Digital power meter feature 0.1% of reading accuracy from a few mA up to 40A

January 10, 2013 // By Julien Happich
Yokogawa's WT300 series of digital power meters combine accurate and reliable power measurement over a wide power range with flexibility, ease of use and a choice of communication interfaces.

The new instruments will help developers and manufacturers of electrical equipment – ranging from domestic “white goods” to lighting systems and air-conditioning equipment – to ensure that their products comply with emerging IEC and EN standards and increasingly complex and stringent specifications on energy efficiency. Key features of the new instruments include a basic accuracy of 0.1% of reading, guaranteed accuracy over the entire measurement range (from 1% to 130% ), a wide measurement range from standby power levels of a few mA up to the 40A currents used in induction cookers, and flexibility to enable users to target different technical and commercial applications.

This includes a range of communications interfaces, allowing the WT300 series of digital power meters to be integrated into laboratory test benches or automated test set-ups on production lines. USB and GPIB or RS232 is fitted as standard, and Ethernet is available as an option. In addition to standard power measurements, the new meters offer a wide range of harmonic measurement capabilities, including the ability to carry out simultaneous measurement of normal power parameters such as RMS, mean or DC power along with measurement of harmonics up to the 50th order. The guaranteed accuracy of the new power meters results from the fact that Yokogawa has its own European standards laboratory at its European headquarters in The Netherlands. This facility is the only industrial (i.e. non-government or national) organisation to offer traceable power calibration, to national and international standards, at frequencies up to 100 kHz: a requirement for higher harmonic measurements specified in quality standards such as ISO9000.

Other features of the new instruments include a bandwidth of DC and 0.5 Hz to 100 kHz (up to 20 kHz for 40 A on the WT310HC), plus an auto-range function for measurement and integration. Software is also available for testing equipment compliance to industry energy-saving standards such as IEC62301 Ed2.0 and IEC62018 for standby mode equipment or