JP2001116781A - Method for controlling insulation resistance tester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a measuring time without considering a decision delay time and to set the measuring time equal to a pass or fail decision time in measuring an insulation resistance of a material to be measured including a capacity component. SOLUTION: When a measuring time is started after at least a decision standard value, a decision delay time Tb and a measuring time Ta are set to a control means (microcomputer) 30, a control means 30 generates a measuring voltage from a measuring voltage generator 10, and measuring of the time Tb is simultaneously started. After the time Tb is elapsed, measuring of the time Ta is started this time, and an insulation resistance value is compared with the standard value and decided during the measuring time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an insulation resistance meter, and more particularly, to a method for controlling an insulation resistance meter having a timer function such as a judgment delay time and a measurement time.

[0002]

2. Description of the Related Art Insulation resistance meters measure the insulation resistance of a device under test from the leakage current when a DC voltage is applied to the device under test. Are compared with each other to make a pass / fail decision. Some have a timer function that can set the voltage application time.

When an object to be measured contains a capacitance component (capacitor component), immediately after a DC voltage is applied, a current is consumed for charging the capacitance component. The insulation resistance value becomes a small value. When the charging of the capacitance component is completed, only the original leakage current flows through the device under test, so that the insulation resistance value is stabilized.

[0004] Therefore, if there is a capacitance component in the object to be measured, if the pass / fail judgment is made during the charging period immediately after the voltage is applied, there is a possibility that an erroneous judgment may be made. To prevent this,
The determination function is not operated for a certain period immediately after voltage application, and this is a determination delay function.

[0005]

In an insulation resistance meter having a timer function and a judgment delay function, prior to measurement, a microcomputer as a control unit determines a judgment reference value, a voltage application time, a judgment delay time, and the like from an input unit. (Abbreviation: microcomputer). The measurement and determination of the insulation resistance are automatically performed based on a start signal (measurement start signal) from the input unit. However, the related art has the following problems. This will be described with reference to FIG.

FIG. 1 shows an applied voltage waveform (vertical axis; voltage, horizontal axis; time) when a measured object contains a capacitance component. In the figure, ta is set by an input unit. The applied voltage application time tb is the determination delay time.

As can be seen from this figure, in the prior art,
When the start signal is input, the measurement voltage is applied to the device under test, and the voltage application time ta and the determination delay time t
The timing of b is started at the same time. After the elapse of the judgment delay time tb, the judgment function starts up and the measured value is compared with the judgment reference value.

When the voltage application time ta elapses,
The measurement voltage is turned off and the measurement ends. The pass / fail judgment by the judgment function is performed a plurality of times at a predetermined sampling interval. If at least one of the judgments is an NG judgment (also referred to as a NOGO judgment), the result is an NG judgment.

Therefore, a higher accuracy is obtained as the pass / fail judgment time is longer, but the pass / fail judgment time is ta-t
b time, the time t actually set as the measurement time
This is shorter than a, which is not preferable in terms of measurement accuracy. However, in order to solve this point, when setting the voltage application time ta, the time ta may be extended by that amount in consideration of the determination delay time tb.

However, the voltage application time ta is often understood as the measurement time (pass / fail judgment time) itself, and unless the user is very familiar with the equipment, the judgment delay time tb is included in the voltage application time ta on the user side. There are few people who understand that this is the case, and in most cases the decision delay time tb will not be added.

Note that the voltage application time ta includes a determination delay time t.
Even if b is added, the determination delay time tb may be set in advance by the manufacturer, and in such a case, it is necessary to check the determination delay time tb using a specification or the like, which is troublesome. Further, the determination delay time tb is provided to the user side.
Voltage setting time ta
Is set, the determination delay time tb must be added, and the addition may be forgotten.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to set a measurement time without considering a judgment delay time, and to determine whether the measurement time is equal or not. An object of the present invention is to provide a control method of an insulation resistance meter that can be used as a determination time.

