JP2013242251A - Continuity testing apparatus and continuity testing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuity testing apparatus capable of performing continuity testing with a desired detection accuracy.SOLUTION: A portable digital multi-meter 1 includes: a threshold memory part in which a threshold for continuity determination is changeably set; switches 6a, 6b for threshold setting operation for operating setting of the threshold to the threshold memory part; a resistance measurement part which measures a resistance value of a test object; a comparison part which outputs continuity detection signals when the resistance value is less than the threshold in comparison between the resistance value and the threshold; and a buzzer 15 which performs notification of output of the continuity detection signals.

Description

  The present invention relates to a continuity inspection apparatus and a continuity inspection method for inspecting the presence or absence of continuity of a test object.

  A continuity testing device such as a portable digital multimeter is used to check for breaks and shorts in printed circuit board pattern wiring, to check the connection between printed circuit board pads and mounted component terminals, and to check the wiring harness connection. ing. The continuity inspection device is configured to notify a measurer by sounding a buzzer or turning on a lamp when an inspection object such as a pattern wiring is conductive. Such a continuity inspection apparatus is described in Patent Document 1, for example.

  In the continuity inspection device (continuity inspection machine) of Patent Document 1, when a zero ohm or a circuit close to zero ohm is connected as a circuit to be inspected, the LED emits light and the buzzer sounds.

JP 2005-17263 A

  The threshold value (resistance value) for determining the continuity for determining that the continuity testing device is conductive differs depending on the device manufacturer and model, and is not unified. For this reason, depending on the model of the continuity test apparatus, the buzzer may sound as it is conductive even if it is the same measurement object, or the buzzer may not sound as it is not conductive. For example, in a model having a threshold value for continuity determination of 20Ω, a buzzer does not sound even when a continuity test is performed on a 30Ω wiring. On the other hand, a buzzer sounds for a model with a threshold value for continuity determination of 50Ω. Therefore, the continuity test may not be performed with the detection accuracy expected by the measurer depending on the model.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a continuity inspection apparatus and a continuity inspection method capable of performing detection accuracy of continuity inspection with desired accuracy.

  The continuity testing device according to claim 1, which has been made to achieve the above object, includes a threshold value storage unit in which a threshold value for continuity determination is set to be changeable, and the threshold value storage unit. When the resistance value is equal to or less than the threshold value by comparing the resistance value with the threshold value, the threshold value setting operation unit for performing an operation for setting the threshold value, the resistance measuring unit for measuring the resistance value of the test object A comparison unit that outputs a continuity detection signal and a notification unit that notifies the output of the continuity detection signal.

  The continuity test apparatus according to claim 2 is the one according to claim 1, wherein the threshold value storage unit stores in advance a plurality of candidate values that can be the threshold value, and the threshold value setting operation unit is operated. Thus, one of the plurality of candidate values is selected as the threshold value and set in the threshold value storage unit.

  The continuity testing device according to claim 3 is the one according to claim 1 or 2, and the maximum value that can be set in the threshold value storage unit as the threshold value by the operation of the threshold value setting operation unit is at least 1 kΩ. It is characterized by being.

  According to a fourth aspect of the present invention, there is provided the continuity test apparatus according to any one of the first to third aspects, further comprising a display unit that displays the resistance value and the threshold value.

  According to a fifth aspect of the present invention, there is provided the continuity testing apparatus according to any one of the first to fourth aspects, wherein each of the parts is accommodated in a portable housing.

  The continuity inspection method described in claim 6 includes a threshold value storage unit in which a threshold value for continuity determination is set to be changeable, a threshold value setting operation unit for performing an operation of setting the threshold value in the threshold value storage unit, A resistance measurement unit that measures the resistance value of the object to be inspected, a comparison unit that compares the resistance value with the threshold value and outputs a continuity detection signal when the resistance value is less than or equal to the threshold value; and A continuity inspection method using a continuity inspection apparatus including an informing unit for informing an output, wherein the threshold value setting operation unit is operated to set the threshold value in the threshold value storage unit, and then the measurement of the inspection object A value is measured, and a continuity test is performed based on the presence or absence of notification from the notification unit.

