Dr. Johannes Heidenhain Gmbh

Johannes Heidenhain Gmbh

Walter Schmitt

Dieter Michel

Franz Ritz

Alfons Ernst

Gunther Nelle

Norbert Huber

Reinhold Schopf

Josef Weiss

An apparatus is provided for inductive transfer of the scanning signal from a sensing head to a machine body. The apparatus includes cooperating inductive coupling elements between a receiving lug of the sensing head and the spindle of the machine. Cooperating coupling elements for inductive coupling are also provided between the spindle and the machine body. The coupling element of the receiving lug includes a coil with a ferromagnetic core. The spindle includes a second cooperating coil lying opposite to the receiving-lug coil which also includes a ferromagnetic core. The scanning signal is conducted from the detector to the coil in the receiving lug and is transferred inductively to the spindle. The scanning signal then passes over a transfer coil to a receiving coil. The transfer coil and receiving coil are configured such that the signal is transferred independently of rotation of the spindle relative to the machine body.

Apparatus for inductive signal transfer in sensing heads

A measuring device is provided in which a graduated plate is scanned in at least two scanning locations. The scanning signals from the different scanning locations are transmitted to a testing circuit which determines whether the phase displacement between the scanning signals exceeds a limit value. If the limit value is exceeded, one of the scanning locations is weighted higher than the other. The weighting is implemented by increasing the components of the signals from one scanning location while decreasing the components from the signals from the other scanning location.

Position measuring apparatus with multiple scanning locations

A position measuring device including a scale carrier member and a scanning device for scanning the scale. A temperature difference is generated between the scale carrier member and/or the scanning device, on the one hand, and a housing surrounding the scale carrier member and the scanning device, on the other hand. The temperature difference ensures that condensate is always precipitated on the colder housing.

Position measuring device

A process and apparatus for use in digital length or angle measuring systems for regulating the keying ratio of at least one periodic electrical signal. A signal is produced, proportional to the desired keying ratio, and compared with the periodic electrical signal. A momentary difference signal is generated from the comparison. If the frequency of the periodic electrical signal is within a selectable frequency range, the momentary difference signal is applied to a correction circuit, which is circuited parallel to a storage unit. The correction circuit supplies a correction signal, based on the momentary difference signal, to a sum amplifier. The sum amplifier is operative to superpose the correction signal on the periodic electrical signal, thereby regulating the keying ratio of the periodic electrical signal. The storage unit is operative to store a signal proportional to the difference signal. If the frequency of the periodic electrical signal is outside the selectable frequency, the correction signal is derived from the contents of the storage unit.

Process and arrangement for regulating the keying ratio of at least one

A system for distinguishing identical reference marks located on a graduation used in an instrument for measuring the relative position of two objects. An individual code mark, comprised of multiple code mark elements, is allocated to each reference mark. Each code mark element can occupy one of two possible locations. A binary number associated with each code mark is obtained during scanning of the reference marks and code mark elements. The binary number is generated from a stored raster by a decoding unit and is dependent upon the position of each code mark element, the spacing between adjacent code mark elements and the spacing between the reference mark and an adjacent code mark element.

Measuring scale coding system for length or angle measuring instruments

In a measuring instrument for measuring the relative position of two objects, the graduation of a scale as well as a number of identical reference marks absolutely positioned with respect to this graduation and associated code marks are scanned by a scanning unit. The periodic scanning signals obtained in the scanning of this graduation are transferred via first signal lines, and the reference signals obtained in the scanning of the reference marks are transferred over a second signal line to an evaluating arrangement. Code signals obtained in the scanning of the associated code marks by the scanning unit are also transmitted over the second signal line to the evaluating arrangement. The reference signals and the code signals on the second signal line are distinguished from one another by means of AND gates which ensure that the reference signals and the code signals are present on the second signal line only during respective predetermined signal states of the periodic scanning signals.

Signal transmission system

A system for error monitoring in a photoelectric incremental length measuring device for the measurement of the relative position of two objects is described. The measuring device generates at least one measuring signal obtained during the scanning of a scale by means of a scanning unit. This signal is fed simultaneously to an evaluating unit and to an error monitoring unit. In the event of faulty signal parameters of the measuring signal, the error monitoring unit generates an error signal. The measuring signal is applied to an inverter and to a first AND gate. The output of the inverter is applied to a second AND gate. The two AND gates also receive the error signal as a second input. This error signal brings about an in-phase switching of the output signals of the two AND gates. The in-phase state of the signals generated by the AND gates is detected by a phase discriminator of an external evaluating unit, which generates an error signal on a respective line.

Measuring device error monitoring system

A measuring system is described which includes a scale which defines a measuring graduation and an array of reference marks. The reference marks are positioned at predetermined absolute positions with respect to the graduation and are used to generate reproduceable electric reference control pulses. In order to identify each of the reference marks a serially allocated code mark is provided which is made up of at least one nonzero code mark segment. Each nonzero code mark segment agrees in spatial pattern with the nonzero associated reference mark in the measuring direction. In order to distinguish nonzero code mark segments from reference marks, the width of the nonzero code mark segments perpendicular to the measuring direction is made less than the width of the reference marks.

