Displacement measuring unit

Abstract

To provide a displacement measuring unit which removes a measured value obtained by bringing a measurement element into a measurement target by an inappropriate approach and can surely acquire a precise measured value.SOLUTION: A displacement measurement unit 1 includes: an encoder E for bringing a measurement element 2 into contact with a measurement target surface and detecting a moving displacement amount of the measurement element 2 by using the moving direction of the measurement element 2 as a measurement direction; operation means 4 for operating a measured value from at least the moving displacement amount; and display means 10 for displaying at least the measured value. The operation means 4 includes: a measurement unit 5 for calculating the measured value and causing the display means 10 to display the measured value; rate acquisition means 6 for acquiring the rate of the measurement element 2; an approach analysis unit 7 for determining whether approach of the measurement element 2 to the measurement target is normal or abnormal on the basis of the shift of the rate detected by the rate acquisition unit 6 in a predetermined period of time immediately before the measurement element 2 stops; and a warning unit 8 for issuing a warning in a case where the approach analysis unit 7 determines that approach of the measurement element 2 to the measurement target is abnormal.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a displacement measuring instrument that measures a measurement target from the displacement of a measuring element. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there has been known a displacement measuring instrument in which a measuring element is stopped in a state in which it is in contact with the surface of a measurement object, and the position of the measuring element is calculated. As an example of such a displacement measuring instrument, a micrometer described in Patent Document 1 displaces a spindle (corresponding to a measuring element) in the axial direction by rotating an operating sleeve, and measures the dimension of a measurement target from the displacement of the spindle. Specifically, the micrometer includes an encoder that detects the displacement of the spindle and a digital display unit. The display unit displays the displacement of the spindle detected by the encoder on the display unit, and informs the user of the displacement amount.

[0003] In such micrometers, even if the spindle is stopped in contact with the object to be measured, the user may further rotate the operating sleeve and push the spindle into the object to be measured, which may result in variations in the measured values ​​or damage to the object to be measured. To prevent these problems, a method of controlling the measuring force at a constant level is adopted. For example, an operating sleeve is rotatably provided at the outer end of the spindle, and a constant pressure mechanism (such as a ratchet mechanism) is provided between the spindle and the operating sleeve. With this configuration, when a load above a certain level is applied to the spindle, the constant pressure mechanism is activated and the operating sleeve rotates freely, so that the micrometer can control the measuring pressure at a constant level. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-141402 A Summary of the Invention [Problem to be solved by the invention]

[0005] Here, while a normal micrometer has a lead pitch of 0.5 mm / rev, a micrometer with a large lead pitch of 2 mm / rev, four times the normal pitch, advances the spindle a great distance in one revolution. In a displacement measuring instrument in which the probe tends to advance at a relatively fast speed, if the user is unfamiliar with the operation, they may advance the probe toward the measurement object at high speed, causing the probe to crash into the measurement object. The impact caused when the probe crashes into the measurement object cannot be prevented by a constant pressure mechanism such as a ratchet mechanism, resulting in problems such as the probe digging into the measurement object and variations in the measured values.

[0006] An object of the present invention is to provide a displacement measuring instrument that can reliably obtain highly accurate measurement values ​​by eliminating measurement values ​​obtained by bringing a measuring element into contact with a measurement object using an inappropriate approach. [Means for solving the problem]

[0007] The displacement measuring instrument of the present invention includes an encoder that detects the amount of displacement of the measuring probe by bringing the measuring probe into contact with the surface of a measuring object and using the moving direction of the measuring probe as the measurement direction, a calculation means that calculates a measurement value from at least the amount of displacement, and a display means that displays at least the measurement value. The calculation means includes a measurement unit that calculates the measurement value from the amount of displacement and displays the measurement value on the display means, a speed acquisition unit that acquires the speed of the measuring probe, an approach analysis unit that analyzes and judges whether the approach of the measuring probe to the measuring object is normal or abnormal based on the change in the speed acquired by the speed acquisition unit during a predetermined period immediately before the measuring probe stops, and a warning unit that issues a warning when the approach analysis unit judges that the approach of the measuring probe to the measuring object is abnormal.