  According to the continuity test apparatus of the present invention, the threshold value for the continuity test can be changed and set, so that the detection accuracy of the continuity test can be performed with desired accuracy. Therefore, for example, even if the model is changed from a continuity inspection apparatus to which the present invention is not applied to a continuity inspection apparatus to which the present invention is applied, the accuracy of the continuity inspection can be adjusted by adjusting the threshold value.

  When a threshold value is selected from a plurality of candidate values that can be the threshold value, the threshold value can be quickly set by a simple operation.

  When the maximum value that can be set as the threshold value is at least 1 kΩ, not only the continuity test but also a resistance value test such as whether the resistance value of the circuit is, for example, 1 kΩ or less can be performed. The inspection result can be known by notification from the notification unit.

  When the display unit for displaying the resistance value and the threshold value is provided, the measurer can conveniently see the measurement value and the set threshold value, which is convenient. In addition, when a portable housing is provided, continuity inspection can be performed at various measurement sites, which is very convenient.

1 is a front external view of a portable digital multimeter to which the present invention is applied. It is a block diagram of the state which act | operated the portable digital multimeter of FIG. 1 as a continuity inspection apparatus to which this invention is applied. It is a figure which shows another example of a display of the display part of the portable digital multimeter of FIG.

  Hereinafter, although the form for implementing this invention is demonstrated in detail, the scope of the present invention is not limited to these examples.

  FIG. 1 shows the appearance of a portable digital multimeter which is an example of a continuity test apparatus to which the present invention is applied. The portable digital multimeter 1 is also called a portable digital tester, and is a measuring instrument capable of measuring voltage values, resistance values, current values, and conducting continuity tests. As an example, the portable digital multimeter 1 has a portable housing 10 having a size that can be easily held with one hand. The portable digital multimeter 1 includes a rotary switch 2 for switching a measurement mode, a display unit 3 such as a liquid crystal panel or a 7-segment LED panel, and inspection probes Pa and Pb on the front surface (front panel) of the housing 10. Connectors 5a, 5b, 5c and 5d for connection, operation switches 6a and 6b, and the like are provided. In addition, the portable digital multimeter 1 includes a buzzer 15 inside or on the back.

  The portable digital multimeter 1 rotates the rotary switch 2 so that an AC voltage measurement mode, a DC voltage measurement mode, a resistance value measurement mode, a continuity test mode, a current measurement mode (μA measurement mode, mA measurement mode, 10A The measurement mode) can be switched. The rotary switch 2 also serves as a power switch. By setting the rotary switch 2 to the position 2a, the portable digital multimeter 1 operates in the continuity test mode. Since other measurement modes are the same as those of a known portable digital multimeter, detailed description thereof is omitted.

  The connector 5a is a reference terminal (COM terminal), and is connected to an inspection probe Pa having a black handle. The connector 5b is connected to the inspection probe Pb whose pattern is red in the voltage measurement mode, resistance value mode, and continuity inspection mode. The connectors 5c and 5d are connected to the inspection probe Pb in the current measurement mode.

  Each of the operation switches 6a and 6b is a push button type switch. The operation switches 6a and 6b correspond to the threshold setting operation unit in the present invention, and are used for an operation for setting a threshold for continuity determination in the continuity inspection mode, and used for an operation for changing the measurement range in other measurement modes. It is done.

  FIG. 2 shows a block diagram of the state in which the portable digital multimeter 1 is operated in the continuity test mode.

  The portable digital multimeter 1 includes a resistance measurement unit 21, a threshold control unit 22, a threshold storage unit 23, a comparison unit 24, a display control unit 25, and a battery 30 inside the housing 10.

  The resistance measuring unit 21 is a circuit similar to a known portable digital multimeter. The resistance measurement unit 21 passes the measurement signal to the DUT 90 that is the inspection object via the inspection probes Pa and Pb, and detects the voltage value at both ends of the DUT 90 and the current value of the measurement signal. The voltage value and the current value are detected by a digital value after being sampled by an analog / digital converter (not shown). The resistance measurement unit 21 calculates a resistance value from the detected voltage value and current value. The calculation is performed by a CPU (Central Processing Unit). The resistance value measured by the resistance measurement unit 21 is output to the comparison unit 24 and the display control unit 25.

