Design for Industry A new “Twiist” on position transducer design measures multiple data points

from DESIGN WORLD JULY 2023

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After 10 years of research, Gefran, an Italian sensor and control company, has launched its Twiist contactless linear position transducer to the North American market. The transducer not only measures position but can also measure temperature, velocity, acceleration, and tilt angle.

“There are several products on the market that measure position, and Gefran has them as well, but only Twiist can measure position, acceleration, speed, vibration, and three spatial angles (x, y, and z axes) all at the same time,” said Edoardo Zilioli, marketing manager, Sensors Division, at Gefran. “And if desired, Twiist can also monitor the ambient temperature inside the transducer. Readings and data processing happen simultaneously.”

This multi-variable position transducer is in the Hall e ect category, but what truly sets it apart is its unique helical magnetoelectronic design, its ability to take multiple measurements simultaneously, and its focus on improving operator safety. This patented technology results from a decadelong partnership between Gefran’s internal R&D department and the University of Brescia’s engineering department in Brescia, Italy.

“The Twiist is perfect for mobile and industrial hydraulic applications,” said Ron Akers, business development manager for ﬂuid power at Gefran. “It allows for multiple types of measurement in one component. Signals for linear and angular positioning and temperature readings are all communicated at the same time. Furthermore, with the onboard electronics, Twiist provides real-time velocity, acceleration, and tilt angle measurements to keep operators safer.”

The compact design is not limited to 250 mm stroke ranges like traditional Hall e ect sensors.

“Measuring linear displacement with a Hall e ect chip encapsulated by a magnetic helix is an innovative and ingenious idea. It revolutionizes the classic Hall e ect sensor in the range of 5 mm, which among other things, is limited to strokes of up to 250 mm,” said Zilioli. “Not only does Twiist reduce the number of expensive components needed for a project, but it is a redundant position transducer with a more useful electrical stroke of 50 to 900 mm.”

Twiist’s compact, air-tight design has a steel barrel with a diameter of 5/8-in. (16 mm), and it comes with a choice of two types of connection points, ball joints for swivel connections and rod ends with eyes for pivot connections. Available in full-scale (FS) strokes from

50 to 900 mm, it has typical linearity of 0.15% FS and typical repeatability of 0.05% FS. It can operate in a temperature range from -40° to 185° F (-40° to 85° C).

The Twiist has an IP67 environmental protection rating, o ering complete protection against dust, airborne particles, water, and other liquids when submerged up to 39 in. (1 m) deep. This resistance to contamination makes it ideal for ﬂuid power applications and extends the life of the part and equipment.

In mobile hydraulics, applications abound. For example, when steering a vehicle and using spatial inclination and acceleration, the Twiist veriﬁes, at each millisecond, if the ground is stable underneath the construction equipment and can alert the operator if there is a danger of unstable ground. All of this is directly on the steering axis, without any mechanical interference — or worse, mechanical play.

Other applications include control of stabilization footings in area platforms (extension and subsidence), monitoring position and vibration for mining, fracking, and drilling, and measuring position and inclination for phytochemical sprayer arms on agricultural sprayers. Practically all medium-complex vehicles could use a Twiist multi-variable transducer. DW Ge