Reconfigurable Two-Current Source Supplied Signal Conditioner for Resistive Sensors

The principle of operation, its practical realization and measurement research of a reconfigured system of a signal conditioner are presented. A two-sourced conditioner supplied by direct current with four resistance sensors and four switching keys was experimentally tested. In the example application the resistance of sensors in the function of the same point load, caused by perpendicular force, was measured. In order to compare the results achieved with the use of a conditioning circuit, similar tests were carried out for a four-channel Wheatstone's bridge-based commercial acquisition card. The research aimed at confirming the possibility of implementing the constructed signal conditioner in cheap measurement equipment

Comparative Evaluation of the Two Current Source Supplied Strain Gauge Bridge

Metrological properties of a two-current-source bridge circuit were tested with the use of the method of measuring resistance increments of strain gauges. An unconventional system was investigated in comparison with the commonly used Wheatstone's half-bridge, quarter-bridge and Anderson's loop. Input-output characteristics of the systems tested with a current supply were examined experimentally.Error values of offset and gain of the characteristics in relation to the characteristics of reference were taken as the criterion of comparison. Moreover, standard uncertainties of y-intercept and slope coefficients (of the straight lines) were analysed. The coefficients with their uncertainties are presented in tables. Errors for three tested systems with two metal strain gauges or with one semiconductor are presented on graphs. Additionally, the errors change, resulted from the spread of initial resistances as the quantity influencing the uncertainties of offset and gain coefficients, was defined for the bridge circuits

Temperature Influence Analysis on the Selected Current Sources Stability in the Static and Dynamic Operating States

The present work contains the stability test results of the current sources located in an environment of variable temperature. Two types of tests were conducted for four circuits stabilizing the current of the value close to 50 mA. One test consisted in changing the temperature in which the current sources loaded with variable resistance were placed. The other test related to the analysis of the transient state during switching on and off the load for two values of temperature. The article presents the obtained results of experiments and discusses the reasons of the measurement errors

Calibration procedure and uncertainty analysis of an electronic scale based on two-current source supplied circuit

Rad predstavlja verziju prototipa originalne vage u kojoj je primijenjeno neuobičajeno napajanje ćelija tenziometra. U radu se razmatra konstrukcija električnog strujnog kruga, način povezivanja pretvarača tenziometra i postupak mjerenja. Koliko je autorima poznato, taj novi električni krug i njegova primjena na sustav vage nisu do sada spomenuti u literaturi. Specifikacije za vage s direktnim očitavanjem tipično uključuju čitljivost, ponovljivost, linearnost i ekscentričnost. Procijenjene su vrijednosti tih parametara i primijenjene u proračunu nesigurnosti mjerenja težine u ispitivanom rasponu mjerenja konstruiranog uređaja.The article presents the prototype version of an original weight scale in which a non-conventional supplying circuit of strain gauge load cells is applied. The paper discusses construction of an electrical circuit, the way of strain gauge transducer connection and the measuring procedure. As far as the authors know, this novel electrical circuit and its application in a weight scale system have never been mentioned in literature. The specifications for direct-reading weight scales typically include readability, repeatability, linearity and eccentricity. The values of these parameters were estimated and used for calculation of the weight measurement uncertainty in the tested measuring range of the designed device

Two thermocouples low power wireless sensors network

This paper presents technologies and experiments of a wireless sensors using two thermocouples network. It was established that the energy consumption during sensor measurements is usually up to 10 times lower compared to the energy consumption at the time of establishing wireless connection for most protocols. For this reason, new simplified wireless connection protocol was created. Extremely low energy wireless sensor hardware and software equipment was designed. The newly created universal measurement module allows the use not only thermocouples, but also various types of analogue sensors, thermocouples, pressure bridges, Resistance Temperature Detectors (RTD) and digital sensors communicating through SPI or I2C interface. The newly designed specific power supply scheme allows to supply the sensor and radio module with the voltage from 1.2 V to 3.6 V batteries. When conducting periodic measurements every second, the use of newly designed hardware and software equipment enables the wireless sensor to be operated for up to 3 years from two 1200 mAh capacity batteries.A grant (No. SEN-10/15) from the Research Council of Lithuania. Project acronym: “CaSpine”.http://www.journals.elsevier.com/locate/qeue2019-02-20hj2018Electrical, Electronic and Computer Engineerin

Evaluation of Pt100 sensor deflection effect during strain measurements

The present work concerns description of additional error sources of temperature measurement done with Pt100 sensors placed on the deflected elements. The authors came across certain problems with temperature measurement while working on an original signal conditioner. For this reason it was decided to conduct more measurement experiments. The aim of experiments was to examine the influence of deflection of Pt100 sensors on their resistance changes. In the article a laboratory stand and the procedure of conducting the research are presented.Web of Science214262

Design and Evaluation of Low-Cost Vibration-Based Machine Monitoring System for Hay Rotary Tedder

Vibration monitoring provides a good-quality source of information about the health condition of machines, and it is often based on the use of accelerometers. This article focuses on the use of accelerometer sensors in fabricating a low-cost system for monitoring vibrations in agricultural machines, such as rotary tedders. The aim of the study is to provide useful data on equipment health for improving the durability of such machinery. The electronic prototype, based on the low-cost AVR microcontroller ATmega128 with 10-bit ADC performing a 12-bit measurement, is able to acquire data from an accelerometer weighing up to 10 g. Three sensors were exposed to low accelerations with the use of an exciter, and their static characteristics were presented. Standard experimental tests were used to evaluate the constructed machine monitoring system. The self-contained prototype system was calibrated in a laboratory test rig, and sinusoidal and multisinusoidal excitations were used. Measurements in time and frequency domains were carried out. The amplitude characteristic of the preformed system differed by no more than 15% within a frequency range of 10 Hz–10 kHz, compared to the AVM4000 commercial product. Finally, the system was experimentally tested to measure acceleration at three characteristic points in a rotational tedder, i.e., the solid grease gearbox, the drive shaft bearing and the main frame. The RMS amplitude values of the shaft vibrations on the bearing in relation to the change in the drive shaft speed of two tedders of the same type were evaluated and compared. Additionally, the parameters of kurtosis and crest factor were compared to ascertain the bearing condition