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Interesting facts about displacement sensors with magnetostrictive technology
Guide for Magnetostrictive Linear Sensors
Magnetostrictive Position Sensors
Displacement sensor with shear wave technology for measuring the transit time difference between two points
Magnetostrictive linear sensors are robust, absolute measuring systems with a resolution down to 2 µm. The measured values are recorded without contact, so that the sensor life is unlimited, wear and maintenance-free. Thanks to shear wave technology and innovative design, the effects of shock, vibration and EMC influences have been reduced to a minimum.
Our magnetostrictive linear sensors detect mechanical measuring distances up to 4000 mm. They are used in hydraulic applications with high pressure up to 500 bar as well as in automation or level measurement. The slide-guided or free-floating position magnets open up a wide range of applications.
Some demanding applications require product optimization. MEGATRON is your partner for this adaptation process. With high delivery reliability and assured quality products we focus on long-term partnerships. Our claim is to provide each customer individually with the best functional and economical result.
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Basic questions about linear sensors? Here you will find the answers
Magnetostrictive linear measuring principle
Magnetostriction is the deformation of magnetic, especially ferromagnetic materials as a result of an applied external magnetic field. The displacement sensor consists of a measuring rod with a waveguide made of ferromagnetic wire, a movable permanent magnet, signal converters and electronics. The measured values are recorded without contact. The displacement measurement is based on a transit time difference measurement between two points.
A short current pulse at the speed of light (299,792,458 m/s) is triggered in the measuring rod. The current pulse generates a circular magnetic field around the waveguide. The movable permanent magnet is placed just above the measuring rod to determine the position. The generated pulse magnetic wave meets the magnetically right-angled field lines of the permanent magnet. The magnetic fields overlap and a torsional-mechanical-elastic density wave (Wiedemann effect) is generated in this area in the waveguide. The mechanical density wave moves at the speed of sound (2,850 m/s) to the inductive signal converter, which converts it into electrical signals (Faraday effect). Between the generated current pulse and the arrival of the density wave in the electronics, the time required and, based on this, the distance to the permanent magnet are determined. The distance information is usually output as an analogue signal.
Our magnetostrictive displacement transducers use an innovative form of the density wave - a shear wave. The design modifications of the transducer in combination with this shear wave result in a much better signal quality, which allows a much higher accuracy than conventional systems. In addition, the optimized sensor technology has a positive effect on vibration, shock and EMC behaviour. The displacement transducers are therefore significantly more resistant and meet numerous standards.
Advantages of magnetostrictive displacement transducers
Numerous technological advances have been implemented in the newly designed magnetostrictive displacement sensors from MEGATRON. Particularly noteworthy is the significantly improved signal quality and the associated accuracy. Furthermore, the effects of shock, vibration and EMC influences have been reduced to a minimum.
Advantages of the technology:
- Non-contact, wear-free and maintenance-free measuring principle
- Theoretically unlimited life
- Quasi infinitely high resolution
- Robust against shock and vibration influences
- Very precise measuring principle
- Absolute measuring system
- Long measuring distances are possible
- Low thermal drift
- Measurement from 50…1500 mm
- Wear-free measuring principle and absolute analogue signal
- Direct and inverse analogue output
- For harsh conditions IP67
- Very flat construction with only 14 mm
- High precision due to high resolution and good linearity
- Electromagnetic compatibility 2014/30/EU (EMC)
- Measuring strokes from 50 mm to 4000 mm
- High IP protection class IP67 and 350 bar operating pressure (peak pressure max. 500 bar)
- Made of stainless steel AISI 316
- With external cursor
- Mounting via external flange (metric / inch)
- Electromagnetic compliance EMC 2014/30/EU
- RoHS 2011/65/EU
- Mech. connection by ball coupling to compensate for the angular offset or free position sensor
- Small space requirement without push rod
- Measuring lengths from 50 mm to 4000 mm
- Very precise due to high resolution and good linearity
- Electromagnetic compatibility 2014/30 /EU (EMC)
- Very accurate measuring principle up to 4000 mm
- Suitable for applications up to 500 bar peak
- For heavy-duty applications IP67
- Absolute true power on signal