CN204988942U

CN204988942U - A high accuracy instrument of weighing for metal material fatigue damage

Info

Publication number: CN204988942U
Application number: CN201520802564.7U
Authority: CN
Inventors: 肖敏; 杨世锋; 何瑾; 罗迎社
Original assignee: Central South University of Forestry and Technology
Current assignee: Central South University of Forestry and Technology
Priority date: 2015-10-16
Filing date: 2015-10-16
Publication date: 2016-01-20
Anticipated expiration: 2025-10-16

Abstract

The utility model discloses a high accuracy instrument of weighing for metal material fatigue damage, including weighing sensor, enlarge module, AD converter, digital processing circuit, four select an analog switch, memory, display and a plurality of button K, weighing sensor, enlarged module, AD converter, digital processing circuit and display are consecutive, button and memory all link to each other with digital processing circuit, enlarged module cascade by a AD620 of amplifier for the appearance and an operational amplifier OP07 and form, the appearance uses amplifier AD620 and operational amplifier OP07 all to connect the mode as inverting amplifier, this a high accuracy instrument of weighing for metal material fatigue damage easy to carry out, the range is adjustable, and measurement accuracy is high.

Description

A kind of high-precision weighing instrument for Fatigue Damage of Metal

Technical field

The utility model relates to a kind of high-precision weighing instrument for Fatigue Damage of Metal.

Background technology

Hydrometer method is adopted to come in the process of measuring metallic materials fatigue damage, need the quality of measuring metallic materials sample, existing weighting device structure is complicated, cost is high, and measuring accuracy does not reach the requirement of experiment, moreover, its range cannot regulate, dirigibility is poor, therefore, is necessary to design a kind of novel weighing device.

Utility model content

Technical problem to be solved in the utility model is to provide a kind of high-precision weighing instrument for Fatigue Damage of Metal, and this high-precision weighing instrument being used for Fatigue Damage of Metal is easy to implement, and range is adjustable, and measuring accuracy is high.

The technical solution of utility model is as follows:

For a high-precision weighing instrument for Fatigue Damage of Metal, comprise LOAD CELLS, amplification module, A/D converter, digital processing circuit, four select an analog switch, storer, display and multiple button K:

LOAD CELLS, amplification module, A/D converter, digital processing circuit are connected successively with display; Button is all connected with digital processing circuit with storer;

Described amplification module is formed by an an instrumentation amplifier AD620 and operational amplifier OP07 cascade; Instrumentation amplifier AD620 and operational amplifier OP07 are all connected for sign-changing amplifier pattern;

The output signal of LOAD CELLS connects the reverse input end of instrumentation amplifier AD620, and 1 pin of instrumentation amplifier AD620 connects through resistance R1, R2, R3 and R4 correspondence 4 signal input parts that four select an analog switch; And resistance R1, R2, R3 are different with the resistance value of R4;

8 pin of instrumentation amplifier AD620 also connect the output terminal that four select an analog switch;

Four select 2 of an analog switch channel selecting ends to connect 2 output ports of digital processing circuit respectively;

The output terminal of instrumentation amplifier AD620 connects the reverse input end of operational amplifier OP07 by resistance R21, between the reverse input end of operational amplifier OP07 and output terminal, cross-over connection has resistance R23; The output terminal of operational amplifier OP07 is the output terminal of amplification module, the input end of the output termination A/D converter of amplification module.

The first end of described button K meets DC power anode Vcc by pull-up resistor R0, the second end ground connection of button K; The signal input part of the first termination digital processing circuit of button K.

Described A/D converter adopts 16 bit A/D converter chip AD976A.

Described display is LCDs.

Digital processing circuit is existing proven technique, digital device can be adopted to build, also can adopt integrated process chip, as single-chip microcomputer and DSP etc., when adopting the integrated device such as single-chip microcomputer or DSP, does not relate to progresses and methods.

