In this paper the realization and optimization of two coreless open-loop bus bar current transducers based on a Hall effect sensor are presented. Two types of bus bar are evaluated: flat rectangular and rectangular with a restrictive region in the middle. Both realized transducers are capable of measuring AC and DC currents up to 300 A and 10 kHz frequency with nonlinearity less than 0.3% in the entire range. Several methods for resolving issues with the skin effect and stray magnetic fields are presented along with the experimental test results. Some of the presented methods are novel and have never been evaluated.

In this paper a prototype of wireless system for dust density measurement is presented. The system is developed with inexpensive commercially available components and can measure dust density up to 0.5mg/m ³ . The system is modular and consists of a base station connected to a PC via USB communication and an autonomous sensing node equipped with an optical dust sensor GP2Y1010AU0F. A virtual instrument made in LabVIEW is created to monitor the system operation, data acquisition and data storage.

Temperature Measurement of Photovoltaic Modules Using Non-Contact Infrared System Photovoltaic modules;Temperature measurement;Infrared temperature sensor;Thermal imaging camera; This paper presents temperature measurement of solar photovoltaic modules using the custom-made system composed of an infrared temperature sensor and a microcontroller. The obtained measurement results are processed, displayed and stored on a PC using the custom-made virtual instrument. The proposed system overcomes some of the problems related to the contact sensor application, and at the same time offers accurate readings and better flexibility. The proposed system is especially suitable for applications where the cost is a limiting factor in the choice of measuring system. The conducted analysis and the obtained results have shown an excellent accuracy of the proposed system in comparison to a high quality thermal imaging camera used as the reference instrument.

The paper provides an overview of coreless open-loop current transducers based on Hall effect sensor CSA-1V. Depending on the implementation method and current range, the presented transducers are divided in the four groups. The transducers are capable to measure AC and DC currents ranging from several tens of miliamperes up to several hundreds of amperes. Methods for resolving issues with the skin effect and stray magnetic fields are also presented including the experimental test results. Some of these methods are novelty and have never been presented in literature.

Optical rotary encoders generate nonlinear sine and cosine signals in response to a change of angular position that is being measured. Due to the nonlinear shape of encoder output signals, encoder sensitivity to very small changes of angular position is low, causing a poor measurement accuracy level. To improve the optical encoder sensitivity and to increase its accuracy, an improved linearization circuit based on pseudo-linear signal generation and its further linearization with the two-stage piecewise linear analog-to-digital converter is presented in this paper. The proposed linearization circuit is composed of a mixed-signal circuit, which generates analog pseudo-linear signal and determines the first four bits of the final digital result, and the two-stage piecewise linear analog-to-digital converter, which performs simultaneous linearization and digitalization of the pseudo-linear signal. As a result, the maximal value of the absolute measurement error equals to 3.77168·10⁻⁵ [rad] (0.00216°) over the full measurement range of 2π [rad].