WT300E Digital Power Analyzer

The WT300E series digital power analyzer provides extremely low current measurement capability down to 50 micro-Amps, and a maximum of up to 26 Amps RMS. This instrument is ideal for engineers performing stand-by power measurements, Energy Star®, SPECpower and IEC62301 / EN50564 testing, battery charger and other low-level power measurements.

The WT300E's wide range of functions and enhanced specifications, allows handling of all the measurement applications from low frequency to high frequency inverters using a single power meter.

Accuracy with fast display and update rate: 
The WT300E series with the fast display update rate of 100ms, offer’s engineers a short tact time in their testing procedures. The basic accuracy for all input ranges is 0.1% rdg + 0.05% rng (50/60Hz) and DC 0.1% rdg + 0.2% rng.

Simultaneous Measurement:

U/I/P/Freq/Integ(+/-)/Harmonics components/ THD with max. 100ms cycle.

In addition to standard power measurements, the WT300E series measures all DC and AC parameters. Additionally, the WT300E series can measure harmonics and perform integration simultaneously without changing the measurement mode. The accompanying WTViewerFreePlus software can monitor and save the 200 parameters used.

Auto ranging function available in selected ranges.

The auto-range function is used to select or change the ranges automatically, within specified ranges. This results in shorter range changing times, allowing more efficient testing.

3 Input Signal Change

Auto Ranging Function For Integration Measurement
Typically, when power meters operate in an integration mode to measure power consumption and standby power, the measuring ranges need to be fixed. However, if the level of the input exceeds the maximum of the selected range, the test will need to be repeated. The WT300E Series has a high-speed automatic ranging capability in integration mode, which removes the need to repeat any test.

Bandwidth: DC and 0.1Hz to 100 kHz (WT310EH is up to 20 kHz for 40A).

Direct Input: Maximum direct input of up to 600V and 20A, or 40A (incase of WT310EH). The wide current input ranges on the WT310E series, give users the option to measure current as low as 50 micro-Amps to as high as 40Arms (incase of WT310EH).

High-speed data update (up to 10 readings per second.)

The WT300E series offers a wide range of communication interfaces such as USB, GP-IB or RS-232 (selectable) and Ethernet Modbus/TCP (Optional)

Wide current input range

WT300E Lineup

  • Wide current input ranges: The WT300E series covers a broad range of current inputs, from few mA up to 40 A rms. Both AC and DC waveforms can be measured.
  • Simultaneous measurement of all parameters: The WT300E can measure all DC and AC parameters. The WT300E series can also measure harmonics and perform integration simultaneously without changing the measurement mode.
  • Fast display and data update rate: The fast display and a maximum data update rate of 100ms on the WT300E series, offers a short tact time in testing procedures.
  • MAX hold function: The maximum values of RMS/PEAK Voltage & Current, Active Power, Reactive Power and Apparent Power can be held.
  • Line filter and frequency filter capabilities: These filter functions will cut off unnecessary noise & harmonic components for fundamental waveform measurements.

Users therefore have the flexibility to choose a variety of settings according to their application needs e.g. from production lines to engineering test benches. Users can use WTViewerFreePlus software to set up all basic and advanced measurements. Additionally, the numeric values, waveform display* and trend graphs of the measurement data can be displayed and saved.

*Waveform display requires the /G5 Harmonic option

4 Waveform Display WT300E

Connectivity of Modbus/TCP*1 with YOKOGAWA’s recorders and Ethernet*1 with PLC

Digital data measured by the WT series can be acquired by YOKOGAWA’s recorder GP10*2, *3 and GM*2, *3 via Ethernet or Modbus/TCP directly. It is also possible to make use of the GA10*2 data logging software to monitor and record data.

The WT300E series can also be connected with YOKOGAWA’s PLC, FA-M3V*2 using Modbus TCP protocol for production fields.

*1 /C7 Ethernet option is required.
*2 GP10/GM/GA10/FA-M3V are manufactured by Yokogawa Electric Corporation.
*3 /E2 and /MC options are required.

5 Modbu WT300E 1

D/A output for measurement recording

The D/A option is used to output Voltage, Current, Power, and other measured data for recording to data loggers using the +/-5Vdc scaled outputs. 

6 D A Output Measurement Recording WT300E 1

Comparator Mode

This mode will compare measured, computed, and integrated values with previously set determined values by the communication command, and output (from -5V to +5V) determined results by D/A output.

Automatic Zero Adjustment

The WT300E series compensates for any drift in the zero level by automatically performing a zero adjustment when the input ranges are changed. This is achieved in less than 100 ms and does not require disconnecting wires.

The WT300E series power meters are easy to use, cost effective, and accurate for a wide range of applications, such as production, testing, evaluation, and research and development.