  The operation switches 6 a and 6 b are connected to the threshold control unit 22. A threshold storage unit 23 is connected to the threshold control unit 22. The threshold control unit 22 changes the threshold and sets (stores) it in the threshold storage unit 23 by operating the operation switches 6a and 6b. The threshold value storage unit 23 is set so that the threshold value for continuity determination can be changed. The threshold value storage unit 23 is a rewritable nonvolatile memory, and is, for example, a flash memory, an EEPROM, or a hard disk. The threshold control unit 22 outputs the threshold set in the threshold storage unit 22 to the comparison unit 24 and the display control unit 25. The display control unit 25 controls the contents displayed on the display unit 3.

  The functions of the threshold control unit 22, the display control unit 25, and the comparison unit 24 are realized by a CPU that operates by a program as an example. The program is stored in a memory (not shown) such as a ROM, a flash memory, or a hard disk.

  The output of the comparison unit 24 is connected to the buzzer 15. The buzzer 15 is an example of a notification unit in the present invention, and is a piezoelectric buzzer as an example. The portable digital multimeter 1 has a replaceable battery 30 serving as a power source for operation of each unit.

  Next, the operation of the portable digital multimeter 1 to which the present invention is applied will be described.

  As shown in FIGS. 1 and 2, when the rotary switch 2 is set to the continuity test mode, the information is input to the display control unit 25 (see FIG. 2), and the display control unit 25 inputs the continuity test mode to the display unit 3. A measurement mode display 13 (see FIG. 1) is displayed.

  Before starting the continuity test, a threshold value for continuity determination is set in accordance with the inspection target, but when the threshold value storage unit 23 shown in FIG. 2 stores the initial value or the threshold value set at the previous test. The threshold control unit 22 reads the threshold set (stored) in the threshold storage unit 23 and outputs it to the comparison unit 24 and the display control unit 25. The display control unit 25 causes the display unit 3 to display a threshold value display 12 (see FIG. 1) indicating the threshold value. The threshold display 12 in FIG. 1 shows an example in which the threshold is set to 20.00Ω. As an example, the display control unit 25 displays the threshold value by adding “REF” to the front so that the threshold value display 12 is obtained. If this threshold is sufficient, the inspection is started as it is.

  The resistance measuring unit 21 shown in FIG. 2 measures the resistance value of the DUT 90 brought into contact with the inspection probes Pa and Pb, and outputs the measured resistance value to the comparison unit 24 and the display control unit 25. The resistance measurement unit 21 measures an auto range or a measurement range in which a threshold value can be measured.

  The display control unit 25 causes the display unit 3 to display the resistance value display 11 (see FIG. 1) indicating the resistance value. The resistance value display 11 in FIG. 1 shows an example in which the measured resistance value is 15.03Ω.

  The comparison unit 24 compares the resistance value and the threshold value, and outputs a conduction detection signal to the buzzer 15 when the resistance value is equal to or less than the threshold value. In the display example of FIG. 1, since the resistance value “15.03Ω” is equal to or less than the threshold value “20.00Ω”, the continuity detection signal is output to the buzzer 15 and the buzzer 15 sounds. The buzzer sound informs the measurer that there is continuity.

  When the threshold value is changed and set before starting the continuity test or during the test, the measurer operates the operation switches 6a and 6b. The upward triangle operation switch 6a is a switch for greatly changing the threshold value, and the downward triangle operation switch 6b is a switch for changing the threshold value small. When the operation switch 6a is pressed (operated), the threshold control unit 22 greatly changes the threshold value and stores the threshold value in the threshold value storage unit 23, and outputs the threshold value to the comparison unit 24 and the display control unit 25. In addition, when the operation switch 6 b is pressed, the threshold control unit 22 changes the threshold to a small value and stores it in the threshold storage unit 23, and outputs the threshold to the comparison unit 24 and the display control unit 25. The comparison unit 24 compares the changed threshold value with the resistance value. The display control unit 25 causes the display unit 3 to display the changed threshold value.

  FIG. 3 shows a display example of the threshold display 12 when the threshold is changed to 10.00Ω. In this display example, since the resistance value “15.03Ω” is not less than or equal to the threshold value “10.00Ω”, the comparison unit 24 does not output a conduction detection signal and the buzzer 15 does not sound. Since the buzzer does not sound, the measurer knows that he / she does not have the conductivity defined by the threshold.

