SU576539A1

SU576539A1 - Digital automatic bridge

Info

Publication number: SU576539A1
Application number: SU7602321329A
Authority: SU
Inventors: Али Мансималы Амиров
Priority date: 1976-02-04
Filing date: 1976-02-04
Publication date: 1977-10-15

Description

1one

Изобретение относитс к измерительиой технике и предназначено дл измерени различных электрических параметров (емкости, индуктнвностн , проводимости, активного сопротивлени ) с устойчивым отсчетом.The invention relates to a measuring technique and is intended to measure various electrical parameters (capacitance, inductance, conductivity, resistance) with a stable reading.

Известны цифровые автоматические мосты со след щим уравновешиванием, содержащие генератор питани , мостовую схему, к одному плечу которой подключаетс измер емый объект , а к измерительной диагонали - детектор равновеси , который управл ет работой реверсивного счетчика соответственно сигналу разбаланса мостовой схемы, регулирующего значени уравновешивающего плеча мостовой схемы, и цифровой отсчетный блок, но показа-нию которого ири равиовесии моста снимаетс отсчет измер емой величины 1.Digital automatic bridges with the following balancing are known, containing a power generator, a bridge circuit, to one arm of which a measured object is connected, and an equilibrium detector controlling the operation of a reversible counter corresponding to the balance arm signal to the measuring diagonal diagrams, and a digital readout block, but by showing the number of the measured value 1, the reading of the bridge is taken.

Известен также экстремальный мост, в котором дл обеспечени устойчивого отсчета использован метод параметрической модул ции. Известное устройство содержит генератор питани , мостовую схему, избирательный усилитель , детектор, два ключа, триггер реверса, генератор импульсов, модул тор, реверсивный счетчик, коммутациоиный блок и цифровой отсчетный блок 2.An extremal bridge is also known, in which a parametric modulation method is used to provide a stable reference. The known device comprises a power generator, a bridge circuit, a selective amplifier, a detector, two keys, a reverse trigger, a pulse generator, a modulator, a reversible counter, a switching unit, and a digital reading unit 2.

Недостатком известного устройства вл етс то, что, с целью получени устойчивого отсчета , требуетс слишком высока точность подгонки образцовых мер.A disadvantage of the known device is that, in order to obtain a stable reference, the accuracy of fitting the exemplary measures is required too high.

Целью изобретени вл етс обеспечение устойчивого отсчета и снижение требований к точности образцовых мер.The aim of the invention is to provide a stable reference and reduce the accuracy requirements of exemplary measures.

Это достигаетс тем, что цифровой автоматический мост, содержащий генератор, питающий мостовую схему, на выходе которой включены последовательно соединенные избирательный усилитель, детектор, ключ возврата, триггер реверса, реверсивный счетчик, коммутационный блок, соединенный с мостовой схемой , блок управлени , один из выходов которого соединен с ключом возврата, и цифровой отсчетиый блок, снабженный носледовательно включенными схемой переноса кода и регистром иам ти, а также элементом ИЛИ, один из входов которого соединен с выходом ключа возврата, другой вход соединен со вторым выходом блока уиравлени , а выход соединен с реверсивным счетчиком, выход которого, в свою очередь, соединен с одним из входов схемы нереноса кода, другой вход которой соединен с третьим выходом блока управлени , выход регистра пам ти иодключен к цифровому отсчетному блоку.This is achieved by the fact that a digital automatic bridge containing a generator, supplying a bridge circuit, the output of which includes a series-connected selective amplifier, detector, return key, reverse trigger, reversible counter, switching unit connected to the bridge circuit, control unit, one of the outputs which is connected to the return key, and a digital counting unit, equipped with a code-transfer circuit and a register of these types, and the OR element, one of the inputs of which is connected to the output oh return key, another input is connected to the second output of the accumulator, and the output is connected to a reversible counter, the output of which, in turn, is connected to one of the inputs of the code non-transfer circuit, the other input of which is connected to the third output of the control unit and connected to a digital reading unit.

