JP2008014648A - measuring device - Google Patents

Abstract

A measuring apparatus capable of displaying a measurement result in an easily viewable manner.
A measurement unit for measuring an insulation resistance between conductor patterns on a circuit board in a predetermined measurement range and outputting a measurement value R0; and a lower digit of the measurement value R0 is an integer of a predetermined reference value S A control unit 13 that executes a rounding process for rounding the measurement value R0 so as to be doubled, and displays the processed value R1 after the rounding process on the display unit 16. The rounding process is executed by changing the reference value S according to the magnitude of R0.
[Selection] Figure 2

Description

  The present invention relates to a measuring apparatus configured to display a processing value obtained by executing a rounding process on a measurement value on a display unit.

As this type of apparatus, an inspection apparatus disclosed by the applicant in Japanese Patent Laid-Open No. 2001-91562 is known. This inspection device has a plurality of range resistors and converts the current flowing between the probes into a voltage by generating a voltage signal. The voltage signal output from the range resistor circuit is converted from analog to digital voltage data. A conductor pattern as a measurement object based on the A / D conversion circuit that generates the voltage, the voltage data output from the A / D conversion circuit (that is, the current value flowing between the probes), and the voltage value of the inspection voltage output to the probe Insulation inspection for circuit boards, etc. with an arithmetic circuit that calculates the insulation resistance value between them and a control circuit that performs switching control of the input range (measurement range) by switching range resistance and judgment processing of insulation quality Configured to be executable.
Japanese Patent Laid-Open No. 2001-91562 (page 4, FIG. 1)

  However, the above inspection apparatus has the following problems to be improved. That is, in this type of inspection apparatus, when a measurement value such as an insulation resistance value is displayed numerically (digital display) on the display unit, the display value is frequently switched due to the fluctuation of the measurement value, making it difficult to read. In order to avoid this, a rounding process is performed to round the measurement value so that the lower digit of the measurement value is an integral multiple of a predetermined reference value, and the processed value after the rounding process is displayed. In this case, the reference value is generally defined as one value for one measurement range.

  Here, it is assumed that the insulation resistance value is measured in the measurement range of 100 MΩ to 1000 MΩ using the inspection apparatus. In this case, assuming that the reference value is defined to be 10 MΩ for this measurement range, when the measurement value is about 100 MΩ, which is the lower limit value of the measurement range, the measurement value varies by about 1% due to the influence of noise or the like. However, since the fluctuation value (fluctuation amount) falls within the range of 1 MΩ to 2 MΩ, the display value is maintained at 100 MΩ. On the other hand, when the measured value is about 990 MΩ in the vicinity of the upper limit value of the measurement range, the measured value fluctuates by about 1% due to the influence of noise or the like, and the fluctuation value becomes about 9 MΩ. For this reason, when such a change occurs, as shown in FIG. 7, the display value fluctuates in the range of 980 MΩ to 1000 MΩ, for example.

  On the other hand, the insulation resistance value is calculated based on the current value flowing between the probes as described above and the voltage value of the inspection voltage output to the probe. In this case, if the insulation resistance value is R, the current value is I, and the voltage value is V, the relational expression of R = V / I is established. That is, when the voltage value is constant, the current value decreases as the insulation resistance value increases. For this reason, even if the amount of noise superimposed on the current flowing between the probes is constant, the closer the measured value of the insulation resistance value is to the upper limit value of the measurement range, the smaller the current value becomes, and the noise value for that current value becomes smaller. As a result of increasing the influence, the fluctuation value due to noise of the insulation resistance value (measured value) calculated based on the current value and the voltage value becomes large, and the tendency that the display value fluctuates becomes remarkable. Therefore, in this type of inspection apparatus including the above-described inspection apparatus, the display value tends to be difficult to read as the measured value is closer to the upper limit value of the measurement range, and improvement of this point is desired.

  In this case, a method of increasing the reference value is also conceivable, such as changing 10 MΩ in the above measurement example to 20 MΩ. However, when the reference value is increased, the difference value between the display value and the measurement value becomes too large in the vicinity of the lower limit value of the measurement range (for example, the difference value when the reference value is 20 MΩ in the above measurement example). May exceed 9%). Further, for example, in an apparatus that is stipulated in the JIS standard or the like that the difference value between the display value and the measured value is ± 5% or less, it is necessary to conform to this standard. Therefore, it is difficult to adopt this method.