For home appliances and office equipment

Production line or QA testing of electric devices

  • Compact half rack mount size helps engineers build smaller test systems with a better return on investment
  • D/A output and Modbus/TCP* functions for data recording
  • Multiple communication interfaces: USB, RS-232 or GP-IB and Ethernet capability

The simultaneous measurement of power consumption parameters such as U, I, P, frequency, power factor and harmonics for production line or QA testing, results in reduced tact times, thereby, reducing time and cost of testing. The D/A outputs and communication interfaces enable data to be remotely and flexibly captured. *“Modbus/TCP” function is available with the Ethernet (/C7) option.

8 Production Line WT300E 1


Development and evaluation tool for home appliances

  • 5mA range allows for small current measurements (WT310E)
  • Auto ranging function during integration mode
  • Range skip (range configuration) function provides the ability to select usable ranges in advance. Auto ranging enables the WT300E series to rapidly adapt to changing input conditions.

The range skip function reduces the transition period between range changes. The WT310E can measure both large and small currents accurately in a single test. This can reduce the total evaluation period or remove the need to use two, rather than one, power meters for the application, thereby saving on capital cost of testing.

3 Input Signal Change

Testing to international standards, such as IEC62301, Energy Star and SPECpower*1

  • The WT310E has a high measurement resolution of maximum 100 μW under the 5 mA range setting.
  • Simultaneous measurement of normal power parameters, harmonic components and THD.
  • Dynamic input capability of crest factor maximum 300 (Peak value/minimum effective RMS value)
  • Free PCM software for IEC62301*2 testing

The WT310E together with the Power Consumption Measurement (PCM) software enables users to perform standby power testing in accordance with international standards.
*1 Coming soon
*2 The IEC62301E2.0 is a reference standard in the EN50564: 2011 Directive. This software corresponds to a test method of those two standards.

9 International Standard WT300E 1


Evaluation of large current equipment

  • Direct high current measurements of up to 40Arms without using external sensors (WT310EH)
  • Auto ranging function for Integration mode.

The WT310EH allows 40 Arms to be directly connected to the input without the requirement to use current clamps or current sensors. This not only provides more precise measurement but also saves on investment costs. The wide current ranges are from 1 A to 40 A and voltage ranges are from 15 V to 600 V.
Users can use it to evaluate special waveform driven devices such as, IH cookers and heaters.

10 IH Cooking Heater WT300E 1

For industrial equipment and transportation

Automotive- Battery or DC driven device evaluation

  • Accurate DC measurements: 0.3% total
  • Direct high current measurement of up to 40A without any external current sensor.
  • Charge/Discharge energy measurements for batteries

11 Automotive WT300E 1


Duration testing and efficiency measurement for industrial motors and rotating machinery


The WT300E series provides reliable current integration (Ah) and Energy (Wh) measurements for up to 10,000 hours. The D/A option can be used to transmit these measurements to an external data logger or recorder, such as a ScopeCorder, and monitor and log data along with other parameters, such as temperatures, torque, and rotation speed. The Modbus/TCP communication with /C7 option is used to save and monitor the measurement results of up 200 chs. YOKOGAWA GA10 data logging software can be used directly to save data along with other parameters such as temperatures, torque and rotation speed by this Modbus/TCP Protocol.


  • Integration measurements over long periods of time
  • Modbus/TCP Protocol for data recording
  • DC, 0.1 Hz to 100 kHz broad bandwidth capability 

13 Durantion Testing WT300E 1

Conformance and evaluation testing of uninterruptable power supplies (UPS)

  • Maximum harmonic order settings for THD calculations
  • Efficiency measurements using a single power meter
  • Average Active Power measurement under integration mode

The WT300E series enables users to conduct conformity tests according to UPS performance testing standards. The WT300E series is used to measure and calculate input & output levels, efficiency, frequency and THD. The average active power data also provides accurate values of power consumption. This equipment along with the WTViewerFreePlus software helps to simultaneously measure all necessary parameters required to test a UPS, thereby reducing the evaluation time.

14 Confomrance WT300E 1


Reduced energy, emission of CO2 about 18% compared to the previous model.

Results of Life Cycle Assessment

Reduced energy, emission of CO2 about 38% compared to the previous model.

Results of Life Cycle Assessment

B9284LK External Sensor Cable

For connection the external input of the WT3000 to the current sensor.
Length: 50cm

758917 DMM Measurement Lead Set

  • Set of 0.8m long red and black multimeter test leads
  • Used in combination with a pair of optional 758922 or 758929 alligator-clip adapters
  • 1000 Vrms, 32 Arms CAT II

705926 Connection Cable for DA4, DA12, Scanner Box (701953)

Applicable for DL850 and WT300 series.

