current, active power, reactive power, integrated current and
integrated power factor in terms of primary-side values.
Averaging
This function is used to perform exponential or moving averaging on the measured
values before displaying them in cases where the measured values are not stable.
Four Arithmetic Operation
Results from six types of arithmetic operations can be displayed. (A+B, A–B, A*B, A/B,
A2/B, A/B2)
Crest Factor
This function determines the crest factor of the voltage and current using peak and
RMS values.

1-3
IM 253421-01E
Functional Overview and Digital Display
1
1.2 Functions
Average active power during integration
This function computes the average active power within the integration period. It is
derived by dividing the watt hour (integrated active power) by the elapsed time of
integration.
Integrator Functions
This function enables integration of active power and current. All measurement values
(and computed values) can be displayed, even when integration is in progress, except
for the integrated values (watt hour and ampere hour) and elapsed integration time.
Since also integrated values of negative polarity can be displayed, the consumed watt
hour (ampere hour) value of the positive side and the watt hour value returning to the
power supply of the negative side can be displayed seperately.
The following two integration methods are available:
• Standard type
Integrates the active power or current that is obtained using the normal measurement
method, which obtains the active power or current from the sampled data over the
period that is synchronized to the input signal. Select the standard type for steady-
state input signals that have a constant period such as a sinusoid.
• Advanced type
Integrates the active power or current obtained over a fixed period of sampled data,
irrespective of the period of the input signal. Select the advanced type for intermittent
signals with a frequency of 50 or 60 Hz.
Frequency Measurement Function
This function measures the frequency of the voltage and current.
Measuring range is from 10 Hz to 50 kHz (however, depending on the internal timing of
the instrument, measurement might be carried out in the range from 4 Hz to 10 Hz
also).
Harmonic Analysis Function (optional)
This function enables computation of voltage, current, active power and so forth of up
to the 50th order, the relative harmonic content of harmonic orders and the phase angle
of each order compared to the fundamental (first order). Furthermore, the total rms
value (fundamental +harmonic) of the voltage, current and active power, and the
harmonic distortion factor (THD) can be calculated.
Storing/Recalling Measured Data and Setting Parameters
This function enables the storage of measured data and setting parameters into the
internal memory. Furthermore, after recalling measured data or setting parameters,
these data can be displayed or output by communication interface.
D/A Output Function (optional)
This function enables output of measured values of voltage, current, active power,
apparent power, reactive power, power factor and phase angle as a DC analog signal
with full scale of ±5 V. Output items of up to 4 channels can be selected.
Comparator Function (optional)
This function compares the measured values of voltage, current, active power,
apparent power, reactive power, power factor and phase angle and such with preset
limit values. When the measured values cross those preset limits, a contact output
relay will be activated. Output items up to 4 channels can be set.

1-4 IM 253421-01E
Remote Control Functions (optional)
External Input
This instrument can be controlled using the following TTL-level, low pulse, logic
signals.
EXT HOLD (when options /DA4, /CMP are installed)
Holds updating of the displayed values or releases the hold status.
EXT TRIG (when option /DA4 is installed)
Updates the displayed values in hold mode.
EXT START (when option /DA4 is installed)
Starts integration.
EXT STOP (when option /DA4 is installed)
Stops integration.
EXT RESET (when option /DA4 is installed)
Resets the integration results.
External Output
This instrument can output the following TTL-level, low pulse, logic signals.
EXT BUSY (when option /DA4 is installed)
Outputs continuously from integration start through integration stop.
Communication Functions (Option)
Either a GP-IB or RS-232-C interface is provided as standard according to the
custormer’s preference. Measured/computed data of up to 14 channels can be output.
It is also possible to control this instrument from the personal computer.
Output Function to an External Plotter and Printer
Measured/computed data can be printed on an external plotter or printer using the GP-
IB or RS-232-C interface.
Other Useful Functions
Backup of Setting Parameters
This instrument backs up the setting parameters (including computed values) in case
power is cut off accidentally as a result of a power failure or for any other reason.
Initializing Setting Parameters
This function enables you to reset the setting parameters to initial (factory) settings.
Zero-level compensation
Zero level compensation refers to creating a zero input condition inside the WT200 and
setting the level at that point as the zero level. Zero level compensation must be
performed in order to satisfy the specifications of this instrument. When the
measurement range is changed, zero level compensation is performed automatically.
However, if the measurement range is not changed for a long time, the zero level may
shift due to environmental changes around the instrument. In such case, you can
manually perform zero level compensation.
1.2 Functions

