Software placed directly on object will transform not electrical quantity of X to electrical quantity At. Except the term "primary converter" "the sensor of not electrical quantity" or simply "sensor" apply the term to designation of the element transforming not electrical quantity in electric.
If to subject the ferromagnetic core of the converter to mechanical influence of F, owing to change of magnetic permeability of material of the core μ. magnetic resistance of a chain that will cause change of inductance of L and mutual inductance of M of windings will change. Magnetoelastic converters (rice are based on this principle
It is expedient to classify them by the physical nature of the phenomena which are the cornerstone of their work, taking into account a type of the transformed energy. On the specified signs primary converters can be subdivided on:
Constancy in transformation function time. At change eventually function of transformation should repeat graduation that is extremely undesirable, and in certain cases it is impossible (for example, the converter works in inaccessible places.
The wire for a winding is carried out from alloys (a platinum alloy with iridium (5 — 30%), a constantan, nichrom and ). For a winding of the converter the wire isolated by enamel or an oxidic film After production of a winding is usually used isolation of a wire is cleaned off in places of its contact with a brush.
However we will describe only an electric way of measurement as it is the most widespread way of measurement. It has a number of advantages which promoted it a wide circulation, namely the accuracy, convenience in operation of measuring devices, ease performed by (design, productions of measuring devices, well studied mathematical material, compactness of measuring devices, possibility of interface to the computer.
The given ratios show that inductance and mutual inductance can be changed, for example, vozdeystv\I to length of 8, section of an air site of a magnetic conductor and, to losses in a magnetic conductor and other ways.
the amplifier will give such current of Iyk that power failure on the Rm resistor counterbalanced tension gain on the resistor R Thus at the exit, the bridge will remain in balance and the scale of the device will be linear at increments ΔR1 and resistance of Rm will determine ratio scale between ΔR1 and Iyk. Measuring chains of the counterbalancing transformation with compensation of the measured not electrical quantities are applied often to measurement of mechanical efforts, torques, magnetic sizes, etc.
sizes at the same time and besides with different signs change two gaps of two electromagnets. Differential converters in combination with the corresponding scheme (usually bridge) have higher sensitivity, than ordinary converters, give the chance to reduce nonlinearity of function of transformation, come under smaller influence of external factors. In these converters the resulting effort to an anchor from electromagnets is less, than in not differential.
Values of output sizes of the majority of primary converters — thermocouples, thermoresistors, ionization converters, gas analyzers and others are insignificant and are usually in range of 10-6 — 10-2 V and 10-10 — 10-5 And. without preliminary strengthening so small tension and currents cannot neither be measured by the showing electric devices, nor to transfer on communication without essential errors. Therefore one of problems of modern measuring equipment is strengthening with high precision and functional transformation of small tension and currents.
where δmax — a limit of the allowed relative error of measurement of not electrical quantity; δ — the maximum value of a relative error of primary converter; δ — a relative error of a measuring chain; δr — a relative error of measurement of the output showing device; δ — a methodical error.
If change of not electrical quantity leads to change of the software passive parameter — resistance, capacities, inductance or mutual inductance, software are called parametrical, and if to generation of active size (EMF current, generating.
The basic principle of creation of ITs of direct transformation with generating software is the principle of coordination of output and entrance resistance of consistently switched on converters providing the minimum losses of measuring information in the channel of transformation.