Иа фиг. 1 приведена блок-схема предложенного устройства; на фиг. 2 представлена зависимость модул выходного напр жени моста от изменени регулируемого плеча моста.FIG. 1 shows a block diagram of the proposed device; in fig. Figure 2 shows the dependence of the output voltage module of the bridge on the change in the adjustable arm of the bridge.

Claims

The device contains a power generator 1, a bridge circuit 2, a selective amplifier 3, a detector 4, a return key 5, a reverse trigger 6, a reversible counter 7, a switching unit 8, a control block 9, an OR element 10, a code transfer circuit AND, a memory register 12 and a digital reading unit 13. The device operates as follows. The generator 1 feeds the bridge circuit 2, the output of which is fed through the selective amplifier 3 to the input of the detector 4. The detector selected by the envelope is fed as a control voltage to the control input of the switch 5, which is locked only by negative pulses. Reversible counter 7 when pulses are output at the output of the element OR 10, according to the position of the flip-flop of the reverse 6, using block 8 increases or decreases the adjustable arm of the bridge circuit 2. Block 9 sequentially feeds its pulses to the inputs of the element OR 10, key 5 and the code transfer circuit 11. The impulse from the second output of the control unit through the OR element is fed to the counting input of the reversible counter 7, which, having carried out one probe, transfers the bridge circuit 2 to a new position. If the test step corresponds to removing the washing circuit 2 from equilibrium, then a positive polarity pulse appears at the output of detector 4, which does not lock the key 5. At the same time, the pulse that appears on the first output of block 9 passes through key 5 and changes the state of the flip-flop of the reverse 6, as well as, having entered through the element OR 10 at the counting input of the reversible counter 7, returns it to the previous state. After that, the pulse from the third output of the control unit 9 goes to the control input of the AND code transfer circuit and transfers the reading of the reversible counter 7 to the memory register 12. Then, from the second output of the block 9, the pulse is fed through the OR element 10 to the input of the reversible counter, which performs new trial step, but in the direction of balance. At the same time, a pulse with negative polarity appearing at the output of detector 4 does not pass the returning pulse through key 5. Consequently, the reversible counter remains in the new polus. Thus, the bridge approaches equilibrium. In the proposed device, the reversible counter 7 itself is also a modulator, therefore the lengths of the modulation step and the true step of the reversible counter are equal. Due to this, even with an extended (due to different marks of tolerances for making exemplary measures) step (bs in Fig. 2) of the reversible counter 7, only one - at the closest point to point M of true equilibrium on the envelope of the output voltage of bridge circuit 2 - unipolar polar impulses occur which are a sign of equilibrium. Therefore, the reversible counter, after the test leads are made back and forth, immediately returns to state b. At equilibrium, the reading of the reversible counter oscillates in the following order: a b b b b 5 .... The code from the reversible counter is transferred to memory register 12 only after passing through the return pulse. Consequently, at equilibrium, the readings of the memory register will always correspond to the state b of the reversible counter, providing a steady count of the digital readout unit 13. Invention Digital automatic bridge containing a generator supplying a bridge circuit, the output of which includes a series-connected selective amplifier, detector, switch return, reverse trigger, reversible counter, switching unit connected to the bridge circuit, the control unit, one of the outputs of which is connected to the key in a digital readout block, characterized in that, in order to provide a stable count, reduce the accuracy requirements of exemplary measures, it is equipped with a series-connected code transfer circuit and memory register, as well as an OR element, one of whose inputs is connected to the output of the return key the other input is connected to the second output of the control unit, and the output is connected to a reversible counter, the output of which, in turn, is connected to one of the inputs of the code transfer circuit, the other input of which is connected to the third output of the control unit detection, the output of register memory is connected to a digital readout unit. Sources of information taken into account in the examination 1.P. P. Ornatsky, "Automatic Measurements and Instruments, Kiev, ed. Vishcha School, 1973, p. 458.

2.F. B. Grinevich, A.V. Chebotaryov, A.I. Novik, “Elements and schemes of digital extreme bridges of alternating current, Frunze, ed. The Academy of Sciences of the Kirghiz SSR, 1963, p. 125