Getting The Best Results; Dry Mode - Loma IQ2 User Manual

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Using the metal
detector
When there is nothing between the coils the voltage in each receiver coil will be identical,
because they are an equal distance from the transmitter coil, and the signal is zero.
Any conductive object moving between the coils will interact with the magnetic field to
produce a voltage difference between each of the receiver coils. Although any object will
produce a slight difference, metal objects produce a significantly larger difference, allowing
them to be detected in non-metal objects such as foodstuffs. The metal detector can thus
distinguish between an uncontaminated product, and one containing metal contanimation.

Getting the best results

Before using the metal detector with a new product it is important to calibrate it with the
product, to allow the metal detector to adjust itself to the highest possible sensitivity.
The metal detector can use three alternative modes of operation: Dry, Resistive, or Reactive.
During calibration it automatically selects the operating mode that will give the best results
for a particular product.

Dry mode

Dry mode is used for products with low moisture content such as tea and coffee. Frozen
foods can also use dry mode, because water does not conduct when it is frozen.
Dry mode gives the best sensitivity, and in dry mode the metal detector can typically detect a
one millimeter ferrous or non-ferrous metal contaminant in a typical 100 millimeter aperture
size.
Resistive mode
Resistive mode is used for products with a slight moisture content, such as flour or cocoa, or
are iron fortified, such as cereal.
Reactive mode
Reactive mode is used for products with a considerable moisture content, which are
therefore conductive causing the product to give a large effect when it passes through the
metal detector.
In reactive mode the metal detector takes advantage of the difference between the resistive
and the reactive signal to distinguish between the effect of the product, and the effect of a
product with a metal contaminant. Because the product can mask the signal generated by
the metal contaminant, the sensitivity is generally slightly lower than in dry or resistive mode.
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