JP3958098B2 - Displacement measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a displacement measuring device, and more particularly to a displacement measuring device using a displacement sensor.
[0002]
[Prior art]
Displacement measuring devices using displacement sensors are used for small measuring instruments such as digital calipers, digital micrometers, height gauges, etc., and generally use low-power-consumption devices that use capacitance type or electromagnetic induction type displacement sensors. Is popular. An electromagnetic induction type displacement sensor has a large number of coil patterns arranged on a main scale as a fixed element and a slider as a movable element that moves on the main scale. The displacement of the slider is detected by taking out the change in the periodic signal of the magnetic field generated in the slider.
[0003]
As this type of displacement sensor, a continuous counting operation is performed for an incremental type sensor that detects the amount of displacement by continuously counting a periodic signal generated by the slider moving from the reference position of the main scale. There is a so-called absolute type that can detect the absolute displacement of the slider with respect to the main scale without performing it.
[0004]
The absolute type displacement sensor can output a periodic signal having a coarse pitch, an intermediate pitch, and a fine pitch, for example, depending on the shape of the magnetic field pattern. By synthesizing the phase information of the periodic signals of these pitches, The absolute displacement of the slider with respect to the scale can be detected.
[0005]
Such an absolute type electromagnetic induction type displacement sensor is used in, for example, an electromagnetic induction type solar cell type digital caliper (hereinafter referred to as “solar cell type digital caliper”), and a detection value based on the displacement amount of the displacement sensor. An electronic circuit that calculates the detected value, a display that includes an LCD that displays the detected value, a solar cell that generates power necessary to drive the electronic circuit and the display, and a capacitor that stores the power supplied from the solar cell Have
[0006]
In this solar cell type digital caliper, the brightness of the display device decreases as the storage voltage of the capacitor decreases, and increases as the storage voltage increases.
[0007]
In this electronic circuit, as a display update speed of a detection value displayed on the display (hereinafter referred to as “update speed”), a high-speed update mode in which slider displacement amount detection and display update of the detection value are performed 8 times per second, and There are two types of modes, a low-speed update mode in which slider displacement amount detection and display update of the detected value are performed twice per second, and these update speeds are obtained when the storage voltage of the capacitor is equal to or higher than a predetermined threshold Vth. When the high-speed update mode is set and the storage voltage of the capacitor is less than the predetermined threshold Vth, the low-speed update mode is set to reduce power consumption.
[0008]
This update speed setting switching is executed by the process of FIG.
[0009]
FIG. 6 is a flowchart showing the update speed setting switching process of the conventional displacement measuring apparatus.
[0010]
In FIG. 6, the electronic circuit of the conventional solar cell type digital caliper resets the value of the timer TIM to 0 (step S41) when the measurement is started when the power switch is turned on (step S41), and the storage voltage Vdet of the capacitor. Is greater than or equal to the threshold voltage Vth (1.5 V) of the storage voltage (step S42).
[0011]
As a result of the determination in step S42, when the storage voltage Vdet is equal to or higher than the threshold value Vth, the display update time T is set to the high-speed update mode display update time T1 (125 ms (= 8 times per second)) (step S43). The slider displacement is detected and the display value is updated (step S44). The process continues until the value of the timer TIM reaches the display update time T1 for the high-speed update mode (NO in step S45), and the value of the timer TIM is T1. When the above is reached (YES in step S45), the processes in and after step S41 are repeated until the power switch is turned off (NO in step S46). If the power switch is turned off (YES in step S46), this process ends. To do.
[0012]
On the other hand, if the result of determination in step S42 is that the storage voltage Vdet is less than the threshold value Vth, the display update time T is set to the low-speed update mode display update time T2 (500 ms (= twice per second)) (step S47). ), Slider displacement amount detection and display update of the detected value are performed (step S48), and the process continues until the value of the timer TIM reaches or exceeds the display update time T2 for the low speed update mode (NO in step S49). Is equal to or greater than T2 (YES in step S49), the processes in and after step S41 are repeated until the power switch is turned off (NO in step S46). If the power switch is off (YES in step S46), this process is performed. Exit.