[0008] According to the present invention, the warning unit issues a warning when the approach analysis unit determines that the approach of the probe to the measurement target is abnormal, so that the user can recognize that the operation method of the probe was inappropriate. Also, the user can be prompted to perform measurement with appropriate operation. Therefore, the displacement measuring instrument can eliminate measurement values ​​obtained by bringing the probe into contact with the measurement target with an inappropriate approach, and can reliably obtain highly accurate measurement values. Also, it is possible to suppress the probe from colliding with or biting into the measurement target, thereby reducing the variation in measurement values.

[0009] In this case, it is preferable for the approach analysis unit to analyze the speed over a specified period of time, and determine that there is an abnormality if the change in speed over the specified period is not monotonous and if the speed at one or more times immediately before stopping during the specified period does not fall within a specified range.

[0010] With this configuration, the approach analysis unit analyzes the speed over a specified period of time, and if the change in speed over the specified period is not monotonous and the speed at one or more times immediately before stopping in the specified period does not fall within a specified range, it can more accurately determine whether the approach is normal or abnormal, compared to not going through the step of determining that there is an abnormality.

[0011] At this time, it is preferable that the speed acquisition unit acquires the speed until the measuring element stops by calculation based on the amount of movement displacement from the encoder.

[0012] According to such a configuration, the speed acquisition unit acquires the speed by calculation based on the moving displacement amount, and therefore the speed can be acquired without providing a speed sensor, etc. Therefore, the displacement measuring device can suppress an increase in parts and damage, etc., that may occur due to the provision of the displacement measuring device, and can reduce costs.

[0013] At this time, it is preferable that the warning unit notifies the warning by using the display means to blink the measurement result by the measurement unit.

[0014] According to this configuration, when a warning is issued, the measurement result flashes, so that the warning unit can reliably notify the user of the warning. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram illustrating a displacement measuring instrument according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing a displacement measuring device. [Diagram 3] 4 is a graph showing a principle of velocity calculation by a velocity acquisition unit. [Figure 4] FIG. 13 is a diagram showing a transition of approach speed in a normal state in a displacement measuring instrument. [Diagram 5] FIG. 5 is a diagram showing a transition of approach speed in a normal state in the displacement measuring instrument different from that in FIG. 4. [Figure 6] FIG. 13 is a diagram showing a transition of an approach speed when an abnormality occurs in a displacement measuring instrument. [Figure 7] 5 is a flowchart showing a procedure for determining whether an approach of a probe to a measurement target in a displacement measuring instrument is normal or abnormal. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, one embodiment will be described with reference to FIGS. FIG. 1 is a schematic diagram showing a displacement measuring instrument 1 according to an embodiment. As shown in FIG. 1, the displacement measuring instrument 1 is a micrometer that stops a probe 2 in contact with the surface of a measurement target (not shown), moves the probe 2 in the measurement direction (X direction), and calculates a measurement value from the position of the probe 2. In the following description and in each drawing, the measurement direction, which is the direction of movement of the probe 2, is defined as the X direction, the width direction of the displacement measuring instrument 1 perpendicular to the X direction is defined as the Y direction, and the height direction of the displacement measuring instrument 1 perpendicular to the X and Y directions is defined as the Z direction.

