JP3705020B2 - Measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a measurement device, and more particularly, to a measurement device suitable for measuring, for example, the dimensions of a measurement object such as a workpiece based on the output of a linear sensor in synchronization with a trigger signal from a timing sensor. .
[0002]
[Prior art]
Conventionally, in this type of measuring apparatus, as shown in the schematic configuration diagram of FIG. 12, a workpiece 11 that is a measurement object conveyed to a predetermined measurement position is detected by a timing sensor 12, and the timing sensor 12 In some cases, the height of the workpiece 11 is measured based on the output of the linear sensor 13 in synchronization with the trigger signal and compared with a preset comparison value (tolerance) to determine whether the workpiece 11 is good or bad. .
[0003]
[Problems to be solved by the invention]
However, such a conventional measuring apparatus measures the period during which the trigger signal is input as a measurement period. For example, when measuring the height of a part of the workpiece 11 to be conveyed or the like. However, it is not easy to set the timing of measurement, and the installation position of the timing sensor 12 must be actually shifted and adjusted so as to be at a desired timing, so that adjustment work is troublesome.
[0004]
The present invention has been made in view of the above points, and is intended to facilitate adjustment of measurement timing without requiring troublesome work such as adjustment of the installation position of the timing sensor. Objective.
[0005]
[Means for Solving the Problems]
The present invention is configured as follows in order to achieve the above-described object.
[0006]
That is, the measuring device according to claim 1 is a measuring device that measures a measurement object based on an output of a sensor and starts and ends the measurement based on an input of a trigger signal. the timing of termination, comprising a setting means is operated to set a reference to at least one of the input start and end of input timing of the trigger signal, and a measuring means for performing measurements at set timings, said setting means Is capable of setting the start and end timing of the measurement at any timing before or after the reference, and the measuring means has a maximum setting range set before the reference. When the corresponding measurement data is provided with a memory capable of being updated and stored, and set by the setting means at a timing before the reference Is the measurement data corresponding to the set width is for updating stored in the memory.
[0007]
According to a second aspect of the present invention, the measuring device according to the first aspect of the present invention is based on the subtracting means for subtracting a preset reference value from the measured value, and the quality of the measurement object based on the measured value subtracted by the subtracting means. And a correction unit that corrects the reference value using a measurement value of the measurement object determined to be good.
[0008]
According to a third aspect of the present invention, there is provided the measuring device according to the first or second aspect, wherein the measuring device measures a measurement object while changing a measurement position, and holds a measurement value in a measurement period based on the trigger signal. A counting means for counting pulses from the pulse generating means for generating a pulse in response to a change in the measurement position in the measurement period, and a pulse count value corresponding to the measurement value held by the hold means Storage means for outputting, and output means for outputting the stored count value.
[0011]
(Function)
According to the measuring apparatus according to claim 1, the start and end of timing measurements on the basis of the trigger signal, can be adjusted by the setting operation, troublesome had to adjust by shifting the installation position of the timing sensor as in the conventional Work becomes unnecessary. In addition, since at least one of the trigger signal input start timing and input timing timing is set as a reference, the measurement timing can be easily adjusted. Furthermore, since the timing for starting and ending the measurement can be set before or after the reference, the timing can be adjusted over a wide range.
[0012]
According to the measuring apparatus of claim 2, the reference value is subtracted from the measured value to determine pass / fail, and the reference value is corrected using the measured value when determined to be good. Even if the output of the sensor fluctuates gently, the reference value will be corrected using the measured value obtained according to the fluctuation. Therefore, it is necessary to reset the reference value according to the fluctuation of the ambient temperature. Absent.
[0013]
According to the measurement device of claim 3, for example, when the measurement position changes as in the case of measuring a moving measurement object, the pulse corresponding to the measurement position is counted and the measured value held, for example, Since the count value of the pulse corresponding to the held maximum value can be stored and output, the measurement value held, for example, the measurement position of the measurement object corresponding to the maximum value can be grasped from the count value of the pulse.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0017]
FIG. 1 is a front view of a measuring apparatus according to one embodiment of the present invention, and FIG. 2 is a block diagram of the inside thereof.
