CN217403570U

CN217403570U - Electronic scale with gain temperature compensation

Info

Publication number: CN217403570U
Application number: CN202123276080.8U
Authority: CN
Inventors: 林超
Original assignee: Avia Semiconductor Xiamen Co ltd
Current assignee: Avia Semiconductor Xiamen Co ltd
Priority date: 2021-12-23
Filing date: 2021-12-23
Publication date: 2022-09-09
Anticipated expiration: 2031-12-23

Abstract

The utility model provides a take gain temperature compensation's electronic scale, including power module, sensor interface, analog to digital converter module, voltage detection module, display module, keyboard module and singlechip, the model of singlechip is HXM6002, and the analog to digital converter chip is HX 710A. The power module is electrically connected with a 16 th pin and a display module of the single chip microcomputer, the 2 nd pin and the 4 th pin of the single chip microcomputer are electrically connected with the analog-to-digital converter module, the analog-to-digital converter module is electrically connected with the sensor interface, and the single chip microcomputer is electrically connected with the display module. The single chip microcomputer is electrically connected with the keyboard module. The data measured by HX710A need not be converted to absolute temperature values and used directly in the temperature compensation calculations described above. Besides converting the voltage signal into a digital signal, the temperature signal is also provided to the single chip module 7, that is, temperature data is provided to the gain temperature compensation program, so that the complexity of compensation of gain drift is greatly reduced.

Description

Electronic scale with gain temperature compensation

Technical Field

The utility model relates to an electronic scale technical field, concretely relates to take electronic scale of gain temperature compensation.

Background

The temperature characteristic of the electronic scale is mainly determined by the sensor and the A/D converter, and is represented by zero drift and gain drift. The compensation of zero drift can be reduced and eliminated by adopting a method of starting zero setting and zero tracking. But the compensation of the gain drift is relatively complex.

SUMMERY OF THE UTILITY MODEL

The utility model relates to a solve foretell problem, the utility model provides a take electronic scale of gain temperature compensation, including power module, sensor interface, analog to digital converter module, voltage detection module, display module, keyboard module and singlechip, the model of singlechip is HXM6002, 16 th pin, the display module of power module electric connection singlechip, 2 nd pin, the 4 th pin electric connection analog to digital converter module of singlechip, analog to digital converter module electric connection interface, singlechip electric connection display module. The single chip microcomputer is electrically connected with the keyboard module.

Preferably, the sensor interface is used for connecting a weighing sensor.

Preferably, the analog-to-digital converter chip of the analog-to-digital converter module is of model number HX 710A.

Preferably, the display module is a segment code type liquid crystal display screen or a digital tube.

Preferably, the power module includes an interface P1, the interface P1 is connected with an external transformer, the interface P1 is electrically connected with four diodes D1, D2, D3 and D4, and then is electrically connected with an electrolytic capacitor C3 and an electrolytic capacitor C4 for rectifying an alternating current signal into a direct current signal, and the electrolytic capacitor C3 and the electrolytic capacitor C4 are electrically connected with two parallel 7533 voltage-regulator tubes for outputting two sets of direct current signals.

Preferably, the two parallel-connected 7533 voltage regulator tubes are electrically connected with a P4 interface at the input ends, and the P4 interface is used for connecting a lead-acid battery.

Preferably, the positive electrode BT of the lead-acid battery is electrically connected with the ADC interface of the single chip microcomputer after being subjected to voltage division by R6 and R7.

A power supply module: the device is used for connecting a charger, charging the lead-acid battery and stabilizing the voltage of the battery;

a sensor interface: the pressure sensor is used for connecting the weighing sensor and converting the pressure signal into an analog voltage signal;

an analog-to-digital converter module: the temperature sensor is used for measuring temperature data, converting an analog voltage signal into a digital signal and outputting the digital signal to the single chip microcomputer for processing;

the voltage detection module: the charging device is used for detecting the voltage of the battery to prompt charging; the positive electrode BT of the lead-acid battery is input to an ADC port of the single chip microcomputer after being subjected to voltage division by R6 and R7, and when the voltage of the battery is lower than 3.7v, the electronic scale prompts charging.

A display module: for displaying weight information, unit price information, amount information, and the like;

a keyboard module: carrying out weight calibration, function setting, pricing operation and the like on the electronic scale;

a single chip microcomputer: the method is mainly used for processing digital signals of the analog-digital converter, battery voltage detection, display, key operation and the like.

