Loma IQ3+ST, User Manual

Page: 19 / 247

Safety First
9
Phasing
The diagram below shows how the magnetic and conductive properties of a product affect the product
phase angle.
Utilising the ‘Learn’ feature provided in the IQ
3
+ ST Metal Detector, an average for the net signal
received from a product during inspection is digitally processed to provide a phase angle and
amplitude.
This is then memorised for later recall against the product as a product ‘window’, as shown in the
Product Signal diagram below and essentially provides a ‘filter’ so that signals of a known phase and
amplitude can be ignored. This is called ‘phasing out’ the product signal.
Product Signal Contaminated Product Signal
The Contaminated Product Signal diagram above shows how a signal from a metal contaminant,
although much smaller than the product signal, can be easily detected.
The metal detector sees the one resultant signal of the metal contaminant and product signals
presented together at the same time.
This resultant signal still falls well outside of the product ‘window’ which then triggers detection and
provides an opportunity for the contaminated product to be rejected from the production line.