A device has a displaceable device part, a drive, which is configured to drive the displaceable device part and to thus induce a movement in the displaceable device part, and a control unit, which is connected to the drive and is configured to control the drive. The device further has a first signal transmitter for determining a position and/or speed of the displaceable device part. The first signal transmitter and/or a first signal evaluation device, which is connected to the signal transmitter, are connected to the control unit such that the control unit receives information from the signal transmitter about the position and/or speed of the displaceable device part during operation of the device and controls the drive on the basis of the information received. A second signal transmitter of the device serves to monitor and/or redundantly determine the position and/or speed of the displaceable device part.

A method is provided for detecting a reciprocal position between a cylinder and a piston of a piston-cylinder unit of a vehicle. The method includes measuring, by means of an optical sensor, a value of an indicative parameter of a color of a reference mark positioned on a portion of the piston. The method also includes comparing the measured value with at least a predetermined threshold value thereof different to a minimum detected threshold of the indicative parameter by the optical sensor; and

emitting an alarm signal perceptible by a driver of a vehicle if the measured value is comprised between the threshold value and the minimum value.

A linear encoder can have a mass embodiment having a position code marking, a read head having a calibration means, and a control and analysis unit, and calibration method for calibrating a position code made of code elements using the read head. The read head has a sensor unit having at least two detection reference points, the detection distance of which establishes at least one standard with high precision. In the scope of the calibration method, calibrated position values are prepared for code elements with the aid of the standard, which is determined with high precision, and are stored in the control and analysis unit.

Some embodiments include an absolute displacement detection device configured to calculate, from a plurality of displacement detection signals provided by a plurality of displacement detection mechanisms that detect displacement amounts, an absolute periodic signal having an absolute periodic signal period larger than displacement detection signal periods of the plurality of the displacement detection signals. Other embodiments of related devices and methods are also disclosed.

A sealed linear encoder apparatus provides a measure of relative displacement of two relatively movable members. The sealed linear encoder apparatus includes at least one elongate sealing lip wherein at least a sealing portion of the elongate sealing lip is held in tension along its length.

A measurement device has: a slider which holds a substrate and is movable parallel to the XY plane; a drive system that drives the slider; a position measurement system which emits beams from a head section to a measurement surface in which grating section are provided on the slider, which receives respective return beams of the beams from the measurement surface, and which is capable of measuring position information in at least directions of three degrees of freedom including the absolute position coordinates of the slider; a mark detection system that detects a mark on the substrate; and a controller which detects the marks on the substrate using the mark detection system while controlling the drive of the slider, and which obtains the absolute position coordinates of each mark based on the detection result of each mark and measurement information by the position measurement system at the time of detection.

A position detecting member includes a base portion including a light-receiving surface having a black color tone and a back surface located on an opposite side to the light-receiving surface. A surface layer portion including at least the base portion is made of ceramic. An average value of root mean square slopes (RΔq) on the light-receiving surface in a roughness curve is larger than an average value of root mean square slope (RΔq) on the back surface.

A linear gage includes a spindle, a guide cylinder surrounding a portion of the spindle and configured to guide the spindle to move forward and rearward in an axis line direction, and a guide slit portion having a guide slit extending parallel to the axis line of the guide cylinder, with a gap provided between the guide slit and an outer surface of the guide cylinder. An attitude adjustment pin extends into the guide slit and is fixed to a side surface of the spindle. The attitude adjustment pin is an eccentric pin.

A decoding device for an absolute positioning code is provided. The decoding device includes a linear feedback shift register (LFSR), a lookup table (LUT) circuit, a counter circuit, and a computation circuit. The LFSR includes n registers, for loading the absolute positioning code with a first frequency. The LFSR performs shifting operation according to a clock signal having a second frequency greater than or equal to the first frequency. The LUT circuit outputs a lookup result and a valid flag according to values stored in the n registers. The lookup result has k different data, k≦(2.sup.n−1). The counter circuit resets according to the valid flag, and performs counting operation according to the clock signal to generate a counting result. The computation circuit performs calculation according to the lookup result and the counting result to generate a decoding result when the valid flag indicates valid.

An absolute-type linear encoder absolute signal consistency correction method, related to the field of absolute-type linear encoder measurements, for solving the problem of narrow linear range for photoelectric responses and large signal dispersion found in an existing consistency correction method for a photoelectric conversion component and a processing circuit thereof. The correction method allows for enhanced absolute signal quality and increased system measurement precision.