  The present invention has been made in view of such problems, and a main object of the present invention is to provide a measuring apparatus that can easily display a measurement result.

  In order to achieve the above object, the measuring apparatus according to claim 1 is a measurement unit that measures a parameter of a measurement object in a predetermined measurement range and outputs a measurement value, and a lower digit of the measurement value is a predetermined reference value. And a control unit that executes a rounding process for rounding the measurement value so as to be an integer multiple of the rounding process and displays the processed value after the rounding process on a display unit, wherein the control unit includes the measurement Within the range, the rounding process is executed by changing the reference value according to the magnitude of the measured value.

  The measuring device according to claim 2 is the measuring device according to claim 1, wherein the reference value is such that an absolute value of a ratio of a difference value between the measured value and the processed value to the measured value is equal to or less than a predetermined value. It is prescribed to be.

  Further, in the measurement apparatus according to claim 3, in the measurement apparatus according to claim 2, the reference value is associated with each divided range obtained by dividing the measurement range into a plurality of ranges, and the control unit The rounding process is executed using the reference value associated with the divided range including the.

  According to the measuring apparatus of claim 1, the control unit changes the reference value according to the magnitude of the measurement value within the measurement range and executes the rounding process, so that a large reference is obtained when the measurement value is large. By using the value and rounding the measured value using a small reference value when the measured value is small, it is possible to prevent fluctuations in the processing value due to slight fluctuations in the measured value due to the influence of noise or the like. Therefore, according to this measuring apparatus, it is possible to surely avoid a situation in which the processing values are frequently switched and displayed, and the reading becomes difficult.

  In addition, according to the measuring apparatus of claim 2, by defining the reference value so that the absolute value of the ratio of the difference value between the measured value and the processed value to the measured value is equal to or less than a predetermined value, By making the prescribed value a predetermined value, the measuring device can be surely adapted to these standards.

  According to the measurement apparatus of claim 3, the reference value is associated with each divided range obtained by dividing the measurement range into a plurality of ranges, and the control unit is used using the reference value associated with the divided range including the measured value. By executing the rounding process, the processing value can be calculated simply by specifying the division range and reading the reference value associated with the division range. For example, an appropriate reference value according to the measurement value Can be executed in a short time compared to the configuration that is calculated when executing the rounding process.

  Hereinafter, the best mode of a measuring apparatus according to the present invention will be described with reference to the accompanying drawings.

  First, the configuration of the measuring apparatus 1 will be described with reference to the drawings. A measuring apparatus 1 shown in FIG. 1 is an example of a measuring apparatus according to the present invention. For example, each conductor pattern 201 (a pair of conductors in the figure) in the circuit board 200 (measurement object in the present invention) shown in FIG. The insulation resistance (parameter in the present invention) between the patterns 201 (only the pattern 201 is illustrated) can be measured. Specifically, as shown in FIG. 1, the measuring apparatus 1 includes a main body 2 and probes 3 and 3 configured to be connectable to the main body 2. As shown in FIG. 2, the main body unit 2 includes a power supply unit 11, a measurement unit 12, a control unit 13, an operation unit 14, a storage unit 15, and a display unit 16.

  The power supply unit 11 generates a measurement voltage V (for example, a DC voltage). The measurement unit 12 includes a current detection circuit 21, an A / D conversion circuit 22, and a measurement circuit 23. The current detection circuit 21 includes a plurality of switchable range resistors, and the measurement range Rm can be switched by switching the range resistors. The current detection circuit 21 converts the current I flowing between the probes 3 and 3 by the output of the voltage V from the power supply unit 11 into a voltage by converting the voltage I at a predetermined conversion rate defined in advance for each measurement range Rm. A signal Sv is generated. The A / D conversion circuit 22 generates voltage data Dv by performing analog-digital conversion on the voltage signal Sv output from the current detection circuit 21. The measurement circuit 23 measures the insulation resistance between the conductor patterns 201 and 201 based on the voltage data Dv output from the A / D conversion circuit 22 and the voltage value of the voltage V generated by the power supply unit 11, and the measured value R0 is output.

