KR20000072271A - Detection system which measures and detects physical quantity of structure by transformational detector applied from strain guage - Google Patents

Abstract

PURPOSE: A detection system is provided to be diffused as a universal detector sensor by being simplified and standardized to enable a novice to readily use. CONSTITUTION: A strain transformer is made up by connecting several sensors with a strain gauge. A summing box and conditioner box calibrates an output value previously processed by a temperature change in the strain transformer. An indicator amplifies and converts an analog voltage to a digital as well as sends a signal for remote control by adding up the output value. Then, the output value by the signal is induced on a screen of a computer so that a physical amount of a structure is measured.

Description

Detect system which measures and detects physical quantity of structure by transformational detector applied from strain guage}

The present invention relates to a detection system for measuring a physical quantity of a structure by using a strain gage applying strain gauge, and more particularly, a temperature compensation sensor (Temperature calibrate sensor) in a strain transducer including a strain gage formed in a structure. A micro voltage is output by connecting a Summing box & conditioner box, and the output value is amplified and digitally converted from analog voltage at the indicator, and the output value is aggregated and remotely controlled. When the signal is sent and the signal is drawn on the computer to measure the physical quantity of the structure, the temperature according to the lead wire length from the strain detector to the indigate is compensated for as well as the change in the change in temperature. It is possible to actively compensate for the output error caused by the change. A system is intended to contribute accuracy to the detection of quantities.

The strain gauge is also called a strain or displacement gauge. When strain is applied to a resistor of a metal or a semiconductor, its resistance is changed and the voltage output by the Wheatstone bridge effect is applied. As a use, it is widely used for the measurement of a differential pressure, a pressure transmitter, a vortex flowmeter, a torque meter, and other real stresses.

In this way, the method of measuring the load using the strain gauge, the method of measuring the stress of the bolt, the sensor installed in the vehicle to detect the impact, the scale using the load cell (Load cell), the method of measuring the pressure when writing In many ways, it is widely used to measure stress.

In general, bridges need to be maintained for more than a few decades, so the beams and columns are installed in the bridges to keep the bridges in view of the continuously repeated loads.

Although bridges are designed and constructed to last for more than a few decades, bridges, dynamic loads, or oxidation, which are continuously applied, sometimes fail to maintain as originally designed and collapse. The collapse of the bridge causes a catastrophic disaster, so the manager checks it once, but measures the strength due to the appearance or repulsion at the time by using an external abnormality or a tester, and internal fatigue, yield state, stress The physical quantity such as the state is difficult to measure, and considering the size of the bridge, it is measured by the tester.However, it is difficult to measure several parts continuously in succession. There was a difficulty in grasping.

In addition, it is common to make a structure with a support structure that supports and supports a large tank to store grain or powdered powder, and when the grain or powder stored in the storage tank is withdrawn for some time, the tank Not only is the quantity unknown for the residuals in the unit, but the devices that display the capacity in the existing volume cause a difference from the actual amount when the internal filling state is uneven or the upper and lower packing densities are different, and the pupils in the gate portion at the time of emission are released. Formation causes errors in both membranes.

In particular, a factory that purchases cheap rice paddies includes a process of drying moisture while storing it in a tank for a long time, so it is not easy to grasp the final stock, and since the commerce is carried out by weight instead of being shipped in volume, the actual quantity and assumed Cause a noticeable difference in volume.

So, the developed level was introduced to the structure by using a weight leveler (Weighing leveler) using a deformation sensor, a low-precision leveler that measures the load of the structure has been introduced and used, but the change of output according to the temperature, such as the temperature deviation between the structure and the sensor Due to the low accuracy of the measurement and the extremely limited use range, it has not escaped the basic leveler stage. In addition, the method of analyzing the structure by directly attaching the strain gauge to the structure has been developed and distributed.However, the cost is high due to limitations in the adhesion state between the structure and the gauge, the temperature compensation problem between the circuits, the heat treatment problem, the insulation and airtightness, and the proficiency and knowledge experience of the implementer At the same time, the problem of precision accuracy is pointed out because of inefficiency and lack of reliability between individuals.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and is intended to maximize performance by dissecting electrical circuits and mechanical mechanisms, and analyzing and controlling the output change factors according to temperature. In addition, it is invented to increase the range of use in consideration of special conditions in the field, and its purpose is to be unified and standardized so that even a beginner can easily install and operate it, so that it can be spread as a universal detector sensor.

