Absolute encoder and absolute value signal generation method
First Claim
1. An absolute encoder comprising:
- a plurality of slit streams having different pitch numbers from each other, in which positional information of the same pitch is formed;
a plurality of sensors which are relatively moved with respect to said slit streams so as to detect said positional information;
a phase modulating section for converting a signal derived from said sensor into a phase signal;
a phase difference signal producing section for converting both said phase modulation signal and a phase difference signal between two pieces of arbitrary phase signals into a digital signal; and
an absolute value signal producing section for producing a signal which is related to an absolute value position in a constant time period based upon the digital signal converted by said phase difference signal producing section and the phase difference signal;
wherein;
the absolute encoder is arranged by;
a first memory for storing thereinto an absolute value signal which is produced by said absolute value signal producing section every constant time period;
a second memory for storing thereinto an absolute value signal which has been produced in one-preceding time period with respect to a time period of an absolute value signal entered into said first memory;
a comparing/calculating section for comparing the absolute value signal stored in said first memory with the absolute value signal which has been produced in said one-preceding time period and has been stored in said second memory so as to calculate an increase/decrease amount;
a dividing process section for dividing said increase/decrease amount in an equal rate within a producing time period of said absolute value signal; and
an interpolated absolute value signal producing section for reading the absolute value signal which has been produced in said one-preceding time period, and thereafter, for adding/subtracting said divided increase/decrease amount in a stepwise manner with respect to the read absolute value signal wherein the absolute encoder is operable to provide the result of adding/subtracting as a position information.
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Abstract
An absolute encoder comprising a first memory operable to store a first absolute value signal produced every constant time period, the absolute value signal representing an absolute value position. A second memory stores a second absolute value signal produced in a previous time period. A comparing/calculating section compares the first absolute value and the second absolute value and produce a difference amount. A dividing process section divides the difference amount in an equal rate within a producing time period of said first absolute value signal. An interpolated absolute value signal producing section reads the second absolute value signal and adds the difference amount in a stepwise manner.
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Citations
4 Claims
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1. An absolute encoder comprising:
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a plurality of slit streams having different pitch numbers from each other, in which positional information of the same pitch is formed; a plurality of sensors which are relatively moved with respect to said slit streams so as to detect said positional information; a phase modulating section for converting a signal derived from said sensor into a phase signal; a phase difference signal producing section for converting both said phase modulation signal and a phase difference signal between two pieces of arbitrary phase signals into a digital signal; and an absolute value signal producing section for producing a signal which is related to an absolute value position in a constant time period based upon the digital signal converted by said phase difference signal producing section and the phase difference signal;
wherein;the absolute encoder is arranged by; a first memory for storing thereinto an absolute value signal which is produced by said absolute value signal producing section every constant time period; a second memory for storing thereinto an absolute value signal which has been produced in one-preceding time period with respect to a time period of an absolute value signal entered into said first memory; a comparing/calculating section for comparing the absolute value signal stored in said first memory with the absolute value signal which has been produced in said one-preceding time period and has been stored in said second memory so as to calculate an increase/decrease amount; a dividing process section for dividing said increase/decrease amount in an equal rate within a producing time period of said absolute value signal; and an interpolated absolute value signal producing section for reading the absolute value signal which has been produced in said one-preceding time period, and thereafter, for adding/subtracting said divided increase/decrease amount in a stepwise manner with respect to the read absolute value signal wherein the absolute encoder is operable to provide the result of adding/subtracting as a position information.
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2. In an absolute encoder in which:
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positional information as to a plurality of slit streams having different pitch numbers from each other is detected by a plurality of sensors; a signal derived from said sensor is converted into a phase signal by a phase modulating section; both said phase modulation signal and a phase difference signal between two pieces of arbitrary phase signals are converted into a digital signal by a phase difference signal producing section; and a signal related to an absolute value signal is produced in a constant time period based upon the digital signal converted by said phase difference signal producing section and the phase difference signal by an absolute value signal producing section, an absolute value signal producing process method of the absolute encoder wherein; an absolute value signal which is produced by said absolute value signal producing section every constant time period is stored into a first memory; an absolute value signal which has been produced in one-preceding time period with respect to a time period of an absolute value signal entered into said first memory is stored into a second memory; the absolute value signal stored in said first memory is compared with the absolute value signal which has been produced in said one-preceding time period and has been stored in said second memory by a comparing/calculating section so as to calculate an increase/decrease amount; said increase/decrease amount is divided by a dividing process section in an equal rate within a producing time period of said absolute value signal; and after reading the absolute value signal which has been produced in said one-preceding time period, said divided increase/decrease amount is added/subtracted in a stepwise maimer with respect to the read absolute value signal by an interpolated absolute value signal producing section and providing a result of the addition/subtraction as a position information.
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3. An absolute encoder comprising:
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a first memory operable to store a first absolute value signal produced every constant time period, the absolute value signal representing an absolute value position; a second memory operable to store a second absolute value signal produced in a previous time period; a comparing/calculating section operable to compare the first absolute value and the second absolute value and produce a difference amount; a dividing process section operable to divide the difference amount in an equal rate within a producing time period of said first absolute value signal; an interpolated absolute value signal producing section operable to add the difference amount in a stepwise manner to the second absolute value signal wherein the absolute encoder is operable to provide the result of adding/subtracting as a position information.
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4. A position producing method comprising:
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storing a first absolute value signal in a first memory at every constant time period; storing a second absolute value signal produced in one-preceding time period with respect to the first absolute value signal into a second memory; calculating a difference amount between the first absolute value signal and the second absolute value signal; dividing the difference amount in an equal rate within a producing time period; and adding the difference amount in a step-wise manner to the second absolute value signal and providing a result of the addition as a position information.
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Specification