Carrier wave excitation strain type weighing system and excitation method thereof

Abstract

The invention discloses a carrier wave excitation strain type weighing system which comprises a strain gauge measuring bridge, wherein the input end of the strain gauge measuring bridge is connected with a carrier wave excitation signal generating module; the output end of the strain gauge measuring bridge is connected with an alternating current amplifier; the output end of the alternating current amplifier is connected with a demodulator; the demodulator is also connected with a demodulation reference signal generating module; the output end of the demodulator is connected with a signal selection module; and the output end of the signal selection module is the output end of the system. When the system disclosed by the invention is used for measuring, carrier wave excitation signals are generated to apply a carrier wave voltage signal as excitation for the strain gauge measuring bridge, and the strain gauge measuring bridge outputs the alternating current voltage signals which have the same frequency and the same phase with the carrier wave excitation signals; and when the alternating current voltage signals are transmitted to a subsequent circuit to be processed, the system completely avoids the defects because of a direct current excitation technique, has the advantages of high precision and strong interference resistance and is stable and reliable to use.

Description

technical field [0001] The invention relates to a strain weighing system, in particular to a strain weighing system which uses a carrier voltage signal for excitation, and a carrier excitation method thereof. Background technique [0002] The existing strain gauge weighing system is composed of two links: the transformation and measurement of the gravity signal: [0003] Gravity signal transformation: Paste the resistance strain gauge on the surface of the stressed elastic object. Under the action of external force W, the slight deformation of the surface of the elastic object causes the strain gauge to be stretched or compressed, resulting in a change in its resistance value. Quantity characterizes the magnitude of the force on an elastic object. Connect four strain gauges according to rules to form a Wheatstone bridge, and apply a voltage signal to the bridge as an excitation. As the external force on the elastic object changes, the measured voltage signal Vout output by ...

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Problems solved by technology

[0016] This ΔVos is always superimposed on the input signal. Even if the DC voltage measurement signal output by the bridge is very stable, the output signal after it passes through the amplifier will have temperature drift and time drift, which will affect the long-term stability of the measurement system.

[0017] ③When the DC voltage measurement signal enters the subsequent electronic circuit for signal processing, it is easily interfered by the power frequency clutter conducted from the power system

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