Dual Loop Detector for Truck and Trailer Detection with Automatic
Sensitivity Boost Function
The Dual Loop Detector for Truck and Trailer Detection with Automatic
Sensitivity Boost Function is developed for vehicle access applications where long vehicles,
articulated trucks, trailers, and high-chassis vehicles can be
difficult to detect continuously with standard loop settings. With
two independent detection channels, CH1 and CH2, the unit can
monitor separate induction loops or operate in coordinated
dual-loop modes for more advanced vehicle movement control. Its Automatic Sensitivity Boost (ASB) function increases detection sensitivity after a vehicle is
detected, helping maintain a stable signal as different sections of
a truck or trailer pass over the loop. This reduces the risk of
relay dropouts caused by gaps between the tractor and trailer or by
vehicle structures that produce weaker inductive responses.
In addition to enhanced heavy-vehicle detection, the detector
supports 8-level sensitivity adjustment, four selectable operating
frequencies, a 20–2000 μH loop inductance range, permanent presence
detection, automatic reset, and six operating modes for flexible system integration. CH1 and CH2 can be configured for
independent presence detection, entry or exit pulse output, or
vehicle direction recognition, while dedicated relay outputs allow
easy connection to barrier gates, sliding gates, industrial doors,
parking controllers, traffic signals, and weighing systems. LED
status and fault indicators assist with on-site diagnostics, and
DIP-switch programming simplifies setup and commissioning. With LD-200 100–240 VAC and LD-202 12–24 V versions available, this dual loop vehicle detector provides a
dependable solution for logistics centers, industrial parks, truck
entrances, toll stations, weighbridges, and other heavy-vehicle
access control applications.

Feature
- 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. Diagnostic Capabilities & LED Indication
- Comprehensive diagnostics capabilities enable accurate diagnosis of
loop and installation problems and shows through the LED state,
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. 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.
- 6. 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.
- 7. 17 Dip Switch Setting
- 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.
- 8. Dual Channels work Cooperatively or Independently
- Dual channel loop detector can be used as two single channel
versions, Supports two independent detection channels.
- Also allowing for the simultaneous monitoring of multiple loops,
loop detector has the ability to recognize direction in
single-channel applications. enhancing the flexibility and accuracy
of vehicle detection.
- 9. 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.

Connections

Modes Of Operation
The LD-200 series detector may be configured for any one of the
following modes:
| Presence Mode | Pulse Mode |
| AB Logic Presence Mode(Barrier Operation) | AB Logic Pulse Mode(Counting Logic) |
Indicates And Switch
❀Power Led: RED Power LED Indicates “Power ON”
- CH1 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.
- CH2 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 Selection
- Sensitivity and frequency of the loop can be adjusted by 7-way dip
switch and 10-way dip switch setting.
- User can select 8 different setting by changing the setting of the
dip-switch to different modes as in the dip-switch setting tables
below. Dip switch 6, 7 and 8 for CH1 sensitivity selection with 0.8
being the least sensitive and 0.015 being the most sensitive.
- Dip switch 3, 4 and 5 for CH2 sensitivity selection with 0.8 being
the least sensitive and 0.015 being the most sensitive.

❀Switch1=S1:Channel 1 Loop Function Selection (10 Way Dip Switch)
- (Switch 1)DIP1 & DIP2 Special Sensitivity Increase For Both Trailer
(Both Channels)

(Switch1=S1)D3,D4,D5 and(Switch2=S2)D1,D2 Setting Special Functions(Mode1,2,3 Direction Detection. Mode4,5,6 Normal mode, two loop
detection are separated.)

(Switch1=S1)D6 & D7 & D8 and (Switch2=S2)D3 & D4 & D5 Setting CH1
and CH2 Sensitivity Selection. (Eight Levels Choices)

(Switch1=S1)D9 & D10 and (Switch2=S2)D6,D7 Setting Frequency (20 K
to 100 KHz).

Reset Button: Please note: The LD-200 must be reset every time a setting change
is made to the Dip switches.
Loop Installation
The loops are sealed using a “quick-set” black epoxy compound or
hot bitumen mastic to blend with the roadway surface.

When installation, please keep the product plug and socket in the
vertical direction

Troubleshooting

Product Series
| LD-100 | LD-102 | LD-200 | LD-202 | JTHT-11 |
|---|
 Single Channel 100-240 V AC |  Single Channel 12-24 V AC/DC |  Dual Channel 100-240 V AC |  Dual Channel 12-24 V AV/DC |  Loop cable 305 m Teflon coil |
| LCR-MT |
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 Multimeter |
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