  In the control unit 13, the lower digits (for example, the last three digits of the integer part) of the measured value R 0 of the insulation resistance measured by the measuring circuit 23 of the measuring unit 12 are an integral multiple of the predetermined reference value S. A rounding process 50 (see FIG. 4) for rounding the measured value R0 is executed. Further, the control unit 13 causes the display unit 16 to display the processing value R1 calculated by executing the rounding process 50. As shown in FIG. 1, the operation unit 14 includes various switches such as a power switch 41, a range switch 42, and a measurement start switch 43, and is disposed on the front panel of the main body 2. The operation unit 14 outputs an operation signal corresponding to the switch operation.

  The storage unit 15 stores a reference value S used for the rounding process 50 executed by the control unit 13. In this case, as shown in FIG. 3, the storage unit 15 stores each of the divided ranges Rp1 to Rp4 (hereinafter referred to as “divided range Rp” when not distinguished) by dividing one measurement range Rm into a plurality (for example, four). The reference value S associated with each is stored. That is, in this measuring apparatus 1, a plurality of different reference values S are prepared for one measurement range Rm, and the control unit 13 is switched (selected) by the range changeover switch 42 of the operation unit 14. In the range of the measurement range Rm, the rounding process 50 is performed using the reference value S associated with the divided range including the measurement value R0 (by changing the reference value S according to the magnitude of the measurement value R0). Execute.

  Here, as described above, the larger the measured value R0, the smaller the value of the current I flowing between the probes 3 and 3, and the smaller the current I value, the greater the influence of noise and the like on the current I, and the measured value R0. The fluctuation value of becomes large. For this reason, in order to suppress the fluctuation (fluctuation) of the processing value R1, it is preferable to increase the reference value S as the measurement value R0 is larger in one measurement range Rm. Therefore, in this measuring apparatus 1, the reference value S that is larger as the numerical value (upper and lower limit values) of the divided range Rp is larger is associated with one measurement range Rm. As an example, as shown in FIG. 3, the reference value S of the divided range Rp2 is larger than the reference value S of the divided range Rp1, and the reference value S of the divided range Rp3 is larger than the reference value S of the divided range Rp2. The reference value S of the division range Rp4 is larger than the reference value S of Rp3. For this reason, in this measuring apparatus 1, even when the measurement value R0 is large, it is possible to suppress the fluctuation of the processing value R1 to be small. On the other hand, the ratio of the difference value R2 (that is, R1-R0) between the processing value R1 and the measurement value R0 to the measurement value R0, specifically, ((R1-R0) / R0 × 100)%. The JIS standard stipulates that the difference rate R3 should be 5% (an example of a predetermined value in the present invention) or less. For this reason, each reference value S is defined so as to conform to this standard.

  Next, a method for measuring insulation resistance using the measuring apparatus 1 will be described with reference to the drawings.

  First, as illustrated in FIG. 1, by operating the range changeover switch 42 of the operation unit 14, for example, “100 to 1000 MΩ” (exactly, a range of 100 MΩ to less than 1000 MΩ) is selected as the measurement range Rm. Next, as shown in FIG. 2, probes 3 and 3 are brought into contact with a pair of conductor patterns 201 and 201 on a circuit board 200 as a measurement object. Subsequently, the measurement start switch 43 of the operation unit 14 is operated. In response to this, the power supply unit 11 generates a measurement voltage V, and the voltage V is output to the conductor patterns 201 and 201 via the probes 3 and 3. Next, the current detection circuit 21 of the measurement unit 12 converts the current I flowing between the probes 3 and 3 by the output of the voltage V at a conversion rate associated with the measurement range Rm to generate a voltage signal Sv. .

  Subsequently, the A / D conversion circuit 22 of the measurement unit 12 generates voltage data Dv by performing analog-digital conversion on the voltage signal Sv output from the current detection circuit 21. Next, the measurement circuit 23 of the measurement unit 12 measures the insulation resistance between the conductor patterns 201 and 201 based on the voltage data Dv output from the A / D conversion circuit 22 and the voltage value of the voltage V, thereby measuring the measured value R0. Is output. Subsequently, the control unit 13 executes a rounding process 50 shown in FIG. In this rounding process 50, the control unit 13 specifies the divided range Rp in which the measurement value R0 is included in the measurement range Rm (step 51). In this case, for example, when the measurement value R0 is 104 MΩ, the control unit 13 specifies the division range Rp1 (see FIG. 3) as the division range Rp including the measurement value R0.

