16 January 2014 - Yokogawa has combined its world-leading expertise in power measurement and its long heritage in oscilloscope design to create the world’s first Precision Power Scope: the PX8000.The PX8000 brings oscilloscope-style time-based measurement to the world of power measurement. It can capture voltage and current waveforms precisely, opening up applications and solutions for a huge variety of emerging power measurement problems.
“As more and more innovation focuses on energy efficiency and the integration of electronics into power-based systems, more and more engineers are demanding accuracy and precision from their power measurement”, comments Terry Marrinan, Yokogawa’s Vice President, Test & Measurement, for Europe & Africa: “With the launch of the PX8000, R&D professionals need no longer compromise on their need for high-accuracy time-based power measurement: a need that conventional power analysers and oscilloscopes were never designed to meet.”
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 1000 V RMS and currents up to 5 A 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 PX8000 not only has four inputs but also enables the simultaneous capture and display of voltage and current across all three phases.
In addition to delivering precision power measurement to give true insight into energy consumption and performance, the PX8000 incorporates a number of innovative features that support the crucial measurement and analysis of transient power profiles. It provides simultaneous voltage and current multiplication to give real-time power sampling, supporting both transient measurement (as standard) and numerical values averaged across the sample period. Up to 16 different waveforms – including voltage, current and power – can be displayed side-by-side, giving engineers instant “snapshots” of performance.
The PX8000 is powered by Yokogawa’s isoPRO(tm) technology, which offers industry-leading isolation performance at the highest speeds. isoPRO 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 PX8000 has built-in functions for the direct calculation of derived parameters, such as root mean square (RMS) and mean power values, to enable the identification of cycle-by-cycle trends.
The PX8000 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.
The instrument also supports the capture of power waveforms over specific periods of time through the definition of start and stop “cursors”. This is particularly useful for examining transient phenomena and in the design of periodically controlled equipment. To ensure that such equipment complies with energy standards, it is vital to measure power consumption across a range of different modes from “sleep” to full activity – and all the transient states in between.
The PX8000 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.
Like Yokogawa’s digital oscilloscope family, the PX8000 incorporates a history memory function that automatically records up to 1000 historical waveforms which can be recalled and redisplayed at any time. Recorded waveforms can also used to redefine trigger conditions. Historical waveforms are explored via condition-based searches to locate specific hard-to-isolate abnormal phenomena during repeated high-frequency measurements.
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 PX8000 makes it possible to simultaneously measure the harmonic components of voltage and current waveforms as well as the harmonic distortion factor. Harmonic measurements take place in parallel with conventional voltage and current measurements. Harmonics up to the 500th order of the fundamental can be measured.
The PX8000 comes with an accompanying PC software application called PowerViewerPlus that can be used to capture waveform data for further analysis. This dramatically extends the number of data points it is possible to analyse, making the PX8000 ideal for capturing and analysing 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 for the PX8000 cover everything from sustainable power to advanced robotics. 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.