Incremental rotary encoder for measuring horizontal or vertical angles
AssigneeAsahi Kogaku Kogyo Kabushiki Kaisha
InventorsKatsuhiko Kenjo, Masami Shirai
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Abstract
An incremental rotary encoder outputs two sine wave signals having a phase difference of 90 degrees when the incremental rotary encoder is in operation, the incremental rotary encoder including a binary coding circuit which codes each of the two sine wave signals into a binary signal, a voltage detector which detects the voltage of one of the two sine wave signals at the moment of variation in a signal level of the binary signal, and a controller which includes a calculator which takes an even number of voltage values from each of the two sine wave signals to take an average of the even number of voltage values for each of the two sine wave signals.
Claims10
An incremental rotary encoder which outputs two sine wave signals having a phase difference of 90 degrees when said incremental rotary encoder is in operation, said incremental rotary encoder comprising:
- a binary coding circuit which codes each of said two sine wave signals into a binary signal;
- a voltage detector which detects the voltage of one of said two sine wave signals at the moment of variation in a signal level of said binary signal of the other of said two sine wave signals;
- and
- a controller comprising a calculator which takes an even number of voltage values detected by said voltage detector to generate an average of said even number of voltage values for each of said two sine wave signals.
An incremental rotary encoder which outputs two sine wave signals having a phase difference of 90 degrees when said incremental rotary encoder is in operation, said incremental rotary encoder comprising:
- a binary coding circuit which codes each of said two sine wave signals into a binary signal;
- a voltage detector which detects the voltage of one of said two sine wave signals at the moment of variation in a signal level of said binary signal of the other of said two sine wave signals;
- a controller comprising a calculator which takes an even number of voltage values detected by said voltage detector to generate an average of said even number of voltage values for each of said two sine wave signals;
- a closed-loop circuit which compares said average voltage with a predetermined target voltage to bring said average voltage close to said predetermined target voltage.
A surveying instrument comprising:
- a leveling board;
- a pedestal coupled to said leveling board to be rotatable about a vertical axis relative to said leveling board;
- a collimating telescope coupled to said pedestal to be rotatable about a horizontal axis relative to said pedestal;
- a horizontal-angle measuring device for measuring an angle of rotation of said pedestal relative to said leveling board;
- and
- a vertical-angle measuring device for measuring an angle of rotation of said collimating telescope relative to said pedestal;
- wherein at least one of said horizontal-angle measuring device and said vertical-angle measuring device comprises an incremental rotary encoder;
- wherein said incremental rotary encoder comprises a rotary portion, a first sensor and a second sensor;
- said first and second sensors being arranged so as to be opposite from each other with respect to the axis of said rotary portion;
- wherein said incremental rotary encoder outputs two sine wave signals having a phase difference of 90 degrees when said incremental rotary encoder is in operation, said incremental rotary encoder comprising:
- a binary coding circuit which codes each of said two sine wave signals into a binary signal;
- a voltage detector which detects the voltage of one of said two sine wave signals at the moment of variation in a signal level of said binary signal of the other of said two sine wave signals;
- and
- a calculator which takes an even number of voltage values from each of said two sine wave signals to take an average of said even number of voltage values for each of said two sine wave signals.
Dependencies are inferred from the claim text.