304UM0001 Rev 00
PD160 Enhanced Series User Manual
Page: 10 of 39
3.2.1 Idle Display
The idle display is the normal display shown when not in the menu
system. It displays the model of the unit. Any button pressed will
enter the menu system. The up (
↑
) and down (
↓
) arrows are used to
navigate the system, while the enter button is used to select items,
e.g. changing settings, going deeper into the menu, or going back.
Under normal operating conditions, if a button is inadvertently
pressed, or during the use of the menu system, the menu will go back
one display every 25 seconds. This is not the case in the diagnostics
thus keeping certain desired information on display.
The menu system does NOT interfere with the operation of the unit; it merely provides the ability to
change settings and to view diagnostics. The unit is fully operational while menu settings are changed
and most settings have immediate effect.
3.2.2 Frequency
The frequency settings menu is the first menu and is used to shift the
operating frequency of the detector. This is primarily used to handle
situations in which more than one detector is used at the same site.
The detectors must be set-up to ensure no crosstalk (interference)
occurs between adjacent loops connected to different detectors. This
is achieved by ensuring that the loops of the two detectors are
spaced sufficiently apart (approximately 2 metres between adjacent
edges) and also ensuring that the detectors are set to different
frequencies.
The loops connected to multichannel detectors are not susceptible to crosstalk due to the design of the
loop interface. For more information about crosstalk refer to section 5.2.2.
The frequency setting allows the operating frequency of the loop to be shifted higher or lower
depending on the selection. However, the operating frequency of the detector channel is determined
by a combination of:
Inductance of the loop and feeder cable
Detector frequency settings
The operating frequency of the detector channel increases as the loop inductance decreases and vice
versa. The inductance of the loop and feeder cable is determined by:
Size of the loop
Number of turns in the loop
Length of feeder cable
As a general rule, the detector connected to the inductive loop with the greatest inductance should be
set to operate at the lowest frequency.
If the frequency reading from the on-board diagnostics is close to the maximum frequency, the
inductance of the loop is too low and more turns need to be added to the loop. However if the reading
is close to the minimum frequency, the inductance of the loop is too high and you need to remove
turns from the loop.
If the detector is operating close to either limit, it is possible that either the frequency drift caused by
environmental changes or the shift in frequency caused by a large %
∆
L/L detect will cause the
frequency to go outside the limits and cause a retune.
