Loma IQ2 User Manual page 101

84
Installing the metal
detector
The input voltage should not be subject to voltage fluctuations outside the limits
(NWML0320):
• Minus 15% to plus 10% of the nominal supply voltage (230V or 110V).
• Zero voltage for more than 20mS.
• 50% of nominal voltage for more than 40mS.
• 80% of nominal voltage for more than 100mS.
Operation outside these limits may cause loss of function until the supply condition recovers
to within limits.
Other EMC considerations
Any signal I/O which is connected to the auxiliary connections should be in screened cable,
grounded at one end by a low impedance path to RF, and kept free from sources of electrical
noise (eg mains supplies for large electrical machines).
The metal detector is a highly sensitive RF measuring device, which is well screened from
outside interference and has excellent electronic discrimination against unwanted
electromagnetic fields. However, due to its sensitivity it is possible that other devices which
emit high levels of RF noise at the operating frequency of the detector could cause
interference, thereby degrading the performance of the detector. It is therefore important to
avoid siting the detector next to any devices which emit abnormally high levels of RF
interference if proper operation is to be maintained.
Further information is contained in your Service Manual.
These guidelines are based on the PPMA EMC Code of Practice, which should be referred to
if in doubt about any aspect of making external electrical connections to the detector.
Radio frequency interference
A metal detector is, essentially, a Radio Frequency (RF) receiver. As such it is sensitive to RF
noise in the general vicinity of the detector location. While those frequencies not close to the
operating frequency of the detector will usually be filtered out (this includes most 'walkie talkie'
frequencies, unless the transmitter is held very close to the detector aperture), it is not
uncommon for the control frequency (or multiple of it), used in modern speed controllers, to
cause interference.
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