CN115574915A - Calibration method of newborn scale - Google Patents

Calibration method of newborn scale Download PDF

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Publication number
CN115574915A
CN115574915A CN202211343466.2A CN202211343466A CN115574915A CN 115574915 A CN115574915 A CN 115574915A CN 202211343466 A CN202211343466 A CN 202211343466A CN 115574915 A CN115574915 A CN 115574915A
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Prior art keywords
calibration
scale
newborn
sections
value
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Inventor
王志宾
陈小海
胡祥
刘天晴
连金钏
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Zhengzhou Dison Instrument And Meter Co ltd
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Zhengzhou Dison Instrument And Meter Co ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G23/00—Auxiliary devices for weighing apparatus
    • G01G23/01—Testing or calibrating of weighing apparatus

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  • General Physics & Mathematics (AREA)
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Abstract

The invention discloses a calibration method of a newborn scale, which comprises the steps of determining the maximum error H of a weighing and sampling circuit through a two-point calibration experiment; according to the ratio of the maximum error H to the standard precision G of the newborn scale, after the minimum number of the calibration sections is determined, the optimum number n of the calibration sections is selected; dividing the measuring range of the newborn scale into n sections, and ensuring that the increment of the nominal weights at the adjacent calibration points is equal; and determining the slope of each calibration section by recording the zero point and the sampling value of the weighing sampling circuit at each calibration point. The method has the advantages that the scale is calibrated by adopting a multi-section respective calibration method, and the calibration points replace the actual measurement sampling values with the standard theoretical values, so that the maximum value of system error accumulation which possibly occurs is effectively reduced, the linear compensation of the sensor by using hardware is avoided, and the cost performance is higher.

