Doc. Ref.No: Q875-0143/ENG
Issue 2
Met 30+ Operating Manual
12/01/10
11. GLOSSARY
11.1 Aperture
The hole in the metal detector through which product passes.
11.2 Bargraph
On the bottom line of the detector's display, after power on or reset, a line of circles
is displayed. The more circles, the larger the signal from the product. Solid circles
indicate that metal has been detected, while hollow circles indicate product effect or
noise.
11.3 Test Setup
This product setting is set up at the factory to detect the standard test sample
provided with the detector, without false triggering. By selecting TEST SETUP and
passing the standard test sample it is possible to see if the basic sensitivity of the
detector has reduced since it left the factory. If it sees the sample but false triggers,
then the environment is noisier (see
noise
below) than when the detector was initially
set up.
11.4 False Triggering
False triggering is when the detector indicates that it has seen metal when none is
present. This can mean that good product is incorrectly rejected.
11.5 Metal-Free Zone
Any metal that moves near to the aperture may be detected by the metal detector.
This could result in false triggering. To prevent this, there should be a metal-free
zone around the detector aperture i.e. an area where no metal is present.
11.6 Noise
In connection with metal detectors, noise usually refers to electrical noise,
sometimes called interference. Noise is unwanted signal picked up by the metal
detector, sometimes resulting in false triggering or reduced sensitivity. Noise can be
generated by unsuppressed solenoids, inverters, earth loops, high-current-carrying
cables, welding equipment operating nearby etc.
11.7 Noise Test
This is a fault diagnosis test, it is an automatic setup which can be carried out in the
event of a fault occurring on the detector. The auto setup values should be noted
and then passed to the Lock when calling for assistance.
11.8 Product Effect
Some products have a signal, which can be seen by the metal detector - this is
called the product effect. Its effect, in some cases, is to partially mask the signal from
metal contamination resulting in a lower sensitivity. Product effect can be caused: by
small amounts of metal in the product's recipe e.g. iron-fortified cereals, vitamin
File Name: Q875-0143 ENG Iss2 Met30+ Operating.doc
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