In order to achieve the above object, the present invention provides a measurement voltage generator for applying a predetermined measurement voltage to an object to be measured, a current detector for detecting a current flowing through the object to be measured, And a control unit for calculating an insulation resistance value from a measurement voltage applied to the control unit and a measurement current detected by the current detection unit, and measurement conditions such as a determination reference value, a determination delay time, and a measurement time for the control unit. And an input unit for setting an insulation resistance meter, wherein the measurement is performed by the control unit based on the measurement conditions set in the input unit. After the determination reference value, the determination delay time and the measurement time are set, when a measurement start signal is issued from the input unit, the control unit generates a predetermined measurement voltage from the measurement voltage generation unit, Timing of the determination delay time is started, and after the determination delay time has elapsed, timing of the measurement time is started, and during the measurement time, the comparison determination between the calculated insulation resistance value and the determination reference value is performed. And outputting the final result of the comparison determination, and stopping the measurement voltage generation unit after the lapse of the measurement time.

According to the present invention, the measurement time does not include the determination delay time, and the measurement time is measured after the determination delay time has elapsed. Therefore, the set measurement time itself is the pass / fail judgment time by the judgment function.

According to another aspect of the present invention, the control means has a function of discriminating whether the measured current or the voltage applied to the device under test has reached a stable state. Then, the measurement of the measurement time is started, and during the measurement time, the calculated insulation resistance value and the determination reference value may be compared and determined. Setting is unnecessary.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described with reference to an embodiment shown in the drawings. FIG. 1 is a schematic block diagram of an insulation resistance meter according to this embodiment.

This insulation resistance meter has the following basic configuration.
A measurement voltage generator 10 for applying a predetermined DC voltage to the device X; and a current detector 2 for detecting a leakage current of the device X
0 and a microcomputer 30 as a control unit.

Measurement voltage generator 10 and current detector 20
May be a known one, and the measurement voltage generator 10 includes:
Voltage detector 11 for detecting the voltage applied to the device under test X
Is connected. The measurement current detected by the current detection unit 20 is input to the microcomputer 30 via the A / D converter 21. The applied voltage detected by the voltage detection unit 11 is also input to the microcomputer 30 via the A / D converter 21. The microcomputer 30 calculates the insulation resistance value of the device under test X based on the measured current and the applied voltage.

The microcomputer 30 includes an input unit 40 having, for example, a numeric keypad and various setting dials, a display unit 50 having a display panel, an LED, a buzzer, and the like, an I / O port 60 for connection to an external personal computer, for example. A memory 70 such as a RAM is connected.

The microcomputer 30 has a timer function and a judgment function. In addition, the microcomputer 30 supplies the measurement voltage generator 1
0 is supplied with a voltage range switching signal.
The range and gain switching signals are supplied to the current detection unit 20.

The operation of the insulation resistance meter will be described.
First, as a preparatory work for measuring the insulation resistance of the device under test X including the capacitance component, in this embodiment, the measurement time Ta, the judgment delay time Tb, the judgment reference value (for example, Lower limit value), an applied voltage (test voltage), and the like.

The voltage waveform applied to the device under test X (vertical axis;
Referring to FIG. 2 in which voltage, horizontal axis, and time are shown, when a start signal is issued from the input unit 40, the microcomputer 3
0 sends an ON signal to the measurement voltage generator 10 to apply a predetermined measurement voltage to the device under test X, and starts counting the determination delay time Tb. At this time, the measurement time Ta is not measured. Also, the determination function is in the off (pause) state.

When the determination delay time Tb elapses, the microcomputer 30 starts measuring the measurement time Ta and turns the determination function on (operating). During this measurement time Ta,
The microcomputer 30 calculates the insulation resistance value based on the measured current and the applied voltage taken from the A / D converter 21 at a predetermined sampling interval, and each time compares the insulation resistance value with the judgment reference value to make a pass / fail judgment. .

When the measurement time Ta has elapsed, the microcomputer 30 sends an off signal to the measurement voltage generator 10 to reduce the voltage applied to the device under test X to zero. The determination function is also turned off, and the result of the pass / fail determination is output to the display unit 50.

If at least one of the pass / fail judgments made within the measurement time Ta includes an NG judgment, the NG judgment is finally made. The GO judgment is issued only when all of the GO / NG judgments are made in the pass / fail judgments performed a plurality of times.

