SU1509606A1 - Device for measuring weight - Google Patents

Abstract

The invention relates to weighing technology and allows to improve the measurement accuracy by eliminating the influence on the result of measuring external conditions, the drift of the characteristics of the elements. For this, in the device, the primary converter is designed as an inductive converter, on one half of the U-shaped magnetic circuit 6 of which three measuring coils 8-10 are movable, as well as the excitation coil 7, the winding pins of which are connected to the excitation source 11. When measuring the mass of the cargo, the signals from the coils 8-10 initially go to the computing unit 21 via the interface blocks 12-14. Then, after connecting to the load-receiving platform 1 using the electromagnet 4 of the cargo 5 of known mass, the signals from the coils 8 and 10 arrive at the block 21 rigidly fixed on the elastic element 3. The coils 8 and 9 are rigidly connected to each other, and the ratio of the distances from the junction of the coils 8 and 10 to the elastic element to the center of the platform 1 is equal to the specified coefficient of test transformations. Based on the measurement results, the weight of the goods to be weighed is determined. 1 il.

Description

The invention relates to a weight measuring technique,

The purpose of the invention is to improve the accuracy of measurement. $

The drawing shows a diagram of the device.

The device comprises a load receiving platform 1 mounted on a mass measuring transducer 2, on the 10th elastic element 3 of which an electromagnet 4 is placed, by means of which a load 5 of known mass P _{о is} connected to the load receiving platform 1, as well as a primary transducer included in the mass measuring transducer 3.

The primary transducer is made in the form of an inductive transducer consisting of a U-shaped magneto-20 wire 6 with an excitation coil 7 and three measuring coils 8-10. The conclusions of the windings of the field coil are connected to the field source 11, and the measuring coils 8-10 are placed 25. They can be moved on one half of the magnetic circuit 6, while the coils 8 and 9 are rigidly connected to each other and to the elastic element 3, on which the third measuring coil 30. The ratio of the distances from the connection points is measuring. 8–10 reels with an elastic element 3 to the center of the load receiving platform 1 is equal to a given coefficient of test transformations. The conclusions of the windings of the measuring coils 810 are connected to the interface blocks IB 12-14.

Each information security contains an analog-to-digital converter (ADC) and a control unit. (BOO). The control unit receives and decrypts the address, generates, issues and receives signals. IB 12 includes ADC 15 and BU '16, 45 IB 13 includes ADC 17 and BU 18, IB 14 ADC 19 and BU 20. The inputs and outputs of IB 1214 are associated with the corresponding outputs and inputs of the computing unit WB 21, which consists of from the central processor CPU 22, random access memory RAM 23 and the remote control terminal 24. Computing unit 21 controls the electromagnet 4.

The device operates as follows — 55 at a time.

The load is placed on the load platform 1. The elastic element 3 receives a force proportional to the measured mass. The measuring coils 8-10 are displaced along the tape recorders of the wire 6, as a result of which the voltage in the windings of the coils changes. WB 21 through IB 12-14 polls the measuring coils 8-10 and the corresponding values of the voltage signals Υ ₍ , and Yj are stored in RAM 23. Next, WB 21 issues a command to connect, using electromagnet 4 to the load receiving platform 1, cargo 5 of known mass R _о The elastic element 3 is bent, displacing the measuring 8-10 coils, which leads to a change in the voltage on them.WB 21 interrogates the measuring coils 8 and 10 and the values of Y _tf and Yj are entered in RAM 23. Then the load 5 is disconnected from the load platform 1 .

The measured mass, device parameters and measurement results are related by the ratio

^{= a} i + ^a 2 (1st + A R) ^at ₂ = A + ^a 2 1 ~ o ABOUT R) ^{= a} f t O10 kP) = ^a t + a _g (1 _1C , (P +)) = ^a 1 4- ^a r ^ -Zo ABOUT k (P + P _o )]) where 1 about ' Cho “Constants

the initial positions of the measuring coils on the magnetic circuit of the inductive transducer;

· K - coefficients determined by the deflection of the elastic element in the places of its connection with the measuring coils;

, aJ - parameters of the device conversion function.

The solution of the system with respect to the measured quantity P has the form (Y ₃ -Y,) - (Υ ₂ -Υ ₄ ) (Y _y - Y ₃ ) - (Υ ₄ __1 ^ 0.

Yj

The measurement result does not depend on the parameters of the device conversion function a _f , but _r , coefficients / 3,, k, i.e. the dependence of measurement accuracy on changes in external conditions, drift of the characteristics of elements, non-linearity of characteristics within the accuracy of piecewise-linear approximation is excluded. The error of the result is determined by the errors of the mass of the known cargo, the values of l _f0 , _1st , I30, and the approximation of the conversion function of the device.

Claims (1)

Claim A weight measuring device comprising a load receiving platform mounted on a mass transducer, on an elastic element of which an electromagnet connected to the computing unit is placed, and a primary transducer, characterized in that, in order to increase the measurement accuracy, three interface units are inserted into it, and the primary the converter is made in 1509606 ^{6 in the} form of an inductive transducer, consisting of an excitation coil, the terminals of the windings of which are connected to an excitation source, and placed on one half of a U-shaped magnetic circuit with the possibility of moving three measuring coils, two of which are rigidly interconnected and ed with an elastic element, on which is attached to the third measuring coil, while the ratio of the distances from the junction of the measuring coils with the elastic element to the center 15 of the receiving platform is equal to the specified coefficient of test transformations, and the conclusions of the windings of the measuring coils through the corresponding interface units are connected to the inputs and outputs of the computing unit.