Position measuring device and error detecting method for the same, and electromagnetic induction position detecting device
AssigneeMitutoyo Corporation
InventorsTetsuro Kiriyama, Toshiharu Miyata, Nobuyuki Hayashi, Kouji Sasaki, Yoshiaki Shiraishi
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Abstract
In an electronic caliper, a detecting circuit 112 detects displacement of a grid with respect to a scale, on the basis of a signal from a transducer 110. A CPU 114 displays the detected position on a display device 124. The CPU 114 performs error detection on the transducer, only when the relative speed of the grid with respect the scale is zero, or becomes equal to or smaller than a predetermined value. Since error detection is performed only at a predetermined timing, power consumption can be reduced.
Claims40
A position measuring device for detecting displacement between two members, said device comprising:
- a transducer that outputs an electric signal based on the displacement between the two members;
- and
- a detecting section that performs a detection of malfunction of said transducer only when a relative speed between the two members is equal to or smaller than a predetermined value, wherein the relative speed is determined using the electric signal output to the detecting section.
An electromagnetic induction position detecting device having a transducer, comprising:
- a first member;
- a second member disposed to be opposed to said first member in a relatively movable manner;
- a driving coil, which is disposed on said first member, that generates a primary changing magnetic flux;
- a magnetic modulating section, which is disposed on said second member, that modulates the primary changing magnetic flux to generate a magnetic pattern that is changed in a predetermined spatial period and in a direction of the relative movement;
- polyphase receiving coil, which is disposed on said first member and formed in a predetermined spatial period and with portions of the polyphase receiving coil being shifted in spatial phase from one another, that detects the magnetic pattern and that outputs polyphase reception signals;
- and
- a fault detecting and informing section that detects an occurrence of a fault within the transducer based on an amplitude balance among the polyphase reception signals output from said receiving coil, and that informs of the occurrence.
An electromagnetic induction position detecting device having a transducer, comprising:
- a first member;
- a second member disposed to be opposed to said first member in a relatively movable manner;
- a plurality of position detection tracks of different spatial periods which are formed on said first and second members, each of said tracks comprising:
- a driving coil, which is disposed on said first member, that generates a primary changing magnetic flux,
- a magnetic modulating section, which is disposed on said second member, that modulates the primary changing magnetic flux to generate a magnetic pattern that is changed in a spatial period inherent to said track and in a direction of the relative movement, and
- polyphase receiving coil, which is disposed on said first member and formed in the spatial period and with portions of the polyphase receiving coil being shifted in spatial phase from one another, that detects the magnetic pattern and that outputs polyphase reception signals;
- a transmission signal generating section that supplies a transmission signal that generates the primary changing magnetic flux to said driving coil of each of said tracks;
- and
- a fault detecting and informing section that detects an occurrence of a fault within the transducer based on an amplitude balance of polyphase reception signals among said tracks, and that informs of the occurrence.
A method for detecting an error in a position measuring device having a transducer that detects a displacement of a second member with respect to a first member, said method comprising:
- outputting an electric signal from the transducer based on the displacement of said second member with respect to said first member;
- detecting a relative speed of said second member with respect to said first member on the basis of the electric signal;
- and
- performing detection of malfunction of said transducer when the detected relative speed is equal to or smaller than a predetermined value.
Dependencies are inferred from the claim text.