JPS5833117A - Electronic measuring device provided with accuracy display - Google Patents

Abstract

PURPOSE:To provide convenience in actual use, by displaying the measured value of an object to be measured, and computing and displaying the accuracy of the measured value at the same time. CONSTITUTION:The output signal from a measuring signal generator 10 is supplied to the object to be measured 14 through a standard resistor 12. The output thereof is given to a measuring circuit 20 comprising an operation amplifier circuit 22 and a range resistor 24. The output frequency fs from the measuring signal generator 10, a variable control signal for measuring parameters including a voltage Vs to be applied to the standard resistor 12, measured data VX of the measuring circuit 20, and a variable control signal VR of the range resistor 24 are supplied to an operation processor 16. Then the measured value of impedance and its accuracy are computed and displayed by a display device 18. Since the measured value as well as the accuracy of the measured value are displayed, the device is convenient in the actual use.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic measuring instrument equipped with a measurement accuracy display function.

In general, the accuracy of an electronic measuring instrument is the limit value of error specified by the manufacturer for the measured value of the instrument operating under specified conditions. This accuracy is calibrated by superior standards and established by traceability to national standards. On the other hand, in electronic measuring instruments, measurement parameters (eg, measurement frequency, measurement level, etc.) applied to the measurement object are continuously changed as the objects to be measured become more diverse. In such a measuring instrument, the accuracy of the measured value also changes as the measurement parameter changes.

In fact, when the measured quantity of the object under test (for example, circuit elements such as O and R) changes or the measurement parameters change, the accuracy at each measurement point is the measurement signal level of the measurement circuit versus the noise. Analyze the ratio and the frequency characteristics of the circuit in the used frequency band, express the amount of change in error of the measurement circuit due to changes in measurement parameters using an approximate formula, and based on this, calculate the amount of change in error of the measurement circuit due to changes in measurement parameters or measured quantities. Accuracy was determined using an approximate formula. Therefore, when determining the accuracy at all measurement points, the measured value (measured quantity) at each point
and the measurement parameter D data given to the object to be measured are substituted into an approximation formula and calculated. .

In order to eliminate the above-mentioned drawbacks, the present invention incorporates a control circuit K of an electronic measuring instrument, for example, a microprocessor, and
The microprocessor stores approximation formulas for accuracy at all measurement points in advance, and displays the measured values for each measurement at all measurement points, and also displays the accuracy for each measurement value using the approximation formula. This is related to an electronic measuring device that calculates and displays 5K. The present invention will be explained below using the drawings.

FIG. 1 is a block diagram of an electronic measuring instrument according to an embodiment of the present invention, and FIG. 2 is a specific circuit diagram of the measuring circuit 12 in FIG. 1. In both figures, 10 is a measurement signal generator, the output signal of which is sent to the object to be measured 14 via a standard resistor 12. 20 is an operational amplifier 22 and a range resistor 2
4, the inverting input terminal of the operational amplifier 22 is connected to the object to be measured 14 and to its output terminal via a range resistor 24, respectively. Here, the output frequency fs sent out from the measurement signal generator 10
and the voltage level V applied to the standard resistor 12, and the variable control signal for the range resistor 24 in the measurement circuit 20 (the value of which is assumed to be Le) are each controlled by an arithmetic function (for example, microprocessor)
The data is sent out from an arithmetic processing unit 16 equipped with a. The arithmetic processing unit 16 receives the voltages ψt and Vx from the measurement circuit 20.
Introduce measurement value information. Note that 18 is a display device.

As described above, in the impedance measurement example, the arithmetic processing unit 16 first calculates the measured value ix by the following equation (1) based on the measured value information (Vl, Vx 1: obtained from the measuring circuit 20), and then This measured value is displayed on the display device 18.
will be displayed.

Simultaneously or in parallel with the execution of the above calculation, the arithmetic processing unit 16 executes a calculation for the accuracy of the measured value ix based on the approximation formula shown in the following equation (2)K, and calculates 9 (1+ to 7( 1+Ksβ) −)−1−−=−0−1,
-+21. 6, r=v3. β=fishing, K+, K2
6,--1Ke. Yo.

With different coefficients for measurement range, measurement function (inductance, capacitance, resistance, etc.), each of these coefficients is pre-calculated and stored in memory in the processing unit.

As is clear from the above description, the present invention is convenient for practical use because it can simultaneously display measured values at each point, that is, measured values for changes in measurement parameters, and the accuracy of each of the measured values. The above accuracy is displayed as absolute value accuracy or percentage accuracy -Wx
” 00%). Also, once the accuracy of the measured value is obtained, the minimum and maximum values of the measured value that can be guaranteed by this measuring device can be determined. When performing sweep measurements and plotting K (measurement frequency) versus (measurement value) such as a CRT screen or recording meter, it is also possible to plot the minimum and maximum value curves for each measurement value at the same time. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an electronic measuring instrument according to an embodiment of the present invention, and FIG. 2 is a specific circuit diagram of the measuring circuit 20 in FIG. 1. 10: measurement signal generator, 14: object to be measured, 16: arithmetic processing unit, 18: display device, 20: measurement circuit, 22: operational amplifier, 24: range resistor.

Claims (1)

[Claims] In an electronic measuring instrument that measures constant values of an object to be measured according to certain set measurement parameters, accuracy for each measurement value is sequentially determined based on parameter information or measurement value information of a measurement signal supplied to the object to be measured. An electronic measuring device comprising an arithmetic processing unit that performs calculations and a display device that simultaneously displays the measured value and accuracy.