[0017] The displacement measuring instrument 1 comprises a probe 2 , a position measuring means 3 , and a calculation means 4 . The probe 2 has a structure in which an abutment surface 22 is provided at one end of a cylindrical spindle 21. The abutment surface 22 is a surface provided at the tip of the spindle 21 for abutting against the surface of the measurement target. The position measuring means 3 measures the position of the probe 2 relative to a reference position in the X direction, which is the measurement direction. The position measuring means 3 includes a thimble 31, a ratchet knob 32, a sleeve 33, and an encoder E (see FIG. 2). The thimble 31 and the ratchet knob 32 are rotated to move the spindle 21 forward and backward relative to the measurement object. The sleeve 33 is disposed on the side of the spindle 21 opposite the abutment surface 22. The encoder E detects the amount of displacement of the probe 2 from a reference position (for example, a position where the abutment surface 22 abuts against the anvil 13, which will be described later).

[0018] The displacement measuring instrument 1 moves the spindle 21 toward and away from the object to be measured by rotating the thimble 31 or the ratchet knob 32 around the spindle 21 as an axis in the direction of the arrow in the figure. The displacement measuring instrument 1 measures the object to be measured from the amount of displacement of the rotation angle caused by the rotation of the thimble 31 or the ratchet knob 32. The measurement results, such as the measured values, obtained by the displacement measuring instrument 1 are displayed on the display means 10.

[0019] The display means 10 displays at least the measured values ​​and is composed of a liquid crystal panel. The display means 10 mainly displays the measured values ​​and the like using a 7-segment digital display. Note that the display means 10 is not limited to a liquid crystal panel, and may also be an organic EL (Electro-Luminescence) display or electronic paper. In other words, it is sufficient for the display means 10 to be able to display information about the displacement measuring instrument 1, the measured values, and the like.

[0020] The displacement measuring instrument 1 further includes a clamp 11 that fixes the spindle 21, a plurality of button-type operating units 12a to 12c for receiving operations from the user and operating the displacement measuring instrument 1, an anvil 13, and an arm unit 14. Operation unit 12a is an ON / OFF button. The user operates operation unit 12a to turn the power of displacement measuring instrument 1 ON / OFF. Operation unit 12b is a ZERO button. The user operates operation unit 12b when setting the origin when starting measurement with displacement measuring instrument 1. Operation unit 12c is a HOLD button. The user operates operation unit 12c when holding a value measured by displacement measuring instrument 1. Note that operation units 12a to 12c may be of a sliding type, and may have any configuration as long as the user can operate them. Furthermore, operation units 12a to 12c may have any function and may be located in any position as long as the user can operate them.

[0021] The anvil 13 is a reference position in the displacement measuring instrument 1, which is disposed opposite the contact surface 22 of the probe 2. The arm 14 is formed in a substantially U-shape. The probe 2 and the position measuring means 3 are disposed on one end of the arm 14. The anvil 13 is disposed on the other end of the arm 14. The displacement measuring instrument 1 measures the length from the contact surface 22 of the probe 2 to the anvil 13 by sandwiching the measurement target between the contact surface 22 of the probe 2 and the anvil 13. Here, the state in which the contact surface 22 of the probe 2 and the anvil 13 are in contact is defined as the reference position (zero). The direction in which the contact surface 22 of the probe 2 and the anvil 13 move away from the contact state is defined as the +X direction, and the direction in which the contact surface 22 of the probe 2 and the anvil 13 move closer to each other from the separated state is defined as the -X direction. The measured value increases as the contact surface 22 of the probe 2 and the anvil 13 move away from each other in the +X direction. Moreover, the measured value decreases as the contact surface 22 of the probe 2 and the anvil 13 approach each other in the -X direction.

[0022] Fig. 2 is a block diagram showing the displacement measuring instrument 1. As shown in Fig. 2, the displacement measuring instrument 1 includes a probe 2, a position measuring means 3, a calculation means 4, and a display means 10. The calculation means 4 includes a measurement unit 5 , a speed acquisition unit 6 , an approach analysis unit 7 , a warning unit 8 , and a memory unit 9 . The measuring unit 5 calculates a measurement value from the amount of movement and displacement by the encoder E, and causes the display means 10 to display the measurement value. The speed acquiring unit 6 acquires the moving speed of the probe 2. Specifically, the speed acquiring unit 6 calculates the speed until the probe 2 stops by calculation based on the moving displacement amount from the encoder E. Note that while the speed acquiring unit 6 in this embodiment acquires the speed by calculation, it may also acquire the speed by detection using a speed sensor, for example.

