Miller AL4 Series

Miller AL4 SeriesAir CylindersLinear Position Sensor OptionGeneration of the ultrasonic torsion pulse ina metallic conductor based on the principleof magnetostriction.ElectromagneticfieldDampingMechanicalwaveMechanicalwaveWaveguideInitial pulsePosition markerwith magnetsCopperconductorSignal converter coil (patented process)ReceiverPrinciples of OperationThe measuring element ("waveguide"), consists of aspecial nickel-alloy tube.A copper conductor is introduced through the length ofthis tube. The start of measurement is initiated by a shortcurrent pulse.This current generates a circular magnetic field whichrotates around the waveguide. A permanent magnet atthe point of measurement is used as the marker element,whose lines of field run at right angles to the electromagneticfield. In the area on the waveguide where thetwo fields intersect, a magneto-strictive effect causes anelastic deformation of the waveguide, which propagatesalong the wave guide in both directions in the form of amechanical wave.The propagation velocity of this wave in the waveguide is2830 m/s, and is nearly insensitive to environmentaleffects (e.g., temperature, shock, contamination).The component of the wave which reaches the far end ofthe waveguide is damped there, whereas the componentwhich arrives at the signal converter is changed into anelectrical signal by reversing the magnetostrictive effect.The wave travel time from its point of origin to the signalconverter is directly proportional to the distance betweenthe permanent magnet and the signal converter. A timemeasurement then allows the distance to be determinedwith extremely high accuracy.DesignThe transducers are made to the same safety andreliability standards for use in the harshest conditions:– The electronics unit is compactly designed using SMDtechnology. The boards are protected in a space-saving,rugged aluminum extruded housing.– The waveguide is protected in the extruded aluminumhousing.QualityEach and every transducer undergoes a speciallydesigned, computer-controlled testing procedure whichincludes 100% checking of all specified data.42