CN104123436A - Accurate and reliable intermediate check method - Google Patents

Abstract

The invention discloses an accurate and reliable intermediate check method. According to the method, only one stable check standard is needed, economic cost is low, labor intensity is lowered, and result judgment is absolutely clear. The method includes the specific steps that (1) a single measurement standard deviation is obtained; (2) the minimum measurement times m of check are determined; (3) a check control limit is determined, wherein serves as a center line CL, +MPEV-(x-xN) serves as the upper control limit UCL, -MPEV-(x-xN) serves as the lower control limit LCL, UCL-U equals to +MPEV-(x-xN)-U which is an inner warning line of the upper control limit UCL, UCL+U equals to +MPEV-(x-xN)+U which is an outer warning line of the upper control limit UCL, LCL-U equals to -MPEV-(x-xN)-U which is an outer warning line of the lower control limit LCL, and LCL+U equals to -MPEV-(x-xN)+U which is an inner warning line of the lower control limit LCL; (4) a control chart is drawn according to the control limits; (5) a check result is judged.

Description

One is Intermediate Checks method accurately and reliably

Technical field

This area relates to one Intermediate Checks method accurately and reliably.

Background technology

Measuring equipment is the requisite technological means of metering detection field, in practical application, described equipment (for example there will be the variation of part aging, drift and environment for use and the generation of some other situation, collision, vibrations, overload running etc.) all can have influence on its performance and accuracy, thus directly have influence on laboratory verification, calibration, testing result accurately and reliably.In the 5.6.3.3 of document [1], specify: should program and schedule according to the rules normative reference, benchmark, Transfer Standards or working stamndard and standard substance (reference material) be verified, to keep the degree of confidence of its align mode.In the 7.6.3.3 of document [2], also specify: should program and schedule according to the rules normative reference, benchmark, Transfer Standards or working stamndard and standard substance be verified, to keep the degree of confidence of its calibrating or align mode.Intermediate Checks just becomes laboratory grasps the effective means of measuring equipment align mode during sending school twice.The error change direction that but the operation of current Intermediate Checks method is more loaded down with trivial details, workload is large, operation easier is verified measurement result greatly, at every turn and size are difficult for observing, although the statistical control method that patent CN102495961A proposes has effectively solved the problems referred to above, need the accumulation of long-time many group preliminary dates to set up control limit.

Summary of the invention

Object of the present invention is exactly in order to address the above problem, propose a kind of by the measurement to selected check standard, utilize the calibration result and the uncertainty thereof that are provided by the limits of error of check standard and calibration certificate, determine and verify " center line ", upper lower control limit and the warning line measured, draw control chart according to these boundaries, the error change direction and the size that make to verify measurement result high-visible in the drawings at every turn.This result also can be used as the foundation of measurement standard stability assessment.

For achieving the above object, the technical solution used in the present invention is as follows:

One is Intermediate Checks method accurately and reliably, comprises step:

1) obtain single measurement standard deviation: under repeat condition, selected check standard is carried out to independent measurement n time, obtain single measurement standard deviation s;

2) determine and verify minimal number of measurements m:

3) definite kernel is looked into control limit: verifying first measurement is to carry out after higher level's calibration is fetched in measurement standard, according to step 2) definite minimal number of measurements m, under reference conditions, check standard is carried out to m time and measure, the mean value calculating is designated as get centered by line CL, for upper control limit UCL, for lower control limit LCL; UCL-U for warning line in upper control limit UCL, UCL+U for the outer warning line of upper control limit UCL; LCL-U for the outer warning line of lower control limit LCL, LCL+U for warning line in lower control limit LCL; Its Plays actual value x _nand uncertainty U is that calibration certificate provides;

4) draw control chart according to verification control limit definite in step 3, will verify the mean value of measurement at every turn on figure, mark;

5) result is verified in judgement:

According to step 4) obtain each mean value of measuring of verifying the difference of distributing position is carried out result and is judged: between upper and lower interior warning line, be that qualified district is for satisfied; Between the inside and outside warning line of upper control limit or lower control limit, be security area, should analyze immediately reason, processed, and remeasure, in security area, measurement standard is served as early as possible to level calibration as still; Exceed outer warning line, analyze immediately reason, processed, and remeasure, as still exceeded outer warning line, measurement standard is served to level calibration immediately.

Described step 1) in, frequency n >=12 measured.

