Wavetronix SmartSensor Advance Extended Range (SS-200E) - Use Manuel d'utilisateur télécharger pdf (Page 88)

CHAPTER 7  CHANNELS-ALERTS-ZONES 87

Qualied Count and Dynamic Density™. ese lters are mutually exclusive (only one may

be active at a time).

e qualied count lter is used to limit a zone’s outputs to times when there are a certain

number of qualied detections in the zone at one time.

Click in the Qualied Count range and the Edit Qualied Count lter will appear. Edit the

min and max values to set the qualied count range (see Figure 7.23). Only qualied detec-

tions within the set range will activate zone outputs. e minimum qualied count value is

1 and the maximum qualied count value is 25.

Figure 7.23 – Qualiﬁed Count Filter

Click the radio button to the le of the Qualied Count label to enable the qualied count

lter.

Dynamic Density

Dynamic Density is a type of vehicle platoon detection that activates a zone’s output when

the number of qualied detections within a zone equals or exceeds a density requirement.

e following equations explain the density requirement formula, called the Dynamic Den-

sity Count Requirement (DDCR).

First, trac density is dened as the number of vehicles within a zone, divided by the area

of the zone (see Figure 7.24).

Density =

Number of Vehicles in a Zone

Zone Size (ft.) x Lane Tuning Factor

Figure 7.24 – Required Density Equation

To maintain a given level of eciency, the required density increases as speeds decrease;

similarly, the required density decreases as speeds increase. erefore, to achieve a Required

Flow Rate, the density of trac will dynamically change with the speed of the vehicles as

shown in Figure 7.25.

Density =

Required Flow Rate

Speed

Figure 7.25 – Flow Rate Equation

In addition, the Required Flow Rate is equal to the ideal ow rate multiplied by the required

% Utilization. Since ideal ow rate is inversely proportional to the ideal time Headway be-

tween vehicles, this can be written as show in Figure 7.26.

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Wavetronix SmartSensor Advance Extended Range (SS-200E) - Use Manuel d'utilisateur Page 88