HELMHOLTZ COIL INSTALLATION AND CALIBRATION
Figure 3: Read Tab - Offsets
Once you have achieved the lowest possible reading, lock the locking nut (ensuring that you keep the
potentiometer in place). Note that you may need to progressively tighten the locking nut, and fine tune
the offset as you do so.
•
Scaling:
This is a check (and adjustment if required) to ensure that the coil is generating the appropriate field.
With the sensor remaining in the same position as for the offset checks, return to the generator tab. The
settings should be as follow:
o
Set the amplitude to ¾ of the sensor range or the maximum field which can be generated by
the coils, whichever is the lowest
o
Set the frequency to 35Hz
o
Set to Sinewave
o
Select each axis in turn (after each axis is selected, you will need to go to the read tab).
Other information required will be the scaling error of the sensor, as these can be taken into account
and used to fine tune the accuracy. For example, if the sensor’s scaling error is +1% this means that for a
field of 100uT, the sensor will read 101uT. An error of -1% will mean that the sensor will read 99uT in a
100uT field.