SU581386A1 - Strain-gauge weight-measuring device - Google Patents

Description

one

This invention relates to a weight measuring technique.

Known tensometric weighing devices, contains a parametric transducer in the form of strain gauges combined into a pavement measuring circuit, and register one instrument.

However, these devices do not provide the required accuracy and reliability.

Also known are frequency modulators containing a pulse generator and matching elements.

The use of such modulators in weighing equipment does not provide the necessary accuracy and speed.

The closest in technical essence to the proposed invention is a device comprising a bridge converter, a phase shifter, an amplifier and a matching unit.

In the known device, the amplifier and the phase shifter form a harmonic oscillator, the signal of which is fed to a bridge parametric converter. Frequency

generation depends on the magnitude of its imbalance.

The disadvantages of this device are the poor dependence of the generation frequency on the magnitude of the imbalance of the bridge converter, which limits the small values of the deviation or significantly complicates the converter circuit, and the insufficient speed characteristic of electoral systems.

The aim of the invention is to improve the speed and accuracy of measurement.

This is achieved by the fact that the point on the electrical connection line of the elements of the alternating-RC circuit of the generator is connected through the matching unit and the bridge parametric converter to the input of the matching amplifier, the output of which is connected to that point on the line connection of its elements.

The generation period of the modulator is linearly related to the magnitude of the unbalance of the bridge converter. The magnitude of the frequency deviation is large (the frequency may vary by more than ten times). This allows / significantly increases

measurement accuracy. The speed of the modulator roller) - since the frequency control circuits and the main generation circuit are separated and their values differ by more than two orders of magnitude,

The drawing shows a block diagram of the proposed device.

The device contains a pulse generator 1 with the time setting the RC block of the matching unit 2, the bridge parametric converter 3 and the matching amplifier 4.

The device works as follows.

When the balance of the bridge parametric converter 3 (consisting, for example, of strain gauges assembled according to М1Э "; to the wiring diagram on the elastic element of the force-measuring sensor), its output value is equal to Tru.

With a parametric breakthrough of gel 3, a signal appears at the output of matching amplifier 4 that affects and actually affects the voltage across the capacitor of the IC circuit, which leads to a change in the generation period, i.e. T TO,

The generation period (T) is linearly related to the magnitude of the unbalance of the bridge of the parametric converter 3, i.e. directly proportional to its output signal.

Measurement of the generation period, control of issuing commands to actuators and indications of measurement results is carried out by methods known in the art.

Claims (1)

Invention Formula Tensometric weighing device containing a pulse generator with the time specifying the resistive-capacitance; circuit, a parametric converter in the form of a strain gauge connected to the bridge circuit, a matching unit and match the amplifier, so on, so that, with aim), TO4Ho.ctK-, in it coupling the resistor-capacitive circuit elements through a matching unit and a parametric converter connected; to the input of the matching amplifier, the output of which is connected to the same connection point of the elements of this circuit through one of the elements of the resistor-capacitive circuit.