  Each time the operation switches 6a and 6b are pressed once, the threshold control unit 22 is set to a predetermined value such as 0.01Ω, 0.1Ω, 1Ω, 5Ω, 10Ω, 20Ω, or 100Ω. The threshold value may be changed (increased / decreased) step by step and set (stored) in the threshold storage unit 23. Further, when the operation switches 6a and 6b are pressed and held for a predetermined period (for example, 1 second) or longer, the threshold control unit 22 continuously performs predetermined step values while the operation switches 6a and 6b are pressed. The threshold value may be changed to be larger / smaller and set in the threshold value storage unit 23. In this case, the measurer releases his / her finger from the operation switches 6a and 6b when the desired threshold value is reached.

Alternatively, a threshold value table indicating a plurality of candidate values that can be threshold values as shown in Table 1 below is stored in advance in the threshold value storage unit 23, and a plurality of candidate values can be determined by operating the operation switches 6a and 6b. May be selected and set as a threshold value in the threshold value storage unit 23.

  For example, when 30Ω of candidate value number 4 is already set in the threshold value storage unit 23 as a threshold value, when the operation switch 6a is operated (pressed) once, the threshold value control unit 22 sets 50Ω of candidate value number 5 Is set in the threshold value storage unit 23 as a threshold value. Further, when the operation switch 6a is operated once, the threshold control unit 22 sets 100Ω of the candidate value number 6 as a threshold in the threshold storage unit 23. As described above, each time the operation switch 6a is operated once, the threshold value control unit 22 sequentially sets a threshold value that is one larger candidate value number in the threshold value storage unit 23.

  In addition, when 30Ω of candidate value number 4 is already set in the threshold storage unit 23 as a threshold, when the operation switch 6b is operated once, the threshold control unit 22 sets 20Ω of candidate value number 3 as a threshold. It is set in the threshold storage unit 23. Further, when the operation switch 6b is operated once, the threshold control unit 22 sets 10Ω of the candidate value number 2 as a threshold in the threshold storage unit 23. In this way, each time the operation switch 6b is operated once, the threshold value control unit 22 sequentially sets a threshold value that is one candidate value number smaller in the threshold value storage unit 23.

  The threshold control unit 22 stores the set threshold value or its candidate value number in an area different from the area stored in the threshold table in the threshold storage unit 23. The threshold value table and the set threshold value (candidate value number) may be stored in different physically different memories.

  Thus, it is preferable to be able to select a threshold value from a plurality of candidate values because the threshold value can be quickly set with a small number of operations.

  The range that can be set as the threshold value can be an appropriate range. For example, a range of a small resistance value such as 0.1Ω to 1 kΩ that is assumed for the continuity test may be set as a range that can be set as the threshold value.

  The range that can be set as the threshold is a maximum value that can be set, for example, 0Ω (or the minimum resistance value that can be measured by the resistance measurement unit 21) to 10MΩ (or the maximum resistance value that can be measured by the resistance measurement unit 21). May be a large resistance value. Thus, it is preferable to increase the maximum value that can be set as the threshold value because it can be used not only as a continuity testing apparatus but also as a resistance testing apparatus. For example, by setting the threshold value to 10 kΩ, it is possible to inspect whether or not the resistance value of the circuit is 10 kΩ or less based on whether or not the buzzer 15 rings. Therefore, the maximum value that can be set as the threshold value is preferably at least 1 kΩ, 10 kΩ, 100 kΩ, 1 MΩ, or 10 MΩ. A larger maximum value is more preferable.

  As described above, by making it possible to change the threshold value of the continuity test, the continuity test can be performed with a desired test accuracy. Therefore, for example, when switching from a continuity testing device that does not apply the present invention to a continuity testing device to which the present invention is applied on an inspection line, the continuity is detected with the same detection accuracy by first setting the threshold value to match. Inspection can be performed. Therefore, even in the case of inspecting the inspection object at the boundary of whether the buzzer sounds or not depending on the model of the continuity measuring device, the inspection is performed by defining the threshold value using the continuity testing device of the present invention. Errors can be eliminated. Therefore, the anxiety of relying only on the buzzer sound during the continuity test is eliminated, and it becomes unnecessary to visually recognize the resistance value displayed on the display unit.

