JP3569382B2 - LCR meter - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an LCR meter, and more particularly, to an LCR meter having a short / open correction mode.
[0002]
[Prior art]
When measuring a resistance having a small resistance value, it is necessary to consider the influence of the resistance value of the measurement lead and its contact resistance. Further, when measuring a resistance having an extremely large resistance value, it is necessary to know the open voltage of the measurement lead prior to the measurement.
[0003]
For this reason, a normal LCR meter has a short / open correction mode in addition to the element constant measurement mode. In the short / open correction mode, the correction value is taken in a state where the pair of measurement leads (measurement terminals) are shorted or opened.
[0004]
Then, the correction value is compared with a reference value for comparison and determination set in advance for each device, and it is determined whether the correction value is within an effective range. If the correction value is within the valid range, the correction value is stored in a memory or the like, and short / open correction based on the correction value is performed on a measurement value in a subsequent element constant measurement mode.
If the correction value is outside the valid range, the correction value is invalidated, and short / open correction is not performed in the subsequent element constant measurement mode.
[0005]
[Problems to be solved by the invention]
According to this, the user can determine whether the acquisition of the correction value was successful or failed, but even if it was successful, how much the impedance of the measurement lead etc. as the correction value was actually what value I couldn't know until.
[0006]
This has an effect when manually selecting the measurement range. That is, as an easy-to-understand example, for example, if the resistance value to be measured is 10Ω and the resistance value by a lead or the like is 1 kΩ, the measurement should be performed in the 1 kΩ range. The proper range cannot be determined.
Further, even when the correction value is not successfully captured, the actual value of the correction value is unknown, so that it is difficult to determine the cause.
[0007]
SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a short / open correction mode in which the actual value of the correction value itself is used together with the validity and invalidity of the correction value. It is an object of the present invention to provide an LCR meter capable of knowing the same.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a measurement data detection circuit for A / D converting and taking in a signal to be measured obtained from a sample to be measured via a pair of measurement leads, and performing a predetermined operation on the measurement data. LCR meter including a CPU as control means for calculating parameter values and the like of the sample to be measured and a display for displaying the parameter values and the like, and having a short / open correction mode in addition to the element constant measurement mode In the short / open correction mode, the CPU sets the correction value captured via the detection circuit in a state where the pair of measurement leads are short-circuited or opened, and a preset reference value for comparison and determination. Is displayed on the display together with a message indicating whether the correction value is valid or invalid, and the correction value itself. It is characterized in the thing.
[0009]
In this case, it is preferable to display the correction value in a predetermined display area (for example, a small screen) of the display even in the element constant measurement mode. This correction value display may be performed at all times, or may be appropriately displayed based on an instruction from a user.
[0010]
In any case, according to the present invention, since the actual value of the correction value is known, when the measurement range is manually selected, the measurement range can be easily determined. Further, even when the acquisition of the correction value fails, the cause of the error can be easily estimated from the value.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, in order to better understand the technical concept of the present invention, embodiments will be described with reference to the drawings.
[0012]
As schematically illustrated in FIG. 1, the LCR meter includes a data detection circuit that detects a current and / or a voltage signal as a signal to be measured from a sample to be measured X via a pair of measurement leads 11 and 11. 12 are provided. In the element constant measurement mode, a predetermined measurement signal is applied to the sample X from a measurement signal source (not shown).
[0013]
In this case, the data detection circuit 12 has an A / D conversion function, and a CPU (Central Processing Unit) 13 as a control means performs a predetermined operation on the A / D converted measurement data to perform a predetermined operation on the sample X to be measured. Is calculated. Note that these measurement data and parameter values are stored in the data storage RAM 14.
[0014]
The measurement data, parameter values, and the like are read from the RAM 14 by a key operation on the operation unit 15 or an instruction to the CPU 13 from an external interface 16 such as GP-IB and displayed on a display 17 as a display unit.
[0015]
Next, the operation in the short / open correction mode will be described. First, the measurement leads 11 are short-circuited or opened. Then, when a short / open correction instruction is given to the CPU 13 from the key operation of the operation unit 15 or the external interface 16, the measurement value data in a state where the measurement leads 11 and 11 are short-circuited or opened is taken into the detection circuit 12. .
