7.4.1Numbering of sensors#
This section outlines the recommended numbering sequence for installed sensors. Where a different numbering system is used, it must be documented for future reference.
The following recommended rules apply for the numbering sequence of sensors:
- 1.The sensors on the travelling direction nearest to the counting equipment (for example, cabinet or logger) shall precede the sensors on the farthest direction.
- 2.For lanes in the same travelling direction, the sensors on the left lane shall precede the sensors on the right.
- 3.The leading sensor shall precede the trailing sensor on the same lane.
- 4.The sensors on the main road shall precede the sensors on the branches (such as on ramp and off ramp). Branch precedence is determined by angular distance in clockwise manner from the cabinet, with reference to the vector from the first sensor (on the main road) to the cabinet.
Refer to Figure 7.4.1 for an illustration of these rules.
7.4.1.1Pneumatic tubes#
Pneumatic tubes in a counter / classifier site shall be numbered sequentially according to the numbering rules in Section 7.4.1. For example, the leading and trailing tubes on the lane which is closest to the logger can be numbered as 1 and 2 respectively; the leading and trailing tubes in the opposite direction lane can be numbered as 3 and 4 respectively.
7.4.1.2Loops#
Loops in a counter / classifier site shall be numbered sequentially according to the numbering rules in Section 7.4.1. For example, on a dual carriageway 2 lane road with 2 loops on each lane, the loops can be numbered as shown in Figure 7.4.1.
7.4.1.3Piezoelectric sensors#
Piezoelectric sensors in a counter / classifier site shall be numbered sequentially as per Section 7.4.1. The examples shown in Figure 7.4.1 is also valid for numbering piezoelectric sensors by substituting loops with piezoelectric sensors in Figure 7.4.1.
