ZS Series

End of Life Notification: We will discontinue production of ZS single-range electronic loads with effect from December 31,2018. The successor series is PLI. A comparison document with functions and command set of both series can be found here. The multi-range devices ZS5xx-3 and ZS5xx-4 remain in the portfolio.

  • Features
  • Details
  • Model Overview


tl_files/upload/produkte/Serie ZS/ZS5HE_front.png Voltage up to 800 V (1200V on request)
Currents up to 2,250 A
Power 500 W ...  28.8 kW
Depending on model, temporary overload capacity
Current, voltage, resistance, power mode
Dynamic loads
SCPI programming with measurement function
•Electronic protection
Analog measurement outputs for voltage and current
Analog control input
MPP tracking
Dynamic function with synchronized data logging



Operating Modes

The ZS series electronic loads have the four operating modes constant current, voltage, power and resistance. In addition, depending on the operating mode limit values can be set for the maximum permissible current and the minimum permissible voltage.

To increase the resolution for each device, along with the full setting range, a reduced setting of 1/3 of the rated current is available. The load can be preset even without a connected test unit. The display then shows the values directly in amps, ohms, volts or watts.

Dynamic and Control Time

The inbuilt modulator enables two independently adjustable currents and times from 100 μs ... 1 s. The control speed of the devices can be adjusted to the test unit in three stages (fast - medium - slow).

Protective Devices

The following protective devices are built in:

  • Overcurrent protection
  • Overpower protection
  • Overtemperature protection
  • Protection of the GND lines on the Analog I/O interface

Voltage Switching

A trigger voltage can be set for peak-free voltage hook-up. The current is enabled when the input voltage exceeds the trigger voltage.

Overload Capacity

Depending on the model the devices have temporary overload capacity. The level and duration of the possible overload depends on the operating temperature of the output stage. The device can therfore be used for significantly higher performance tasks.

Remote Control

Most load functions can be controlled remotely via Analog I/O Interface. The control inputs can be operated with TTL levels and 24 V from PLC controllers.

A version (ZS06) which is electrically isolated from the load input is optionally available.

Analog Control

In the operating modes CC, CV and CP the setting value can be controlled by 0...5 V or 0...10 V DC.

Analog Measurement Outputs

There are 0...10 V analog  measurement signals available for voltage, current and power. The GND terminals can float ±2 V with respect to the negative load input (also optionally isolated - Option ZS06).


The units are air-cooled. To keep the operating noise low, the fans are temperature and current-dependently controlled. For better utilization of the maximum possible overload capacity the fans can be set to full power.


The ZS is a sturdy 19“ rack design and can also be used as a table-top device. From 5 height units there are retractable handles on the top of the device.
Optional castors can be mounted on heavy devices. No separate installation kits are needed for 19“ rack installation.


All connections are at the rear side. The current connections are solid copper rails with screw connectors.


Covers are available as contact protection for units for dangerous contact voltages.

Interfaces (optional)

  • RS-232 + USB
  • GPIB
  • Ethernet-RS-232 Converter
  • System Interface Cable or Fiber Optic
  • Data Acquisition Tool

Hardware Expansions (optional)

  • Electrically Isolated Analog I/O Interface
  • Power I/O Card
  • Analog I/O Extension Card
  • Temperature Interface
  • Castors
  • Zero-Volt Option

Factory Calibration Certificate

A free Factory Calibration Certificate (FCC) is supplied with the devices. The FCC meets the requirements according to DIN EN ISO 9000ff. This calibration certificate documents the traceability to national standards to illustrate the physical device in accordance with the international System of Units (SI). Within the warranty period we calibrate a second time for free.

--> Conditions for a second free calibration

The recommended calibration interval is 2 years.

Software Tools

The H&H Homepage has a program library for Windows with a controll tool an LabVIEW drivers.


We supply a User Manual as pdf file and printed General Safety Instructions, each in German and English.

Type Overview