Description

Calibration method of newborn scale
Technical Field
The invention relates to the field of neonate scales, in particular to a calibration method of a neonate scale.
Background
A newborn scale is a measuring tool for measuring the weight of a newborn and has the characteristics of wide measuring range (0 to 12kg) and high precision (1 g). The calibration method of the newborn scale determines the error of the newborn scale. As shown in fig. 1, calibration of a typical newborn scale is performed by software to determine w/m, i.e., the slope K, while ensuring the linear output of the sensor. Then, the display value w is restored to correspond to the true value m, or the intercept (b) is directly changed to correspond to the true value, and the intercept (b) is changed to coincide with a previously fixed straight line as shown in the output of the straight line 1 in fig. 1 for any calibration object. The straight line 2 in fig. 1 is determined by a look-up table or a hardware circuit to determine the fixed slope k. However, in practical application, the dispersion of the slope of the weighing sensor with low price seriously affects the precision of the weighing scale for the newborn baby.
Disclosure of Invention
The invention aims to provide a calibration method of a newborn scale.
In order to achieve the purpose, the invention adopts the following technical scheme:
the calibration method of the newborn scale comprises the following steps:
s1, performing linear compensation through the output of a hardware symmetric retransmission sensor;
s2, determining the maximum error H of the weighing sampling circuit through a two-point calibration experiment;
s3, determining the minimum number of the calibration sections according to the ratio of the maximum error H to the standard precision G of the newborn scale, and then selecting the optimum number n of the calibration sections;
s4, dividing the measuring range of the newborn scale into n sections according to the optimal number n of the calibration sections, determining the intersection point of the adjacent calibration sections as a calibration point, and ensuring the increment of the nominal weights at the adjacent calibration points to be equal;
and S5, recording the sampling values of the weighing sampling circuit at the zero point and each calibration point, and determining the slope of each calibration section.
Further, the minimum number in the calibration section is a ratio of the maximum error H to the standard precision G of the newborn scale, and the minimum number is rounded up.
Further, the optimal number of the calibration sections is greater than or equal to the minimum number of the calibration sections and is determined according to user requirements.
Further, any sampling value of the weighing sampling circuit
Figure 100002_DEST_PATH_IMAGE002
The indication value is determined according to the following formula
Figure 100002_DEST_PATH_IMAGE004
：
Figure 100002_DEST_PATH_IMAGE006
Wherein,
Figure 100002_DEST_PATH_IMAGE008
is the slope of the ith segment;
Figure 100002_DEST_PATH_IMAGE010
sampling value of the i-1 th calibration point; m is the increment of the nominal weight at the adjacent calibration point; i takes on a value of
Figure 100002_DEST_PATH_IMAGE012
An integer of (d); and is determined according to the measuring range from large to small
Figure 100002_DEST_PATH_IMAGE014
And determining the value of i in the calibration section.
The invention has the advantages that the scale is calibrated by adopting a multi-section respective calibration method, and the calibration point replaces the actual measurement sampling value with the standard theoretical value, thereby effectively reducing the maximum value of possible system error accumulation, avoiding using hardware to carry out linear compensation on the sensor and having higher cost performance.
Drawings
Fig. 1 is a schematic diagram of the calibration principle of the scale for a newborn baby according to the present invention.
Fig. 2 is a schematic diagram illustrating the method for calibrating a newborn scale in a slope manner according to the present invention.
FIG. 3 is a schematic diagram of the 2-segment calibration method of the present invention.
Fig. 4 is a flow chart of the method of the present invention.
Fig. 5 is a circuit diagram of a weight sampling circuit in the method of the present invention.
Fig. 6 is a flow chart of the calibration in the 4 th stage of the embodiment of the method of the present invention.
FIG. 7 is a schematic diagram of calibration in paragraph 4 of the embodiment of the method of the present invention.
Fig. 8 is a flowchart of the method of the present invention, in accordance with an embodiment of the present invention, showing the weighing process of 4 stages of the scale.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
Methods for calibrating a newborn scale in a slope-finding manner are known in the art. The basic principle formula 1:
Figure DEST_PATH_IMAGE016
formula (1)
Wherein,
Figure DEST_PATH_IMAGE018
is the tare weight of the scale (i.e. the sampled output of the load cell when no object is placed),
Figure DEST_PATH_IMAGE020
the sampling output of the weighing sensor after weights are placed on the scale,
Figure DEST_PATH_IMAGE022
is the standard weight value when the weight mass is zero,
Figure DEST_PATH_IMAGE024
the standard weight value is the weight when the weight mass is m.
According to formula 1, sampling value of any weighing sensor
Figure DEST_PATH_IMAGE026
The value is calculated as formula 2:
Figure DEST_PATH_IMAGE028
formula (2)
Wherein,
Figure DEST_PATH_IMAGE030
sampled value for any of the load cells
Figure DEST_PATH_IMAGE032
Corresponding indication values;
Figure DEST_PATH_IMAGE034
the standard weight value of the weighing mass of the newborn baby scale at the moment is obtained.
