VD-108B Loop Detector Specification Version 1.0

VD108B Loop Detector Specification (Version 1.00)

Shenzhen Tenet Technology Co.,Ltd Add: 4A, 7th Seat Nanyou Tianan Industrial Park Dengliang Road Nanshan Shenzhen China Http: www.chinatenet.com E-mail: [email protected] Tel: 0086-755-26647666 26413293 Fax: 0086-755- 26419610

VD-108B Loop Detector Specification Version 1.0

Content: 1. Introduction...........................................................................................................................3 2. Technical data........................................................................................................................3 3. Operating Guide....................................................................................................................3 3.1 VD108B connection pin Diagram...............................................................................3 3.2 Adjustment of the sensitivity.......................................................................................4 3.3 Reset............................................................................................................................4 3.4 Output delay 2S...........................................................................................................5 3.5 LED work condition guide..........................................................................................5 3.6 Debugging criterion ....................................................................................................5 4. Installation Guide..............................................................................................................5 4.1 OPERATIONAL CONSTRAINTS .......................................................................6 4.1.1 Crosstalk............................................................................................................6 4.1.2 Reinforcing........................................................................................................6 4.2 Installation Information.........................................................................................6 4.2.1 Loop and Feeder Specification..........................................................................6 4.2.2 Sensing Loop Geometry....................................................................................6 4.3 Loop Installation ...................................................................................................7

VD-108B Loop Detector Specification Version 1.0

1. Introduction VD-108B single loop detector is used for detecting vehicles and which were fit for parking lots, vehicle roll station or controlling traffic light systems .and so on. The way of output of VD-108B is TTL.

2. Technical data Supply Voltage: 7-12VDC@200mA Frequency range: 29 KHz-90 KHz Reaction time: 100ms Output Delay: 2s (alternative) Sensitivity: 0.02%-0.2% adjustable in 4 grades. Environmental compensation: Automatic drift compensation Loop inductance: 80uH-300 uH (include the connecting wiring) Ideal 150Uh uH (41khz) Loop conn. Wiring: Max.5 meters. Twisted at least 20 /meter. Storage temp: -40ºC-+85ºC Operating temp: -20ºC-+55ºC Relative humidity: ≤95% Package: standard relay package Dimensions: 27mm (L)*21mm (W)*37mm (H)

3. Operating Guide 3.1 VD108B connection pin Diagram

Diagram 1

VD-108B Loop Detector Specification Version 1.0

3.2 Adjustment of the sensitivity There are four grades for choice of the VD108B loop detector and which can be set by the three-stage sliding switch on the front of the housing broad. “3”is the high sensitivity“0” is the low sensitivity（just like the picture one show）. Sensitivity

Sensitivity grade

2 1 0

Change of the

DIP1

DIP2

0N

ON

0.03%

ON OFF OFF

OFF ON OFF

0.05% 0.10% 0.20%

electricity

Diagram 2

LED

1

2

3

DI P ON

RESET

Top broad of VD108B

Diagram 3

3.3 Reset When the loop detector is on power, it will automatically detect and turn to the loop which connected with it. This procession will last 5S while the lights on the top broad flash with 1HZ frequency output. （bright 0.5S，extinguish 0.5S）。

VD-108B Loop Detector Specification Version 1.0 The reset procession is the same with which is on power. After pressing the reset switch.

3.4 Output delay 2S When the switch of DIP3 of VD108B on the top broad is “on” that enable the time of output to delay 2 seconds and which is convenient detect the vehicles or trailer with high speed more than 10 miles per hour.

3.5 LED work condition guide Through the LED on the top broad, we can know the work condition. a. When the system is resetting and LED will bright with 1Hz frequency output and the procession will last 5 seconds（bright 0.5 second，extinguish 0.5 second）； b. LED will bright with 4Hz frequency output in the open circuit, short circuit condition or exceeding the permissible range c. When the system is in the self-inspected condition，LED will bright with 1Hz frequency output.（bright0.1S，extinguish 0.9S）； loop.

d. when vehicles and metal are inspected, LED will not extinguish until they left the detect

