JPH0658765A - Measuring instrument - Google Patents

Abstract

(57) [Summary] [Purpose] To be able to instantly inform the measurer of the tolerance range that represents the accuracy of the measuring instrument and the reliability of the displayed value. [Configuration] A plurality of types of error data 20a of a measuring instrument according to types of various physical quantities and measurement ranges are stored in advance in an error data storage means 20. The error data selection means 30 accesses the error data storage means 20 based on the measurement condition setting signal 10a by the setting of the function 11 and the range 12 in the measurement condition setting means 10 to read the corresponding error data 20a. The accuracy calculation means 50 calculates the accuracy D of the measuring instrument based on the error data value A and the measurement data value B. The tolerance range calculation means 60 determines the tolerance C
The allowable difference range E is calculated based on the measured data value B and the measured data value B. The calculated accuracy D and tolerance range E are displayed on the display means 70.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring instrument for measuring various physical quantities or supplying various physical quantities for measurement, such as a digital multimeter of an electronic measuring instrument.

[0002]

2. Description of the Related Art Measuring instruments measure various physical quantities,
It supplies various physical quantities for measurement and is used in various fields.

By the way, very few measurers work while paying attention to the reliability of the measured value displayed by the measuring instrument. In other words, it is very rare to perform measurement while considering the inherent error of the measuring instrument, and in many cases, the measured value displayed by the measuring instrument is swallowed and read as it is, and it is believed that it is the correct value. Is used as.

In particular, when the display value is stable in a digital measuring instrument, it is easy to read, and all the data including the lowest display digit are apt to be handled as correct data. Whenever a measurer makes a measurement, it is rare to calculate and confirm how reliable the displayed value is by looking at the specifications of the instruction manual of the measuring instrument to be used.

[0005]

Even if the physical quantity is measured or supplied in such a state, the displayed value may include a large error depending on the selected range of the measuring instrument, the function, or the like. However, there is a problem that the unreliable value is treated as if it were a true value.

Nowadays, many of them have excellent resolution, which is the minimum change amount indicating how finely a measuring instrument can measure or supply a physical amount, and it is becoming possible to display it digitally.

However, even if many display digits of such a digital measuring instrument are lined up, the numerical values of all the digits cannot be relied upon. In short, the display value of the measuring instrument is unexpectedly unreliable, and if carelessly, there are meaningless digits in the data, and some invalid values enter.

In order to avoid such a situation, "how accurate is the current measurement condition?", "How reliable is the displayed value?", "How many digits are valid and necessary values?" It is necessary to know "Noka" by all means.

The present invention was devised in view of such circumstances, and it is possible to inform the measurer of the accuracy of the measuring instrument at the time of measurement, and the tolerance indicating the reliability of the displayed value. It is an object of the present invention to provide a highly reliable measuring instrument capable of reporting a range.

[0010]

A first measuring instrument according to the present invention comprises a storage means for storing a plurality of types of inherent error data of the measuring instrument according to the type of physical quantity and the measuring range, and a setting condition. Error data selection means for reading error data from the error data storage means, accuracy calculation means for calculating accuracy based on the read error data and the measured value, and display means for displaying the calculated accuracy. It is characterized by having.

A second measuring instrument according to the present invention is a storage means for storing a plurality of types of inherent error data of the measuring instrument according to the type of physical quantity and the measuring range, and the error data according to a setting condition. Error data selecting means for reading the error data from the storage means, accuracy calculating means for calculating the accuracy based on the read error data and the measured value, and the tolerance and the tolerance obtained in the process of calculating the accuracy. The present invention is characterized by including a tolerance range calculation means for calculating a tolerance range for the measurement value based on the measurement value and a display means for displaying the calculated accuracy and the tolerance range.

The first or second measuring instrument is configured to supply a physical quantity to the measuring instrument for measurement, and the supplied value is similar to the measured value in the error data storage means. Data may be stored, the accuracy or the tolerance range may be calculated by the calculating means, and the calculation result may be displayed.

[0013]

The error data selection means reads the corresponding error data from the error data storage means according to the setting conditions of the type of physical quantity and the range of measurement quantity / supply quantity. The accuracy calculation means calculates the accuracy based on the read error data and the actual measured value / supplied value. The tolerance range calculation means calculates the tolerance range based on the tolerance and the measured value / supply value obtained in the accuracy calculation process. These accuracy and tolerance range are displayed on the display means, and the operator can be informed of the accuracy and tolerance range (lower limit value, upper limit value) regarding the measured value / supply value at that time through the display.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a measuring instrument according to the present invention will be described below in detail with reference to the drawings. INDUSTRIAL APPLICABILITY The present invention is applied to a measuring instrument that measures an arbitrary physical quantity, and a measuring instrument that supplies an arbitrary physical quantity required for measurement to the measuring instrument.

