Loma IQ2 Service Manual page 58

Reverse mode
Feature only appears if photo eye is set to YES in the configuration menu, Tracker is
set to OFF, Cal trigger is set to OFF and PV test is set to NO.
Selecting YES enables the Metal Detector "Reverse Mode" option.
This will then cause an extra menu position to appear in the Product setup menu,
which enables the Metal Detector to be set to operate either in NORMAL or REVERSE
mode for the product selected.
NOTE
Wherever possible, LOMA will have set the entries within this menu to those required
by your application before the dispatch of your system, or during a commissioning visit
by a Loma engineer as applicable.
Tracking Limits (V1.4 & below)
This facility allows the detector to automatically adjust its threshold between two preset
limits, so that the sensitivity of the machine can be optimised in situations where the
product signal drifts up and down as the product effect changes.
For instance, for a frozen product the product effect signal is very small when the
product has just come out of the freezer, so that a low threshold can be used to give
high sensitivity. However, if the line stops for any reason then the product could thaw
slightly, or build up a layer of moisture on the packaging, creating a significant product
signal. In this event, the threshold will have to be raised to allow the product to be
passed, without false rejection. However, this means that the sensitivity will become
degraded when the product again becomes hard frozen, as there will be a large
difference between the product signal and threshold. Turning the tracker facility on
allows the machine to automatically switch the threshold between two upper and lower
limits, thereby optimising the sensitivity.
The Tracker works by looking at the product signals from the last 100 packs, according
to the following conditions. If the threshold is working at the lower limit and there are
five or more packs, within the last 100, that have product signals between the lower
and upper limits, then the threshold will switch to the upper limit. If the threshold is
working at the upper limit and all of the last 100 packs have product signals less than
the lower limit, then the threshold will switch to the lower limit.
" " " "
[
Press the
Tracking
This menu entry allows the tracker facility to be turned on or off for the product.
Upper thrsh
This menu entry allows the upper threshold limit to be set. The value should be set as
low as possible, so that when product is running with high product signal no false
rejects occur.
Module 7026
] key to give access to the product signal tracking menu.
Configuration and Set up Information
5-36