The method for calibrating the newborn scale in the slope calculation mode is very simple, but due to the discreteness of the parameters of the weighing sensors, the linear output of the sensors is difficult to ensure by hardware, and finally, the indicating value error is still too large. As shown in fig. 2. In figure 2 to
Figure DEST_PATH_IMAGE036
、
Figure DEST_PATH_IMAGE038
、
Figure DEST_PATH_IMAGE040
、
Figure DEST_PATH_IMAGE042
Determining a straight line with a slope k for which any standard weight value
Figure DEST_PATH_IMAGE044
The sampling value of the corresponding weighing sensor is
Figure DEST_PATH_IMAGE046
And in fact, any standard weight value is due to the fact that the output of the load cell is not linear, but rather the curve shown in fig. 2
Figure DEST_PATH_IMAGE048
The sampling value of the corresponding weighing sensor is actually
Figure DEST_PATH_IMAGE050
，
Figure DEST_PATH_IMAGE052
And
Figure DEST_PATH_IMAGE054
difference of (2)
Figure DEST_PATH_IMAGE056
To indicate value errors. In order to reduce the indication error, the output of the hardware symmetrical weight sensor needs to be linearly compensated, which leads to the increase of the cost of the weighing scale for the newborn and the reduction of the cost performance.
Therefore, the calibration method of the newborn scale provides a concept of sectional calibration. The output of a common hardware symmetric retransmission sensor is adopted to carry out conventional linear compensation, in order to realize mass production and cost performance, the output of the sensor is not excessively emphasized to be infinitely close to linear output, and the residual nonlinear output after the hardware linear compensation is subjected to value indicating error reduction by a program segmented calibration method, as shown in fig. 3, the method is a related curve chart of 2-segment calibration. In the context of figure 3 of the drawings,
Figure DEST_PATH_IMAGE058
formula (3)
Figure DEST_PATH_IMAGE060
Formula (4)
When the sampling value of the weighing sensor
Figure DEST_PATH_IMAGE062
Then it indicates the value
Figure DEST_PATH_IMAGE064
Comprises the following steps:
Figure DEST_PATH_IMAGE066
formula (5)
From the above, theoretically, the more calibration segments, the smaller the absolute error. However, errors are also inevitable when calculating the slope k of each calibration segment, and the cumulative amount of these errors may exceed the error requirements of the newborn scale. To solve this problem, the calibration method of the newborn scale of the present invention, as shown in fig. 4, includes the following steps:
s1, determining an R value in a weighing sampling circuit; the sampling circuit is shown in FIG. 5, wherein Rt is a thermosensitive element or a thermosensitive sensing probe, and the sampling circuit is determined according to the characteristic parameters of the thermosensitive element or the thermosensitive sensing probe and the connection mode in the circuitRThe value is that the sampling value of the thermosensitive element or the thermosensitive sensing probe, namely the output value UO, is in linear relation with the weighing capacity. I.e. the output of the hardware symmetric retransmission sensor is used for linear compensation.
S2, determining the maximum error H of the weighing sampling circuit through a two-point calibration experiment; and on the basis of the step S1, the sampling precision of the weighing sensor is further improved by a multi-section calibration method. And (3) carrying out a section of two-point calibration experiment on a batch of sampled thermosensitive elements or thermosensitive sensing probes, and determining the maximum error H of the weighing sampling circuit in the experiment result.
S3, determining the minimum number of calibration sections according to the ratio of the maximum error H to the standard precision G of the newborn scale, and then selecting the optimum number n of the calibration sections; the minimum number of calibration sections is the rounding-up of the ratio of the maximum error H to the standard precision G of the newborn scale. The optimal number of the calibration sections needs to be more than or equal to the minimum number of the calibration sections, and is determined according to user requirements such as the measuring range of the newborn scale, the nominal weight, the calibration convenience and the like.
S4, dividing the measuring range of the newborn scale into n sections according to the optimal number n of the calibration sections, determining the intersection point of the adjacent calibration sections as a calibration point, and ensuring that the addition amount of the nominal weights of the calibration sections is equal; instant game
Figure DEST_PATH_IMAGE068
Formula (6)
Wherein,
Figure DEST_PATH_IMAGE070
the sampling value of the weighing sensor at the zero point is;
Figure DEST_PATH_IMAGE072
、
Figure DEST_PATH_IMAGE074
、
Figure DEST_PATH_IMAGE076
、
Figure DEST_PATH_IMAGE078
sampling values of the weighing sensors at the intersection points of the adjacent calibration sections;
Figure DEST_PATH_IMAGE080
、
Figure DEST_PATH_IMAGE082
、
Figure DEST_PATH_IMAGE084
the slope of the calibration segment.
The essential meaning of the formula (6) is that the increase of the nominal weight at the adjacent calibration point is
Figure DEST_PATH_IMAGE086
Are equal, i.e.
Figure DEST_PATH_IMAGE088
Formula (7)
Combining the formula (5) and the formula (7), it can be known that any sampling value of the symmetric resampling circuit
Figure DEST_PATH_IMAGE090
Indication of value
Figure DEST_PATH_IMAGE092
Comprises the following steps:
Figure DEST_PATH_IMAGE094
formula (8)
Wherein,
Figure DEST_PATH_IMAGE096
is the slope of the ith segment;
Figure DEST_PATH_IMAGE098
sampling value of the i-1 th calibration point; m is the increment of the nominal weight at the adjacent calibration point; i takes a value of
