Auxiliary sizes are summarized at to which the measured sizes will be transformed x. Therefore there are methods of summation () of currents, tension, impulses, magnetic fluxes, the rotating moments, angular and linear movements, parameters of electric chains (resistance, capacities, induktivnost). Conditions of summation are written down in a look
Error — extent of approach of indications of the reception device to the valid value of the measured size. The error of a is defined as the maximum difference between indications of the device on the reception party and the valid value a size tele-ism-ryaemoy determined by indications of the model device.
Summation of the measured sizes. Need of summation arises in the presence of many sources of the same information on the reception party. In this case summation is on the transferring party. At strongly dispersed objects and a large number of controlled points summation of the telemeasured sizes is carried out on the reception party.
Telemeasurement on a call — telemeasurement on the team sent from point of management to controlled point and causing connection on controlled point of sending devices, and on point of management — the corresponding intakes.
The telemeasured sizes have to be reproduced in the analog or digital way on the specifying or registering devices in absolute values of the measured sizes. It means that if the transferred size is expressed in tons, that, despite all transformations of this size, inevitable by transfer, the device on the reception party has to be in tons. Only in special cases reproduction of telemeasurements as a percentage is allowed.
Characteristics of systems of telemeasurement and shown to them. The main requirement imposed to STI is that it has to provide the set telemeasurement accuracy. Therefore the main characteristic of STI is accuracy. Accuracy by a static error, or simply an error.
Direct transformation of tension to a code. In these the code formed in the coding device will be transformed to tension which is compared to the measured tension. At equality of tension formation of a code stops and it moves on an exit.
big accuracy of telemeasurement. The error in kodoimpulsny systems arises when transforming of the measured size to a code. The of the converters transforming the measured sizes to a code to be less than 0,1%, i.e. it is higher than an accuracy of converters of other systems which lies within 0,5 — 1,5%;
In kodoimpulsny systems (PUSSYCATS) the measured size is transferred in a type of a certain combination of impulses (a code. Previously it is quantized on level and on time. Further kodoimpuls-ny modulation (KIM) is carried out.
Absolute wasps a novny error of the channel of a of the device (a complex — the greatest difference of the output size specified to entrance according to calibration, and entrance size:
Lack of the decoding grids with consecutive connection of the digit. resistors is that at inclusion of different number of resistors various values of day off a scheme turn out that reduces the transformation accuracy if the works not in the mode of a single code, and it is loaded on an entrance of the subsequent device. This shortcoming grids with parallel turning on of digit resistors of R type — 2R and with the weighed resistors are deprived.
As reformative devices the digital-to-analog converters (DTAC) executed in the form of the decoding grids from resistors are used. The parallel code is necessary for transformation of a code parcel to current or tension. Therefore before transformation the code registers in the register and at the right time from all its cells the parallel code is removed. Resistance of resistors in a grid choose so that the output tension of a grid was proportional to the decoded number. On a way of construction ' grids subdivide on consecutive and parallel, and on an operating mode — with summation of tension and currents.