DEVICE AND METHOD FOR EVALUATING SIGNALS OF LOAD CELLS WITH STRAIN GAUGES

摘要

A device and a method for evaluating signals from load cells with strain gauges (SG), which require electronic signal evaluation with very low offset voltages due to the small output signal. In order to be able to use inexpensive components as well, two different operating points of the SG are set in two consecutive measurements, each being determined by a single voltage reference. The voltage in the zero branch of the bridge circuit of the SG is amplified in a differential amplifier and digitised with an ADC. In this context, the reference for the ADC is derived from the operating point of the SG that is determined by the respective voltage reference. The digitised offset and the initial value of the load cell are calculated from the two measurement values in an arithmetic logic unit.

主权项

1. A device in which signals from load cells with strain gauges are evaluated, comprising:
a load cell with one or more strain gauges for indicating, in the form of a voltage signal, a change in load on the load cell, at least one differential amplifier for amplifying the voltage signal from the load cell, an analogue/digital converter for converting the amplified signal into a digital signal, and an arithmetic logic unit for evaluation of the digital signal, wherein the one or more strain gauges (2) are operated at two different operating points that are determined by two voltage references (6, 7), and wherein the reference for the analogue/digital converter (5) is derived from the respective operating point.