In the above embodiment, the judgment delay time is set by the input unit 40, but the present invention includes the following modifications. That is, the current detection unit 2 is connected to the microcomputer 30.
A function of identifying whether the measured current detected by 0 or the applied voltage of the DUT detected by the voltage detecting unit 11 has reached a stable state is provided, and after the measured current or the applied voltage is stabilized, the measurement time Ta Timing may be started.

According to this, it is not necessary to set the judgment delay time from the input unit 40. Whether the measured current or the applied voltage is stable can be identified by, for example, whether the maximum value and the minimum value of the current waveform or the voltage waveform are within a predetermined width.

[0028]

As described above, according to the first aspect of the present invention, first, the determination delay time is measured, and after the elapse of the time, the measurement time is measured. The measurement time can be set without taking into account the above, and the measurement time can be used as the equality pass / fail judgment time.

According to the second aspect of the present invention, the microcomputer (control unit) determines whether the measurement current detected by the current detection unit or the applied voltage of the DUT detected by the voltage detection unit has reached a stable state. With the provision of the identification function, in addition to the effect of the first aspect, the effect of saving the trouble of setting the determination delay time can be achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a configuration of an embodiment of an insulation resistance meter according to the present invention.

FIG. 2 is a waveform diagram showing an applied voltage waveform applied to a device under test in the above embodiment.

FIG. 3 is a waveform diagram showing an applied voltage waveform applied to a device under test in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Measurement voltage generation part 11 Voltage detection part 20 Current detection part 21 A / D converter 30 Microcomputer 40 Input part 50 Display part 60 I / O port 70 Memory

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoki Nakayama 81 Sakuramachi, Koizumi, Ueda-shi, Nagano F-term (reference) 2G015 AA01 BA04 BA06 CA04 DA04 2G028 AA02 CG03 DH03 DH12 FK02 FK08 GL07 LR02 LR03 LR04

Claims (2)

[Claims] 1. A measurement voltage generator for applying a predetermined measurement voltage to an object to be measured, a current detector for detecting a current flowing through the object to be measured, a measurement voltage applied to the object to be measured, and the current A control unit that calculates an insulation resistance value from the measurement current detected by the detection unit, and an input unit that sets measurement conditions such as a determination reference value, a determination delay time, and a measurement time for the control unit, A control method of an insulation resistance meter, wherein the measurement is performed by the control unit based on the measurement conditions set in the input unit, wherein at least a determination reference value, a determination delay time, and a measurement are transmitted from the input unit to the control means. After the time is set, when a measurement start signal is issued from the input unit, the control unit generates a predetermined measurement voltage from the measurement voltage generation unit, and starts timing the determination delay time, Up After the elapse of the determination delay time, the measurement of the measurement time is started, and during the measurement time, a comparison between the calculated insulation resistance value and the determination reference value is performed, and the final result of the comparison determination is determined. A method for controlling an insulation resistance meter, comprising: outputting an output and stopping the measurement voltage generator after the elapse of the measurement time. 2. A measurement voltage generator for applying a predetermined measurement voltage to an object to be measured, a current detector for detecting a current flowing through the object to be measured, a measurement voltage applied to the object to be measured, and the current A control unit for calculating an insulation resistance value from the measurement current detected by the detection unit, and an input unit for setting measurement conditions such as a criterion value and a measurement time for the control unit; In the method for controlling an insulation resistance meter, wherein the measurement is performed by the control unit based on the measurement conditions set in the control method, the control unit determines whether the measurement current or the applied voltage to the device under test has reached a stable state. The identification function is provided, after at least the determination reference value and the measurement time are set from the input unit for the control unit, when a measurement start signal is issued from the input unit, the control unit,
Simultaneously with the generation of a predetermined measurement voltage from the measurement voltage generator, the measurement current or the applied voltage is monitored, and when it reaches a stable state, timing of the measurement time is started. Performing a comparison judgment between the calculated insulation resistance value and the judgment reference value, outputting a final result of the comparison judgment, and stopping the measurement voltage generation unit after a lapse of the measurement time. Control method of insulation resistance meter.