FIG. 1 is a block diagram showing the electrical configuration of the measuring instrument according to the embodiment. The measurement condition setting means 10 includes a function 11 for selecting the type of physical quantity and a range 12 for switching according to the magnitude of the measurement quantity, and outputs a measurement condition setting signal 10a according to any combination thereof. Has become. Error data storage means 20
Stores various inherent errors for various physical quantities and measurement ranges, that is, error data such as reading error 21, full-scale error 22, digit error 23, calibration cycle error 24, and temperature characteristic error 25 in advance. is there. The error data selection means 30 accesses the error data storage means 20 based on the input measurement condition setting signal 10a, reads the error data 20a corresponding to the measurement condition setting signal 10a, and outputs the value A to the accuracy calculation means 50. It is what is sent. The measurement data 40 is data of the result measured by the measuring instrument according to the measurement condition indicated by the measurement condition setting signal 10a, and the value B of the measurement data 40 is sent to the accuracy calculation means 50.

The accuracy calculating means 50 first obtains the tolerance C based on the error data value A and the measurement data value B, and calculates the accuracy D of the measuring instrument from the tolerance C and the measurement data value B. The signal of the accuracy D is sent to the display means 70. The tolerance range calculation means 60 calculates a tolerance range E based on the measurement data value B and the tolerance C calculated in the middle of the accuracy calculation means 50, and the signal of the tolerance range E is displayed on the display means 70. Send out.

The display means 70 displays the measured data value B and the accuracy D.
And the tolerance range E are displayed to inform the measurer.

In the description of the embodiments so far,
Although the measuring instrument used for measurement has been described, the measuring instrument that supplies the physical quantity required for measurement to the measuring instrument also has the same function as above, so the accuracy of the output physical quantity and the stable output quantity are stable. Therefore, it is possible to display a tolerance range that indicates that there is reliability, and it is possible to configure a measuring instrument as a highly reliable physical quantity output instrument.

As an example of a measuring instrument that performs the above operation, a digital multimeter (DMM) for measuring a voltage / current which is an electric quantity will be described below as an example. As shown in FIG. 2, the digital multimeter 100 has a push-button function key 81 for selecting a plurality of functions 11 such as DC voltage, AC voltage, DC current, AC current, resistance, and temperature on the front panel 80 thereof. And a range adjustment key 82 including up and down keys for adjusting a plurality of ranges 12 for switching according to the measurement range, and a measured data value B
The measured value display section 83 for displaying, accuracy D and tolerance range E
The accuracy / tolerance range lower limit value display section 84 for switching and displaying the upper limit value E _{1 of the above,} and the tolerance range upper limit value display section 85 for displaying the lower limit value E ₂ of the tolerance range E are provided.

Various methods are conceivable for the measurement condition setting means 10 to obtain the measurement condition setting signal 10a composed of the combination of the function 11 and the range 12. For example, as shown in FIG. 3, the measurement condition setting signal 10a is obtained by turning on / off the interlocking switches SW _i (i = 1, 2 ...) That output signals corresponding to the function keys 81 and the range adjustment keys 82. Can be Assuming that one interlocking switch corresponds to one key, the upper 4 bits correspond to the function 11 and the lower 4 bits correspond to the range 12, and automatically generate the measurement condition setting signal 10a of 8 bits and the error. It shall be sent to the data selection means 30. When there are a large number of functions 11 and a large number of ranges 12, a 16-bit signal is used as the measurement condition setting signal 10a.

The error data selection means 30 accesses the error data storage means 20 based on the measurement condition setting signal 10a input from the measurement condition setting means 10 and selects the error data 20a corresponding to the measurement condition setting signal 10a. Read out and send the error data value A to the accuracy calculation means 50.

Here, the format of the error data 20a in the error data storage means 20 will be described with reference to FIG. In FIG. 4, the top rdg in each cell
Indicates a reading error 21 (reading), and f. s is full scale error 22 (full scale)
e) is shown. For example, if the error data 20a is “00010100” corresponding to FIG. 3, the upper 4 bits “0001” representing the function 11 designates a DC voltage (DCV), and the lower 4 bits representing the range 12 are represented. Since "0100" designates the 20V range, in this case, as the error data 20a, the reading error 21 is ± 0.01% and the full-scale error 22 is ± 0.0.
The error data of 1% will be selected and read.

