Incremental length or angle measuring system
First Claim
1. In an incremental measuring system of the type which comprises a measuring scale which defines a first plurality of scannable markings including an incremental graduation and at least one reference mark, the position of which is absolutely fixed with respect to a zero point of the graduation;
- a scanning unit which comprises a plurality of scanning fields for scanning selected ones of the first plurality of scannable markings along a scanning direction and means for generating scanning signals in response thereto, said scanning signals including periodic measuring signals generated in response to the incremental graduation; and
an evaluating system for evaluating the scanning signals, said evaluating system comprising means for counting pulses derived from the measuring signals as a measure of relative movement between the scanning unit and the measuring scale;
the improvement comprising;
a carrier body which defines a second plurality of scannable markings;
means for mounting the carrier body for movement relative both to the measuring scale and the scanning unit such that the second plurality of scannable markings can be brought into alignment along the scanning direction with at least a portion of the first plurality of scannable markings and scanning fields; and
means for controlling the operation of the evaluating system upon alignment along the scanning direction of selected ones of the second plurality of scannable markings and selected ones of the scanning fields and first plurality of scannable markings.
1 Assignment
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Accused Products
Abstract
An incremental measuring system is disclosed in which a reference position can be determined at any time. A rotating carrier body carries an additional incremental graduation for which scanning fields are arranged on a scanning plate. During a calibrating operation an additional marking on the rotating carrier body is used to determine coincidence with an associated scanning field. At this point a measuring value counter is started which counts graduation increments associated with rotation of the carrier body by means of associated scanning fields until the measuring value counter is stopped. This stopping of the counter is controlled by a signal generated on coincidence of an additional marking of the carrier body with the next reference mark on the graduated disc which carries the measuring graduation. Simultaneously, an additional marking of the carrier body reads a code mark associated with the reference mark. Each of the code marks contains in coded form the absolute position of the associated reference mark with respect to the zero point of the measuring graduation. The reference position is determined from the counting value of the increments which are superposed on the absolute position value of the overrun reference mark.
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Citations
13 Claims
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1. In an incremental measuring system of the type which comprises a measuring scale which defines a first plurality of scannable markings including an incremental graduation and at least one reference mark, the position of which is absolutely fixed with respect to a zero point of the graduation;
- a scanning unit which comprises a plurality of scanning fields for scanning selected ones of the first plurality of scannable markings along a scanning direction and means for generating scanning signals in response thereto, said scanning signals including periodic measuring signals generated in response to the incremental graduation; and
an evaluating system for evaluating the scanning signals, said evaluating system comprising means for counting pulses derived from the measuring signals as a measure of relative movement between the scanning unit and the measuring scale;
the improvement comprising;a carrier body which defines a second plurality of scannable markings; means for mounting the carrier body for movement relative both to the measuring scale and the scanning unit such that the second plurality of scannable markings can be brought into alignment along the scanning direction with at least a portion of the first plurality of scannable markings and scanning fields; and means for controlling the operation of the evaluating system upon alignment along the scanning direction of selected ones of the second plurality of scannable markings and selected ones of the scanning fields and first plurality of scannable markings. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- a scanning unit which comprises a plurality of scanning fields for scanning selected ones of the first plurality of scannable markings along a scanning direction and means for generating scanning signals in response thereto, said scanning signals including periodic measuring signals generated in response to the incremental graduation; and
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9. An incremental measuring system comprising:
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a measuring scale comprising a first incremental grid and a set of reference marks; a carrier body mounted for movement with respect to both a frame and the measuring scale, said carrier body comprising a second incremental grid and at least first and second control marks; a scanning unit mounted for movement with respect to the measuring scale and the carrier body to scan the measuring scale and the carrier body, said scanning unit comprising means for generating first and second sets of measuring signals in response to the first and second incremental grids, respectively, and means for generating control signals in response to the control marks; means for evaluating the measuring signals and the control signals, said evaluating means comprising means, responsive to the first measuring signal, for counting first pulses derived from the first measuring signal to measure relative movement between the measuring scale and the scanning unit during a measuring mode of operation, and means, responsive to the second measuring signal and the control signals, for counting second pulses derived from the second measuring signal to measure the absolute position of the measuring scale with respect to the frame during a calibrating mode of operation. - View Dependent Claims (10, 11, 12, 13)
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Specification