CT9557 Sensor Unit

Compatible Hioki current probes and wattmeters (including possible adapters) - but if you are not sure, please contact us

Application examples of the different variants of the CT955x series

Detailed Product Overview

The CT9557 is a 4-channel current sensor interface designed for use with HIOKI highprecision fluxgate current sensors and current clamps with ME15W connectors. The unit supplies power to connected sensors via the four channels. The sensor signals are available as waveform outputs on BNC connectors and can be used with oscilloscopes and other data acquisition systems. 

HIOKI current sensors with ME15W connectors provide a standardized output signal of 2 V full scale. The CT9557 outputs these sensor signals directly via the BNC waveform outputs without modification. As a result, the waveform output accuracy corresponds to the accuracy of the connected current sensors. 

Combining Multiple Current Sensor Signals

In large inverter systems or battery storage systems, high currents are often distributed across multiple parallel conductors. The CT9557 allows each conductor to be measured individually and the signals to be combined, enabling several conductors to be treated as a single measurement channel. 

In addition to the four individual waveform outputs, the CT9557 provides a total waveform output and a total RMS output. These outputs combine the signals of the selected sensors into a single signal. The four individual waveform outputs, the total waveform output and the total RMS output are available simultaneously. 

The total waveform output and the total RMS output are available on BNC connectors with 2 V full scale and 2 V DC full scale respectively. The accuracy of the combined signals is also very high. The total waveform output accuracy is ±0.06% of reading ±0.03% of full scale, and the total RMS output accuracy is ±0.2% of reading ±0.1% of full scale (DC, 50/60 Hz). These values are added to the accuracy specifications of the connected current sensors. 

For example, when four CT6877A current sensors (AC/DC 2000 A each) are connected, the system can measure a combined current of up to 8000 A while using only a single measurement channel on the connected instrument. 

Applications and Integration

The total waveform signal can also be output via the ME15W connector. This allows the CT9557 to be connected to HIOKI power analyzers such as the PW8001 or PW4001 using the CT9904 connection cable. 

Typical applications include current measurement in complex inverter wiring, evaluation of charge and discharge currents in large-scale batteries, motor current waveform observation, and measurement of battery ripple currents. 

Because the CT9557 provides a dedicated RMS output, AC currents can also be measured with instruments that do not provide their own RMS conversion, such as simple loggers or DC measurement inputs. The unit can be powered using the supplied AC adapter or from an external DC power source, allowing flexible integration into laboratory setups, mobile measurements and automated test systems.