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FlexPS Product Guide
5.
Snow removal (as required)
If the weather conditions at your site include snow falls, the fence should be kept clear of
accumulating snow. If snow accumulates against and around the fence, it will absorb and
dampen the vibrations caused by an intrusion attempt. In addition, if there is significant snow
accumulation, the snow can serve as a bridging or tunneling aid to defeat the sensor.
Adjusting the Filter Settings
The FlexPS processor’s frequency response range is from 100 Hz to 900 Hz. In most installations,
the default setting of 300 Hz and 700 Hz should be used. However, in some instances, nearby
equipment that generates noise at a specific frequency, can affect the sensor’s detection. It is also
possible that fence conditions can result in an area that has a significantly higher, or lower, signal
magnitude at certain frequencies. To prevent detection problems caused by either circumstance,
the processor’s Filter Settings can be adjusted to exclude the suspect frequencies.
To verify the sensor’s frequency response, open the Calibrate tool and start a Frequency plot. Use
Auto Scale to fit the frequency response in the plot window. With the system in a quiescent state
with minimal fence noise, the response should be minimal. Any frequency spikes on a quiet
system indicate a problem (interference or fence condition).
1.
Start the Calibrate tool and select Frequency.
2.
Look at the frequency response while the system is quiet (light wind, no precipitation, no
disturbance of the fence). The frequency response should be very low and flat.
3.
Perform the tap test as described in the Cable setting procedure.
4.
Review the frequency response looking for any frequencies at which the results were
significantly higher or lower than the average response.
5.
Adjust the Filter Settings sliders to exclude any frequencies that are well outside the average.
6.
Apply the changes and repeat the tap test while viewing the frequency response.
7.
If the Frequency response is adequate close the Calibrate tool and download the new settings
to the processor.
8.
Retest the zone to verify cut and climb detection.
To set the Filters to screen out background noise you can use the Calibrate tool during inclement
weather that can cause noisy fence conditions, such as strong winds. (You can also simulate
strong winds by gripping the center of a fence panel and shaking the panel back and forth.)
1.
Open the Calibrate tool, setup the tool for Frequency response and begin recording.
2.
Observe the response caused by the elements (or the simulation).
3.
Look for frequencies at which the response is unusually high.
4.
Adjust the Filters to eliminate those frequencies and apply the changes.
5.
Select the Reset Peaks button and observe the response. If the resulting frequency response
is adequate close the Calibrate tool and download the new settings to the processor.
6.
Retest the zone to verify cut and climb detection.
Note
A direct USB connection is required to use the Frequency Plot mode on
the Calibrate tool.
Note
The response should be similar throughout the zone for impacts of
similar force. If the response increases dramatically in an area even
though the force used is consistent and the fence conditions are
unchanged, there may be a “sweet spot” that amplifies the signal. If
this occurs, use the filters to exclude the affected frequencies.