Figure DEST_PATH_IMAGE100
An integer of (a); and is determined according to the measuring range from large to small
Figure DEST_PATH_IMAGE102
And determining the value of i in the belonged calibration section.
This can solve the problem of limiting the inevitable error accumulation to the minimum when calculating the slope k of each calibration segment.
And S5, recording the sampling values of the weighing sampling circuit at the zero point and each calibration point, and determining the slope of each calibration section. Fig. 6 shows a flow chart of 4-stage calibration, and fig. 7 is a schematic diagram of four-stage calibration. The measuring range of the whole newborn scale is averagely divided into 4 sections, and the increment of each section of nominal weight is
Figure DEST_PATH_IMAGE104
。
Firstly, weighing and sampling are carried out without weights, namely, the sampling value of a weighing and sampling circuit is recorded at the zero point
Figure DEST_PATH_IMAGE106
Doubling the nominal weight increment at adjacent calibration points
Figure DEST_PATH_IMAGE108
That is, the weight with the weight of 1m is weighed and sampled, and the sampling value of the weighing and sampling circuit is recorded
Figure DEST_PATH_IMAGE110
Recording and calculating the slope of the 1 st calibration segment
Figure DEST_PATH_IMAGE112
. Weighing and sampling a weight with the weight of 2m, and recording the sampling value of the weighing and sampling circuit
Figure DEST_PATH_IMAGE114
Recording and calculating the slope of the 2 nd segment calibration segment
Figure DEST_PATH_IMAGE116
Weighing and sampling a weight with the weight of 3m, and recording the sampling value of the weighing and sampling circuit
Figure DEST_PATH_IMAGE118
Recording and calculating the slope of the calibration segment 3
Figure DEST_PATH_IMAGE120
. Weighing and sampling a weight with the weight of 4m, and recording the sampling value of a weighing and sampling circuit
Figure DEST_PATH_IMAGE122
Recording and calculating the slope of the calibration segment 4
Figure DEST_PATH_IMAGE124
. Thus, the calibration of the whole newborn scale is completed. Wherein
Figure DEST_PATH_IMAGE126
、
Figure DEST_PATH_IMAGE128
、
Figure DEST_PATH_IMAGE130
、
Figure DEST_PATH_IMAGE132
Is the sampled value of the calibration point.
Figure DEST_PATH_IMAGE134
The sample value at zero.
In use, when the newborn scale is weighed, any sampling value of the weighing sampling circuit is used
Figure DEST_PATH_IMAGE136
The indication value is determined according to the following formula
Figure DEST_PATH_IMAGE138
：
Figure DEST_PATH_IMAGE140
Formula (8)
Wherein,
Figure DEST_PATH_IMAGE142
is the slope of the ith segment;
Figure DEST_PATH_IMAGE144
sampling value of the i-1 th calibration point; m is the increment of the nominal weight at the adjacent calibration point; i takes a value of
Figure DEST_PATH_IMAGE146
An integer of (d); and is determined according to the measuring range from large to small
Figure DEST_PATH_IMAGE148
And determining the value of i in the belonged calibration section.
Referring specifically to FIG. 8, the use of a newborn scale with 4-stage calibration is taken as an example to explain any sampling value of its symmetrical resampling circuit
Figure DEST_PATH_IMAGE150
How to determine the indication.
First, it is judged
Figure DEST_PATH_IMAGE152
Whether it is zero, i.e. determined from large to small in terms of range
Figure DEST_PATH_IMAGE154
The associated calibration section is provided with
Figure DEST_PATH_IMAGE156
If yes, the weighing quantity to be weighed exceeds the total measuring range of the newborn scale, and the weighing is processed according to the overmeasuring range. If it is
Figure DEST_PATH_IMAGE158
If not, continue to judge
Figure DEST_PATH_IMAGE160
Whether it is true, namely, under judgment
Figure DEST_PATH_IMAGE162
Whether or not greater than
Figure DEST_PATH_IMAGE164
Is less than
Figure DEST_PATH_IMAGE166
. If the judgment is true, the result is that
Figure DEST_PATH_IMAGE168
In the 4 th calibration phase, the indication is calculated according to equation (8) as:
Figure DEST_PATH_IMAGE170
that is, i in formula (8) is 4, w is formula (8)
Figure DEST_PATH_IMAGE172
。
If it is
Figure DEST_PATH_IMAGE174
If not, continue to judge
Figure DEST_PATH_IMAGE176
Whether it is true, namely, under judgment
Figure DEST_PATH_IMAGE178
Whether or not greater than
Figure DEST_PATH_IMAGE180
Is less than
Figure DEST_PATH_IMAGE182
. If the judgment is true, the result is that
Figure DEST_PATH_IMAGE184
In calibration phase 3, the value is calculated according to equation 8 as:
Figure DEST_PATH_IMAGE186
that is, i in formula (8) is 3, w is formula (8)
Figure DEST_PATH_IMAGE188
。
If it is
Figure DEST_PATH_IMAGE190
If not, continue to judge
Figure DEST_PATH_IMAGE192
Whether or not it is true, namely, under
Figure DEST_PATH_IMAGE194
Whether or not greater than
Figure DEST_PATH_IMAGE196
Is less than
Figure DEST_PATH_IMAGE198
. If the judgment is true, the result is that
Figure DEST_PATH_IMAGE200
In calibration phase 2, the indication is calculated according to equation (8) as:
Figure DEST_PATH_IMAGE202
that is, if i in formula (8) is 2, w is the same as in formula (8)
Figure DEST_PATH_IMAGE204
。
If it is
Figure DEST_PATH_IMAGE206
If not, continue to judge
Figure DEST_PATH_IMAGE208
Whether it is true, namely, under judgment
Figure DEST_PATH_IMAGE210
Whether or not greater than
Figure DEST_PATH_IMAGE212
Is less than
Figure DEST_PATH_IMAGE214
. If the judgment is true, the result is that
Figure DEST_PATH_IMAGE216
In the 1 st calibration phase, the indication is calculated according to equation (8) as:
Figure DEST_PATH_IMAGE218
that is, if i in the formula (8) is 1, w is the same as that in the formula (8)
Figure DEST_PATH_IMAGE220
。
If it is
Figure DEST_PATH_IMAGE222
If not, the value is 0.