[0023] FIG. 3 is a graph showing the principle of calculation of the velocity by the velocity acquisition unit 6. The speed acquisition unit 6 obtains the speed using the value of the counting index, which is an index for grasping the rough position based on the amount of movement displacement. The counting index is a numerical value that changes periodically according to the amount of movement displacement, and takes on numerical values ​​from 0 to 11, for example. By obtaining this counting index, the position of the spindle 21 (probe 2) can be roughly grasped. The speed acquisition unit 6 calculates the speed from the change in this counting index per unit time. Specifically, as shown in FIG. 3, the vertical axis represents position and the horizontal axis represents time, and the speed is calculated using equation (1) based on the counting index.

number

[0024] The speed acquisition unit 6 acquires a counting index based on the amount of movement displacement at a predetermined time interval (for example, every 6 milliseconds), and stores a predetermined number of calculated speeds, starting from the most recent, in the memory unit 9 provided in the calculation means 4, overwriting older ones as needed. In this embodiment, the latest eight speeds among those acquired by the speed acquisition unit 6 are stored in the storage unit 9. That is, the oldest speed among those stored in the storage unit 9 is overwritten with a newly acquired speed, so that the latest eight speeds are stored in the storage unit 9 at any time. The storage unit 9 may be anything that can store the speed, etc. For example, the storage unit 9 may be a microcomputer or an externally connected storage device.

[0025] As shown in FIG. 2 and FIGS. 4 to 6 described later, the approach analysis unit 7 analyzes and judges whether the approach of the probe 2 to the measurement target is normal or abnormal based on a predetermined threshold and the speed acquired by the speed acquisition unit 6. Specifically, the approach analysis unit 7 analyzes the speed in a predetermined period immediately before the probe 2 comes into contact with the surface of the measurement target and stops. Then, if the speed transition in that period changes monotonically toward a stopped state (i.e., a state in which the speed is 0), it is deemed that the probe 2 has stopped without hitting the measurement target, and is not treated as abnormal. If the change in speed is not monotonous and is within a predetermined threshold, it is deemed that the probe 2 has come into contact with the surface of the measurement target and stopped due to an appropriate speed transition, and it is determined that the approach to the measurement target was normal. If the change in speed is not monotonous and exceeds a predetermined threshold, it is deemed that the probe 2 has come into contact with the surface of the measurement target and stopped due to an inappropriate speed transition, and it is determined that the approach to the measurement target was abnormal (inappropriate).

[0026] As shown in FIG. 2, the warning unit 8 issues a warning when the approach analysis unit 7 judges that the approach of the probe 2 to the measurement target is abnormal. Specifically, the warning unit 8 issues a warning by using the display means 10 to blink the measurement result by the measurement unit 5. The warning unit 8 also restricts the function of the displacement measuring instrument 1. Here, the restriction of the function means not displaying the measurement result on the display means 10, or stopping the output if the measurement result is output by communication. This restriction of the function is not released unless a predetermined action is performed. The predetermined action is preferably an action of moving the probe 2 in the opposite direction to the direction of travel until the warning is issued. Since there is a possibility that the probe 2 is embedded in the measurement target, it is preferable to adopt the above-mentioned action as a release method.