[0013]
According to FIG. 6, when the storage voltage Vdet of the capacitor becomes equal to or higher than the threshold value Vth (1.5V) (YES in step S42), the display update time is switched to the high-speed update mode display update time (step S43). The display update time is detected when the scale displacement amount is detected and the detection value is updated eight times, that is, every 125 ms (steps S44, 45), and the storage voltage Vdet of the capacitor falls below the threshold value Vth (NO in step S42). Is switched to the display update time for the low-speed update mode (step S47), and the scale displacement is detected and the display value is updated twice every second, that is, every 500 ms (steps S48, 49). As a result, when the update speed setting is in the low-speed update mode, the power supply to the solar cell increases more than the power consumption due to the power consumption reduction, and the storage voltage increases. Is switched to the fast update mode (FIG. 7).
[0014]
[Problems to be solved by the invention]
However, in the above solar cell type digital caliper, as shown in FIGS. 7A and 7B, for example, when the illuminance is in the range of 50 to 100 lux, the storage voltage Vdet of the capacitor is close to the threshold value Vth. In this case, display in the high-speed update mode (8 times / second) and display in the low-speed update mode (2 times / second) are repeated. Therefore, the user feels uncomfortable due to the non-uniformity of the display update of the detected value. This discomfort is particularly increased because the numerical value in the display does not change following the movement of the slider while the slider is moving on the main scale.
[0015]
An object of the present invention is to provide a displacement measuring device that improves the uniformity of the number of display updates per unit time of a detected value.
[0016]
[Means for Solving the Problems]
In order to achieve the above-described object, the displacement measuring apparatus according to claim 1 includes a fixed element and a movable element movable on the fixed element, and the movable element includes a solar cell and the solar cell. Power storage means for storing the supplied power, voltage detection means for detecting the storage voltage of the power storage means, voltage determination means for determining whether the detected storage voltage is equal to or higher than a predetermined voltage, and Displacement amount detection means for detecting the displacement amount of the movable element with respect to the fixed element, a display unit that updates and displays the detected displacement amount a predetermined number of times per unit time, and the detected stored voltage is equal to or higher than the predetermined voltage wherein in the range with the when the detected storage voltage is less than the predetermined voltage of a predetermined display update frequency per unit time for updating the display of the unit time granted Symbol predetermined number of the display unit when the In the displacement measuring apparatus and a updating means for resting the update of radical 113 includes a counting means for counting the number of times to pause the update of the win display part and the unit time, the update means, the detected storage voltage is the Even if the voltage is equal to or higher than a predetermined voltage, the number of times that the updating of the display unit per unit time is paused is 1 from the number of times that the updating of the display unit per unit time measured by the preset counting unit is paused. When the number of times of decrement is less than the number of times , the display unit is not updated.
[0017]
According to the first aspect of the present invention, even if the stored voltage detected by the voltage detecting means is equal to or higher than a predetermined voltage, the number of times that the updating of the display unit per unit time is paused by the preset counting means. When the update of the display unit per unit time is less than the number of times decremented by one , the display unit is not updated, so by gradually reducing the number of times the display is not updated. In addition, it is possible to prevent the user from feeling uncomfortable when viewing the display unit by eliminating the non-uniformity of the display update frequency .
[0020]
The displacement measuring device according to claim 2 is the displacement measuring device according to claim 1 , wherein the updating means has a number of times of pausing updating of the display unit per unit time being equal to or greater than a preset maximum non-display number. Performs the update.
[0021]
According to the second aspect of the present invention, the update means updates the display when the number of cycles in which the display is not updated (update pause) is equal to or greater than the predetermined maximum non-update count, so that the storage voltage is less than the predetermined voltage. Forcibly updating the display when the state continues, it is possible to prevent display non-update from continuing and to prevent the user from misidentifying an apparatus failure.
[0022]
A displacement measuring device according to a third aspect is the displacement measuring device according to the first or second aspect , wherein the predetermined voltage is a voltage capable of operating the display unit.
[0023]
The displacement measuring device according to claim 4 is the displacement measuring device according to any one of claims 1 to 3 , wherein the unit time is 1 second, and the number of updates of the display unit per unit time is 2 times. It is the above .
