JPH03200085A - Automatic calibrating system for digital measuring instrument - Google Patents

Abstract

PURPOSE:To enable calibration with high reliability in a short time without depending on the technique of a measuring person by successively automatically inputting analog reference signals corresponding to the measuring items of a digital measuring instrument as an object. CONSTITUTION:Connection through a signal source selecting and switching device 2 and an input terminal switching device 3 to a reference signal source 1 is executed to a digital measuring instrument 4 as the calibrating object by a control signal. A reference signal (s) is inputted to the measuring instrument 4 and a measuring value instruction output (a) and the reference signal (s) are inputted from an output terminal to a measurement error arithmetic part 6. Measurement error (c) is outputted from the arithmetic part 6. On the other hand, concerning a reference output signal (b), measurement range signal (e) and allowable different (d), data are inputted to an allowable difference arithmetic part 5 and an allowable difference signal (f) is outputted by calculation under the calibrating condition of the measuring instrument 4. An acceptance or rejection comparison arithmetic part 7 decides the acceptance or rejection of the calibration by the measurement error (c) and the allowable difference signal (f) and the decided result is compared with relative measurement data. Then, a compared result and the relative measured data are displayed at a compared result output part 8.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a digital measuring instrument automatic calibration system that automatically performs everything from selecting an analog reference signal corresponding to a digital meter to be calibrated to recording calibration data. It is something.

<Prior Art> Digital measuring instruments have come to be commonly used in various fields because they display analog Hitoyoshi signals in highly accurate digital form. However, in order to maintain this digital measuring instrument with high measurement accuracy, periodic calibration is required every six months or one year depending on the measurement accuracy.

<Problems to be Solved by the Invention> Even in periodic calibration of digital measuring instruments, the reference signal from the reference signal source is first manually connected to the input terminal of the digital meter 611, and the digital measurement displayed by the digital measuring instrument is performed. The value,
After calculating the error based on the value read visually, items (functions) such as current and voltage that are measured by the measuring device
, measuring range, or 1tll fixed point, etc., to determine pass/fail by comparing several different tolerances, and to fill in the calibration report for the IS+S meter.

The above calibration work was repeated manually and visually for each function of the digital measuring instrument and each function's calibration point.

In manually calibrating a digital measuring device as described above, the higher the precision of the measuring device, the longer it takes, and differences in measured values may also occur depending on the handling of the device and the measurement procedure. The proofreaders needed to become proficient in the technology.

As mentioned above, manual calibration of digital measuring instruments takes a long time, and measurement values may change due to differences in the vision and sense of the person in charge of calibration, resulting in a lack of reliability in calibration. was there.

The present invention solves the problems of the digital measuring instrument calibration method as described above, and provides a digital measuring instrument calibration system that can perform highly reliable calibration in a short time without depending on the skill of the person performing the measurement. It is intended to.

<Means for Solving the Problems> The digital measuring instrument automatic calibration system of the present invention, which solves the above-mentioned problems, inputs an analog reference signal according to the calibration item program determined for each digital measuring instrument, and inputs a corresponding digital measuring instrument. In order to automate the calibration by measuring the measurement value indication output (output signal) of the measuring instrument, we have created a calibration system that has the following means.

First, an input terminal selection means for sequentially selecting input terminals of a digital measuring instrument to be calibrated, an input signal selection means for sequentially inputting an analog reference input signal to the selected input terminals, and an input signal and a digital measuring instrument for the input signal. means for calculating the error of the output signal by calculating from the output signal of the output signal; tolerance calculation means for calculating the tolerance at the reference input signal value from various individually determined tolerances; A pass/fail comparison calculation unit that compares the error and calculated tolerance and determines pass/fail, and a comparison result output unit that outputs the above measurement data and error comparison data to the outside and records it in the file of the calibrated digital measuring instrument, etc. It consists of

<Operation> The automatic calibration system for digital measuring instruments according to the present invention sequentially automatically inputs analog reference signals corresponding to the measurement items of the target digital measuring instrument, and performs calibration using the output signals corresponding to the input signals VC. All calibration work is automated by calculating according to the program set in
The reliability of calibration can be improved because the measured values do not change depending on the person in charge.