Beneficial effect:

High-precision weighing instrument for Fatigue Damage of Metal of the present utility model adopts instrumentation amplifier AD620 as pre-amplifier, simple circuit, adopt OP07 as post-amplifier, amplified by faint signal, and adopt the A/D converter of 16 to carry out analog-digital conversion, thus measuring accuracy is high, in addition, the parts adopted are the parts of conventional maturation, and easy to implement, cost is low.

Another large feature of the present utility model is that enlargement factor is adjustable, namely by 4 different resistance, one four select the cooperation of an analog switch and digital processing circuit to achieve the adjustable of range, therefore, this weighing device dirigibility is good.

Accompanying drawing explanation

Fig. 1 is the overall circuit block diagram of the high-precision weighing instrument for Fatigue Damage of Metal;

Fig. 2 is key circuit schematic diagram;

Fig. 3 is the circuit theory diagrams of amplification module.

Embodiment

Below with reference to the drawings and specific embodiments, the utility model is described in further details:

As Figure 1-3, a kind of high-precision weighing instrument for Fatigue Damage of Metal, comprises LOAD CELLS, amplification module, A/D converter, digital processing circuit, four selects an analog switch, storer, display and multiple button K;

Described A/D converter adopts 16 bit A/D converter chip AD976A.

Described display is LCDs.

In Fig. 2, when button K does not press, P30 place is high level (Vcc), and when button K presses, P30 place ground connection is low level, and whether this circuit can detect button K and press thus.

This key circuit is multiple, and at least one measures button and a heavy button of unhairing.

In Fig. 3,2 operational amplifier A 1 and A2, all as sign-changing amplifier, adopt different resistance configuration, can obtain different enlargement factors, and after cascade, this amplifier is still forward amplifying circuit.Ui is the signal that sensor exports, and Uo is the output signal of amplification module, is connected with A/D converter.

For AD620, the computing method of its enlargement factor are Uo1/Ui=-(1+49.4k/Ri); I is 1,2,3,4, i.e. the corresponding R1 ~ R4 of Ri.

For OP01, its enlargement factor is Uo/Uo1=-R23/R21.

Four select the principle of work of an analog switch part to illustrate: four select an analog switch can only select connection one road signal at every turn, because R1-R4 resistance is different, therefore, different resistance is corresponding different enlargement factors for AD620, see formula Uo1/Ui=-(1+49.4k/Ri), correspond to and measure range difference, four select the function of an analog switch to be exactly convert resistance passage, channel selecting end B1 with B0 is used for the different passage of gating, as B1B0 be 00 time, gating first passage, 01, the corresponding gating 2,3 of 10 and 11 difference, 4 passages.The numerical value of B1 and B0 is controlled by digital processing circuit.

The measuring process of this weighing device is used to be: first to claim gross weight, then unhairing key is pressed, weight to be measured is put in display screen prompting, after weight is put into, press measurement key again, then the weight now recorded deducts the weight (concrete subtraction is performed by the subtracter in digital processing circuit) that gross weight is weight, and the weight of weight shows in the display, for reading, namely complete one-shot measurement.

Claims

1. for a high-precision weighing instrument for Fatigue Damage of Metal, it is characterized in that, comprise LOAD CELLS, amplification module, A/D converter, digital processing circuit, four select an analog switch, storer, display and multiple button K;

The output terminal of instrumentation amplifier AD620 connects the reverse input end of operational amplifier OP07 by resistance R21, between the reverse input end of operational amplifier OP07 and output terminal, cross-over connection has resistance R23; The output terminal of operational amplifier OP07 is the output terminal of amplification module, the input end of the output termination A/D converter of amplification module;

2. the high-precision weighing instrument for Fatigue Damage of Metal according to claim 1, is characterized in that, described A/D converter adopts 16 bit A/D converter chip AD976A.

3. the high-precision weighing instrument for Fatigue Damage of Metal according to claim 1 and 2, is characterized in that, described display is LCDs.