Metrology applications require traceable measurements and measurements able to be duplicated by multiple labs. Accreditation by certified body enables labs to easily and quickly trace measurements (be they in or out of tolerance) and resolve potential deficiencies.
Traceable current measurements become critical in electric drive efficiency measurements for vehicle and industrial standards such as electricity metering. Measurements can be made at DC or AC for variable speed motors applications.
Danisense Zero-Flux Current Transducers make up the traceable (with measurement from NRC, Canada) calibration standard for ppm accuracy measurement at DC and AC currents. GMW offers accredited calibration for current probes from DC to 400Hz and current magnitudes from 20A to 8kA.
Bergoz Instruments NPCT DC Current Transformer acts as the one true reference measurement (displaying DC Beam Current) in nearly every Light Source Storage ring worldwide,
Magnetic Field Reference Magnetometers
Organizations such as the US FDA require MRI to have Magnetic Field “quality” (technically uniformity) to be measurable to certain levels before approval for patient use.
The gyromagnetic ratio of water (i.e. the proton) is (42.576 MHz/T and is the fundamental traceable constant (accurate to +/-5ppm) in Nuclear Magnetic Resonance measurements and the principal of operation behind Metrolab NMR Teslameters and Magnetic Field Cameras. This value is about 5ppm higher than water for the silicone rubber samples used in the teslameter.
When developing low magnetic field instrumentation, fluxgate offer a good low field reference sensor. The Bartington Mag-13MS range will be the most suitable, with the ability to provide accredited calibration by the National Physical Laboratory in the UK.
Magnetic Field Sensor Calibration
To calibrate magnetometers, whether these are used in consumer electronics, or precision instruments, a known magnetic field needs to be generated.
The range of Bartington Helmholtz coils available allow for stable fields to be generated with the size of the coils dependent on the size of the sensor to be placed inside. The Helmholtz Coil Systems can also be used for calibration of other environmental field sensors, including the MAG-13 line of high precision (magnitude and orthogonality) magnetometers.