  Next, the control unit 13 reads the reference value S (in this case, “5”) corresponding to the specified division range Rp1 from the storage unit 15 (step 52). Subsequently, the control unit 13 calculates a processing value R1 (step 53). Specifically, as an example, the control unit 13 divides the measured value R0 (104) by the reference value S (5), and rounds off the decimal value of the divided value (104 ÷ 5 = 20.8). The processing value R1 (21 × 5 = 105) is calculated by multiplying (21) by the reference value S. Next, the control unit 13 controls the display unit 16 to display the processing value R1 as shown in FIG. 1 (step 54), and ends the rounding processing 50.

  Next, the probes 3 and 3 are brought into contact with the other pair of conductor patterns 201 and 201, respectively, and the measurement start switch 43 is operated. In response to this, the power supply unit 11 and the measurement unit 12 operate in the same manner as described above, whereby the measurement value R0 is output from the measurement circuit 23 of the measurement unit 12. Next, the control unit 13 executes a rounding process 50. In this case, for example, when the measured value R0 is 307 MΩ, the control unit 13 specifies the divided range Rp2 (see FIG. 3) as the divided range Rp including the measured value R0 (step 51).

  Subsequently, the control unit 13 reads the reference value S (in this case, “10”) corresponding to the specified division range Rp1 from the storage unit 15 (step 52). That is, the reference value S is changed according to the magnitude of the measured value R0. Next, the control unit 13 divides the measured value R0 (307) by the reference value S (10), and rounds off the decimal point of the divided value (307 ÷ 10 = 30.7) to the reference value (31). A processing value R1 (31 × 10 = 310) is calculated by multiplying S (step 53). Subsequently, the control unit 13 displays the processing value R1 on the display unit 16 (step 54), and ends the rounding processing 50.

  Similarly, the probes 3 and 3 are brought into contact with the pair of conductor patterns 201 and 201 on the circuit board 200 while changing the combination, and the insulation resistance between the conductor patterns 201 and 201 is sequentially measured. In this case, for example, when the measurement value R0 measured (output) by the measurement unit 12 is 603 MΩ, the control unit 13 in the rounding process 50 uses the division range Rp3 (see FIG. 3) as the division range Rp including the measurement value R0. ) Is specified, and “20” as the reference value S corresponding to the divided range Rp3 is read from the storage unit 15. That is, the reference value S is changed according to the magnitude of the measured value R0. Next, the control unit 13 calculates the processing value R1 as “600” using the reference value S (see FIG. 5).

  For example, when the measurement value R0 measured by the measurement unit 12 is 864 MΩ, the control unit 13 specifies the division range Rp4 (see FIG. 3) as the division range Rp including the measurement value R0 in the rounding process 50. Then, “50” as the reference value S corresponding to the division range Rp4 is read from the storage unit 15. That is, the reference value S is changed according to the magnitude of the measured value R0. Next, the control unit 13 calculates the processing value R1 as “850” using the reference value S (see FIG. 5). In this case, as described above, since the reference value S is defined so as to conform to the JIS standard, the difference rate R3 between the processing value R1 and the measured value R0 is suppressed to 5% or less as shown in FIG. It has been.

  On the other hand, when the measurement value R0 is about 990 MΩ near the upper limit value of the measurement range Rm, the control unit 13 reads “50” as the reference value S corresponding to the division range Rp4 from the storage unit 15 in the rounding process 50. That is, the reference value S is changed according to the magnitude of the measured value R0. Next, the control unit 13 calculates a processing value R1 using the reference value S. In this case, in order to round the measurement value R0 using “50” which is a reference value S larger than the reference values S (“5”, “10” and “20”) associated with the other division ranges Rp. As shown in FIG. 6, even if the measurement value R0 fluctuates by about 1% (about 9 MΩ) due to the influence of noise or the like, the control unit 13 calculates the processing value R1 as “1000”. Therefore, as a result of the processing value R1 displayed on the display unit 16 being kept constant, a situation in which the processing value R1 is frequently switched and displayed and is difficult to read is reliably avoided.