[0027] Fig. 4 is a diagram showing the transition of approach speed in the displacement measuring instrument 1 under normal conditions, and Fig. 5 is a diagram showing the transition of approach speed in the displacement measuring instrument 1 under normal conditions different from those shown in Fig. 4. Fig. 6 is a diagram showing the transition of approach speed in the displacement measuring instrument 1 under abnormal conditions. In each of Figs. 4 to 6, the vertical axis represents speed and the horizontal axis represents time. In the following description, the transition of approach speed may be referred to as a speed profile. 4 to 6, a process will be described in which the approach analysis unit 7 analyzes whether an approach is normal or abnormal based on the transition of the approach speed using the speed acquired by the speed acquisition unit 6. In the figures, eight points (0 to 7) indicate the speeds acquired by the speed acquisition unit 6, and in the following description, they will be expressed as speed value 0 to speed value 7 in order from the most recent one.

[0028] First, the approach analysis unit 7 determines that the probe 2 has stopped if the speed acquired by the speed acquisition unit 6 has been 0 three consecutive times. In the examples of Figures 4 to 6, the speed is 0 three consecutive times from speed value 0 to speed value 2 in the figures, so it is determined that the probe 2 stopped at the time of speed value 2. Next, the approach analysis unit 7 determines that the probe 2 stopped for a specified period (from speed value 3 to speed value 7 in the examples of Figures 4 to 6) as the immediately preceding time, and analyzes the speed change during that period.

[0029] 4 to 6, if the interval at which the speed acquisition unit 6 acquires the speed is 6 milliseconds, then 30 milliseconds ago is taken as the immediately preceding specified period, and first, an analysis is performed to see if the change in speed up to the point of stopping is monotonic for five points in this period (speed value 3 to speed value 7). If the change in speed up to the point of stopping is monotonic, then it can be interpreted that the probe 2 stopped without colliding with the surface of the measurement target, and if the change in speed up to the point of stopping is not monotonic, then it can be interpreted that vibration occurred due to the probe 2 colliding with the surface of the measurement target, etc.

[0030] As shown in FIG. 4, if the change in speed from speed value 3 to speed value 7 is monotonous, the approach analysis unit 7 determines that the vehicle has stopped without colliding with the surface of the measurement object. In addition, if the change in speed from speed value 3 to speed value 7 is not monotonous, and if the speeds of speed value 3 and speed value 4 immediately before the vehicle stopped are between the first threshold and the second threshold, the approach analysis unit 7 determines that the approach to the measurement object is normal. Specifically, as shown in FIG. 5, although the change in speed from speed value 3 to speed value 7 is not monotonous due to vibrations or the like, especially if the speeds of speed value 3 and speed value 4 immediately before the vehicle stopped are between the first threshold and the second threshold, the approach analysis unit 7 determines that the approach to the measurement object was normal.

[0031] On the other hand, as shown in FIG. 6, if the change in speed from speed value 3 to speed value 7 is not monotonous, and in particular, if the speeds of speed value 3 and speed value 4 just before stopping are not between the first threshold and the second threshold, the approach analysis unit 7 determines that the approach to the measurement target was abnormal.

[0032] 7 is a flowchart showing the process of determining whether an approach is normal or abnormal in the displacement measuring instrument 1. The process of determining whether an approach is normal or abnormal will be described below with reference to FIG. First, as shown in FIG. 7, the speed acquisition unit 6 executes a speed acquisition step of acquiring the speed until the probe 2 stops (step ST01). The speed acquisition unit 6 acquires the speed at a predetermined time interval, and overwrites and updates the latest eight speeds stored in the memory unit 9 as needed. Next, the approach analysis unit 7 executes a stop determination step of judging whether the probe 2 has stopped (step ST02). If the speed acquisition unit 6 acquires three consecutive speeds that are zero, the approach analysis unit 7 judges that the probe 2 has stopped. If the approach analysis unit 7 judges that the probe 2 has not stopped (NO in step ST02), it causes the measurement unit 5 to execute a result display step of displaying the measurement results by the displacement measuring device 1 on the display means 10 (step ST04), and returns to the speed acquisition step (step ST01). On the other hand, if the approach analysis unit 7 determines that the sensor 2 has stopped (YES in step ST02), the approach analysis unit 7 determines whether the approach was normal or not based on the speed profile, which is the change in speed until the sensor 2 stopped (step ST03).

