The error brought by the connecting line (communication channel) has to be considered as a component of the methodical error entering a total error of measurements of not electrical quantity. Accuracy of result of such measurement can be estimated by an approximate maximum error on a formula:
With parametrical software three types of measuring chains of direct transformation (rice are used: chains of consecutive inclusion (chains in the form of dividers (and chains in the form of not balance (nonequilibrium) bridges (.
In nonequilibrium bridges this defect is eliminated. Besides, ITs on the basis of not balance bridges have more opportunities as parametrical primary converters can be switched on in one, two or all four shoulders of the bridge that corresponds to increase in output power of ITs, i.e. increase of its sensitivity.
Complex automation of production and measurements is connected with data acquisition about value of various physical quantities characterizing a condition of object of management (research) — mechanical, thermal, chemical, optical and other sizes which it is accepted to call not electric.
The entrance of primary converter except entrance size X is affected also by other parameters of object and environment. In these conditions primary converter has to react selectively only to value of entrance size and not react to influence of all other factors. The problem of suppression of sensitivity of primary converter to the influencing sizes belongs to the important tasks solved by constructive and circuit methods.
Each converter has the error, and, obviously, the maximum error of all measuring device constructed on a method of direct transformation will appear to the equal sum of errors of separate. Therefore, despite simplicity and speed of the devices constructed on a method of direct transformation apply an equilibration method to exact measurements of not electrical quantities.