Described step 2) in, the specific operation process of verifying minimal number of measurements m is:

Mean value standard deviation expression is: x _ibe an independent measurement value, 1≤i≤n;

should meet following relation with the absolute value MPEV of the limits of error of being verified measurement standard:

${2s}_{\stackrel{\‾}{x}}\≤\frac{1}{3}\mathrm{MPEV}$

Consider from tighter requirement, above-mentioned relation be adjusted into:

${2s}_{\stackrel{\‾}{x}}\≤\frac{1}{5}\mathrm{MPEV}$

? $2\frac{s}{\sqrt{m}}\≤\frac{1}{5}\mathrm{MPEV}$

So $m\≥{\left(\frac{10s}{\mathrm{MPEV}}\right)}^2$

Verify minimal number of measurements m round numbers, only enter not give up.

Described step 3) in, control chart drawn for utilizing excel spreadsheet lattice to draw.

Described step 4) in, in described control chart, be linked to be broken line by adjacent 2.

Described step 4) in, the mean value that described each verification is measured for periodic measurement or the irregular mean value of measuring.

Described step 1) in, adopt Rye to reach criterion and claim again 3s criterion rejecting abnormalities value, if i.e.: certain measured value x _iresidual error V _imeet the following conditions:

$\left|V_i\right|=|x_i-\stackrel{\‾}{x}|>3s$

This measured value is rejected, residue measured value is asked for to single measurement standard deviation, wherein for measuring mean value, s is single measurement standard deviation.

Beneficial effect

Beneficial effect of the present invention is:

1, can see clearly and be verified the value of measurement standard or the direction of error change and size;

2, only need a stable check standard, check standard does not need to serve level calibration or laboratory measurement at the same level, thereby financial cost is low;

3, confirm minimal number of measurements, thereby can avoid doing some meaningless measurements, reduced labour intensity;

4, the processing of data and the judgement of result adopt the method for verifying control chart, make the judgement of result very clear, are convenient to observe;

5, do not need the accumulation of long-time many group preliminary dates just can set up control limit.

Brief description of the drawings

Fig. 1 is process flow diagram of the present invention;

Fig. 2 is high resistance instrument 100M Ω measurement point Intermediate Checks result.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described further:

1, obtain single measurement standard deviation

Under repeated condition, selected check standard is carried out to n independent measurement, measure number of times and get n >=12, now can adopt Rye to reach criterion (claiming again 3s criterion) and carry out rejecting abnormalities value, first obtain single measurement standard deviation s.

2, determine and verify minimal number of measurements m

The method of reference literature [3] is determined verification minimal number of measurements m.There is the standard deviation s of single measurement, so mean value standard deviation

Mean value standard deviation should meet following relation with the absolute value MPEV of the limits of error of being verified measurement standard:

${2s}_{\stackrel{\‾}{x}}\≤\frac{1}{3}\mathrm{MPEV}$

Consider from tighter requirement, above-mentioned relation be adjusted into:

${2s}_{\stackrel{\‾}{x}}\≤\frac{1}{3}\mathrm{MPEV}$

? $2\frac{s}{\sqrt{m}}\≤\frac{1}{5}\mathrm{MPEV}$

So $m\≥{\left(\frac{10s}{\mathrm{MPEV}}\right)}^2---\left(1\right)$

Verify minimal number of measurements m round numbers, only enter not give up.From above formula, if m is desirable 3, if m is desirable 1, for cautiously, verification now measure number of times can people for increasing to 2 times or 3 times, this is more rational to most measurement standard.

Formula (1) is verified measurement number of times m size for determining provides foundation, can avoid doing some meaningless verifications and measure, thereby increase work efficiency, and reduces labour intensity.

3, definite kernel is looked into control limit

First obtain according to the instructions of measurement standard and higher level's calibration certificate etc. the following information of being verified some x: the absolute value MPEV of the limits of error, standard value (actual value) x that calibration certificate provides _nand uncertainty U.

Different from statistics control, Intermediate Checks starts not need the accumulation of long-time many group preliminary dates to set up control limit.Verifying first measurement is to carry out as early as possible after higher level's calibration is fetched in measurement standard, according to the definite minimal number of measurements m of formula (1), under reference conditions, check standard is carried out to m time and measures, and the mean value calculating is designated as for regular (every mistake one month, two months, a season etc.) or irregular (at any time) measure check standard again, obtain each mean value of measuring of verifying afterwards: , depending on by the stability of check standard, can shorten or extend at the interval of periodic measurement.

