Vehicle Loop Detector for Automatic Bollard Triggering Presence Detection and

Designed for automatic bollard access control, this vehicle loop detector provides reliable vehicle triggering, continuous presence detection, and anti-collision protection through an inductive loop installed beneath the roadway. When a vehicle enters the detection zone, the detector identifies the change in loop inductance and sends a relay signal to the bollard control system. This allows the bollard to lower automatically for vehicle passage and supports controlled re-raising only after the vehicle has fully cleared the protected area.

The detector supports configurable entry pulse, exit pulse, and presence output modes. Entry pulse output can be used to trigger bollard lowering, activate a camera, or confirm vehicle arrival. Exit pulse output can support departure counting or downstream control after the vehicle leaves the loop. In presence mode, the relay remains active while the vehicle stays above the induction loop, helping prevent the bollard from rising beneath a vehicle and reducing the risk of collision or equipment damage.

Permanent presence detection is available for applications where vehicles may stop, queue, or move slowly over the loop. The output remains active without timing out and resets only after the vehicle leaves the sensing area. Adjustable relay release delays from 0 to 30 seconds provide additional flexibility for delayed bollard re-raising, long vehicles, and coordinated operation with access controllers, warning lights, cameras, or security equipment.

With a wide 15–2000 μH inductance range and 16 selectable sensitivity levels, the detector can be configured for different loop sizes, installation depths, vehicle types, and site conditions. Automatic Sensitivity Boost helps maintain stable detection of trucks, trailers, buses, and high-chassis vehicles. Four selectable operating frequencies help reduce electromagnetic crosstalk when multiple loops are installed close together.

Suitable for residential entrances, commercial properties, industrial parks, warehouses, logistics centers, government facilities, and restricted vehicle access points, this vehicle loop detector provides a practical interface between underground loops and automatic bollard systems. Its flexible relay control, permanent presence monitoring, and adjustable delay functions support safer vehicle passage, more reliable bollard operation, and smoother access control management.

• 1. 15-2000 μh detection Range
  • The loop detector supports a wide detection range from 15 µH to 2000 µH, accommodating various loop sizes and configurations for versatile application in different traffic detection scenarios. The wide detection range enables our loop detector to detect all kinds of vehicles, motorcycles, cars, Ultra long truck, buses and so on.
• 2. Compact Side
  • The compact and well-engineered housing combines all industry requirements for features and functionality, allowing this detector to be incorporated into any existing traffic detection system.
• 3. LED Diagnostic Capabilities
  • Comprehensive diagnostics capabilities enable accurate diagnosis of loop and installation problems and shows through LED, ensuring optimal performance and reducing downtime.
• 4. Selectable Presence Time
  • The output of the presence relay can be selected to limit a detect output to a fixed time (greater than 30 minutes) while a vehicle remains on the loop, providing flexibility in traffic management.
• 5. Loop Presence Time
  • Interference between adjacent loop detectors can be identified through integral indication and eliminated by adjusting the frequency setting, ensuring reliable operation.
• 6. Two Separate Output Relays
  • Presence Relay A: Provides presence output and can be extended for 0, 2, 5, 8, 10, 15, 20, or 30 seconds, programmable with external 10-way DIP switches.
  • Pulse Relay B: Programmable with external 10-way DIP switches, it offers presence, pulse on entry, pulse on exit, or failed output, enhancing detection flexibility.
• 7. Automatic Sensitivity Boost (ASB)
  • This feature reliably detects large truck-trailer combinations and high-bed vehicles by automatically boosting the sensitivity to maximum upon vehicle detection, ensuring accurate identification.
• 8. Automatic Environment Drifting Compensation
  • Loop detectors (or other sensors) automatically adjust and calibrate themselves to changes in environmental conditions, maintaining detection accuracy and stability despite varying weather and environmental factors.
• 9. 10 Dip Switch
  • The dip swich design on the shell makes the setting of loop detector easier and clearer, which is very user-friendly for users. Users can set all the functions first and then install the loop detector.
• 10. Anti-crosstalk interference.
  • Through the dip Switch, the frequency of the loop detector can be adjusted to prevent crosstalk interference caused by the installation of two loop coils too close.

(1)Power Led: RED Power LED Indicates “Power ON”

• Detecting Led: Continuously On: Indicates vehicle detection.
• Blinking slowly: Indicates loop is short circuit or the number of twists after the loop is not enough.
• Blinking fast: Indicates loop is open circuit or too many twists after the loop.

• Sensitivity of the loop can be adjusted by the trimpot labeled “Sensitivity”. User can select 16 different setting by turning the trimpot with 0 being the least sensitive and “F” being the most sensitive.

  

1. DIP 1 & DIP 2 Setting Special Functions

2. DIP 3 & DIP 4 Setting Relay B Output

3. DIP 5 Setting Automatic Reset

4. DIP 6 & DIP 7 & DIP 8 Setting Relay A Delay

5. DIP 9 & DIP 10 Setting Frequency (40 K to 100 KHz). Used to avoid the interference

• In the application, where two or more loop detectors and sensing loops have been installed, set one detector to high frequency and the other set to low frequency to minimize the effects of cross-talk between the two systems(The sensing loops and detectors should be positioned at least 2m apart).
• Reset Button:Please note: The LD-100 must be reset every time a setting change is made to the Dip switches.

• Install the detector in a weatherproof housing.
• The detector should be as close to the sensing loop as possible.
• The detector should always be installed away from strong magnetic fields.
• Avoid running high voltage wires near the loop detectors.
• Do not install the detector on vibrating objects.

• When the control box is installed within 10 metres of the loop, normal wires can be used to connect the control box to the loop. More than 10 metres requires the use of a 2 core shielded cable. Do not exceed 30 metres distance between control box and loop.

  

The loops are sealed using a “quick-set” black epoxy compound or hot bitumen mastic to blend with the roadway surface.