The utility model has the advantages that: the utility model discloses a temperature sensor of A/D converter chip HX710A internal integration be fit for such application very much, in practical application, need not turn into absolute temperature value with the data that HX710A surveyed, it can to directly use for foretell temperature compensation calculation. In addition to converting the voltage signal into a digital signal, a temperature signal is also provided to the single chip module 7, i.e. temperature data is provided to the gain temperature compensation program. The complexity of compensation of gain drift is greatly reduced.

Drawings

FIG. 1 is a gain versus temperature curve of the present invention;

FIG. 2 illustrates the gain drift compensation effect of the present invention;

FIG. 3 is a schematic diagram of a power module of the present invention;

FIG. 4 is a diagram of the structure of the single chip microcomputer of the invention;

FIG. 5 is a schematic diagram of the interface and analog-to-digital converter module connection of the present invention;

FIG. 6 is a schematic diagram of a display module of the present invention;

FIG. 7 is a schematic diagram of the voltage detection module of the present invention;

FIG. 8 is a schematic diagram of a keyboard module of the present invention;

FIG. 9 is a block diagram of the software for acquiring gain temperature data according to the present invention;

fig. 10 is a block diagram of gain drift compensation software according to the present invention.

In the figure: the device comprises a power module 1, a sensor interface 2, an analog-to-digital converter module 3, a voltage detection module 4, a display module 5 and a keyboard module 6.

Detailed Description

The preferred embodiments of the present invention will be described hereinafter with reference to the accompanying drawings, and it should be understood that the preferred embodiments described herein are merely for purposes of illustration and explanation, and are not intended to limit the present invention.

As shown in fig. 1 to 10, the compensation method proposed by the electronic scale with gain temperature compensation is simple and easy for the temperature compensation of the gain, and can effectively compensate the temperature drift of the whole electronic scale system including the sensor, thereby reducing the temperature characteristic requirement of the system on the sensor.

The temperature characteristic of the gain refers to the characteristic that the gain of the electronic scale system changes with the change of the temperature, and refer to fig. 1.

The gain drift compensation is performed to compensate the gain of the electronic scale system to be invariant with temperature. The slope of the curve in fig. 1 is defined as the linear compensation coefficient C:

if the electronic scale system is at two temperature points T _A 、T _B Calibration is carried out, then the electronic scale system is at other temperature points T _N Actual gain G of _N Comprises the following steps:

G _N ＝G _A ±ΔG＝G _A ±(C _{positive/negative} ×ΔΤ) ⑶

In the formula (III), the reaction is carried out,

as long as the temperature is T _N Actual gain G of time _N Subtracting DeltaG to make the temperature T _N When the temperature of the water is higher than the set temperature,the gain of the system is compensated and then changed back to G _A Thereby realizing drift compensation of the gain. The gain drift compensation effect is shown in fig. 2.

This compensation principle does not require an accurate temperature measurement, only that the temperature measurement is linear. The utility model discloses a temperature sensor of A/D converter chip HX710A internal integration be fit for such application very much, in practical application, need not turn into absolute temperature value with the data that HX710A surveyed, it can to directly use for foretell temperature compensation calculation.

The power supply module 1 supplies power to the sensor interface 2, the analog-to-digital converter module 3, the display module 5 and the single chip microcomputer after stabilizing the voltage of the input battery; the single chip microcomputer completes human-computer interaction between a user and the electronic scale through a keyboard module 6 and a display module 5, wherein the human-computer interaction comprises worker calibration operation before delivery and user use operation after delivery; the sensor interface 2 converts a weighing signal into a voltage signal through an external weighing sensor, converts the voltage signal into a digital signal through the analog-to-digital converter module 3, and then supplies the digital signal to the single chip microcomputer for processing, and finally displays a weight value through the display module 5; the analog-to-digital converter module 3 of this embodiment adopts HX710A, and not only converts the voltage signal into a digital signal, but also provides a temperature signal to the single chip, i.e., provides temperature data to the gain temperature compensation program.

The method comprises the following steps:

the electronic scale is calibrated at two temperature points, the larger the temperature difference is, the better the compensation effect is, and the lower the requirement on the accuracy of gain calibration is. For example, in an electronic price computing scale with a full scale of 30Kg and a division value of 5g, a compensation effect within 1d (d represents the division value) is achieved within a temperature range of 0-40 ℃, and if the temperature difference between two calibration temperature points is 4 ℃, a gain calibration error is required to be less than 0.1 d; if the temperature difference between the two calibration temperature points is 8 ℃, the gain calibration error must be less than 0.2 d; and so on. This example uses a temperature difference of more than 5 deg.c.