[0024]
The displacement measuring device according to claim 5 is the displacement measuring device according to any one of claims 1 to 4 , wherein the displacement measuring device is a hand tool.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a displacement measuring apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
[0026]
FIG. 1 is a front view of a displacement measuring apparatus according to an embodiment of the present invention.
[0027]
In FIG. 1, an electromagnetic induction solar cell type digital caliper 10 as a displacement measuring device according to an embodiment of the present invention includes a main scale 11 (fixed element) and a slider 12 slidable in the longitudinal direction of the main scale 11. (Movable element).
[0028]
The main scale 11 has an inner measuring jaw 11a and an outer measuring jaw 11b integrally at its tip, and a main scale composed of magnetic poles arranged on the one surface of the main body at a constant pitch along the longitudinal direction. 13 The main scale 13 is covered with a thin sealing film on which the scale 14 is printed.
[0029]
The slider 12 includes a slider case 12a, and an inner measurement jaw 12b and an outer measurement jaw 12c that are integrally provided on one end side of the slider case 12a. The slider case 12a includes an electronic circuit (not shown) described later in FIG. 2 that calculates a detection value based on the amount of displacement, and a displacement described later in FIG. 2 that detects a change in the magnetic field of the magnetic pole of the main scale 13. A sensor 17 (not shown), and a display 17 comprising an LCD for displaying the detected value, a solar cell 18 for generating electric power necessary for driving the electronic circuit and the display 17, and a solar cell The capacitor | condenser (not shown) mentioned later in FIG. 2 which accumulate | stores the electric power supplied from 18 is provided. The solar cell 18 has a power generation capacity of 7.5 μW or more when the illuminance is 50 lux.
[0030]
FIG. 2 is a block diagram of an electronic circuit provided on the slider 12 in FIG.
[0031]
In FIG. 2, an electronic circuit 15 includes a voltage detection circuit 21 (voltage detection means), a position detection circuit 22 (displacement amount detection means), a clock circuit 23, and a microcontroller 24 (voltage) connected to a capacitor 19 (power storage means). Determination means). The microcontroller 24 is connected to the display unit 17.
[0032]
The position detection circuit 22 is connected to a displacement sensor 16 provided on the slider 12, and detects a displacement amount (position) of the slider 12 based on an input signal from the displacement sensor 16. The voltage detection circuit 21 detects the storage voltage of the capacitor 19. The microcontroller 24 detects the displacement amount of the slider 12 detected by the position detection circuit 22, the storage voltage Vdet of the capacitor 19 detected by the voltage detection circuit 21, and Based on the clock signal from the clock circuit 23, the display 17 is updated by the process of FIG. The microcontroller 24 further includes a timer, a non-update count counter, and a non-update count latch. The timer counts the processing time in the display update process described later in FIG. 3, and the non-update count counter does not continuously update the display when the previous process ends in the display update process described later in FIG. In this case, the non-update count is counted, and the non-update count latch sets a threshold value for determining whether or not to perform display update in the display update processing described later with reference to FIG.
[0033]
FIG. 3 is a flowchart showing display update processing executed by the microcontroller 24 in FIG.
[0034]
In FIG. 3, when the measurement is started by turning on the power switch of the solar cell type digital caliper (step S10), the microcontroller 24 resets the value of the timer TIM to 0 (step S11), and the storage voltage Vdet of the capacitor 19 is reset. There it is determined whether or not the on predetermined threshold Vth (1.5V) (capable voltage operation of the electronic circuit 15) than the stored voltage (step S12).
[0035]
If the storage voltage Vdet is greater than or equal to the threshold value Vth as a result of the determination in step S12, it is determined whether or not the value C of the non-update count counter is greater than or equal to the non-update count latch value CL set in step S21 described later. (Step S13). The initial values of the non-update count counter value C and the non-update count latch value CL are zero.
[0036]
If the non-update count counter value C is equal to or greater than the non-update count latch value CL as a result of the determination in step S13 (YES in step S13), the slider displacement is detected and the display of the detected value is updated (step S14). (Update means), it is determined whether or not the value C of the non-update count counter is 0 (step S15).