With centered by line (CL, this line is not necessarily in the centre of upper and lower control limit, as Fig. 1), with for upper control limit (UCL), with for lower control limit (LCL); With UCL-U be for the interior warning line of upper control limit (UCL), with UCL+U be for the outer warning line of upper control limit (UCL); In like manner, with LCL-U be for the outer warning line of lower control limit (LCL), with LCL+U be for the interior warning line of lower control limit (LCL).

4, draw control chart according to control limit

The mean value of measurement will be verified at every turn on figure, mark, and be linked to be broken line by adjacent 2, as shown in Figure 2.Fig. 2 is high resistance instrument 100M Ω measurement point Intermediate Checks result, and related data is: the absolute value MPEV=0.11M Ω of the limits of error; The standard value x that calibration certificate provides _n=100.000M Ω, its uncertainty U=0.02M Ω, measured value x=100.014M Ω; Verify first the mean value of measuring the data of later all previous verification are as table 1.

Table 1100M Ω verifies and measures mean value

Verifying control chart can draw with excel spreadsheet lattice, and the roughly step of drafting is: will be verified the value of some x, the absolute value MPEV of its limits of error, standard value (actual value) x that calibration certificate provides _nand uncertainty U, verify first the mean value of measuring be input in certain cell.The mean value of measurement will be verified at every turn be made as a column data, when beginning, only have it is for subsequent use that h-1 cell left in back, and h is that measurement standard arrives the front number of times of estimating verification of calibration next time; By quoting of cell data, warning line data in warning line, the outer warning line of upper control limit, the outer warning line of lower control limit, lower control limit in center line (CL), upper control limit (UCL), lower control limit (LCL), upper control limit are calculated, be made as respectively 1 row h identical data, choose all these data, click " chart " order in " insertion " menu, there is " subtype " dialog box, select " broken line graph ", click " completing ", can produce the verification control chart as Fig. 2.Every verification is afterwards measured once, and mean value input is verified and measured average data row, is engraved in and in control chart, marks this point, and be connected with broken line with former measurement point.

Other verifies the making of point control figure, as long as copy worksheet will be verified the value of some x, the absolute value MPEV of its limits of error, standard value (actual value) x that calibration certificate provides _nand uncertainty U, verify first the mean value of measuring be input in corresponding cell, just can obtain the verification control chart of this point.Next making of verifying periodic Control figure, standard value (actual value) x that only calibration certificate need be provided _nand uncertainty U is input in corresponding cell.

5, result is verified in judgement

The value of supposing check standard in Intermediate Checks measuring process is constant.Each mean value of measuring of verifying may be distributed in the upper and lower both sides of center line, more than center line, represent that the error of measurement standard " becomes large " towards the direction of " just ", below center line, represent that the error of measurement standard " becomes large " towards the direction of " bearing ", the verification result that verification result (is called qualified district) between upper and lower interior warning line is satisfied; Verify result between the inside and outside warning line of upper control limit or lower control limit when (being called security area), should analyze immediately reason, appropriately process, and remeasure, as still in security area, before getting rid of while not being the reason of check standard, can taking to use measurement standard at every turn, all to verify measurements, and consider measurement standard to serve as early as possible and grade calibrate; In the time that verification result exceeds outer warning line, should analyze immediately reason, appropriately process, and remeasure, as still exceeded outer warning line, in the time that eliminating is not the reason of check standard, can consider measurement standard to serve immediately level calibration.Measure control chart by verification like this, can grasp intuitively and accurately by the variation tendency of the error of check standard or value and change size.This result also can be used as the foundation of measurement standard stability assessment.

Measurement standard repeats above-mentioned steps 1～5 and carries out next round Intermediate Checks after again serving level calibration and fetching.If the value of measurement standard or error change are larger, or adjust, can not affect the Intermediate Checks of next round.

The present invention is by the measurement to selected check standard, utilize the calibration result and the uncertainty thereof that are provided by the limits of error of check standard and calibration certificate, determine and verify " center line ", upper lower control limit and the warning line of measuring control chart, take full advantage of relevant information, draw out control chart according to these boundaries, just can see clearly and be verified the value of measurement standard or the direction of error change and size.This Intermediate Checks only needs a stable check standard, and check standard does not need to serve level calibration or laboratory measurement at the same level, thereby financial cost is low; Before verifying measurement, confirm minimal number of measurements, thereby can avoid doing some meaningless measurements, reduced labour intensity; The processing of data and the judgement of result adopt the method for verifying control chart, make the judgement of result very clear, make lab assistant be happy to verify.