[0016]
After the data has been fetched, the CPU 13 calculates a correction value based on the data, and compares the correction value with a reference value preset in the LCR meter.
[0017]
As a result, if the correction value is an effective range, for example, short correction, if the correction value (impedance | Z | value) is equal to or less than a reference value, the display 17 is displayed as illustrated in FIG. A message “COMPLETED NORMALLY” indicating that the correction value has been successfully acquired is displayed, and the correction value is also displayed. In this example, the correction value is displayed as “Z; 10.000 MΩ, θ; 1.00 °”.
[0018]
On the other hand, when the correction value is out of the valid range, that is, when the correction value is invalid, "ZERO ADJUSTMENT" which means that the acquisition of the correction value to the display 17 has failed as illustrated in FIG. In addition to displaying the message “FAILURE”, the correction value that failed, in this example, “Z; 100.00Ω, θ; 0.01 °” is also displayed.
[0019]
As described above, when the correction value is valid (successful acquisition of the correction value) and invalid (failure of the correction value acquisition), the actual value of the correction value is displayed on the display 17 so that the correction value is valid. , The measurement range can be set appropriately with reference to the value. On the other hand, even when the correction value is invalid, the actual value is displayed, so that clues to guess the cause of the error can be obtained.
[0020]
In the above embodiment, the determination result in the short / open correction mode is displayed on the display 17 as its dedicated screen as shown in FIGS. 2A and 2B. It is also possible to prepare a sub-screen in a predetermined display area of the display 17 and display at least the correction value in the sub-screen. In this case, the correction value display may be always displayed, or may be limited display only when instructed by the user.
[0021]
In this embodiment, the validity and invalidity of the correction value are set in the above-mentioned message format. Instead of the message, a simple symbol, most commonly, a symbol such as "OK" or "NG" may be adopted. Of course. In short, any display may be used as long as the user can determine whether the correction value is valid or invalid.
[0022]
Further, the correction value can be transmitted to an external device such as a personal computer via the external interface 16. Further, when the correction value obtained as described above is different from the correction value under the actual measurement conditions in the subsequent element constant measurement mode, the correction data is displayed and the like. You can also call attention.
[0023]
【The invention's effect】
As described above, according to the present invention, in the short / open correction mode, the correction value captured via the detection circuit in a state where the pair of measurement leads is short-circuited or opened, and the preset comparison determination Compared with the reference value for the correction value, the correction value itself is displayed together with a message indicating whether the correction value is valid or invalid on the display, so that the actual value of the correction value can be known, so measurement is performed manually When selecting a range, the measurement range can be easily determined. In addition, even if the acquisition of the correction value fails, there is an effect that the cause of the error can be easily estimated from the value.
In addition, even in the element constant measurement mode, the correction value is appropriately displayed in a predetermined display area (for example, a small screen) of the display, so that the constant of the device to be measured, that is, each parameter value, is constantly referred to the correction value. It is possible to accurately grasp, and it is possible to more accurately perform the LCR measurement of the sample to be measured.
[Brief description of the drawings]
FIG. 1 is a block diagram schematically illustrating a configuration example of an LCR meter according to the present invention.
FIG. 2 is a screen view of a display showing a message indicating whether or not a correction value has been acquired and a display example of the correction value in a short / open correction mode of the present invention.
[Explanation of symbols]
11 Measurement lead 12 Data detection circuit 13 CPU (control means)
14 RAM (memory for data storage)
15 Operation unit 16 External interface 17 Display

Claims (2)

A measurement data detection circuit that A / D converts and acquires a signal to be measured obtained from a sample to be measured via a pair of measurement leads, and performs a predetermined operation on the measurement data to calculate parameter values and the like of the sample to be measured In an LCR meter including a CPU serving as control means for performing the operation and a display for displaying the parameter values and the like, and having a short / open correction mode in addition to the element constant measurement mode, in the short / open correction mode, Compares the correction value captured via the detection circuit with the pair of measurement leads shorted or opened, and a preset reference value for comparison and determination, and displays the correction value on the display. The LCR mail is characterized in that the correction value itself is displayed together with a message indicating whether the correction is valid or invalid. . The LCR meter according to claim 1, wherein at least the correction value is displayed in a predetermined display area of the display even in the element constant measurement mode.

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