VTW-400 – Electronic Tautwire Fence

DeTekion Security Systems, Inc. is the U.S. manufacturer and distributor of the VTW-400 Electronic Taut Wire Fence Intrusion System. The VTW-400 Taut Wire is a highly reliable perimeter detection system. Barbed wires are strung taut between anchor posts and clamped to the VTW-400 sensor post. The VTW-400 Taut Wire is a physical barrier that will trigger an alarm when there is an attempt of intrusion by:

• Climbing
• Spreading
• Cutting

The VTW-400 utilises the latest technology to provide the highest probability of detection, the lowest false alarm rate, and minimal maintenance compared to any other perimeter detection system on the market.

STW-40 Sensor
DeTekion’s patented sensor design uses multiple strain gauges and state-of-the-art miniature circuitry to provide a highly stable and accurate sensor signal. The VTW-400 Electronic Taut Wire Fence System features a sophisticated design using bridge-compensated strain gauges and a powerful microprocessor-based alarm processor.

Movement of the taut barbed wires causes the flexible circuit board of the sensor to flex, generating a signal as a precise indicator of movement. The miniature circuit board is mounted inside a specially designed rubber housing, sealed from the environment, and connected to the processor via a three-pin connector.

One end of the sensor includes a slotted, threaded stud where the barbed wire is fitted and clamped using a nut. All exposed hardware is stainless steel.

FP-400 Processor
A compact yet powerful microprocessor monitors up to 32 sensors. Through multi-sensor sampling and multiplexing, the FP-400 evaluates events, and if a sensor reading falls outside the normal range, it activates an alarm relay. It uses a dual-window alarm capturing system. If a wire is cut or internal wiring is damaged, a trouble alarm is triggered.

The processor continues to operate the remaining sensors, and trouble alarms reset automatically when resolved. The system self-adjusts for environmental conditions and offers user-programmable sensitivity levels for each sensor. This greatly reduces false alarms.

An optional feature allows the system to detect which side of a sensor is stressed, enabling one sensor to monitor two 50-meter zones.

On-board diagnostics provide real-time display of sensor activity, including readings, averages, alarm and trouble states, and set points—without requiring the system to go offline.

The FP-400 measures 8″ x 6″ x 1″, uses only 200 milliamps (10–30 VDC), and is mounted in a NEMA enclosure, typically fixed directly to the sensor support post, reducing the need for large junction boxes.

Basic Configuration
The VTW-400 system is tailored to client requirements. Sensor posts can be configured to suit nearly any layout. Common configurations include:

• Straight post
• Single outrigger
• Dual outrigger
• Combination of straight and outrigger

It can be installed as a stand-alone system, on an existing fence, wall, or roof. Sectors can span up to 100 meters. A zone can consist of one or multiple sectors wired together.

Each sector includes:

• Anchor posts at both ends
• One sensor post with processor in the center
• Slider posts spaced 10 feet (3 meters) apart
• Barbed wire strung taut and clamped at the sensor post
• Wire tensioners to maintain proper wire tension

Sensor spacing is customised per project. The gap between wires for alarm activation is a critical design factor. The sensor post wire spacing must be such that an alarm activates before the gap exceeds allowed parameters. The VTW-400 software allows unique sensitivity adjustments for each sensor, enabling fine-tuned alarm thresholds between wires.