The two calibration values may not be obtained in the same power-on process, and sometimes need to be calibrated again, so the first calibration parameter must be stored first, and then the compensation coefficient must be calculated by combining the second calibration value. Therefore, the functional module needs to store parameters of Gain, Tem p, Coe, complex _ flag, Character _ flag, and Record _ flag in the NVM data register.

Gain refers to the difference between the internal code value at load and the internal code value at no load, i.e. the Gain. Temp refers to the temperature value. Coe refers to a compensation coefficient, and the initial value is 0. The compensated _ flag indicates a compensation flag bit, and when the compensated _ flag is 0, the temperature compensation is not performed; when the complex _ flag is 1, it indicates that temperature compensation is performed, and the initial value is 0. Character _ flag refers to the temperature characteristic of the a/D converter, and when Character _ flag is equal to 0, it indicates a negative temperature characteristic; when Character _ flag is 1, it indicates a positive temperature characteristic, and the initial value is 1. The Record _ flag is a calibration recording flag bit, when the Record _ flag is 1, the system is calibrated, otherwise, the system is not calibrated. NVM refers to non-volatile memory, and currently includes mainly EEPROM and Flash, which are commonly used to store programs and data.

A specific software implementation block diagram for acquiring gain temperature data is shown in fig. 9.

Step two:

the software implementation of the gain temperature compensation requires that the current temperature value is obtained first, and then the compensated gain coefficient is obtained according to the formula (3), and the software implementation block diagram is shown in fig. 10.

The time of 0.1s is needed for switching from the channel A to the channel B and preparing temperature value data by combining the characteristics of HX710A and adopting the output data rate of 10 Hz; and it takes 0.4s from the time when the B channel is switched back to the a channel until the ADC data is ready, so it takes at least 0.5s to complete one compensation. This means that the scale will not respond to changes in the weight of the scale pan during this time; moreover, temperature changes are generally slow, and if compensation is frequently performed, not only a good compensation effect cannot be obtained, but also weighing continuity is affected. Therefore, in order to obtain a good compensation effect and influence the weighing continuity as little as possible, the electronic scale system can be selected to perform compensation periodically after entering a power-saving mode, for example, for 60 s. For applications where the ambient temperature changes rapidly, the compensation period may be shortened appropriately, for example, 10 s.

In the description of the present invention, it should be noted that the terms "upper", "lower", "horizontal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing embodiments, or equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The electronic scale with the gain temperature compensation is characterized by comprising a power module (1), a sensor interface (2), an analog-to-digital converter module (3), a voltage detection module (4), a display module (5), a keyboard module (6) and a single chip microcomputer, wherein the model of the single chip microcomputer is HXM6002, the 16 th pin of the power module (1) is electrically connected with the display module (5), the 2 nd pin and the 4 th pin of the single chip microcomputer are electrically connected with the analog-to-digital converter module (3), the analog-to-digital converter module (3) is electrically connected with the sensor interface (2), the single chip microcomputer is electrically connected with the display module (5), and the single chip microcomputer is electrically connected with the keyboard module (6).

2. Electronic scale with gain temperature compensation according to claim 1, characterised in that the sensor interface (2) is used for connecting a load cell.

3. An electronic scale with gain temperature compensation according to claim 1, characterized in that the analog-to-digital converter module (3) has an analog-to-digital conversion chip model HX 710A.

4. The electronic scale with gain temperature compensation according to claim 1, wherein the display module (5) is a segment liquid crystal display or a digital tube.

5. The electronic scale with gain temperature compensation of claim 1, wherein the power module (1) comprises an interface P1, an interface P1 is externally connected with a transformer, an interface P1 is electrically connected with four diodes D1, D2, D3 and D4, and then is electrically connected with an electrolytic capacitor C3 and an electrolytic capacitor C4 for rectifying an alternating current signal into a direct current signal, and the electrolytic capacitor C3 and the electrolytic capacitor C4 are electrically connected with two parallel 7533 voltage-regulator tubes for outputting two sets of direct current signals.

6. The electronic scale with gain temperature compensation of claim 5, wherein two 7533 parallel-connected Zener diodes are electrically connected with P4 interface at the input end of the Zener diode, and P4 interface is used for connecting lead-acid battery.

7. The electronic scale with gain temperature compensation of claim 6, wherein the positive electrode BT of the lead-acid battery is electrically connected to the ADC interface of the single chip microcomputer after being subjected to voltage division by R6 and R7.