|VD108B Vehicle Loop Detector(TTL=5V Output)
| Connectors: For input voltage, power connectors,
loop connectors and output, please refer the following left
| When vehicle present, Pin9 output is 0V(HCMOS); When
vehicle does not present, Pin9 output is +5V(HCMOS).
| LED Display and Switches: Please refer the right
diagram for the operation panel.
|1、POWER: LED Indicator 。 When LED is in red full lit, power
2、DETECT: When LED is in red flash(2.5Hz), a vehicle is
detected. When LED changes back to full lit, the vehicle left
3、SW (DIP SWITCH) ： Used to select the sensitivity. ， 0 means
the lowest sensitivity, 3 means the highest sensitivity 。
4、SW (DIP SWITCH) ： When DIP 3 is On, Pin9 detected signal has
2 seconds delay.
| Sensitivity(-ΔL/L) Unit
5、When DIP3 is On, the vehicle will cause no output on
detector if the speed of vehicle is over 8km/h.
6、RESET ： Press the RESET button, the detector will be reset.
It must be used after plugging in the detector.
| Installation and Diagnoses:
| 1、Please refer the bottom diagrams for loop size and
2、We recommend to use 0.75mm2 multi-core copper wire. The total
wire length include feeder can be up to 500m.
3、The loop should be rectangular and avoid any right angle. The
recommended length is from 1.0m-2.0m ， the recommended width is
4、The perimeter and turns:
5、The feeder must be twisted per 15mm.
| Loop Perimeter
| 3 -4 m
|4 - 6 m||5|
|6 - 10 m||4|
|10 - 20 m||3|
6、More turns, lower frequency. Less turns, higher frequency.
7、Place the loop away from the moving metal.
8、Any vehicle can be detected, when the speed is less than
9、Press Reset button will reset the detector.
10、If the LED is not in full lit, please check the power
11、If the LED is in 0.25Hz blink(about 2 seconds ON and 2
seconds, the fault will be loop is in short cut(turns is not
enough) or loop is in open(turns is too much).
12、If turns is not enough, please add more turns(frequency is
13、If turns is not enough, please leave more turns(frequency is