758921 Fork terminal adapter

  • 758921 Fork Terminal Adapters
  • For fitting a 4mm banana plug to a fork terminal
  • One black and one red clip
  • 1000 Vrms-CAT II

CT60/ CT200/ CT1000/ CT1000A/ CT2000A AC/DC Current Sensor

AC/DC current sensors capable of highly accurate measurement starting in DC range.

AC/DC Split Core Current Sensor CT1000S

Measure high currents without disassembling existing cabling. Compatible with power analyzers and waveform measurement instruments.

758922 Small Alligator-Clip Adapter 300V

Rated at 300 V. Attaches to the 758917 test leads. Sold in pairs.

758923 Spring Hold Safety Terminal Adapter Set

Two adapters in a set (spring-hold type).

758924 BNC to Banana Conversion Adapter

For conversion between BNC and female banana plug
Applicable for DL750/DL750P, SL1000 & SL1400.

758929 Large Alligator Clip Adapter 1000V

  • Yokogawa 758929 Alligator Clip Adapter 
  • Rated at 1000V
  • Attaches to 758917 test leads
  • Sold in pairs black/red

758931 Screw-Fastened Safety Voltage Terminal Adapter Set

Screw-fastened adapters. Two adapters in a set. 1.5 mm Allen Wrench.

751533-E2 Rack mounting kit

RACK MOUNTING KIT For an EIA-compliant Single-housing Rack

751533-E3 Rack mounting kit

RACK MOUNTING KIT For an EIA-compliant Single-housing Rack

751533-J2 Rack mounting kit

RACK MOUNTING KIT For a JIS-compliant Single-housing Rack

751533-J3 Rack mounting kit

RACK MOUNTING KIT For a JIS-compliant Single-housing Rack

751534-E2 Rack mounting kit

RACK MOUNTING KIT For an EIA-compliant Dual-housing Rack

751534-J2 Rack mounting kit

RACK MOUNTING KIT For a JIS-compliant Dual-housing Rack

751534-E3 Rack mounting kit

RACK MOUNTING KIT For an EIA-compliant Dual-housing Rack

751534-J3 Rack mounting kit

RACK MOUNTING KIT For a JIS-compliant Dual-housing Rack


Energy consumption in low-power and standby modes is an important issue due to increased awareness that energy resources are becoming limited and demand for energy-saving household electrical appliances continues to grow. IEC62301 Ed2.0 (2011) and EN 50564:2011 define standby mode as the lowest energy consumption of an appliance not performing its main function, when connected to the mains. IEC62301 Ed2.0 (2011) defines test methods and requirements for both the mains supply and the test equipment. It is crucial that design and test engineers choose highly accurate power measurement tools to confirm that their devices meet these requirements.

Application Note
544 KB

【search key】 WT1, WT18, WT180, WT3, WT30, WT5, WT50, WT500, WT

  • Power consumption/quality measurements for product design and test
  • Design, compliance, and customer information
  • Best practices
  • Instruments and components
Application Note
304 KB
  • Yokogawa WT310 Digital Power Meter
  • Lighting products need to evaluate power parameters, temperature

In recent years the buzzword “all electric” is becoming popular, which refers to kitchen appliances, water heaters, and other devices in the home all being supplied with electric power.

Application Note

Evaluation of vacuum cleaner requires to measure distorted waveform.


In the test of new washing machine, voltage, current, power, and the control signal on the time control panel need to be recorded.


The precision beaning testing system of the mechanical and electrical engineering company.

  • Power Analyzer Accuracy and Basic Uncertainty Calculator from Yokogawa Test&Measurement 
  • Determine uncertainty in voltage, current, and active power (watts) measurement values
  • Various frequency ranges and wiring systems

This training module covers the following topics:

  • Introduction & Installation
  • Connecting to Instrument
  • Setup, Measure, and Analyze
  • File Operations: Saving and Loading Data
  • Video Demonstrations



    The Power Consumption Measuring Software from Yokogawa Test&Measurement provides a comprehensive solution for standby power testing and meets the requirements of:

    • IEC 62301:2011 Ed2.0 – Household electrical appliances (measurement of standby power)
    • EN 50564:2011 – Electrical and electronic household and office equipment (measurement of low power consumption)

    In this video, application engineer Kourtney Morrison demonstrates how to use the software for easy standby power measurement.



    Although DC power measurements can be fairly straightforward, complexities with AC power measurements arise when dealing with distorted waveforms, fluctuating power factors, and multiple phases, which introduce intricacies that complicate an otherwise simple measurement process.

    This on-demand webinar provides an informative dive into the various fundamental aspects of power measurement and includes:

    • A look at multi-phase measurements and measurement techniques
    • A review of practical applications
    • Real-world examples

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