A sensor post is located at approximately the midpoint of the wires. Each wire is connected to a sensor. Attempting to climb over the fence or to spread the wires displaces the sensor and causes an alarm. Cutting the wire causes the sensor to be displaced by the tension on the other side of the sensor post. There are several different manufacturers of taut wire sensors.
Some models use a mechanical switch.
Other models use piezo-electric devices or strain gauges. However, the principle of operation is the same for all the taut wire sensors. Movement of the wire is monitored and reported when the wire is moved by more than a preset amount. The taut wire sensor is primarily used for perimeter and border applications. It is important that the anchor and sensor posts be very stable.