Loma IQ2 Service Manual page 65

Resistive and Reactive Components
The search head produces two signals, known as the resistive and reactive
signals (R and X), that tell the control unit about the interaction of the product
with the magnetic field.
In general terms, dry products only produce a small reactive signal, whereas wet
or fresh products such as cheese produce mainly resistive signals. Metal
contamination can produce an interaction that produces both considerable
reactive and resistive signals.
Figure 3 shows the typical signals, which would be traced out, on an
oscilloscope as a block of cheese moves through the search head. A graph can
be plotted of the reactive signal (X) against the resistive signal (R), known as a
locus plot, and this is shown in Figure 4.
R
X
Figure 3 R and X signal as a block of cheese passes through the search head
Module 7026
Block of cheese
in aperture centre
Configuration and Set up Information
time
time
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