In order to achieve the above object, in the present invention, a strain detection unit is configured by connecting several sensors including a strain gauge in connection, while the deformation detection unit is installed such that a bridge, a large storage container, a filling hopper, etc. are installed at an appropriate position. By connecting the junction box of the synthesis condition that forms the temperature compensation sensor to be connected with the strain detection unit, the strain detection unit compensates the unprocessed output value due to the change of temperature, and the output value is transmitted to the indi- vidual to convert the analog voltage into digital. It is an object of the present invention to provide a system for outputting a signal for controlling a remote control by amplifying and simultaneously outputting an output value and outputting the output value by the signal to an image of a computer.

1 is a flow diagram of a system of the present invention.

2 (a) and 2 (b) are basic circuit diagrams for constructing the strain detector of the present invention.

3 is a circuit diagram of a strain detector which is a main part of the present invention.

4 is a schematic diagram of a synthetic condition junction box which is a part of the present invention.

5 is a state diagram used in accordance with an embodiment of the present invention

Figure 6 is an example perspective view of the deformation detection gauge used in the present invention

7 is a cross-sectional view of the deformation detection gauge of FIG.

* Description of Signs of Major Parts of Drawings *

1. Deformation detection unit 2. Temperature compensation sensor

3. Synthetic condition connection box 4. Indicator

5. Lead wire 6. Computer

11. Deformation detection gauge 12. Mounting groove

13. Cohesion 14. Bracket

15. Structure

Hereinafter, the configuration of the present invention in detail with reference to the accompanying drawings as follows.

1 is an overall flow diagram of the system of the present invention, Figure 2 (a) (b) (c) is a basic circuit diagram for configuring the strain detector circuit of the present invention, Figure 3 is a deformation detector which is the main part of the present invention 4 is a schematic diagram of a synthetic condition junction box which is a part of the present invention, and FIG. 5 is described together with a state diagram of use according to an embodiment of the present invention.

As shown in Fig. 1, the system of the present invention comprises means for constituting a deformation detection unit 1 by connecting several sensors including a strain gauge in an interlocked manner; Means for compensating for the unprocessed output value by a change in temperature in the sensor by connecting a composite condition junction box (3) in which a temperature compensation sensor (2) is formed to be linked to the deformation detection unit (1); The output value includes: an indicator (indicator) means for amplifying and converting an analog voltage into a digital signal and simultaneously outputting a signal for totally controlling the output value for remote control; The output value by the signal is constituted by means for causing the image of the computer to be derived.

On the other hand, even if the strain detection unit (1) and the indicator (4) is made of a specially selected conductor, the standard lead wire (5) at the time of manufacturing the temperature compensation, but due to the length of the wire depending on the site conditions due to the resistance component according to the length of the line Due to the temperature deviation factor, the existing Wheatstone bridge application circuit cannot control the output factors according to the temperature change. Therefore, a special circuit is constructed as shown in FIG. 3 to control the temperature deviation factor below a certain level regardless of the lead wire length. I could do it.

The deformation detection unit 1 may be firmly fixed by selecting an appropriate position of the structure 15 such as a support for supporting a proper position of the bottom of the bridge and a storage container and a filling hopper having a large capacity.

The sensor formed in the deformation detection unit 1 has two sets in the direction of increasing resistance when the load increases in the strain gauge on the deformation detection unit base portion as shown in FIG. 2A, and the resistance decreases when the load increases. Two sets are attached in the direction, and the strain detection unit and the strain gauge are bonded so that they are in the same deformation condition, and the basic circuit is connected.

Initially in this state

if i _g = 0

R ₁ = R ₂ , R ₃ = R ₄ i ₁ = i ₂ , i ₃ = i ₄

i ₁ R ₁ = i ₃ R ₃ , i ₂ R ₂ = i ₄ R ₄

At zero parallel condition and Ohm's law

… … … … … … … … … … ①

Is a strain gage and is an active element for displacement.

