For calibration of magnetic field sensors, or for any operation requiring the creation of a known magnetic environment, Bartington Instruments offers a choice of Helmholtz Coil Systems with coil diameters of 500mm (HC1) or 1m (HC2). The systems generate a homogenous field with 0.1% error in 1, 2 or 3 axes, and the two-axis version is available in any combination: X+Y, Y+Z or X+Z.
The coils are operated by a PXI control system, with control software based on National Instruments’ LabVIEW™. Bartington Instruments can supply such a system with an inbuilt PC and A/D acquisition card, or alternatively a PC running Windows and fitted with a PCI Express card PCIe-6353 may be used.
As well as the coil assembly (which includes a non-magnetic mounting table), the systems include the PA1 Power Amplifier and CU1 Control Unit. The PA1 determines the input current to the assembly, which in turn allows the field generated by each pair of coils to be determined. Controls on the unit let the user compensate for variations in the static and generated fields, and adjust orthogonality electronically.
The CU1 buffers and filters signals between the power amplifier and the PXI control system, as well as powering and filtering signals from the device under test and a reference magnetometer.