CN2170502Y - Strain sensor with calibrating function - Google Patents

Abstract

The utility model relates to a strain sensor with a calibrating function, which belongs to an instrument measuring element. The utility model is matched with a secondary instrument. Both ends of a bridge arm of a bridge circuit of the existing strain sensor body or adjacent conducting wires led out by the bridge circuit are connected in parallel with a precise resistor with a switch to form an electric artificial circuit, namely, various strain sensors with precise artificial load output are formed. When the utility model is connected with a machine for adjustment and calibration, the switch is closed to make the sensor output artificial load, so correct adjustment and calibration can be realized conveniently, and heavy and bulky measurement standard load is not needed to be arranged on site.

Description

Strain sensor with calibrating function

The application belongs to measurement instrument element, particularly strain gauge transducer.

In the Detection ﹠ Controling system, large-scale popularization has been used all kinds of strain gauge transducers at present.But in use owing to be subjected to the restriction of situ metrology test condition, sensor and secondary instrument on-line debugging and regular calibration can only use sensor to dispatch from the factory the given sensitivity parameter of calibration certificate and the sensitivity scale of measuring indicating instrument calculates and calibrates.This method is very loaded down with trivial details, and has reduced system accuracy.Improve measuring accuracy as heaviness and huge value standard termination are set at the scene, will on economy, manpower, pay huge cost.

For this reason, the application's purpose is that the means with simple and feasible provide a kind of strain gauge transducer with calibration function, and it can carry out sensor and secondary instrument on-line debugging and calibration easily, and improves The measuring precision.

For achieving the above object, the application discloses a kind of easy scheme, and promptly at the precision resistance of the two ends of a brachium pontis that has the strain gauge transducer bridge circuit now a belt switch in parallel, load is exported as calibration electric analogy breadboardin.This sensor is when dispatching from the factory calibrating or periodic verification, when obtaining transducer sensitivity, open-close on-off can obtain electric analogy load parameter accurately, during with secondary instrument on-line debugging, can finish debugging as long as make the instrument indicated value be equivalent to the electric analogy load, thereby simplified debugging, calibration process, and eliminated influence factors such as long lead, improved the machine system precision effectively.Economical and time saving and energy saving.

Such scheme can both be suitable for for full-bridge, half-bridge, the single armed strain gauge transducer of various measurement functions.If reequip old sensor or for very little sensor, the precision resistance of said belt switch is bad to be placed on the sensor body, also can be connected in parallel on the adjacent wires that bridge circuit draws.

From application point, this programme to dynamometry, weigh, the strain gauge transducer of various measurement functions such as moment of torsion, pressure, displacement of the lines, angular displacement, strain, physical dimension, speed, acceleration, flow, vibration can both be suitable for.

Accompanying drawing is the circuit diagram of the said full-bridge sensors of the application.

Embodiment: solid line partly is original circuit of sensor among the figure, and dotted portion promptly is connected in parallel on R ₂The precision resistance R of the belt switch S at brachium pontis two ends is a calibration electric analogy circuit.Usually switch S is in normally open, and closed back bridge circuit is promptly exported corresponding fictitious load.Said electric analogy circuit can be connected in parallel on R respectively ₂, R ₄, R ₁, R ₃The brachium pontis end is connected in parallel on R ₂, R ₄The brachium pontis end be connected in parallel on R ₁, R ₃The brachium pontis end, function is identical but output symbol is opposite.

Present embodiment adopts the situation of this programme to be described as follows to a pulling force sensor in conjunction with the accompanying drawings: this pulling force sensor is by R ₁=R ₂=R ₃=R ₄4 strain ga(u)ges of=350 Ω are formed full-bridge circuit as shown in the figure.Specified tensile load is 1MN, specified output Q _n=4000 μ ε, when gauge factor K=2, specified output Q ^' _n=2000 μ V/V are at R ₂Two ends precision resistance R in parallel makes sensor output ε '=2000 μ ε, promptly is equivalent to the simulation tensile load of 500kN, calculates R as can be known by the strain effect expression formula ₂Variable Δ R ₂,

ΔR ₂＝Kε′R ₂＝2×2000×10 ^－6×350Ω＝1.4Ω

Promptly be connected in parallel on R ₂On resistance R make R ₂=350 Ω change into:

R ^′ ₂＝350Ω－1.4Ω＝348.6Ω。

Precision resistance in parallel should be

$R=\frac{1}{\frac{1}{R_2^{\′}}-\frac{1}{R_2}}$

$=\frac{1}{\frac{1}{348.6}-\frac{1}{350}}$

＝87.15KΩ

With the closed resistance of switch S is the precision resistance R of 87.15K Ω, and sensor promptly should have the electric analoging signal output of 500KN.

Since the discreteness of sensor processing and debugging precision, the specified output Q of every sensor _n(sensitivity) also not exclusively conforms to calculating, thereby measures on standard in the specified output of the said sensor of the application (sensitivity), measures the fictitious load output Q of mimic channel _m, this moment, fictitious load M can calculate with following formula:

M＝N (Q _m)/(Q _n)

In the formula, N is a nominal load.

When sensor and any indicating instrument on-line debugging, calibration, only need Closing Switch S, adjust indicating instrument excitation power supply or attenuator, make indicated value be equivalent to the fictitious load value, can finish on-line debugging easily.

Claims (3)

1, the strain gauge transducer that has calibration function, belong to the measurement instrument element, with the online use of secondary instrument, it is characterized in that constituting electric analogy breadboardin load output at the precision resistance of the two ends of a brachium pontis that has the strain gauge transducer bridge circuit now a belt switch in parallel.

2, according to the said sensor of claim 1, it is characterized in that said existing strain gauge transducer can be a full-bridge sensors, also can be half-bridge or single armed sensor.

3, according to claim 1 or 2 said sensors, the precision resistance that it is characterized in that said belt switch can be connected in parallel on the adjacent wires that bridge circuit draws.

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