3.6 Debugging criterion Make the sensitive to low（DIP1 and DIP2 were set in “OFF”）； Set the output delay “OFF”（DIP3 is set to the place of “OFF”)； Remove the metal which on the detect loop； Turn on the power and the loop detector start to tune and the LED on the top broad bright with the procession of 5 seconds. LED will bright with 1Hz frequency output（bright0.1s， extinguish0.9s） after finishing this procession. The loop detector will detect the loop with the procession of tuning. LED will bright all the time in the open circuit, short circuit condition or exceeding the permissible range z z z

4. Installation Guide The detector must be installed in a convenient weatherproof location as close to the loop as possible. WARING: 1) This unit must be earthed. 2) Installation and operation by service professional only. 3) Disconnect power before working on this unit. A correct loop configuration and detector installation will ensure a successful inductive loop

VD-108B Loop Detector Specification Version 1.0 detection system.

4.1 OPERATIONAL CONSTRAINTS 4.1.1 Crosstalk When two loop configurations are in close proximity, the magnetic field of one can overlap and disturb the field of the other. This phenomenon, known as crosstalk, can cause false detect and detector lock-up. Crosstalk can be eliminated by: 1. Careful choice of operating frequencies of operation frequency. The closer together the two loops, the further apart the frequencies of operation must be. 2. Separation between adjacent loops .where possible a minimum spacing of 2 meters between adjacent loops. Where possible a minimum spacing of 2 meters between loops should be adhered to. 3. Careful screening of feeder cables if they are routed together with other electrical cables. The screen must be earthed at the detector end only.

4.1.2 Reinforcing The existence of reinforced steel below the road surface has the effect of reducing the inductance, and therefore the sensitivity, of the loop detection system .in this case two additional turns of wire should be added to the loop. The ideal spacing between the loop cable and steel reinforcing is 150mm, although this is not always practically possible. The slot depth should be kept as shallow as possible, talking care that no part of the loop or feeder remains exposed after the sealing compound has been applied.

4.2 Installation Information 4.2.1 Loop and Feeder Specification The loop must consist of insulated wire with a minimum copper cross-sectional area equivalent to 1.5 square millimeters. The feeder should be of the same material but twisted a minimum of 20 twists per meter. Joints in the loop or feeder are not recommended. Where this is not possible, Joints are to be soldered and terminated in a waterproof joint bow. This is extremely important for reliable detector performance. Where long loop feeders are used, or feeders are routed together with other electrical wiring, the use of a screened cable is suggested for the feeder. The screen must be earthed at the detector end only.

4.2.2 Sensing Loop Geometry Sensing loops should, unless site conditions prohibit, be rectangular in shape and should normally be installed with the longest sides at right angles to the direction of traffic movement. These sides should ideally be 1meter apart. The length of the loop will be determined by the width of the roadway to be monitored. The loop should reach to within 300rnmof each edge of the roadway. In general, loops having a circumference measurement in excess of 10 meters should be

VD-108B Loop Detector Specification Version 1.0 installed using 2 turns of wire, while loops of less than 10 meters in circumference should have three or more turns. Loops having a circumference measurement less than 6meters should be have four turns, It is good practice at time of installation to construct adjacent loops with alternate three and four turn windings to escape crosstalk.

4.3

Loop Installation

All permanent loop installations should be installed in the roadway by cutting slots with a masonry cutting disc or similar device. A 45°crosscut should be made across the loop corners to reduce the chance of damage that can be caused to the loop cable at right angle corners. Nominal Slot width: 4mm Nominal Slot depth: 30mm to 50mm A slot must also be cut from the loop circumference at one corner of the loop to the roadway edge to accommodate the feeder. A continuous loop and feeder is obtained by leaving a tail long enough to reach the detector before inserting the cable into the loop slot. Once the required numbers of turns of wire are will into the slot around the loop circumference, the wire is routed again via the feeder slot to the roadway edge. A similar length is allowed to reach the detector and these two tree ends are twisted together to ensure they remain in close proximity to one anther.(Minimum 20 turns per meter).Maximum recommended loop sensitivity decreases as the feeder length increases, so ideally the feeder cable should be kept as short as possible. The loops are seated using a “quick-set” black epoxy compound or hot bitumen mastic to blend with the roadway surface. 0.5m-1.5m

0.5m-1.5m Sliding

road edge

45°cross cut

Traffic direction

Diagram 4

road edge