304UM0001 Rev 00
PD160 Enhanced Series User Manual
Page: 11 of 39
Setting
Offset
8
Highest
8%
7
6%
6
4%
5
2.5%
4
2%
3
1.5%
2
1%
1
Lowest
0%
AFS
Automatic
End1
There are eight manual frequency shift selections to choose from,
numbered from 1 to 8, with 1 producing the lowest frequency and
8 the highest. The amount the frequency is shifted depends on
the inductance of the loop and feeder cable but is approximately
equivalent to the offset value shown in the table (where the value
shown is the percentage shift up in frequency from the lowest
setting). This amount decreases slightly for smaller inductances.
Due to the non-linear nature of the oscillator, the higher
selections produce more of a shift than the lower ones.
The eight settings allow a shift across the tuneable inductance
range of over 20%.
Selecting any one of these manual settings will put the detector into manual frequency selection and
retune the channel to that setting. At each extreme of high frequency and low frequency, there will be
some settings which don’t allow the channel to tune as the frequency shift could push the frequency
out of the acceptable operational range. It is possible for the operational frequency to be sufficiently
high or low that none of the selections are tuneable. In this situation, refer to the on-board diagnostics.
3.2.2.1
Automatic Frequency Selection
The PD160 Enhanced Series introduces the new Automatic Frequency Selection (AFS) which is
turned on by default. This setting allows the detector to briefly evaluate all eight frequency shifts and
select the best frequency offset available. It weighs up each selection based on where the frequency is
located within the operational range, the signal strength, and the level of detected noise. AFS allows
the detector to evaluate all the frequency selections where-as if it is deactivated, the detector only
evaluates the user selected frequency.
Due to the increased processing required, AFS takes longer to tune
than when it is deactivated. When AFS is activated, under the normal
or idle display, the display will indicate that it is attempting to tune.
The tune time with AFS on can range from 5 to 20 seconds. If after
this period of time, the detector still has not tuned, refer to the on-
board diagnostics as it is also possible that none of the frequency
selections are suitable. In this case the detector will indicate a fault
under the diagnostics displays.
Due to the sporadic nature of noise, the channel may seem quiet during the evaluation but still suffer
from cross-talk. There may be some extreme cases where the 20% shift in frequency is insufficient to
handle the amount of cross-talk.
For more information on cross-talk, refer to the installation guide at section 5, specifically section 5.2.2.
For more information about diagnostics, refer to section 3.2.6.
For more information about tuning refer to section 4.1.
AFS can be toggled on or off via the frequency menu. When activated, the channel will be retuned to
find the best frequency of operation. When deactivated, if the channel is tuned, it will not retune but
remain at the previously selected frequency. If deactivated while the detector is tuning, it defaults to
setting 5 of 8. In this situation, it is recommended that the user selects a frequency setting.
While the detector is tuning, it is recommended to allow the previous selection to complete.
On both manual and automatic frequency selection, once a valid frequency offset has been selected,
the detector waits for that setting to settle below the sensitivity setting before allowing normal operation
to continue. If there is sufficient drift from an extreme temperature change in the installation location or
vehicles driving over the loop at the time, it is possible that the tuning will timeout, invalidate that
frequency selection and attempt to tune again. The diagnostic displays will indicate drift in this
