Multifunctional Electronic LoadPLZ-4W Series

Suitable design for fuel cell, faster speed and lower voltage testing application of various devices!

The PLZ-4W Series Electronic Load unit is a multifunctional system designed to offer the highest levels of reliability and safety with operation function of constant voltage, constant current, constant power and constant resistance mode. And its control unit comes with GPIB, RS232C and USB as standard interface. The PLZ-4W Series are available in 5 models and which a 0V input operating voltage is available in 2 models (PLZ164WA, PLZ664WA) suited to meet with the testing demands for the Fuel Cell, DC/DC converter, SW Power Supply, and any other devices required for the lower operating voltage application. The PLZ664WA offers the 132A at 0V input as a largest current rating in its class. (33A for model PLZ164WA) Furthermore, the PLZ-4W features high speed slew rate when switching, it can be used as simulating load for the characteristic, performance, life cycle, aging test in the field of application in Automobile electronics, SW Power Supply manufacturer, Secondary Battery. To achieve large capacity for testing application at low cost, the PLZ1004W can be expanded up to 9kW by using the 2kW booster unit (PLZ2004WB).


Six operation modes

The system can operate in six modes – constant current, constant resistance, constant voltage, constant power, constant current + constant voltage, and constant resistance + constant voltage.

Equivalent circuit and operation in each mode

Support of 0-V input

PLZ164WA and PLZ664WA are 0-V input operating voltage models. This feature is indispensable for testing single-cell fuelcells. The continuing trend toward lower power consumption and semiconductor process miniaturization is driving semiconductor devices to operate on increasingly lower voltages. These models are suitable for evaluating such power supplies.

* This product detects a ‘no-input’ state when the input voltage is below about 0.3 V and when the input current is below about 1% of the range rating. Therefore, if the input voltage is raised gradually from 0 V, no current flows until the input voltage exceeds 0.3V. If a current exceeding 1% of the range rating flows, it is possible to have a current flow at less than 0.3 V.* PLZ164WA and PLZ664WA have bias supplies inside their chassis. In the case of a power supply in which a diode is arranged in the direction from the minus output to the plus output, such as a switching power supply, if the output of the power supply of the device under test is turned off with this system’s load on, the current flows from the bias supply to the diode, generating a reverse connection alarm.

Variable slew rate

The slew rate determines the slope of change in the current when the set cur rent needs to change sharply as in a transient response test. This system lets you set the current change rate per unit time as appropriate for the selected current range.

Variable slew rate

Adequate slew rate performance is guaranteed as long as the change in the current remains within the 2 %-to-100 % range of the rating. The maximum rise time is limited to 10μs. If the change in the current is small, the slew rate value may not be stored for the reason stated above.

High precision and high resolution

The built-in three-range configuration provides both wide dynamic range and high precision. The voltmeter, ammeter and wattmeter functions that display values using up to five digits each and a minimum setting resolution of 10μA (for the PLZ164W/164WA L range) are implemented.

High precision and high resolution

Load on/off operations

In addition to the regular operations, the following types of load on/off operations are available. You can choose any of these operations as suitable for your operating environment.

  • Start in the load on state
  • Display of the elapsed load on time
  • Auto load off after the elapse of the set time
  • Load on/off control using relay and other external signals

Remote sensing function

The remote sensing function compensates for voltage drops in load lines. It is used to set resistance and voltage values correctly and to make accurate voltage and power measure- ments. Particularly, the function improves the transitional characteristics in constant voltage, constant power and constant resistance modes, leading to stable operation. (The maximum voltage that can be compensated for is 2V for one way.)

Sequence function

Any sequence patterns can be stored in the built-in memory. The memory can hold up to 10 normal sequence programs plus one fast sequence program. Each normal sequence program can contain a maximum of 256 steps, with the fast sequence program consisting of up to 1024 steps. You can edit these programs on the large liquid crystal display (LCD) monitor.

Normal sequence

Normal sequence

A different execution time can be assigned to each step individually. You can stop the execution of the sequence temporarily using PAUSE and remove the pause using an external trigger signal.

