Hirst’s current fluxmeter is the IFM06 Integrating fluxmeter. Integrating Fluxmeters are used to measure total magnetic flux with a coil. Fluxmeters are often used when a total flux reading of a magnet is required and unlike Gaussmeters need a changing magnetic environment to support measurement.
Examples of when to use the instrument include:-
To check a magnetisation process
A search coil is embedded into a magnetising fixture (holds the material to be magnetised). The magnet charger magnetises the sample and as it is removed from the fixture an Integrating Fluxmeter measures the sample’s total magnetisation and determines if it is within acceptable production tolerances.
To determine total flux, with Helmholtz coils (produces an area of superior uniformity).
A pair of Helmholtz coils is connected to an Integrating Fluxmeter. The sample to be tested is placed within the pair of coils and rotated. The Integrating Fluxmeter determines the total magnetisation of the sample and displays this value on its screen. See IFM06 and Helmholtz coils
Principle of Fluxmeters
As magnetic flux cuts through the search coil, it induces a voltage in the search coil. As per Faraday’s law of induction, this voltage is the differential of the magnetic flux that passed through the search coil. By feeding this voltage into an integrating fluxmeter, the integration process removes the differential (of the search coil) resulting in the fluxmeter displaying the total magnetic flux. Fluxmeters require a dynamic component for the measurement, as it is necessary for magnetic flux to cut the search coil to produce a voltage.
By calibrating the fluxmeter with the area and number turns of the search coil it is possible to display values of flux density on a fluxmeter (Tesla, gauss) as well as magnetic flux (Webers, Vs or Maxwell turns)
Fluxmeter Selection Factors
One of the most important considerations of integrating Fluxmeters is drift, which is always present due to the extended time of measurement. Drift is the change in the instrument’s displayed values that is not due to flux changes.
All integrating fluxmeters must make compensations for drift.
It is the accuracy of these compensations and the overall stability of the system that give good drift and hence integrator performance.
Hirst’s Integrating Fluxmeters feature fully automatic drift compensation technology. The drift correction operation determines the instruments existing drift rate and makes the necessary adjustment to obtain optimum compensation. When not performing a measurement, the instrument tracks any changes in the drift rate and makes the necessary compensations.
The IFM range of Fluxmeters come equipped with a PLC port to enable control via 24v logic signals. This makes interfacing with existing PLC and mechanical handling systems simple.
Independent output signals are provided for PASS and FAIL and an input signal is provided to initiate a measurement sequence.
The IFM06 features an RS232 and a USB port. Both these ports can be used to control the instrument and acquire data via SCPI protocol.