Simulation of the Analogue Interface for Remote Measurements Using Multiplexer and Resistive Strain Gauges

The simulation of the analog interface circuit based on the measuring amplifier with differential inputs and the ultrasonic scheme and algorithm of non — destructive additive — multiplicative correction have been made. Such schematic of the analog interface reduces the influence of input correlated noise of operational amplifiers and network drives on the «general» resistance. The Fig. 1 shows us the Schematic of the electrical functional analog interface for remote measurement using multiplexer and resistive strain gauges, which contains a measuring chain, a transmitter, the input of which is connected to a DC source through an analog demultiplexer, and the outputs of the measuring chain through the analog multiplexer are connected to the measuring amplifier, and a two-channel analog-digital converter with simultaneous sampling. The measuring chain is made in the form of three resistive current dividers, where one divider is formed by a resistive strain gauge and adjusting resistor, and two others — exemplary resistors. At the Fig. 2 we can see the electric model of the measuring channel in the software Elektronic Workbench. From the analysis of the simulation results it was found that the random additive component of the error would dominate. Since in the simulation of the only random component of the error there is a quantization error, the use of the differential method of measuring the output voltage will significantly improve the metrological characteristics.