[0018]
The measurement apparatus 1 of this embodiment includes a liquid crystal display unit 2 on the front, and the liquid crystal display unit 2 includes a determination output display unit 2a that displays a result of pass / fail determination in the measurement mode, a current value, and the like. Function names assigned to a plurality of function keys 3 constituting the setting means below the current value display section 2b to be displayed, a tolerance display section 2c to display a set tolerance (comparison value), and a liquid crystal display section 2 The key function name display unit 2d to be displayed is configured. In the set mode, a menu display unit to display a setting menu, a setting parameter, and the like is configured. Reference numeral 4 denotes a shift key.
[0019]
As shown in FIG. 2, the measuring apparatus 1 according to this embodiment includes an input circuit 5 to which an output of a displacement sensor is given, an A / D conversion circuit 6 for A / D converting the output of the input circuit 5, and a timing. A control input circuit 17 to which a trigger signal from a sensor is given, a waveform shaping circuit 7 that takes in an output of the control input circuit 17 via a photocoupler and shapes the waveform, and an output circuit 8 that outputs the above-described determination output The above-described keys 3 and 4 and the liquid crystal display unit 2 and a microcomputer 9 for performing measurement and processing described later and controlling each unit are provided.
[0020]
FIG. 3 is a diagram showing a schematic configuration of a measurement system using the measurement apparatus 1 of this embodiment, and portions corresponding to the conventional example of FIG. 12 are denoted by the same reference numerals.
[0021]
This measurement system measures the height of the workpiece 11 as a measurement object conveyed on the conveyor 10 in the direction of the arrow, and determines pass / fail. The measurement apparatus 1 according to the present invention, a proximity sensor, etc. Timing sensor 12 and a displacement sensor (linear sensor) 13 using a laser or ultrasonic wave for detecting a distance (length).
[0022]
The measuring apparatus 1 of this embodiment measures the height l of the workpiece 11 based on the output of the displacement sensor 13 over a period in which the trigger signal from the timing sensor 12 is input.
[0023]
Here, for example, when it is desired to measure a part of the work 11, the timing adjustment is performed so that the displacement sensor 13 detects the part of the work 11 during the period when the trigger signal from the timing sensor 12 is input. Conventionally, as described above, this is performed by adjusting the installation position of the timing sensor 12 by shifting the position.
[0024]
In this embodiment, the following arrangement is made so that the timing can be easily adjusted without performing the troublesome work of adjusting the installation position of the timing sensor 12 by shifting it.
[0025]
That is, the trigger adjustment mode is set by operating the keys 3 and 4 described above, and the measurement start and end timings are set with reference to the trigger signal input start or input timings T1 and T2 shown in FIG. In the actual measurement mode after this setting is made, the microcomputer 9 as the measuring means is based on the input of the trigger signal. The measurement is started and ended at the timing set as.
[0026]
Next, a specific example of timing adjustment will be described. In FIG. 5, the measurement start timing is set to be delayed by 15 msec from the trigger signal input, the measurement end timing is set to be delayed by 30 msec from the trigger signal input end, and the peak hold for holding the maximum value of the measurement period is further set. An example of the case is shown.
[0027]
(A) is a measured value, (b) is a trigger signal from a timing sensor, (c) is an H comparison output, (d) is a PASS comparison output, and (e) is an L comparison. The comparison operation is performed at the end of the measurement. When the maximum value exceeds the H comparison value (H tolerance), the H comparison output is turned ON and the maximum value is the L comparison value (L tolerance). ), The L comparison output is turned ON, and when the H comparison output and the L comparison output are OFF, the PASS comparison output is turned ON.
[0028]
As shown in FIG. 5, when a trigger signal is input, measurement is started with a delay of 15 msec, which is a timing set from this input, and when the trigger signal is no longer input, at a timing set from that timing. The measurement ends with a delay of 30 msec, and the maximum value in the measurement period is held.
[0029]
FIG. 6 is a flowchart for explaining the operation of FIG. 5. It is determined whether or not a trigger signal is input (step n1), and when it is input, whether or not a set time, for example, 15 msec has elapsed since this input. (Step n2), when it has elapsed, the measurement is started and the maximum value is held (step n3), and it is determined whether or not the input of the trigger signal is completed (step n4). If not, the process returns to step n3 to continue the measurement. When the input is completed, it is determined whether or not a set time, for example, 30 msec has elapsed since the end of the input (step n5), and the set time has not elapsed. Sometimes, returning to step n3, the measurement is continued, and when the set time has elapsed, the held maximum value is output to prepare for the next measurement (step n6). .
