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Description of sensor operation in “Default” mode
In this mode the infrared section discriminates the alarms by operating the following controls:
w
signal width and symmetry: the wave shape must exceed minimum thresholds, both in the positive and in the negative direction; besides, the width of the half-waves must be
proportionate.
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the energy level of the signal must be above a minimum value.
The previous controls are completed by two infrared, independently from each other.
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comparison of the two infrared signals in order to evaluate their similarity: signal produced by two infrared sensors must present a certain correspondence as fare as shape, phase
and width.
Sometimes this last criteria may cause a signal that a normal detector would consider an alarm to be discarded. However, it allows the sensor to tolerate very
wide interference signals without going into alarm status, as long as they are not correlated with each other.
In “default mode the microwave completes two types of evaluation:
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it measures signal intensity, that must exceed a minimum established level, and its frequency must be included within the maximum and minimum limits.
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evaluates the degree of directionality of the target, discarding signals that present oscillating characteristics.
Even for the microwave, through to a lesser degree than the infrared, it is possible that even intense signals are discarded because they are not characterised
by a defined sense of movement. Please note that in “default” mode it is not required for the movement direction of the target in a specific direction
(approaching or moving away), any movement direction is fine as long as it is defined.
General sensor alarm takes place when both technologies go into alarm status.
Description of other operational modes
If “medium” or “low” sensitivity is chosen for the infrared, obtained functioning is similar to the “default” mode but the applied decision thresholds are more and more strict for all
parameters that the sensor controls. The width and energy of the signal must be greater and signal correlation must be positive with a tighter temporal gap between the signals.
Besides, with “low” sensitivity, it is required for the infrared to go into alarm status with two impulses instead of only one.
By selecting “high” sensitivity mode instead, all correlation controls between signals are eliminated and the analysis is only based on intensity and frequency, as occurs on
conventional detectors. Choosing this mode is recommended if the sensor is installed outdoors. However, it can also be used if installed indoors.
As far as the microwave, besides the “default” operational mode, the are the “only approaching” and “only moving away” modes that require for target movement to be in a specific
direction to trigger the alarm, and “no control” mode that deactivates movement direction discrimination and makes the detector work in the conventional way, only based on signal
intensity and frequency. This last mode is not recommended for outdoor environments because, in presence of plants moved by the wind, the microwave almost always remains in
alarm. Sometimes this may be necessary when the path the target must go through is very short (in case of tight areas), particularly with a combination of vertical protections lenses
or long range mono-lobe. It is recommended to complete accurate testing before deciding on a mode and, if the “default” mode works in a satisfactory way, keep that one. In any
case, it is recommended to carefully adjust, using the potentiometer, microwave sensibility to the minimum necessary level in order to reach the maximum requested distance and
not go beyond. One must consider that is using HPWIN PC software from PC to adjust the sensors, both locally by way of USB, or remotely by way of modem or GSM, it is possible
to
reduce
microwave sensitivity even more until it reaches about 75% of its original value, if circumstance require it.
AND
Mode and
SECURITY Mode(Only OutSpider DT)
By default the
OutSpider DT
operates in mode
AND
, that is, conditioned in a way that both technologies must be in alarm status within a short period of time in order to give a
general alarm.
The
SECURITY
mode instead foresees that if one of the two technologies is tripped repeatedly within a certain interval of time, the sensor still creates a general alarm.
Specifically, if at least 4 infrared alarms or 7 microwave alarms occur within about 30 seconds, the detectors goes into alarm status. The AND condition remains valid however, since
an alarm for both technologies within a specific amount of time immediately trips the general sensor alarm.
No matter what the mode is, AND or SECURITY, the alarm for each individual technology is processed according to the criteria described in previous paragraphs for sensitivity
levels and the selected operational modes: default, medium, low and high for the infrared; default, only approaching, only moving away and no control for the microwave.
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