Each resistance changes.

Substituting this into ① Is As it becomes

… … … … … … … … ②

Where initial And this Expressed as When the load increases, attach it in the direction of decreasing resistance, When the load increases, the adhesive is attached in the direction of increasing the resistance ego, to be.

Substituting this into ②

… … … … … … … … … … ③

Initial time = 0 ㎵ / V = 0,

≠ Back side (the opposite direction of resistance component) ≠ 0.

here, Changes in resistance due to load strain And change of resistance due to temperature influence Can be represented by Is , Is displayed.

Wow Using the same material, the same manufacturing lot (LOT) with the same temperature characteristics, the same temperature characteristics Is displayed.

… … … … … … … … … … ④

Due to load strain effect on no-load condition Is 0 A self-compensation circuit with 0 is established to achieve temperature compensation over a wide range.

In ④ above Wow If you can design the structure with parts of the same size and different components, and you can glue strain gauge

Can be simplified.

Since the compensation of the temperature under load is not made in the basic circuit, it can be compensated by selecting a gauge sensitive to temperature sensitivity change in the existing circuit.

For example, a strain detector composed of a basic circuit as shown in FIG. 2 (A) was mounted where the temperature was rapidly changed from 20 ° C. to −20 ° C., and the indicated value was 50,000 kg at 20 ° C. FIG. At that time, the strain of the part to be detected ) Is 750μ, look at the load when the output is not compensated at -20 ℃,

However, the thermal expansion coefficient (c) in the material of the detector and the detector is 11PPM / ° C.

Thermoelastic coefficient (k): -220PPM / ℃

→ strain gauge: 20 ℃ resistance ) = 350 yen

Gauge Factor (F): 2.0

Resistance coefficient according to temperature (T): 11PPMΩ / ℃

→ the sensitivity coefficient of the detector is set to 1,

The gauge rudder (F) above

here, Strain

: Human voltage bolt

R: strain gauge resistance

F: gauge hack (can be selected according to user's gauge selection)

。 Resistance change by strain at 20 ℃

Strain at -20 ℃ ): Temperature difference ( )

。 Resistance change by strain gauge temperature at -20 ℃

Resistance change by strain at -20 ℃

Output voltage at 20 ℃ )

Output voltage at -20 ℃ )

Resistance change by temperature at -20 ℃ ) =

As such, if 1.5mV / V indicates 50,000kg, 1.500mV / V is 49,500kg and an indication difference of about 500kg occurs. Since this causes about 1% error factor, it is confirmed that accurate stock management can be achieved only by output compensation.

In addition to the change in the basic circuit using the strain gauge, the output change according to the length of the lead wire is as follows.

In general, the temperature compensation at the time of no load of the strain detector and the temperature compensation for the output at the load are completely done, and even if the detector is manufactured, it is usually composed of 100m to 300m lead wires from the detector to the indicator during the installation process according to the conditions of the site.

When the lead wire is generally composed of an interlocking wire of 54.7 kW / 1 km, the resistance coefficients T, C, and R depending on temperature are 4,000 PPM. Therefore, assuming 200m lead wire, the wire resistance of lead wire is = 54.7 kW / km x 0.2 = 10.94 kW, and when DC1V is applied to the detection a and d terminals in Fig. 2C, the detection circuit portions b and c are dropped due to the line resistance Re and a voltage of 0.94 V is applied. .

In addition, if the strain detector is installed where the installation condition changes from -15 ℃ to 40 ℃, the voltage drop along the lead wire is as follows.

The line resistance of -15 ℃ is lower than 20 ℃

Re = 10.94-1.5316 = 9.408

At 40 ℃

∴Re = 10.94Ω + 0.875Ω = 11.81Ω

Therefore, resistance change of lead wire by temperature

As a result, the output change caused by voltage drop causes 2.44% output change in 55 ℃ deviation. Therefore, the precision grade that can be used for inventory management should be maintained at a level of 0.1%, so it is necessary to compensate the output by the lead wires, and moreover, actively compensate for the length of the lead wires.

