A Measurement System for the Automatic Survey of the Low Frequency Magnetic Field

In this paper we present a measurement system proposed, realized and calibrated for the automatic survey of the low frequency magnetic field. The instrument has a tri-axial sensor and three channels for waveforms processing in 50 Hz - 100 kHz frequency range. The waveforms of the magnetic fields are acquired using a National Instruments card and a virtual instrument created in the LabVIEW software, and then the data are processed and stored on a portable computer. Beside spot measurements, the instrument allows automatic long term survey of the magnetic field. The measurement system was calibrated by means of a simple method based on the standard field. The uncertainty of the instrument of about 15% is adequate for automatic survey of magnetic field.