Based upon the Keynes Controls VibWire-101 &

VibWire-108 sensor interface units

• Options for 900 M Hz/ 2.4 G Hz / Spread spectrum modems

• Indoor/urban range up to 1500 feet

• Outdoor line-of-sight range up to 20 miles

       (with high gain antenna)

For advice on systems design, layout and quotation requests, and data  transmission rates then contact Keynes Controls directly at sales@keynes-controls.com or via the contact for on the website

The Keynes Controls wireless vibrating wire systems are modular in approach and therfore are very flexible and can be configured to operate for many different applications.

The simplest stand-alone systems use the GPRS mobile phone network to transfer data from a remote site to a clients computer system.  The GPRS systems operate where ever there is a mobile phone network and can be moved from place to place to suit any project requirements.

For local remote systems a wide range of radio modems can be used such as spread spectrum units when there is a lot of electrical interference, to long distance radio modems for applications outside the range of the GPRS networks.

All of the Keynes Controls vibrating wire sensor interfaces use the auto-resonance excitation mechanism to maintain the sensors in a continuously vibrating state as-well as minimising the amount of energy required to excite the sensor in order to optimise sensor life.  

The module measures the resonant frequency of the wire between excitations using an advanced  algorithm to determine the sensor frequency. The VibWire-101 and VibWire-108 all provide a true result and not an interpolated answer.

The auto-resonance approach and advanced algorithm provides very fine measurements, and the use of 32 bit conversion provides very stable and high resolution measurements.

Full Steinhart-Hart thermistor temperature calculation support.

• Provides better measurements by significantly reducing incorrect readings caused by cabled noise sources

• Un-limited channel expansion when the MUX-16/32 expansion unit is used

• Self-checking diagnostics give continual feedback on sensor condition

• High resolution—less than 0.001 Hz (industry standard is 0.1 Hz)

• Low current drain - complete power management using the AquaLOG sensor interface.

• Remote, wireless operation with a range of radio Interfaces both temperature and frequency measurements from vibrating wire sensors.

• No vibrating wire sensor setup required. Automatic frequency selection. Built in frequency meter.

• Modem power cycling to prevent communications failure and maintain data integrity.

Measurement Applications

Pore pressure            Water level

Strain                        Displacement

Crack                        Load

Pressure cell              Temperature

Ground movement      Concrete fatigue