[0030]
In FIG. 5 and FIG. 6, the start and end timings of the measurement are delayed to a later timing with respect to the trigger signal, but the present invention is advanced to the earlier timing with respect to the trigger signal. You may do it.
[0031]
FIG. 7 is a flowchart for explaining the operation when the measurement start timing is advanced with reference to the trigger signal input timing.
[0032]
In this case, a memory capable of storing sampling data corresponding to the maximum set width to be advanced is provided, and sampling data corresponding to the set width is constantly updated and stored in the memory before the trigger signal is input. In addition, when a trigger signal is input, the previous sampling data corresponding to the set width is held from the input timing.
[0033]
That is, the sampling data corresponding to the set width is updated and stored in the memory (step n1), it is determined whether or not a trigger signal has been input (step n2). At the same time, the maximum value of the memory and the measured data is held (step n3), and it is determined whether or not the input of the trigger signal is completed (step n4), and when it is completed, the held maximum value is output. Then, in preparation for the next measurement (step n5), when the measurement is not completed, the process returns to step n3 to continue the measurement.
[0034]
Similarly, the measurement end timing may be set earlier than the trigger signal input end timing.
[0035]
In this case, a memory capable of storing sampling data corresponding to the maximum set width to be advanced is provided, and the sampling data corresponding to the set width is updated and stored in this memory, and the old sampling data immediately before being rewritten is stored in this memory. In this way, at the timing when the trigger signal input ends, it is configured to measure with the previous sampling data by the set width, and at the timing when the trigger signal input ends. The sampling data in the memory is canceled.
[0036]
Moreover, the measuring apparatus 1 of this embodiment has the following new functions in addition to the timing adjustment of the start and end of measurement.
[0037]
In a conventional measuring apparatus, when a plurality of types of workpieces having the same tolerance are switched and flowed on a line, the workpiece is measured with a reference height of 100 mm and tolerances of +0.1 and -0.2. Dimensional error without changing the tolerance when the workpiece is switched to the second workpiece with a tolerance of +0.1 or -0.2 and the second workpiece with a tolerance of +0.1 or -0.2. In order to make it possible to change the setup simply by flowing a reference workpiece with a zero and teaching the measured value as a center value (reference value), there is a type having a so-called forced zero function.
[0038]
That is, when the measurement is performed with the first workpiece flowing, the measurement is performed by flowing a reference workpiece having a height of 100.0 with a dimensional error of 0, teaching the measured value as the center value, and setting the forced zero. By doing so, in the subsequent actual measurement, the center value (100.0) is subtracted from the measured value, and the value is compared with the preset tolerances +0.1 and -0.2. In the case of measuring by switching from the first workpiece to the second workpiece, measurement is performed with a reference workpiece having a height of 50.0 with a dimensional error of 0, and the measured value is set as the center value. By teaching and performing a forced zero setting operation, the center value (50.0) is subtracted from the measured value in the subsequent actual measurement, and the value is set to a preset tolerance +0.1, Compared with -0.2, pass / fail is determined And than, whereby, whenever the reference height is measured different work, in which eliminate the need for setting change tolerance.
[0039]
By the way, the displacement sensor 13 has poor temperature characteristics, and its output fluctuates due to changes in the ambient temperature. For example, in the morning, noon, and evening, the output value slightly changes even when a workpiece having the same height is measured. Therefore, when performing highly accurate measurement, according to the change in the ambient temperature, for example, in the morning, noon, and evening, the above-mentioned reference work must be run to teach the center value again. It was troublesome.
[0040]
Therefore, in this embodiment, the influence of fluctuations in the output of the displacement sensor due to a gentle change in the ambient temperature such as morning, noon, and evening is eliminated by correcting the center value set in advance by the reference workpiece. Yes.
[0041]
That is, in this embodiment, when the forced zero correction mode is set in the forced zero function described above, the center value (reference value) set by the reference workpiece is corrected using the measured value determined to be non-defective. Yes, for example, if the measured value determined to be non-defective tends to shift higher, the center value is corrected to be higher, assuming that the output of the displacement sensor has changed due to the ambient temperature and the measured value has increased. On the other hand, if the measured value determined to be non-defective tends to shift to a lower value, the center value is corrected to a lower value, assuming that the output of the displacement sensor changes due to the ambient temperature and the measured value becomes lower. .
