Analysis of four-wire resistance simulators properties
Students Name: Trush Mykhailo Ihorovych
Qualification Level: magister
Speciality: Quality, Standardization and Certification
Institute: Institute of Computer Technologies, Automation and Metrology
Mode of Study: part
Academic Year: 2020-2021 н.р.
Language of Defence: ukrainian
Abstract: In the master’s qualification work, the analysis of metrological characteristics of portable codified DC resistance measures for operational control of measuring channels of sprayed industrial systems showed that they must be connected to the controlled object by a four-wire connecting line. The range of reproducible resistance values should be in the range from tens of ohms to tens of kilohms, the limit of permissible values of their errors should be at the level of several hundredths of a percent, the unit of reproducible resistance values of the order of ten thousandths of an ohm. Traditionally, such metrological characteristics of coded resistance measures at the place of operation are provided by adjusting them by the operator after a certain time for their entry into operation. It is also shown that it is impossible to provide such metrological characteristics on the basis of multivalued resistance or conductivity stores due to the significant influence of residual parameters of switching elements. Therefore, it is proposed to implement coded multivalued resistance measures based on active electrical resistance simulators. The choice of the functional structural scheme of such measures with the possibility of their four-wire connection to the controlled objects is substantiated. The structure is developed, the choice of element base is substantiated and the procedure of adjustment of portable simulators of resistance to a direct current for the purpose of correction of additive and multiplicative components of an error is offered. It is also shown that the uncorrected values of the additive and multiplicative components of the error can be significantly reduced due to the selected element base and the proposed method of its adjustment and will be practically determined only by relatively small time and temperature changes of its elements. This reduces the complexity of the practical use of such measures-simulators in industrial conditions.