Fast sequence

Fast sequence

Each step is executed at high speed. The high time resolution enables high-speed simulations. The fast sequence program can contain up to 1024 steps, which are executed at even intervals.

Sequence setting parameters

 Normal sequenceFast sequence
Operation modeCC, CR, CV, CPCC, CR
Maximum number
of steps
Step execution
1ms to 999h59min25μs to 100ms
Time resolution1ms (1ms to 1min)
100ms (1min to 1h)
1s (1h to 10h)
10s (10h to 100h)
1min (100h to 999h59min)
25μs (25μs to 100μs)
100μs (100μs to 100ms)

Switching function

In constant current and constant resistance modes, switch- ing operations can be performed at up to 20 kHz. The switching setting parameters such as the switching level, switching frequency, and duty factor can be changed even while the load is on.

Switching function

[Setting parameters] ■Operation mode: CC and CR ■Duty factor: 5% to 95%, in steps of 0.1% ■Frequency setting range: 1Hz to 20kHz ■Frequency setting resolution: 0.1Hz for 1Hz to 10Hz; 1Hz for 10Hz to 100Hz; 10Hz for 100Hz to 1kHz; 100Hz for 1kHz to 20kHz ■Frequency setting accuracy: ±(0.5% of set) * The minimum time interval for setting the duty factor is 10 μs.

Soft start function

The soft start function allows the rise time of the current to be changed in constant current or constant resistance mode after the output voltage of the device being tested has risen. Since the rise time for the system can be changed according to the output-voltage rise time for the device being tested, you can conduct tests under highly realistic load conditions. (The soft start time can be selected from the following options – 1, 2, 5, 10, 20, 50, 100, and 200 ms.)

Soft start function

Short-circuit function

When the system is operating in constant current or constant resistance mode, this function allows you to insta n taneously switch to the maximum current value (in constant currentmode) or to the minimum resistance value (in constant resistance mode) of the range. Also, since a contact signal isoutput to the J1 connector, you can short-circuit the output of the device under test by driving the external relay or other element.

you can short-circuit the output of the device under test.

Elapsed time display and auto load off timer

Combining four functions – elapsed time display, under voltage protection (UVP), load off voltage display, and auto load off timer – makes it possible to perform two types of measurements that are useful in battery discharge tests – measurement of the time elapsed from the start of discharge until the final voltage is detected and measurement of the closed circuit voltage after the specified time elapses from the start of discharge.

Elapsed time display and auto load off timer

Configuration setting

This function configures the settings related to the system operation, communication environment, etc. These settings are stored in the system memory, and called when the power is turned on.

  • Number of parallel operated load units and master/slave settings
  • Load on/off operation at power-up
  • Key lock on/off operation at power-up
  • GPIB, RS232C, and USB selection
  • GPIB address
  • RS232C communication speed
  • Operation mode in which the external reference voltage input is used
  • Polarity of load on external control (low/high)

ABC preset memories

Three memories A, B, and C are provided for each range in each mode, and the set values can be saved. The stored set values can be called freely even while the load is on and saved again. In constant current + constant voltage and constant resistance + constant voltage modes, the constant current and constant voltage memories and the constant resistance and constant voltage memories can be called and saved, respectively.

Setup memories

Up to 100 of the set values listed below can be saved in the setup memories.

  • Operation mode (CC, CR, CV, and CP/+CV)
  • Current, resistance, voltage, and power values recorded when saved
  • Range setting
  • Slew rate
  • Switching frequency, duty factor, level, and time
  • protection settings
  • ABC preset memory data

Diverse protection functions

The system features the following protection functions – over current protection (OCP), over power protection (OPP), over voltage protection (OVP), under voltage protection (UVP), over heat protection (OHP), and reverse connection detection (REV). Also available is the alarm input detection function, which turns off the load in response to the input of the external TTL signal.

