Holaday Industries HI-3624, Руководство пользователя, Страница: 15 / 22

HI-3624 / HI-3624A Manual Page 7
Figure 2
It does not matter which orientation of the field sensor is used
for the x orientation but the y and z orientations must be
perpendicular to one another and the x orientation. Figure 2
illustrates one possibility for the three mutually orthogonal
orientations. This figure shows a sensor VDT separation
distance of 30 cm. The 30 cm spacing is commonly used in
VDT measurements but alternative distances may also be used.
In the case of the Model HI-3624A, the user may select the
lower frequency of the band pass for the instrument as either
30 Hz (the value incorporated in the Model HI-3624) or 5 Hz as
specified in the Swedish standard for measurements of
magnetic fields produced by VDTs. It should be noted that
when the instrument is switched to the 5 Hz lower frequency
cutoff, the unit will be very sensitive to motion of the sensor
since movement within the earth's constant field will appear as
a signal to the instrument. When the sensor is accelerated or