Building Bridges: Instrument combines scope and power measurements

This is especially true in the fast growing markets, where Yokogawa has set its cap, for renewable energy and energy efficient products.

“The Precision Power Meter provides simultaneous voltage and current multiplication to give real time power sampling," said Mohammed Hafeez, product marketing manager for Europe and Africa. “This supports both transient measurement and numerical values across the sample period.”

The instrument can capture inrush current and power measurement at switch on conditions and high speed transient,s and it can reduce time spent on identifying irregular and abnormal conditions. In a further innovation to aid engineers Yokogawa has recognised that discovering abnormal phenomena during high frequency measurements can be hard to isolate.

“They usually disappear from the screen as soon as they appear," Hafeez explains. The PX8000 has an always active history function that automatically records up to 1000 historical waveforms. These waveforms can be recalled and redisplayed at any time and can be retriggered for specific conditions.

The instrument supports the capture of power waveforms over a specific period of time using the trigger finction. The captured data can be analysed for specific phenomena using the start/stop cursors. Says Hafeez, “This is important for examining the transient phenomena and in design of periodicaly controlled equipment.”

Trend measurement between waveforms can be calculated by mathematical functions, and the waveforms can be inspected for specific numeric values at any point and averages can be calculated.

The new instrument has 12-bit resolution with 100 MS/s sampling and 20 MHz bandwidth. This means that the PX8000 can be used for accurate measurement of inverter pulse shapes, which can then be used to fine-tune inverter efficiency. A choice of input modules covers voltage, current and sensor measurements at voltages up to 1000V RMS and currents up to 5A RMS (higher values are possible with external current sensors), with basic accuracy down to ±0.1%.

To evaluate three-phase electrical systems, at least three power measurement inputs are required. The new instrument has four inputs, and enables the simultaneous capture and display of voltage and current across all three phases.

The PX8000 is powered by Yokogawa’s isoPRO technology, which offers isolation performance at the highest speeds. This core technology, designed with energy-saving applications in mind, delivers the performance needed to evaluate high-efficiency inverters that operate at high voltages, large currents and high frequency.

The Power Scope provides graphical displays of voltage, current and power readings which can be inspected for specific numerical values at any point or for calculating of average values over a specific period.

It offers X/Y display capabilities which can be used, for example, to show the speed/torque characteristics of motors. It can also display Lissajous waveforms of input and output for phase analysis.

A variety of functions including arithmetical calculations, time shifting and Fast Fourier Transforms enable users to display waveforms with offsets and skew corrections. An automatic de-skewing function eliminates offsets between current and voltage signals that may be caused by sensor or input characteristics. Users can also define their own computations via equations that combine differentials, integrals, digital filters and a wealth of other functions.

The instrument comes with a PC software application called PowerViewerPlus that can be used to capture waveform data for further analysis. This extends the number of data points it is possible to analyse, enabling the capture and analysis of longer-term performance. PC connection is via standard Ethernet/USB/GP-IB connections. The user-friendly software displays waveforms in a simple and clear graphical style that will be familiar to users of Yokogawa’s popular Xviewer software. Researchers who want to use their own analysis software will be able to establish a connection to the PX8000 via the LabVIEW driver.

Applications cover everything from sustainable power to advanced robotics. In fact pretty much any situation where power consumption is at a premium – which means almost anywhere power is consumed. Typical application sectors include inverter and motor testing, reactor loss measurement of inverter boost circuits, transient responses of industrial robots, wireless charger efficiency measurement, and voltage and power measurements in electricity distribution systems.