[0042]
FIG. 8 is a flowchart showing an example of the correction operation in the forced zero function.
[0043]
First, when the measured value A is obtained (step n1), the microcomputer 9 having functions as a subtracting unit and a correcting unit obtains a measured value (center value) and a sign obtained by measuring the reference workpiece from the measured value A. Conversely, the zero value ZRn having the same absolute value is added, that is, the measurement value (center value) of the reference workpiece is subtracted from the measurement value A (step n2), and the value D (= A + ZRn) is within the tolerance. (Step n3), if it is not within the tolerance, output a judgment output and return to step n1 (step n6), and if within the tolerance, output a judgment output indicating that the product is non-defective (step n4). . The above steps are the same as the conventional forced zero function.
[0044]
In this embodiment, when it is determined that the product is a non-defective product, the zero value corresponding to the measured value (center value) obtained by the measurement of the reference workpiece is further corrected. (Step n5).
[0045]
ZRn + 1 = α × ZRn + (1−α) × (−A)
Here, α is a weight of the past zero value, and is, for example, 0.9.
[0046]
In this way, the past zero value is corrected with the measured value of the non-defective product, and accordingly, the zero value is automatically corrected according to the change in the output of the displacement sensor 13 accompanying the change in the ambient temperature. As in the prior art, for example, there is no need to frequently measure the reference workpiece and reset the zero value, such as in the morning, noon, and evening.
[0047]
Furthermore, in this embodiment, a terminal portion for connecting the encoder is provided on the back surface of the measuring device 1, and during the measurement period of the workpiece 11 by the displacement sensor 13, the pulse from the encoder is counted and the maximum value or A function is provided for storing and displaying a count value corresponding to a hold value such as a minimum value.
[0048]
Note that the count value may be read by an external computer or the like by communication.
[0049]
In the conventional measuring device, for example, the maximum value is held in the measurement period, but it is difficult to find which point of the workpiece the held maximum value is, and the workpiece determined to be defective. It was difficult to know which part of the throat was out of tolerance.
[0050]
Therefore, in this embodiment, for example, as shown in FIG. 9, an encoder 16 is installed on the rotary shaft 15 of the belt conveyor 10 on which the workpiece 11 is conveyed, and the output is taken into the measuring device 1. As shown in the time chart of FIG. 10, when measurement is started by the trigger signal of FIG. 10B, counting of pulses from the encoder 16 is started, and when the maximum value is held, The count value of the pulse corresponding to the hold value, for example, 2005 is stored, and the count value of the pulse at that time is output together with the maximum value output, for example, 62.3, after the measurement period ends. ing.
[0051]
For example, if the encoder 16 outputs C pulses per rotation of the rotating shaft 15 of the belt conveyor 10 and the radius from the center of the shaft to the conveyor is r, 2πr = C, so that 2πr / per pulse. This corresponds to the length of the belt conveyor 10 of C, and thus the length of the workpiece 11.
[0052]
Therefore, for example, the length from the count value of the pulse when the maximum value is held to the point of the maximum value of the workpiece, that is, the length from the detection end of the workpiece to which the trigger signal is input to the point of the maximum value. I can know.
[0053]
FIG. 11 is a flowchart for explaining the operation of counting the encoder pulses.
[0054]
For example, in the case of the maximum value hold, first, the maximum value memory storing the measurement value and the count value memory storing the pulse count value are both cleared and initialized (step n1), and the trigger signal is input. It is determined whether or not there is an input (step n2). When there is an input, the measurement is started and the pulses from the encoder 16 are counted (step n3), and the measured value is determined from the value written in the maximum value memory. (Step n4), if so, the value in the maximum value memory is rewritten to the measured value, and the value in the count value memory is rewritten to the pulse count value corresponding to the measured value. Then, the process proceeds to step n6 (step n5), and if not larger, the process proceeds to step n6 without rewriting.
[0055]
In step n6, it is determined whether or not the input of the trigger signal has been completed (step n6). If not completed, the process returns to step n3 to continue measurement and counting. The maximum value and the count value of the count value memory are output to prepare for the next measurement (step n7).