[0033] When the approach analysis unit 7 judges that the approach was normal (YES in step ST03), it causes the measurement unit 5 to execute a result display step of displaying the measurement result by the displacement measuring device 1 on the display means 10 (step ST04), and returns to the speed acquisition step (step ST01). On the other hand, when the approach analysis unit 7 judges that the approach was abnormal (NO in step ST03), it causes the display means 10 to issue a warning via the warning unit 8, and executes a warning step of restricting the function of the displacement measuring device 1 (step ST05). If the user wishes to continue the measurement after the warning is issued, the user moves the measuring probe 2 in the opposite direction to the previous traveling direction, and executes a release step of releasing the restriction on the function of the displacement measuring device 1 (step ST06). When the release step (step ST06) is executed, measurement becomes possible, and the process returns to the speed acquisition step (step ST01).

[0034] According to this embodiment, the following actions and effects can be achieved. (1) Measurement values ​​obtained by bringing the probe 2 into contact with the measurement object using an inappropriate approach can be eliminated, and highly accurate measurement values ​​can be obtained reliably. (2) The warning unit 8 issues a warning when the approach analysis unit 7 judges that the approach of the probe 2 to the measurement target is abnormal, and therefore can instruct the user on the appropriate way to make the probe 2 approach the measurement target, and the user can recognize that the operation method of the probe 2 was not appropriate. It can also urge the user to perform measurement using appropriate operation. Therefore, the displacement measuring instrument 1 can instruct the user on the appropriate way to make the probe 2 approach the measurement target, thereby preventing the probe 2 from crashing into or biting into the measurement target and reducing the variation in the measurement value, thereby enabling more accurate measurement.

[0035] (3) The approach analysis unit 7 analyzes the speed during a specified period (from speed value 3 to speed value 7 in Figures 4 to 6), and if the change in speed during the specified period is not monotonous and the speed at one or more times immediately before stopping during the specified period (speed value 3 and speed value 4 in Figures 4 to 6) does not fall within a specified range (between the first threshold and the second threshold), the approach can be more accurately determined to be normal or abnormal compared to not going through the step of determining that an approach is abnormal. (4) The speed acquisition unit 6 can acquire the speed by calculation from the amount of movement displacement, so that costs can be reduced compared to a case where a speed sensor or the like is separately provided. (5) When a warning is issued, the measurement result flashes, so that the warning unit 8 can reliably notify the user of the warning.

[0036] [Modifications of the embodiment] The present invention is not limited to the above-described embodiment, and modifications and improvements within the scope of the present invention that can achieve the object of the present invention are included in the present invention. For example, in the above embodiment, the displacement measuring instrument 1 is a micrometer, but the type of detector, detection method, etc. are not particularly limited as long as the displacement measuring instrument is a displacement measuring instrument that stops a probe on the surface of the object to be measured and calculates a measurement value from the position of the probe.

[0037] In the above embodiment, the approach analysis unit 7 analyzes the speed immediately before stopping, and judges the speed immediately before stopping as normal if it does not exceed a predetermined threshold and decreases monotonically, judges it as abnormal if it exceeds the predetermined threshold and decreases monotonically, judges it as normal if it does not decrease monotonically and is within the predetermined threshold, and judges it as abnormal if it does not decrease monotonically and exceeds the predetermined threshold. However, the approach analysis unit may adopt any judgment method as long as it can analyze and judge whether the approach of the sensor to the measurement target is normal or abnormal based on the change in speed detected by the speed acquisition unit during a predetermined period immediately before the sensor stops.