Claims (4)

1. A calibration method of a newborn scale is characterized by comprising the following steps: the method comprises the following steps:
s1, performing linear compensation through the output of a hardware symmetric retransmission sensor;
s2, determining the maximum error H of the weighing sampling circuit through a two-point calibration experiment;
s3, determining the minimum number of calibration sections according to the ratio of the maximum error H to the standard precision G of the newborn scale, and then selecting the optimum number n of the calibration sections;
s4, dividing the measuring range of the newborn scale into n sections according to the optimal number n of the calibration sections, determining the intersection point of the adjacent calibration sections as a calibration point, and ensuring that the increment of the nominal weight at the adjacent calibration points is equal;
and S5, recording the sampling values of the weighing sampling circuit at the zero point and each calibration point, and determining the slope of each calibration section.
2. The calibration method of the newborn scale according to claim 1, characterized in that: and in the calibration section, the minimum number is the ratio of the maximum error H to the standard precision G of the newborn scale, and the maximum error H is rounded up.
3. The method for calibrating a neonatal scale of claim 1, wherein: the optimal number of the calibration sections is greater than or equal to the minimum number of the calibration sections and is determined according to user requirements.
4. The method for calibrating a neonatal scale of claim 1, wherein: for any sampling value of the weighing sampling circuit
Figure DEST_PATH_IMAGE002
The indication value is determined according to the following formula
Figure DEST_PATH_IMAGE004
：
Figure DEST_PATH_IMAGE006
Wherein,
Figure DEST_PATH_IMAGE008
is the slope of the ith segment;
Figure DEST_PATH_IMAGE010
sampling value of the i-1 th calibration point; m is the increment of the nominal weight at the adjacent calibration point; i takes a value of
Figure DEST_PATH_IMAGE012
An integer of (d); and is determined according to the measuring range from large to small
Figure DEST_PATH_IMAGE014
And determining the value of i in the calibration section.
CN202211343466.2A 2022-10-31 2022-10-31 Calibration method of newborn scale Pending CN115574915A (en)

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Application Number Priority Date Filing Date Title
CN202211343466.2A CN115574915A (en) 2022-10-31 2022-10-31 Calibration method of newborn scale

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Publication Number Publication Date
CN115574915A true CN115574915A (en) 2023-01-06

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