[0056]
Since the count value of the pulse corresponding to the maximum value held in this way is output, by using this count value as position information for specifying the measurement position of the workpiece, the measurement position of the maximum value of the workpiece can be determined. Can be identified.
[0057]
In the above-described embodiment, the timing for starting or ending the measurement is set based on the timing for starting and ending the input of the trigger signal. However, as another embodiment of the present invention, the timing for starting the input of the trigger signal is used. The measurement timing may be set based on only the reference, or the measurement timing may be set only based on the trigger signal input end timing.
[0058]
【The invention's effect】
As described above, according to the present invention, the following effects can be obtained.
[0059]
That is, according to the present invention of claim 1, the start and end of timing measurements on the basis of the trigger signal, can be adjusted by the setting operation, it had to adjust by shifting the installation position of the timing sensor as in the conventional Troublesome work becomes unnecessary. In addition, since at least one of the trigger signal input start timing and input timing timing is set as a reference, the measurement timing can be easily adjusted. Furthermore, since the timing for starting and ending the measurement can be set before or after the reference, the timing can be adjusted over a wide range.
[0060]
According to the measuring apparatus of claim 2, the reference value is subtracted from the measured value to determine pass / fail, and the reference value is corrected using the measured value when determined to be good. Even if the output of the sensor fluctuates gently, the reference value will be corrected using the measured value obtained according to the fluctuation. Therefore, it is necessary to reset the reference value according to the fluctuation of the ambient temperature. Absent.
[0061]
According to the measurement device of claim 3, for example, when the measurement position changes as in the case of measuring a moving measurement object, the pulse corresponding to the measurement position is counted and the measured value held, for example, Since the count value of the pulse corresponding to the held maximum value can be stored and output, the measurement value held, for example, the measurement position of the measurement object corresponding to the maximum value can be easily grasped from the count value of the pulse. .
[Brief description of the drawings]
FIG. 1 is a front view of a measuring apparatus according to an embodiment of the present invention.
FIG. 2 is a block diagram of the measuring apparatus of FIG.
FIG. 3 is a schematic configuration diagram of a measurement system including the measurement apparatus of the present invention.
FIG. 4 is a waveform diagram showing timing adjustment based on a trigger signal.
FIG. 5 is a time chart for explaining operations;
FIG. 6 is a flowchart for explaining the operation.
FIG. 7 is a flowchart for explaining the operation.
FIG. 8 is a flowchart for explaining the operation.
FIG. 9 is a schematic configuration diagram of a measurement system including the measurement device of the present invention.
FIG. 10 is a time chart for explaining the operation.
FIG. 11 is a flowchart for explaining the operation;
FIG. 12 is a schematic configuration diagram of a conventional measurement system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Measuring apparatus 2 Liquid crystal display part 9 Microcomputer 11 Workpiece | work 12 Timing sensor 13 Displacement sensor 16 Encoder

Claims (3)

A measurement device that measures a measurement object based on an output of a sensor and starts and ends the measurement based on an input of a trigger signal,
Setting means operated to set the timing of the start and end of the measurement based on at least one of the input start timing and the input end timing of the trigger signal ;
Measuring means for measuring at a set timing ,
The setting means can set the timing of the start and end of the measurement at any timing before or after the reference,
The measurement unit includes a memory capable of updating and storing measurement data corresponding to a maximum setting range set before the reference, and when the setting unit sets the timing before the reference. A measurement apparatus that updates and stores measurement data corresponding to the set width in the memory . Subtracting means for subtracting a preset reference value from the measured value;
Based on the measurement value subtracted by the subtraction means, determination means for determining the quality of the measurement object;
Correction means for correcting the reference value using the measurement value of the measurement object determined to be good;
The measuring device according to claim 1, comprising: Measuring the measurement object while changing the measurement position,
Holding means for holding a measurement value in a measurement period based on the trigger signal;
Counting means for counting the pulses from the pulse generating means for generating a pulse in response to a change in the measurement position in the measurement period;
Storage means for storing a count value of a pulse corresponding to the measurement value held by the hold means;
Output means for outputting the stored count value;
The measuring device according to claim 1 or 2 .

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