As described above, the circuit is improved as shown in FIG. 3 to compensate for the output error according to the lead wire length.

Specifically, a voltage is applied across a and b in FIG. Since is an active strain gage, the resistance changes to produce an output at the output g, h.

Is the compensation gauge for the temperature of the output under load Is the shunt resistance, Is a resistance that depends on the lead wire length.

For example, when wiring 200m of 20 ℃ AWG No22 copper wire Is the standard resistance, and the detector used at -15 ℃ to 40 ℃ is the maximum deviation resistance ( )silver

to be.

Therefore, assuming that the resistance change by the lead wire is a maximum of 4.8 Ω at both ends of a and d, and the output change by this is a standard resistance of 430 구 as follows.

Where n is the output ratio

R is the input resistance

Rs is the maximum resistance change,

therefore, N = 0.989

In particular, if a lead wire resistance occurs at a temperature of 4.8 kΩ across a and d, an output drop of 1.1% occurs at the output g, h.

And input voltage is applied to b, c Strain If you derive the change value according to the temperature when outputting

ego

At 20 ℃ to be.

Strain gauge resistance at 40

At that time, strain by load

The change of strain gauge resistance by strain

∴

Therefore, ①

Produces an output

On the other hand, at -15 ℃

From above

Therefore, ①

하면 If voltage is applied at both ends of -15 ℃ and 40 ℃ at both ends of b, c, output voltage rises from 1.4668mV / V to 1.4808mV / V.

If this is expressed as a percentage

Therefore, where the voltage output g, h is changed from -15 ℃ to 40 ℃ in the a, b, c, d sections, the output drop by the lead wire is -1.1% and the output increase by 0.95% is combined. Is generated, and this It is within the controllable range and can be satisfied within 0.1% of possible precision for inventory control of strain detectors.

Therefore, the temperature compensation along the line length is compensated to the precision level by the circuit.

The strain gage circuit configured as described above is attached to the deformation detection unit, and the deformation detection unit is fixed at an appropriate position of a bridge or a large capacity storage container, in consideration of the material of the structure to be fixed and the material, shape and load state of the deformation detector. Fix using a bracket to the structure as shown in FIG. Only by changing the shape and length of the bracket, the best output can be obtained, and the special scope of the site can be reflected to extend the range of use, thereby providing flexibility for installation.

In the same way as described above, the output value of the strain detection part according to the temperature change can be directly compensated after operation in the untreated part, and precise output value can be obtained even with the length of the lead wire and the temperature change along the length.

In addition, the strain detection part and the lead wire are compensated for the temperature change, so that accurate measurement is possible, so it is stable and reliable in the long term. Therefore, it is possible to stably and continuously obtain information such as physical properties such as bending, deflection, fatigue, yield, internal stress state by measuring the amount of contents stored in a large storage container or non-destructive physical properties of large structures such as bridges. Automated introduction can be made by accurately grasping inventory, preventing loss due to measurement errors, reducing costs, and accurately understanding the physical properties of structures to prevent large accidents and reflect them in design Therefore, there is a characteristic that can greatly contribute to industrial development.

Claims (2)

In constructing a detection system that measures the physical quantity of a structure by using a strain detector applying strain gauges, Means for linking several sensors including strain gauges in association to form a strain detection unit; Means for constructing a synthetic condition connection box having a temperature compensation sensor connected to the deformation detection unit to compensate for an unprocessed output value due to a change in temperature in the deformation detection unit; The output value comprises means for constituting an indicator for amplifying and converting an analog voltage into a digital signal and simultaneously outputting a signal for performing a remote control control by aggregating the output value; A strain detection device using a strain gauge, characterized in that the output of the signal is derived from a computer image to measure the physical quantity of the structure. The method of claim 1, The strain detection gauge is a strain gauge applied to the strain gauge, characterized in that the mounting groove to form a mounting groove for mounting the strain gauge, the formation of the mounting groove is configured to measure the physical quantity measurement of the structure.