Sample program

Free sample programs for the PLZ-4W Series are available from our web site ( These downloadable sample programs include the utility software (MEMcopy) that lets you read and save setup memory data in a floppy disk or other type of medium, sequence editing software (StepEdit), and VisualBasic applications for measurement data collection and GUI remote control and their source code (VB samples). Install these software programs and the USB driver to a Windows-running personal computer equipped with a USB port (the system is compatible with Windows 98 and later). Then, connect the PC to the PLZ-4W Series electronic load system using a USB cable, and you can readily get st ar ted with measurements.

Sample program

Capacity Expansion Functions and External Control Functions

Booster (PLZ2004WB)

To offer a large capacity at low cost , PLZ2004WB is available as a booster unit for the PLZ1004W system. Up to four booster units can be connected in parallel with one PLZ1004W unit serving as the master unit (max. 9kW, 1800A). To connect these units requires the use of optional cables – one PC02-PLZ-4W parallel cable and as many PC01-PLZ-4W parallel cables as the number of booster units to be connected.

Booster (PLZ2004WB)

Parallel operation

Without using boosters, you can connect up to five units of the same model in parallel, including the master unit (max. 5kW, 1000 A). In the parallel connection configuration, one control master operates with one or more slave units, enabling you to control the entire system and view its data on the master unit’s panel. To connect the units requires the use of as many optional parallel cables (PC01-PLZ-4W ) as the number of units to be connected.

Number of parallel connected units and capacities
(maximum currents and maximum voltages)
Slave unit1 unit2 units3 units4 units
PLZ164W / PLZ164WA66A99A132A165A

Parallel operation

External controls

External controls are provided by means of the inputs from the GPIB, RS232C, USB, and analog interfaces. The GPIB, RS232C, and USB interfaces comply with the standards listed below. Using the external analog inputs, you can perform such operations as external voltage – or resistance-based control, load on/off, current range switching and input current monitor output.

Voltage- or resistance-based external analog controls
Control methodOperation modeExplanation
VoltageCC, CP, CVA change of 0 to 10 V causes a
change of 0% to 100% of the rated range value.
CRA change of 0 to 10 V causes a change ranging from the maximum to
minimum values of the range.

CC, CP, CVA change of 0 Ω to 10 kΩ causes a change of 0% to 100% of the rated
range value.
CRA change of 0 Ω to 10 kΩ causes a change ranging from the maximum to minimum values of the range.

CC, CP, CVA change of 10 kΩ to 0 Ω causes a
change of 0% to 100% of the rated
range value.
CRA change of 10 kΩ to 0 Ω causes a
change ranging from the maximum to minimum values of the range

External controls

Other external analog controls
  • Load on/off control and monitoring
  • Range control and monitoring in each current range switching mode
  • Pause clear during trigger input sequences
  • Forcible alarm generation upon alarm input
  • Input current monitoring by the current monitor
  • Short signal output from the relay contact
Supported interface standards
  • IEEE Std 488.2-1992
  • IEEE Std 488.1-1987
  • TIA/EIA-232F
  • SCPI 1999.0
  • USB 2.0(Full Speed)
  • USBTMC 1.0

Product line-up

Large Capacity Model SR(Smart Rack),LP(Load Pack)

PLZ-4W SR/LP Series

PLZ-4W SR/LP Series

The PLZ-4W SR/LP Series offers wide range of the “Large-Capacity DC Electronic Load System” that consists of the conventional electronic load model PLZ1004W and PLZ2004WB applying to the large current (maximum 2600 A) installed in the exclusive rack mount system.

  • The system offers from 5kW to 13kW with two types of rack system(SR/LP type), 12 models are available.
  • Assembled with exclusive components based on optimization design concept. Delivered systems are fully assembled and tested, so immediate operation is possible.
  • The industry’s smallest in its class for the multi-functional high-speed response DC electronic load.
  • Expandable by installing additional booster units after purchase.*For the installation, adjustment, please contact your nearest distributor.
  • Equipped USB/RS232C/GPIB interface as standard features.
  • Capable of operation using the Sequence Creation software “Wavy”.

PLZ-4W SR/LP Series



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