Reference mark identification system for measuring instrument

A measuring system includes reference marks provided in the measuring direction alongside the graduation of the scale. These reference marks are absolutely allocated to the graduation and are used to generate reproduceable control pulses. For the identification of each reference mark there is serially allocated to each reference mark a code mark which is made up of code mark segments. The code mark segments follow one upon the other without gaps in the measuring direction, and each includes a homogeneously continuous surface or zone. These code mark segments are arranged in correspondence to their coded information, offset parallel to one another transversely to the measuring direction and are scanned by a scanning field which is integrated in the scanning field used to scan the reference marks. This gapless arrangement of the code mark segments prevents interference with the scanning of the reference marks.

Reference mark coding system

A digital electric length or angle measuring system includes a scanning unit for scanning a measuring scale and an evaluating circuit for evaluating scanning units generated by a plurality of scanning elements of the scanning unit. The scanning elements are connected to differential amplifiers included in the evaluating circuit. In order to balance faulty signal parameters of the scanning signals of the scanning elements, a balancing circuit is provided which includes bridge circuits. In each case, one diagonal of the bridge circuit is circuited in parallel to the scanning elements in the scanning unit and is connected to the inputs of the differential amplifier of the evaluating arrangement. Furthermore, each of the bridge circuits includes at least one balancing element such as a photosensor.

Scanning signal balancing circuit

A digital electronic length or angle measuring instrument includes an arrangement for error correction. A signal generator delivers periodic analog reference signals R.sub.S1, R.sub.S2 which are compared in a comparator with scanning signals S.sub.1, S.sub.2 generated by the measuring instrument. In accordance with the result of the comparison in the comparator, the reference signals R.sub.S1, R.sub.S2 are altered as a function of correction data for symmetry, amplitude ratio, phase angle, and signal form, which correction data are determined in a correction component and are supplied to setting members included in the signal generator. In this way, an in dependence on the correction data, improved reference signals are generated which then form a basis for the next comparison in the comparator.

Error correction system for digital length or angle measuring instrument

An incremental length measuring instrument generates analog scanning signals S.sub.1, S.sub.2 with a certain period P which are applied to a comparator in conjunction with two reference signals R.sub.S1, R.sub.S2. The measuring instrument causes the scanning signals S.sub.1, S.sub.2 to change as a function of relative displacement to two components of the measuring instrument. The comparator generates an analog control signal S.sub.D as a function of the difference of the momentary values of the signals applied as inputs to the comparator. The analog control signal S.sub.D is applied as an input to a signal generator which includes an oscillator. The oscillator generates a number of pulses in dependence on the momentary value of the analog control signal S.sub.D. These pulses cause the reference signals R.sub.S1, R.sub.S2 to be modified by the signal generator. In addition, the pulses are fed in a direction dependent manner into an incremental counter which includes a numerical display. The counter maintains a count which is displayed as an indication of the relative position of the two components of the measuring instrument. The reference signals R.sub.S1, R.sub.S2 are modified by the pulses generated by the oscillator until their momentary values correspond to the momentary values of the scanning signals S.sub.1, S.sub.2. When this occurs, the difference between these momentary values is zero and the comparator no longer delivers the control signal S.sub.D, thereby causing the pulse generation by the oscillator to cease. When this happens, the displayed counter state on the incremental counter and the reference signals R.sub.S1, R.sub.S2 remain in their momentary states.

Apparatus for digitally subdividing analog periodic signals

A speed monitoring circuit is disclosed for an automatic positioning system. This speed monitoring circuit composes a measurement of the actually present speed determined from measurement signals generated by an incremental position measuring device with the desired speed commanded by the positioning system. The difference between the actual and commanded speed is detected and, in the event of an excessive deviation, a warning or an automatic termination of operation of the positioning system is provided. In the disclosed system, the desired speed is determined by a controller in which a digital computer calculates the difference between the instantaneous position of one relatively movable machine component and the desired position of the movable component as established by programmed data.

Monitoring circuit for positioning device

An incremental path measuring instrument is disclosed which includes a plurality of reference marks R.sub.1 . . . R.sub.n which are interposed between respective code marks C.sub.1 . . . C.sub.n. The reference marks and code marks are applied alternately and serially to the reference track included on the measuring scale. A scanning unit is included in the measuring device for scanning in series the reference marks and the code marks. Each of the code marks is unique, and only one of the two adjacent code marks and the respective reference mark must be scanned by the scanning unit in order to identify the reference mark unambiguously. When absolute position values are allocated to respective individual reference marks, the incremental path measuring device can operate in a quasi-absolute mode of operation, since then the position of each of the reference marks is established with respect to a predetermined zero point. Preferably, the code marks each contain beginning of block and end of block symbols in addition to the identifying information needed to identify the respective reference marks. The disclosed path measuring device includes an evaluation circuit which includes a circuit which automatically adapts the trigger threshold required for signal evaluation to the actual amplitudes of the signals.

System for identifying reference marks in a path measuring device

A measuring system for measuring the relative position of two objects, which includes a transducer for converting a mechanical input into an analog electrical signal, is provided with a trigger stage and a reference signal stage. An analog electrical signal generated by the transducer is applied to one input of the trigger stage and to the input of the reference signal stage. The reference signal stage operates to generate a reference signal which is dependent upon the analog signal and is applied to the second input of the trigger stage. The trigger stage generates a trigger signal at its output in response to a change in the analog signal resulting from a change in the mechanical input magnitude.

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Traunreut, Germany

Walter Schmitt