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IM 253421-01E
Functional Overview and Digital Display
1
1.3 Digital Numbers/Characters, and Initial Menus
Digital Numbers/Characters
This instrument is equipped with a 7-segment LED which imposes some restrictions on
the usable characters. The numbers/characters are styled as follows.
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
Small c
Small h
^(Exponent)
U
V
W
X
Y
Z
+
−
×
÷
Initial Menus Every function of this instrument can be set using the menus on the display. The initial
displays which appear when the operation keys are pressed, are shown below.
1.
V RANGE
2.
(Display C)
• Voltage Range Setting
1.
A RANGE
2. 2. 2.
(A)
(A)
(A)
(A)
(A)
(A)
(mA)
(mA)
(mA)
(A)
(A)
(A)
(A)
(A)
(A)
(mV)
(mV)
(mV)
(A)
(A)
(A)
(A)
(A)
(A)
(V)
(V)
(V)
(mA)
(mA)
(mA)
(mA)
(mA)
(mA)
(mA)
(mA)
(mA)
(mA)
(mA)
(mA)
(mA)
(mA)
(mA)
• Current Range Setting
(Display C)
When equipped with
option /EX1
(Display C)
When equipped with
option /EX2
(Display C)

1-6 IM 253421-01E
SETUP
1.
2.
• Setting the Filter, Averaging, Scaling, Ext. Sensor Input,
and Initializing Setting Parameters
( Display C )
(Measurement synchronization source setting)
(MAX hold setting)
(Filter setting)
(Averaging setting)
(Scaling setting)
(Ext. sensor input setting)
(Initiallizing set-up parameters)
(Computation, crest factor settings)
(Number of displayed digits)
1.
SHIFT RESET
INTEG SET
2. (Setting integration mod)
(Setting integration timer)
(Setting integration preset time)
(Integration type setting)
( Display C )
• Integration Setting
SHIFT START
HARMONICS
(Display C)
2.
1.
• Turning the Harmonic Analysis Function ON/OFF
(Setting the element)
(Setting PLL source)
(Setting computation methood
of harmonic distortion)
SHIFT STOP
MEMORY
( Display C )
2. (Storing measurement data)
(Recalling measurement data)
(Storing setting parameters)
(Recalling setting parameters)
1.
• Storing/Recalling to/from Internal Memory
SHIFT SETUP
OUTPUT
( Display C )
2.
(Setting D/A output)
(Comparator setting:relay output setting)
1.
• Setting Output
(Setting items for communication,
plotter, or printer output)
(Execute plotter or printer output)
1.3 Digital Numbers/Characters, and Initial Menus

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IM 253421-01E
Functional Overview and Digital Display
1
1.3 Digital Numbers/Characters, and Initial Menus
SHIFT LOCAL
INTERFACE
( Display C )
2. (Setting addressable mode A)
(Setting addressable mode B)
(Setting talk-only mode)
1.
• Setting Communication Interface (GP-IB)
(Setting communication commands
according to IEEE 488.2-1987)
(Print mode setting: Setting plotter
or printer output)
SHIFT LOCAL
INTERFACE
( Display C )
2. (Setting normal mode)
(Setting talk-only mode)
1.
• Setting Communication Interface (RS-232-C)
(Setting communication commands
according to IEEE 488.2-1987)
(Print mode setting: Setting plotter
or printer output)