Hioki Launches Three Sensor Units for High Precision Current Sensors

Hioki Launches Three Sensor Units for High Precision Current Sensors




December 7, 2016 - Nagano, Japan

CT9557 Features Sum Functionality for Aggregating and Measuring Large Circuits in Multi-Cable Circuits

Hioki is pleased to announce the launch of three sensor units: Models CT9555, CT9556, and CT9557.

The CT9555 is two-thirds smaller than the legacy sensor unit by volume, while the CT9556 provides RMS output capability. Meanwhile, the CT9557 features aggregate functionality to facilitate the measurement of large currents in multi-cable circuits.

Sensor units are power supplies for high-precision current sensors that also provide waveform output functionality.

Hioki’s high-precision current sensors cannot be used on their own; instead, it is necessary to supply power to drive the sensor using one of these newly launched sensor units. Furthermore, since the sensor units are able to output waveform signals from the current sensors to which they are attached, they can be used in conjunction with a data recorder, power meter, or data logger to display and analyze those waveforms.

Enclosure that’s two-thirds smaller than the legacy product by volume - The CT9555 is two-thirds smaller and weighs 200g lighter than the legacy 9555-10 by volume. Its compact footprint offers increased convenience in operation and management.

Ability to generate RMS output
The CT9556 is a sensor unit that can also generate RMS output in addition to waveforms.  Use of a current sensor and data recorder to measure AC current levels requires an expensive recorder that provides advanced functionality for converting readings to RMS values. Since the CT9556 can output a DC signal obtained by converting the AC signal waveform from the current sensor to an RMS value, even an inexpensive logger can be used to measure AC current levels.

*RMS values: The strengths of AC current and voltage are not constant, but rather vary periodically with time. Consequently, the meaning of an RMS value can be expressed as follows: the RMS value expresses the strength of an AC voltage (current) as the DC voltage (current) at which a given resistance would consume the same amount of power as when the corresponding AC voltage (current) flows through it.  The voltage used to describe household electrical outlets in Japan (100 V AC) is an RMS value.

1. A 4-channel power supply

Current measurement often requires that multiple current lines be measured at the same time. Since the CT9557 can serve as a power supply for up to four current sensors, it allows operators to build simpler, cheaper systems than are possible if using four 1-channel CT9555 units.

 2. Aggregate function for measuring large currents in multi-cable circuits in megasolar installations
At large-scale generating facilities such as megasolar installations, extremely large currents on the order of 1000A to 3000 A are split so that they flow through two to four cables, making it impossible to measure them with a single current sensor. Typically, individual cables’ current values are measured with separate current sensors, and either the customer adds together those measured values manually or utilizes the functionality of an instrument with enough channels to accommodate the number of current sensors being used to add the values.

The CT9557 delivers the ability to add together the signal waveforms from multiple current sensors in such applications. Since the current values measured for each branch cable are added together inside the CT9557 and output as a single signal, the troublesome addition process becomes unnecessary, and instruments need only use one channel of input. One application of this aggregate functionality is to simplify measurement of leakage currents in three-phase circuits.

* As a current sensor power supply
* To measure RMS value fluctuations in an AC current in conjunction with a logger
* To measure power in large-current lines in conjunction with a power meter

More information:
CT9555 Sensor Unit
CT9556 Sensor Unit


Established in 1935, HIOKI E.E. CORPORATION (TSE: 6866) has grown to become a world leader in providing consistent delivery of test and measuring  instruments through advanced design, manufacturing, and sales and services. By offering over 200 main products characterized by safety and quality while meeting an expansive range of applications, we aim to contribute to the efficiency and value of our customers' work in research and development, production and electrical maintenance. HIOKI products and services are available around the world through our extensive network of subsidiaries and distributors. Information about HIOKI is available at www.hioki.com.