Intelligent Wire Perimeter System
The WPS FENCE was developed following a detailed study of current requirements for perimeter protection fence systems.
The system has a high probability of detection coupled with a very low nuisance alarm rate. Tampering with the system is made virtually impossible whilst still maintaining simplicity of installation.
Principle of operation
ELCOS cable, designed by GPS Standard displays a particular electrical characteristic which changes in a way that is directly proportional to a physical deformation of the cable. The cable is steel multi-strand single core conductor insulated by a particular dielectric material. This is then screened by braided copper and sleeved.
The cable strength (because it is steel) allows it to be mounted taught on the fence which enhances its signal characteristics. Cutting or altering its quiescent physical state, typically by displacing it in an attempt to enter the protected area, will cause structural changes within the cable which, in turn, will generate a proportional electrical signal. The signal is then filtered and analysed by a powerful micro-processor unit which compares it to a number of pre-set parameters. These include amplitude, timing, existing background noise and other known interference signatures. Various levels of alarm, tamper and fault signal can be set to suit a wide variety of applications.
Application
Typically, WPS Fence is installed a few centimetres away from the inside face of an existing fence or wall. The cable is stretched between special tensioning and support posts which are normally fixed to the existing structure. If required these posts can be free standing. Another very effective system application is on top of a wall, ceiling or floor to provide a high security and extremely stable form of protection.
System layout
The fence will consist of at least two sensor units each monitoring a maximum of 300 metres of ELCOS cable. Each cable length is run back and forth along the perimeter zone in question, maintaining a typical distance of 15 cms between runs. Both ends of the cable are terminated in the sensor and so there will be an even number of runs associated with any one sensor.
For a typical application on top of a wall the cable would be run back and forth along the zone up to 6 times providing protection up to 90cm above the wall.
Automatic sensitivity control
System sensitivity is controlled automatically by the concentrator and allows significant improvements in the rejection of common interference signals.
The concentrator's micro-processor provides continuous analysis of the signal from each sensor with particular emphasis on differential mode signals.
Common mode signals are thus eliminated e.g. wind, traffic etc. The various functions that control this process may be adjusted using the commissioning computer during the installation process. |