<Example> Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a system showing the flow of calibration processing according to the present invention, and FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention.

In the first LAK, in the data file device 10, I'
The control signal Nζ generated by the calibration program for each digital measurement word to be calibrated in the C file is therefore:
Operate each part of this calibration device to make a predetermined measurement, measure the error, and make a pass/fail judgment by comparing the error and tolerance, and
The output of the calibration data and the entry of the file of the digital measuring instrument in the data file into the history file are automatically performed.

The above operation will be explained for each block. Digital measuring instrument 4K to be calibrated in Figure 1, reference signal source + that generates reference signals such as voltage, current or resistance that are calibration items
A signal source selection switching device 2 that selects the reference signal source to be used from (A, B, C, . . . 2), and an input terminal switching device 3 that selects and connects to the input terminal of the corresponding digital measuring instrument 4.
A connection to the reference signal source 1 is effected via a control signal.

The switching devices 2 and 3, which switch the connection of the above reference signals by the control signal from the data file device IO, were previously introduced in 1986 as "input switching devices for measuring instruments".
The switching device proposed in Japanese Patent Application No. 63-324356 filed on February 21st can be used.

The switching device proposed above has a configuration in which relays sealed in vacuum or inert gas are connected in a 7-trix configuration, and the relays are driven by a control signal amplified to the required output using a Darlington-connected transistor, etc. .

If the above-mentioned switching device is used, a constant connection state is achieved according to the control signal, so that changes in connection conditions that occur during manual switching will not cause differences in measured values.

The reference signal S is inputted to the digital measuring instrument 4 by the switching devices 2 and 3, and the measured value instruction output a and the reference signal S from the output terminal thereof are inputted to the constant error calculation unit 61, and the calculation unit 6 When a reference signal corresponding to the reference signal S is outputted, a measurement error C of the in++ constant meter 4 is outputted from the difference between the measured value instruction output a.

On the other hand, the tolerance calculation unit 5 contains the reference output signal S, the measurement range signal e of the measurement aN 4, and various tolerances d of the measuring instrument 4 to be calibrated that have been filed in advance in the data file device 10. This data ρ is input. The above tolerance d includes the full scale (f, s, ) error depending on the measured range.

Reaching (rd) by the magnitude of the measured value in that range
g) Error, digit error in the final digit of the indicated value, and calibration cycle error due to the period since the previous calibration.

From the above input signals s, d, and e, the tolerance calculation section 5Vc outputs a tolerance signal f under the calibration conditions of measurement R94.

Here, the calculation of the tolerance in the tolerance calculating section 5 will be explained for the 11111 fixed range of the direct voltage of the digital measuring instrument 4 as an example.

The range for calibrating the digital measuring instrument is (E), the reference signal selected from the reference signal source is (B), and the settings are as follows.

(E) is 20VL/7ji (7# scale/L/ is 20.0
00 range).

(B) is 20.00QV and 15. QOOV type 2 d has RDG error: 0.01% and f, s, error: 001
%.

(Example 1) When inputting 20.000 V to the 20 V range,
The rdg error of 0.01% is 20.000X0.0+÷l OO=0.002 this r
The dg error will be 0.002V.

Also, the f, s, and error of 001% are: 20,000 ,0
．． It becomes 004V.

This tolerance rate is 0.004X100÷20.000 = 0.02
It becomes 002%.

(Example 2) When 20VL/7jiK15.000V is input, the rdg error of 0, OI':'o is +5.000 Xo, 0! ÷100=0.0015
This rdg error becomes 0.00+5V.

