Assay of direct digital output floating-wiper resistive displacement sensor

Abstract

The principle of operation of a successive approximation type direct displacement to digital converter for a floating-wiper resistive potentiometric sensor, presented earlier, is analyzed in detail to ascertain possible sources of error that can affect the performance of the transducer. Based on the analysis the method is suitably modified to improve its performance. To establish the efficacy of the altered scheme, a prototype signal conditioning circuit has been built and tested using both an emulated sensor and a prototype sensor. While the worst-case error in the former was found to be 0.5%, it was less than 0.8% in the latter. The test results indicate that the digital output is directly proportional to the per-unit displacement and is independent of the value of the coupling capacitance between the floating-wiper and the resistive element.

Successive approximation type resistance to digital converter

“…Table 2 compares different types of direct resistance to digital converters with the SAR-RDC presented here. Since there is only one other SAR type RDC in the literature [15], other types of RDCs are also included in this comparison. The method proposed by Lee et al [15] shown in figure 9 is the only SAR type RDC and requires a 12-bit resistance type DAC.…”

“…Since there is only one other SAR type RDC in the literature [15], other types of RDCs are also included in this comparison. The method proposed by Lee et al [15] shown in figure 9 is the only SAR type RDC and requires a 12-bit resistance type DAC. Moreover, the opamp and comparator must operate with the input at the common mode voltage of V R .…”

“…Analog to digital conversion using the method based on successive approximation technique, namely, the SAR type ADC is quite popular [15][16][17][18]. Hence, it would be quite advantageous if the SAR method is employed to convert a resistance directly into its equivalent digital value thus realizing an SAR-RDC.…”

Modeling Method of Multiplexed Sampling Electrical Parameter Characteristics Based on AIOT Sensing Module

“…Mohan et al built a prototype signal conditioning circuit and tested it using a simulated sensor and a prototype sensor. The test results showed that the digital output was proportional to the displacement per unit, and the error in the coupling capacitance value between resistive elements was less than 0.8% [9]. Siddavatam, R used a high dynamic performance control scheme with vector control to accurately estimate the electrical parameter values of the voltage source inverter, feeder inductor and driver, effectively identifying the six electrical parameters and ensuring the efficiency of the detection of electrical parameters [10].…”