A loop detector is a device used in traffic control systems to detect the presence or passage of vehicles by monitoring changes in inductance caused by the metal mass of a vehicle. It is commonly used in conjunction with traffic signal control systems, automatic gates, toll booths, and other applications where vehicle detection is essential. Here are some key features and applications of detectors:
Key Features:
- Inductive Loop Technology: Loop detectors utilize inductive loop technology, which involves embedding or laying loop coils of wire in the pavement. When a metal object, such as a vehicle, passes over or near the loop, it disrupts the electromagnetic field, leading to changes in inductance that the detector can sense.
- Single and Double Loops:
- Single Loop: A single loop consists of a single coil of wire embedded in the pavement. It is typically used for basic vehicle presence detection.
- Double Loop: A double loop configuration involves two separate loops, allowing for more advanced functions such as vehicle direction detection and length estimation.
- Sensitivity Adjustment: detectors often have adjustable sensitivity settings to accommodate different types of vehicles and environmental conditions.
- Frequency and Pulse Counting: Some detectors are capable of counting the frequency or pulses generated by the disruption of the electromagnetic field, providing information about the type and size of the vehicle.
- Relay Output: Loop detectors typically have relay outputs that can be used to trigger various actions, such as changing traffic signals, opening gates, or activating other control mechanisms.