  In addition, although the example provided with a pair of operation switch 6a, 6b was demonstrated as a threshold value setting operation part in this invention, you may provide the numeric keypad which can set a threshold value numerically. The threshold setting operation unit may be a touch panel. The threshold setting operation unit includes one operation switch. For example, each time the operation switch is pressed once, the candidate value numbers in Table 1 are sequentially set to be larger (or smaller), and the candidates are set. The candidate value number may be returned to 1 by the next operation when the value number reaches the maximum value. In this way, each time the operation switch is operated, the candidate value number changes as 1 → 2 → 3... 6 → 7 → 1 → 2.

  Although the example which provided the buzzer 15 as an alerting | reporting part was demonstrated, you may make it display the image which shows that it is electrically connected to the display part 3 as an alerting | reporting part with the buzzer 15 instead of the buzzer 15. In addition, a lamp that is turned on when conducting may be provided.

  When the present invention is applied to a portable digital multimeter, various electrical characteristics can be carried to various measurement sites and a continuity check can be performed with a desired accuracy, which is very convenient and particularly preferable. The present invention may be applied to a type of digital multimeter. Further, the present invention may be applied to an analog multimeter. Further, the present invention may be applied to a simple continuity testing apparatus that can perform only continuity testing. In this case, a configuration without the display unit 3 that displays the resistance value by enabling the threshold value to be set with a switch that allows the setting state (setting position) such as a rotary switch or a dip switch to be visually recognized as a threshold setting unit. The present invention can be applied to the continuity testing apparatus. In this case, the switch may serve as the threshold value storage unit, and the resistance measurement unit only needs to be able to measure with an accuracy comparable to the threshold value.

  1 is a portable digital multimeter, 2 is a rotary switch, 2a is a position, 3 is a display unit, 5a, 5b, 5c and 5d are connectors, 6a and 6b are operation switches, 10 is a housing, and 11 is a resistance value. Display, 12 is a threshold display, 13 is a measurement mode display, 15 is a buzzer, 21 is a resistance measurement unit, 22 is a threshold control unit, 23 is a threshold storage unit, 24 is a comparison unit, 25 is a display control unit, 30 is a battery, Reference numeral 90 denotes a DUT (inspection object), and Pa · Pb denotes an inspection probe.

Claims (6)

A threshold value storage unit in which the threshold value for continuity determination is set to be changeable;
A threshold setting operation unit for performing an operation of setting the threshold in the threshold storage unit;
A resistance measurement unit for measuring the resistance value of the inspection object;
A comparator that compares the resistance value with the threshold value and outputs a continuity detection signal when the resistance value is less than or equal to the threshold value;
A continuity inspection apparatus comprising: a notification unit that notifies the output of the continuity detection signal. The threshold storage unit stores in advance a plurality of candidate values that can be the threshold,
The continuity test apparatus according to claim 1, wherein one of the plurality of candidate values is selected as the threshold value and set in the threshold value storage unit by the operation of the threshold value setting operation unit.   3. The continuity testing apparatus according to claim 1, wherein a maximum value that can be set in the threshold value storage unit as the threshold value by the operation of the threshold value setting operation unit is at least 1 kΩ.   The continuity test apparatus according to claim 1, further comprising a display unit that displays the resistance value and the threshold value.   The continuity inspection apparatus according to claim 1, wherein each of the parts is housed in a portable housing. A threshold value storage unit in which a threshold value for continuity determination is set to be changeable, a threshold value setting operation unit for performing an operation for setting the threshold value in the threshold value storage unit, and a resistance measurement unit for measuring the resistance value of the inspection object And a comparison unit that compares the resistance value with the threshold value and outputs a continuity detection signal when the resistance value is less than or equal to the threshold value, and a notification unit that notifies the output of the continuity detection signal. A continuity test method using
The threshold value setting operation unit is operated to set the threshold value in the threshold value storage unit, and then the measurement value of the inspection object is measured, and the continuity test is performed based on the presence or absence of notification from the notification unit. Continuity test method.

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