Sagentia enhances mechanical gauges at WIKA: Processing Talk

November 2008

German-based pressure gauge manufacturer WIKA has been keen to incorporate electronic functionality into its range of mechanical gauges, by directly sensing the deflection of the needle pointer.

The company approached Sagentia because of its track record in sensor technology and its ability to provide a full development service from initial product concept through to manufacturing support. Sagentia's approach, involving a contactless sensor technology, has been incorporated into the company's recently launched LIG10 Intelliguage analogue pressure gauge.

Sagentia's first task was to review a range of potential approaches, from which it determined that the use of a magnetic sensing technology based on the Hall effect would be the most efficient solution. A Hall effect sensor is a transducer that varies its output voltage in response to changes in magnetic field. Hall sensors are used for proximity switching, positioning, speed detection and current-sensing applications.

Sagentia has devised an approach whereby the angle of rotation of the mechanical pressure gauge pointer is detected by the sensor and converted into a proportional electrical output signal depending on the angular position of the magnetic field parallel to the sensor surface. This has been achieved with no physical contact between the gauge pointer and sensor.

Sagentia first undertook initial feasibility work to establish the most appropriate technology approach. This was followed by a rapid development and prototyping stage that integrated the pre-existing mechanical gauge with pcb and case work. Sagentia also added valuable insights and input into the development of a calibration rig that was subsequently used for full-scale automated production.

Intelliguage LIG10 is now commercially available from WIKA. The non-contact sensor prevents any interference with the mechanism, maintaining the inherent high accuracy of the gauge. The unit is available with a 0.5 to 4.5V output signal commonly associated with wall-type boilers and can measure pressures up to 25 bar.

'Sagentia's extensive knowledge enabled us to work closely with WIKA's development team to quickly identify the most appropriate technology that met with their requirements. Intelliguage product bridges the gap between the traditional analogue mechanical pressure gauge and solid state electronic sensors,' said Sagentia's Dr Euan Morrison, manager of the Intelliguage project.