Also, the f, s error of 0001% is 20.000 Xo, 0! ÷+00=0.00
．． Therefore, the tolerance between rdg error and f, s error is 0.00
It becomes 35V.

The tolerance rate is 0.0035X+00÷15.000=
It becomes 0.023 to 0.028%.

Next, the pass/fail comparison calculation section 7 performs a pass/fail judgment of the calibration based on the input measurement error C and tolerance signal f, and the comparison result output section 8 displays the pass/fail judgment result, related measurement data, and calculated values. At the same time, it is registered in the history file 9 of the data file device. The contents of the history file 9 registered above can be displayed on the output unit or printed out as required.

What is shown in the following FIG. 2 is a digital measuring instrument 33 of the present invention.
FIG. 2 is a block diagram of an automatic calibration system in which arithmetic processing and data file processing in calibration are processed by a Jl computer 55, and data to be processed is transmitted using CP-IB.

In FIG. 2, a reference signal is generated by a standard device +1 (A, B, C), and a standard device switching device 22 and an input switching device 33 of the digital measuring device 4 are operated by a driving power source 25. This switching device fff22゜23 is the first
The switching device explained in the figure was used.

Measurement error calculation section 6 explained in FIG. 1 above. The calculation processing by the tolerance calculation unit 5, pass/fail comparison calculation unit 7, etc. is performed by the computer 55. The calibration data of the digital measuring instrument 4 calibrated according to the program of the computer 55 is temporarily stored in its internal memory, and then outputted by the output device 88 and registered in the file device 99.

Although the above FIG. 2 is a simple block diagram because it was displayed by the computer 55, a program was created that has the same contents as the method explained in FIG. 1 for specific data processing of calibration. However, the program can be arbitrarily modified depending on the purpose.

As explained above, the present invention includes the selection of a reference signal from a reference signal source, the input to a digital measuring instrument, the calculation of an error from the output signal of the measuring instrument, and the recording of its calibration data. Automation eliminates errors caused by signal input, reading errors, data calculation errors, and recording errors, making it possible to construct a system that easily performs complete calibration of digital measuring instruments in a short period of time.

<Effects of the Invention> According to the present invention, a reference signal from a reference signal source is selected in correspondence with each digital meter 6111 to be calibrated, input of the selected reference signal to the input terminal of the digital measuring instrument, and measurement value indication output. It is possible to automate data processing and calibration data recording, including calculation of measurement errors from , with a relatively simple structure and configuration. Therefore, it is possible to provide an automatic calibration system for digital measuring instruments that can easily perform highly accurate calibration in a short time.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing the digital measuring instrument automatic calibration system of the present invention in functional blocks, and FIG. 2 is a system diagram showing one embodiment of the present invention in blocks.卜...Reference signal source, 2...Signal source selection switching device, 3.
...Input terminal selection switching device, 4...Digital fft
ITIIJ unit, 5...Tolerance calculation unit, 6...6 (1
j Constant difference calculation, 7... Pass/fail comparison calculation section, 8... Comparison result output section, 9... Measurement item and history file, 10
...Data file device, 11...Standard device, 22.
・・Standard device switching device, 25 ・・Drive power supply, 33・・
- Input switching device, 55... Computer, 88...
Output device, 99...file.

Claims (1)

[Claims] 1. means for sequentially outputting a selection signal and tolerance data of an analog reference signal input to a digital measuring instrument to be calibrated from a file device; means for selecting a reference signal source using the selection signal and selecting an analog reference signal; means for inputting the selected analog reference signal to a predetermined input terminal of the digital measuring instrument; and calculation from a comparison between the measured value instruction output (output signal) of the digital measuring instrument by inputting the analog reference signal and the analog reference signal. a calculation unit that compares the error of the output signal with a corresponding tolerance calculated from the plurality of types of tolerance of the digital measuring instrument in correspondence with the output signal to determine pass/fail; and outputs the calculation result to the outside. and means for recording in a calibration data file of the digital measuring instrument.