For the other error data 20a, such as the calibration cycle error 24 and the temperature characteristic error 25, a data file similar to that shown in FIG. 4 is created corresponding to each cycle and temperature. A setting signal is newly generated by a simple switch configuration, and a measurement condition setting signal is obtained by adding several bits to the above 8-bit signal. Then, the error data storage means 20 is accessed by the measurement condition setting signal, and the read error 21 and the full scale error 22 are accessed.
In addition to the above, the calibration cycle error 24 and the temperature characteristic error 25 are also read. However, here, the calibration cycle error 2
4 and the temperature characteristic error 25 are omitted, and only the reading error 21 and the full-scale error 22 are considered.

Next, the operation of the accuracy calculation means 50 will be described in detail. For the accuracy calculation means 50, the error data 20a from the error data selection means 30 (± 0.01% o
frdg), the value A of (± 0.01% of fs)
And the value B of the measurement data 40 obtained as a result of measurement based on the measurement condition setting signal 10a. The error data value A is shown as a combination of the read error 21 for the measurement data 40 in the corresponding range and the full-scale error 22 in that range.

Example 1 The above error data value A is (0.
01% of rdg), (0.01% of f.
In the case of s), as an example, the value B of the measurement data 40 for the DC voltage displayed on the measurement value display unit 83 is “20.
It is assumed that the reading error is 0.0
1% corresponds to 0.002V in voltage value from 20.000 × 0.01 ÷ 100 = 0.002. Also, 0.01% of the full scale error 22 is 20% full scale.
Since V = 20.000V, 200.000 × 0.01 ÷ 100 = 0.002, which corresponds to a voltage value of 0.002V. Therefore, the value of the tolerance C, which is the total of the reading error 21 and the full-scale error 22, is 0.004V from C = 0.002 + 0.002 = 0.004. Become. If it is assumed that the reading error 21 and the full-scale error 22 are omitted, the accuracy D is calculated from the above-mentioned tolerance C value of 0.004 V, and 0.004 × 100 ÷ 20.000 = 0.02 The accuracy D is D = 0.02% ……………………………………………………………….

[Example 2] As another example in the case of the same error data value A as in the above-mentioned [Example 1], the measured value display section 83
The measured data 40 for the DC voltage displayed on
5.000V ". 0.01% of the read error 21 corresponds to 0.0015V in voltage value from 15.000 × 0.01 ÷ 100 = 0.0015. Full-scale error 0.01% of 22 is the same as in [Example 1], and since the full scale is 20V = 20.000V, it is 20.000 × 0.01 ÷ 100 = 0.002, and the voltage value is 0. Therefore, the value of the tolerance C, which is the total of the read error 21 and the full-scale error 22, is C = 0.0015 + 0.002 = 0.0035. The value of this tolerance C is 0.0.
The accuracy D is calculated from 035V, and 0.0035 × 100 ÷ 15.000 = 0.023, so the accuracy D is D = 0.023% ………………………………………………………… ……………… becomes.

The value (or) of the accuracy D calculated as described above is the accuracy / tolerance range lower limit value display section 84.
Is automatically displayed in.

Next, the operation of the tolerance range calculating means 60 will be described in detail. To the tolerance range calculation means 60, the measurement data value B of the result measured based on the measurement condition setting signal 10a and the tolerance C which is an intermediate result of the calculation in the accuracy calculation means 50 are input. come. The tolerance range calculation means 60 calculates the tolerance range E based on the measured data value B and the tolerance C.

Since the tolerance C in the case of the above [Example 1] is 0.004V, ± 0.
By adding 004 V and the measured data value B = 20.000 V, the tolerance range E is E = lower limit value E ₂ to upper limit value E ₁
Taking the expression of, E = 19.996V to 20.04V …………………………………………. In the case of [Example 2], the tolerance C is 0.003.
Since it is 5V, ± 0.0035V and measured data value B =
By adding up with 15.000V, the allowable difference range E becomes E = 14.9965V to 15.0035V ....................................

Tolerance range E calculated as described above
The lower limit value E ₂ is automatically displayed on the accuracy / tolerance range lower limit value display unit 84, and the upper limit value E ₁ is automatically displayed on the tolerance range upper limit value display unit 85. In the case of [Example 1], the measured data value B = 2 displayed on the measured value display section 83.
The true value for 0.000V is 19.996V-20.
It means that the true value for the measured data value B = 15,000 V exists between 14.9965 V and 15.0035 V in the case of [Example 2]. is doing.