  As described above, according to the measurement apparatus 1, the control unit 13 changes the reference value S according to the magnitude of the measurement value R0 within the measurement range Rm, and executes the rounding process 50. When the value R0 is large, the large reference value S is used, and when the measurement value R0 is small, the small reference value S is used to round the measurement value R0, thereby processing values due to slight fluctuations in the measurement value R0 due to the influence of noise or the like. Variations in R1 can be prevented. Therefore, according to this measuring apparatus 1, it is possible to reliably avoid a situation in which the processing value R1 is frequently switched and displayed and it becomes difficult to read.

  Further, according to this measuring apparatus 1, the storage unit 15 defines that the absolute value of the ratio (difference rate R3) of the difference value R2 between the measurement value R0 and the processing value R1 to the measurement value R0 is equal to or less than a predetermined value. The control unit 13 reads the reference value S from the storage unit 15 and executes the rounding process 50, thereby setting the value defined in the JIS standard or the like as a predetermined value. The measuring device 1 can be reliably adapted to these standards.

  Moreover, according to this measuring apparatus 1, the memory | storage part 15 memorize | stores the reference value S each matched with each division | segmentation range Rp which divided | segmented the measurement range Rm into plurality, and the control part 13 contains the measurement range Rm. By reading the reference value S associated with the divided range Rp to be read from the storage unit 15 and executing the rounding process 50, the division range Rp is identified and the reference value S associated with the divided range Rp is read out. Since the processing value R1 can be calculated by, for example, the rounding process 50 is executed in a short time compared to a configuration in which an appropriate reference value S corresponding to the measurement value R0 is calculated when the rounding process 50 is executed. Can do.

  In addition, this invention is not limited to said structure. For example, although the example in which one measurement range Rm is divided into four division ranges Rp has been described above, it can be divided into any number of division ranges Rp of two or more (preferably three or more). Further, the example in which the reference value S stored in the storage unit 15 is read and the measurement value R0 is rounded using the reference value S has been described above. However, the control unit 13 performs the rounding process 50 according to the measurement value R0. It is also possible to adopt a configuration in which an appropriate reference value S is calculated and the measurement value R0 is rounded using the reference value S.

  Further, although the example of measuring the insulation resistance between the conductor patterns 201 and 201 of the circuit board 200 has been described above, the measuring device 1 can also be used for measuring the leakage current (another example of the parameter in the present invention). Further, the measurement apparatus 1 is not limited to the circuit board 200, and the measurement apparatus 1 can also be used for measuring insulation resistance and leakage current with respect to various electric components such as capacitors (measurement object in the present invention).

1 is an external perspective view of a measuring device 1. FIG. 1 is a configuration diagram showing a configuration of a measuring device 1. FIG. It is explanatory drawing for demonstrating the relationship between the division | segmentation range Rp and the reference value S. FIG. 5 is a flowchart of a rounding process 50. It is explanatory drawing for demonstrating the relationship of measured value R0, the reference value S, process value R1, and difference rate R3. It is explanatory drawing for demonstrating the relationship between the measured value R0 in the vicinity of the upper limit of a measurement range, the reference value S, the process value R1, and the difference rate R3. It is explanatory drawing for demonstrating the relationship between the measured value in the conventional apparatus, a reference value, and a display value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Measuring apparatus 12 Measuring part 13 Control part 15 Memory | storage part 16 Display part 50 Rounding process 200 Circuit board R0 Measurement value R1 Process value R2 Difference value R3 Difference ratio Rm Measurement range Rp1-Rp4 Division | segmentation range S Reference value

Claims (3)

A measurement unit that measures a parameter of a measurement object in a predetermined measurement range and outputs a measurement value, and a rounding process that rounds the measurement value so that the lower digit of the measurement value is an integral multiple of a predetermined reference value A measuring device including a control unit that executes and displays the processed value after the rounding process on the display unit,
The said control part is a measuring device which changes the said reference value according to the magnitude | size of the said measured value within the range of the said measurement range, and performs the said rounding process.   The measurement apparatus according to claim 1, wherein the reference value is defined such that an absolute value of a ratio of a difference value between the measurement value and the processing value to the measurement value is a predetermined value or less. The reference value is associated with each divided range obtained by dividing the measurement range into a plurality of ranges,
The measurement apparatus according to claim 2, wherein the control unit performs the rounding process using the reference value associated with the division range in which the measurement value is included.

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