[0038] In the above embodiment, the speed acquisition unit 6 acquires the speed by calculation. However, the speed acquisition unit may adopt any acquisition method as long as it can acquire the speed of the measuring element. For example, it is also possible to adopt a speed sensor. In the above embodiment, the warning unit 8 issues a warning by using the display means 10 to blink the measurement result by the measurement unit 5. However, the warning unit may employ any means as long as it can issue a warning when the approach analysis unit determines that the approach of the measuring element to the measurement target is abnormal.

[0039] For example, the warning may be issued by changing the color of the display screen of the display means or the color of the characters to be displayed, or by sounding a buzzer or the like. The warning may also be issued by applying a stimulus to the human body that is in contact with the displacement measuring device, or by generating vibrations. Furthermore, the warning may be issued using light, for example by lighting or blinking a light-emitting member such as an LED, or by adjusting the amount of light from the backlight of the display screen. [Industrial Applicability]

[0040] As described above, the present invention can be suitably used in a displacement measuring instrument. [Explanation of symbols]

[0041] 1 Displacement measuring instrument 2 Probe 3 Position measuring means 4 Calculation means 5 Measuring part 6 Speed ​​acquisition section 7. Approach Analysis Department 8 Warning part 9 Storage section 10 Display means

Claims

1. A displacement measuring device comprising: an encoder that contacts a measuring probe with the surface of a target to be measured, sets the direction of movement of the measuring probe as the measurement direction and detects the amount of displacement of the measuring probe; and a calculation means that calculates a measured value from at least the amount of displacement, The aforementioned calculation means is A speed acquisition unit for detecting the speed of the measuring probe, An approach analysis unit analyzes and determines whether the approach of the measuring probe to the measurement target is normal or abnormal, using the speed detected by the speed acquisition unit during a predetermined period immediately before the measuring probe stops. A displacement measuring device comprising: an approach analysis unit that determines that the approach of the measuring probe to the object to be measured is abnormal, and a warning unit that issues a warning.

2. The displacement measuring device according to Claim 1, wherein the warning unit determines that the approach of the measuring probe to the object to be measured is abnormal and restricts the function of the displacement measuring device.

3. Further comprising communication means for outputting the measured value to an external device via communication, The displacement measuring device according to claim 2, wherein the warning unit restricts the function of the displacement measuring device by stopping the output of the measurement value via the communication means when it determines that the approach of the measuring probe to the object to be measured is abnormal.

4. The displacement measuring device according to claim 2 or 3, wherein the warning unit releases the restriction on the function of the displacement measuring device when the measuring probe is moved in the opposite direction to the direction of travel until the warning is issued.

5. The displacement measuring device according to claim 1, wherein the approach analysis unit determines that an abnormality exists if the change in velocity during the predetermined period is not monotonous, and the velocity at one or more timings immediately before stopping during the predetermined period does not fall within a predetermined range.

6. The speed acquisition unit, The displacement measuring device according to claim 1, wherein the velocity of the measuring probe is obtained by calculation based on the amount of displacement detected by the encoder.

7. Further comprising a display means for displaying the measured value, The aforementioned warning unit is The displacement measuring device according to claim 1, wherein the warning is notified by changing the display of the display means.

8. The warning unit is The displacement measuring device according to claim 7, wherein the warning is notified by flashing the measured value displayed on the display means.

9. A displacement measuring device comprising: an encoder that contacts a measuring probe with the surface of a target to be measured and detects the amount of displacement of the measuring probe in the measurement direction; a calculation means for calculating a measurement value from at least the amount of displacement; and a display means for displaying the measurement value, The aforementioned calculation means is An approach analysis unit that determines whether the approach of the measuring probe to the object to be measured is normal or abnormal, A displacement measuring device comprising: a warning unit that, when the approach analysis unit determines that the approach of the measuring probe to the object to be measured is abnormal, signals a warning by changing the display on the display means.

10. Further comprising communication means for outputting the measured value to an external device via communication, The displacement measuring device according to claim 9, wherein the warning unit determines that the approach of the measuring probe to the object to be measured is abnormal, and stops the output of the measurement value by the communication means.

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