The error data storage unit 20, the error data selection unit 30, the accuracy calculation unit 50, and the tolerance range calculation unit 60 are specifically realized by a microcomputer, and are displayed by the display unit 70 (the display units 84 and 85). ), The accuracy D and the tolerance range E can be notified to the measurer. The measurer who sees these displays can clearly know the accuracy of the measuring instrument (digital multimeter) and the allowable range of difference between the measured value and the supplied value.

In the above embodiment, one measuring instrument (digital multimeter) is provided with the accuracy calculation means 50 and the tolerance range calculation means 60, and the display means 70 is provided with the accuracy D and the tolerance range E. Although both are configured to be displayed, some measuring instruments may have the accuracy calculation means 50 but omit the tolerance range calculation means 60, or have the tolerance range calculation means 60. The accuracy calculation means 50 may be omitted. Further, not only a measuring instrument used only for measuring a physical quantity, but also a measuring instrument (for example, a power source) configured to supply a physical quantity for measurement to the measuring instrument, the present invention is applied in the same manner as in the above embodiment. You may apply. That is, it stores the data of a plurality of types of inherent error of the measuring instrument according to the type of the physical quantity and the measurement range for the supply value, calculates the accuracy or the tolerance range by the calculating means, and displays the result. Good.

As described above, the measurer can easily determine which digit is effective rather than relying on the measured value and the supplied value as in the conventional case. Become.

Incidentally, recently, the necessity of calibration of the measuring instrument has been questioned by the ISO standard and the like, but the measuring instrument capable of instantaneously displaying the accuracy or the tolerance range with respect to the standard signal input from the standard instrument in the calibration. Therefore, the calibration work becomes very convenient and the work time can be shortened,
Anyone can easily check the performance of the measuring instrument by using the standard signal in daily inspection.

[0035]

As described above, according to the present invention, the accuracy of the measuring instrument according to the type of the physical quantity and the measuring range and the allowable difference range for the measured value and the supplied value are calculated and displayed instantly. Can be informed. It is important for the measurer to treat the displayed measured value / supplied value as highly reliable data, as it is possible to easily determine which digit is valid, rather than overreliance that the lowest value is a true value. Will be able to.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a measuring instrument according to an embodiment of the present invention.

FIG. 2 is a front view showing an appearance of a digital multimeter according to an embodiment.

FIG. 3 is a diagram showing a specific example of measurement condition setting means in the digital multimeter according to the embodiment.

FIG. 4 is a format of an error specification data file in the digital multimeter according to the embodiment.

[Explanation of symbols]

10 measurement condition setting means 10a measurement condition setting signal 20 error data storage means 20a error data 21 reading error 22 full scale error 30 error data selecting means 40 measurement data 50 accuracy calculation means 60 tolerance range calculation means 70 display means 81 function keys 82 Range adjustment key 83 Measurement value display section 84 Accuracy / tolerance range lower limit value display section 85 Tolerance range upper limit value display section 100 Digital multimeter A Error data value B Measurement data value C Tolerance D Accuracy E Tolerance range E ₁ Allowance Upper limit of difference range E ₂ Lower limit of tolerance range

Claims (3)

[Claims] 1. Storage means for storing data of a plurality of types of inherent errors of a measuring instrument according to a type of physical quantity and a measurement range, and error data selection means for reading error data from the error data storage means according to a setting condition. A measuring instrument, comprising: an accuracy calculation unit that calculates an accuracy based on the read error data and an actually measured value; and a display unit that displays the calculated accuracy. 2. A storage unit for storing a plurality of types of peculiar error data of a measuring instrument according to a type of a physical quantity and a measurement range, and an error data selection unit for reading the error data from the error data storage unit according to a setting condition. An accuracy calculation means for calculating the accuracy based on the read error data and the measured value, and the tolerance for the measured value based on the tolerance and the measured value obtained in the process of calculating the accuracy. A measuring instrument, comprising: a tolerance range calculation means for calculating a difference range; and a display means for displaying the calculated accuracy and tolerance range. 3. The measuring device according to claim 1, wherein the measuring device is configured to supply a physical quantity to the measuring device for measurement, and the supplied value is the error data storage means similarly to the measured value. A measuring instrument characterized in that the data of the peculiar error is stored in, the accuracy or the tolerance range is calculated by the calculating means, and the calculation result is displayed.