[0037]
As a result of the determination in step S15, when the value C of the non-update count counter is 0 (YES in step S15), the value of the timer TIM is a predetermined display update time T0 (T0 = 125 ms) (predetermined period) (use (The longest cycle in which the person does not feel the flicker of the display device 17) or more (NO in step S16), and when the value of the timer TIM becomes T0 or more (YES in step S16), the power switch is turned off. Until the process from step S11 is repeated (NO in step S17), if the power switch is off (YES in step S17), this process ends.
[0038]
If the non-update count counter value C is not 0 as a result of the determination in step S15, the non-update count latch value CL is set to a value decremented by 1 from the non-update count counter value C (CL = C−1). (Step S18) (predetermined number of cycles), the value C of the non-update count counter is reset to 0 (Step S19), and the processing after Step 16 is performed.
[0039]
On the other hand, when the storage voltage Vdet is less than the threshold value Vth as a result of the determination in step S12 or when the non-update count counter value C is less than the non-update count latch value CL as a result of the determination in step S13, the slider displacement Without detecting the amount and updating the display of the detected value (step S20) (update means), the value C of the non-update count counter is incremented by 1 (C = C + 1) (step S21) (counting means), and the timer TIM Continue until the value reaches or exceeds the predetermined display update time T0 (T0 = 125 ms) (NO in step S16). When the value of the timer TIM exceeds T0 (YES in step S16), the power switch is turned off. Steps S11 and after are repeated (NO in step S17). If the power switch is off (YES in step S17), this process is performed. To completion.
[0040]
According to FIG. 3, the display update process is performed every predetermined display update time T0 (T0 = 125 ms) (FIG. 4), and the storage voltage Vdet of the capacitor 19 becomes equal to or higher than a predetermined threshold value Vth (1.5 V) (step (YES in S12) (FIG. 4B) When the value C of the non-update count counter becomes equal to or greater than the value CL of the non-update count latch (YES in step S13), the scale displacement amount is detected and the display of the detected value is updated. (Step S14) (Processes 1, 3, 4, 7, and 9 in FIG. 4C), the storage voltage Vdet of the capacitor 19 becomes less than the threshold Vth (NO in Step S12) (FIG. 4B), or When the value C of the non-update count counter becomes less than the value CL of the non-update count latch (NO in step S13), the scale displacement amount detection and the display value update are not performed (step S20). It is incremented by 1 the value C of the capacitor (C = C + 1) (step S21) (processing in FIG. 4 (c) 2,5,6,8).
[0041]
Number of times of decrement by 1 from the number of times when the scale displacement amount detection and the display value of the detected value are not continuously updated even when the storage voltage Vdet of the capacitor 19 is equal to or higher than the threshold value Vth (YES in step S12) (FIG. 4B). Only (step S18), the scale displacement amount detection and the display value display update are not performed (steps S13 and S20), and the number of times the scale displacement amount detection and the detection value display update are not performed is gradually reduced. (Processes 4, 7, and 9 in FIG. 4C), it is possible to prevent the user from feeling uncomfortable by eliminating the non-uniformity of the display update of the detected value.
[0042]
FIG. 5 is a flowchart showing a modification of the display update process of FIG.
[0043]
The processing in FIG. 5 is basically the same as the processing in FIG. 3, and the same steps are denoted by the same step numbers and redundant description is omitted, and only different portions are described below.
[0044]
In FIG. 5, when the storage voltage Vdet is less than the threshold value Vth as a result of determination in step S12 (NO in step S12), or as a result of determination in step S13, the value C of the non-update count counter is the value of the non-update count latch If it is less than CL (NO in step S13), it is determined whether or not the value C of the non-update count counter is greater than or equal to a predetermined non-update count maximum value Cmax (step S30). As a result of this determination, when the value C of the non-update count counter is equal to or greater than a predetermined non-update count maximum value Cmax (YES in step S30), the processing after step S14 is performed, while the value C of the non-update count counter is When it is less than the predetermined non-update count maximum value Cmax (NO in step S30), the processing after step S20 is performed.
[0045]
Note that when the non-update cycle becomes longer than 500 ms, the uncomfortable feeling (flickering feeling) given to the user becomes significant, so Cmax is set to 4 in this process.