List of references of the present invention is:

[1]CNAS—CL01:2006。Testing and calibration laboratories capability Approval criterion [S].

[2]JJF1069—2012。Legal metering validation activity examination specification [S].

[3] Fan Qiaocheng.The Statistical control of measurement process method [J] of simplifying.Metering journal, 2012, (5): 284-288.

By reference to the accompanying drawings the specific embodiment of the present invention is described although above-mentioned; but not limiting the scope of the invention; one of ordinary skill in the art should be understood that; on the basis of technical scheme of the present invention, those skilled in the art do not need to pay various amendments that creative work can make or distortion still in protection scope of the present invention.

Claims (7)

1. an Intermediate Checks method accurately and reliably, is characterized in that, comprises step:

1) obtain single measurement standard deviation: under repeat condition, selected check standard is carried out to independent measurement n time, obtain single measurement standard deviation s;

2) determine and verify minimal number of measurements m:

3) definite kernel is looked into control limit: verifying first measurement is to carry out after higher level's calibration is fetched in measurement standard, according to step 2) definite minimal number of measurements m, under reference conditions, check standard is carried out to m time and measure, the mean value calculating is designated as get centered by line CL, for upper control limit UCL, for lower control limit LCL; UCL-U for warning line in upper control limit UCL, UCL+U for the outer warning line of upper control limit UCL; LCL-U for the outer warning line of lower control limit LCL, LCL+U for warning line in lower control limit LCL; Its Plays actual value x _nand uncertainty U is that calibration certificate provides;

4) draw control chart according to verification control limit definite in step 3, will verify the mean value of measurement at every turn on figure, mark;

5) result is verified in judgement:

According to step 4) obtain each mean value of measuring of verifying the difference of distributing position is carried out result and is judged: between upper and lower interior warning line, be that qualified district is for satisfied; Between the inside and outside warning line of upper control limit or lower control limit, be security area, should analyze immediately reason, processed, and remeasure, in security area, measurement standard is served as early as possible to level calibration as still; Exceed outer warning line, analyze immediately reason, processed, and remeasure, as still exceeded outer warning line, measurement standard is served to level calibration immediately.

2. one as claimed in claim 1 Intermediate Checks method accurately and reliably, is characterized in that described step 1) in, frequency n >=12 measured.

3. one as claimed in claim 1 Intermediate Checks method accurately and reliably, is characterized in that described step 2) in, the specific operation process of verifying minimal number of measurements m is:

Mean value standard deviation expression is: x _ibe an independent measurement value, 1≤i≤n;

should meet following relation with the absolute value MPEV of the limits of error of being verified measurement standard:

${2s}_{\stackrel{\‾}{x}}\≤\frac{1}{3}\mathrm{MPEV}$

Consider from tighter requirement, above-mentioned relation be adjusted into:

${2s}_{\stackrel{\‾}{x}}\≤\frac{1}{5}\mathrm{MPEV}$

? $2\frac{s}{\sqrt{m}}\≤\frac{1}{5}\mathrm{MPEV}$

So $m\≥{\left(\frac{10s}{\mathrm{MPEV}}\right)}^2$

Verify minimal number of measurements m round numbers, only enter not give up.

4. one as claimed in claim 1 Intermediate Checks method accurately and reliably, is characterized in that described step 3) in, control chart drawn for utilizing excel spreadsheet lattice to draw.

5. one as claimed in claim 1 Intermediate Checks method accurately and reliably, is characterized in that described step 4) in, in described control chart, be linked to be broken line by adjacent 2.

6. one as claimed in claim 1 Intermediate Checks method accurately and reliably, is characterized in that described step 4) in, the mean value that described each verification is measured for periodic measurement or the irregular mean value of measuring.

7. one as claimed in claim 2 Intermediate Checks method accurately and reliably, is characterized in that described step 1) in, adopt Rye to reach criterion and claim again 3s criterion rejecting abnormalities value, if i.e.: certain measured value x _iresidual error V _imeet the following conditions:

$\left|V_i\right|=|x_i-\stackrel{\‾}{x}|>3s$

This measured value is rejected, residue measured value is asked for to single measurement standard deviation, wherein for measuring mean value, s is single measurement standard deviation.