[0046]
According to this modification, even if the storage voltage Vdet of the capacitor 19 is less than the threshold value Vth (NO in step S12), or the value C of the non-update count counter is less than the value CL of the non-update count latch (step If the display update process is not performed for a predetermined non-update count maximum value Cmax (YES in step S30), the display is forcibly updated (step S14), and the slider 12 is moved. Therefore, the display update is not performed, and it is possible to prevent the user from misidentifying that a failure has occurred.
[0047]
However, if the voltage detected by the voltage detection circuit 21 has dropped to a level at which the system operation becomes unstable as a result of such a forced display update, the detected value is controlled by the microcontroller 24. Can be processed so as to prevent erroneous measurement as much as possible.
[0048]
【The invention's effect】
As described above in detail, according to the apparatus of claim 1, even when the stored voltage detected by the voltage detecting means is equal to or higher than a predetermined voltage, the number of times that the display unit is paused to be updated per unit time is reduced. When the update of the display unit per unit time measured by a preset counting unit is less than the number of times decremented by 1 , the display unit is not updated, so the display is not updated. By gradually reducing the number of times , it is possible to eliminate the non-uniformity of the number of display updates and prevent the user from feeling uncomfortable when looking at the display unit.
[0050]
According to the displacement measuring apparatus of the second aspect , the updating means updates the display when the number of cycles in which the display is not updated (update pause) is equal to or greater than a predetermined maximum non-update count. By forcibly updating the display when a state below the voltage continues, it is possible to prevent display non-updating from continuing and prevent a user from misidentifying a device failure.
[Brief description of the drawings]
FIG. 1 is a front view of a displacement measuring apparatus according to an embodiment of the present invention.
FIG. 2 is a block diagram of an electronic circuit provided in the slider 12 in FIG.
FIG. 3 is a flowchart showing display update processing executed by a microcontroller 24 in FIG. 2;
4 is a timing chart according to the process of FIG.
FIG. 5 is a flowchart showing a modification of the display update process of FIG. 3;
FIG. 6 is a flowchart showing update speed setting switching processing of a conventional displacement measuring apparatus.
FIG. 7 is a timing chart of update speed setting switching processing of a conventional displacement measuring apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Solar cell type digital caliper 11 Main scale 12 Slider 13 Main scale 14 Scale 15 Electronic circuit 16 Displacement sensor 17 Display 18 Solar cell 19 Capacitor 21 Voltage detection circuit 22 Position detection circuit 23 Clock circuit 24 Microcontroller

Claims (5)

The movable element includes a fixed element and a movable element movable on the fixed element, and the movable element detects a solar cell, a power storage unit that stores power supplied from the solar cell, and a storage voltage of the power storage unit Voltage detecting means for detecting, voltage determining means for determining whether or not the detected stored voltage is equal to or higher than a predetermined voltage, displacement amount detecting means for detecting a displacement amount of the movable element with respect to the fixed element, a display unit for displaying a detected displacement amount by a predetermined number of times update per unit time, the conjunction detected power storage voltage when the above predetermined voltage is updated display the unit time granted Symbol predetermined number of the display unit, displacement measuring apparatus odor wherein when the detected storage voltage is less than the predetermined voltage and a updating means for pausing the updating of the display unit within a predetermined display update frequency per unit time ,
The update unit includes a counting unit that counts the number of times that the display unit is paused to be updated per unit time , and the update unit is configured to display the display unit per unit time even when the detected storage voltage is equal to or higher than the predetermined voltage . When the number of times of suspension of updating is less than the number of times decremented by 1 from the number of times of halting the updating of the display unit per unit time measured by the preset counting means , the display unit is updated. Displacement measuring device characterized by not. Said updating means, when more than the maximum non-impressions preset times to pause the updating of the display unit per unit time, the displacement measuring apparatus according to claim 1, wherein: performing the updating. Wherein the predetermined voltage, the displacement measuring apparatus according to claim 1 or 2, characterized in that it is capable of the voltage operation of the display unit. The displacement measuring apparatus according to any one of claims 1 to 3 , wherein the unit time is one second, and the number of times the display unit is updated per unit time is two or more . Displacement measuring device according to any one of claims 1 to 4, wherein the displacement measuring device is a hand tool.

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