SU935700A1 - Apparatus for measuring non-electric values - Google Patents

Description

(5) DEVICE FOR MEASURING NON-ELECTRIC VALUES

The invention relates to the measurement of non-electric quantities, in particular to measurements of displacements, deformations, dimensions, etc., and can be used for automatic control and adjustment. A device for measuring non-electric quantities is known, comprising a measuring and reference oscillator, two mixers, a low-frequency amplifier, a band-pass filter, a tunable oscillator, and an indicator. The low measurement accuracy in such a device is due to the nonlinear dependence of the frequency of the measuring oscillator on the output parameter of the sensor and the use of elements with nonlinear characteristics, in particular, mixers and an amplifier, or Kcft frequency. The closest to the proposed technical entity is a device for measuring non-electrical values, containing an auto-generator torus with a measuring 1C circuit, which includes a sensor, a second auto-generator with a reference LC circuit, four controllable keys, four pulse counters, two decoders , code match element, subtraction unit, control unit and indicator. The formation of time intervals, which is carried out with the help of two oscillators having limited mutual stability, leads to a loss of the frequency of the oscillators, which affects the duration of the formed time intervals and affects the accuracy of the measurement. The aim of the invention is to improve the accuracy. The goal is achieved by the fact that in a device for measuring non-electric values, containing the first and second oscillators, measuring and reference 1C-circuits / First second, third and fourth keys, first, second, third and fourth

39357004

the counters, the first and second decoders, the device operates as follows a matching element, the block is subtracted, the control block and the indicator, the outputs of the first and second autogenerators are connected to the inputs of the first and third keys, respectively, and the outputs of the first, second and third keys - with the inputs of the first, second and third counters, respectively; the output of the fourth key is connected through the serially connected subtraction unit, the fourth counter and the second decoder are connected 1 to the input of the indicator, the output of the first first counter to the input of the first decoder, the outputs of the second and third counters to the first and second inputs of the matching element, respectively, and the output of the last connected to the first input of the control unit, the second input of which is connected to the output of the first decoder, the first output to control the first and second inputs one third of its keys simultaneously, and the second output to the control inputs of the second and fourth keys at the same time, the fifth, sixth, seventh, and eighth keys are additionally entered, while the fifth and sixth keys are connected to the measuring LC circuit, the seventh and eighth keys to the reference LC circuit, and the outputs of the fifth and eighth keys are connected to the input of the first oscillator simultaneously, while the output of the latter is connected to the input of the fourth key, and the outputs of the sixth and seventh keys the inputs of the second oscillator, the output of which is connected to the input of the second key, in addition, the control inputs of the fifth and seventh keys are connected to the first output of the control unit, to the second output of which are connected the control inputs of the sixth and eighth keys tezhe is a block diagram of an apparatus for measuring a non-electrical quantities. The device contains the first and second autogenerators 1,2, measuring 3 and the reference LC circuits, controllable keys 5-12, first to eighth counters 13-16 pulses first to fourth, first and second decoders 17.18, element 19 coincidence codes , subtraction unit 20, control unit 21 and indicator 22. Measuring LC circuit 3 includes a sensor.

Claims (2)

Set the frequency of the first and second oscillators of 1.2 approximately equal. In the first decoder 17, the number N is chosen, chosen from the ratio N: 1 nom () where the measurement discontinuity error; t is the sensitivity of the sensor; X is the nominal value of the measured non-electric quantity. The measured non-electric quantity is converted, for example, to a change in the inductance of the sensor. When the device is switched on, the measuring LC circuit 3 through the open fifth key 9 is connected to the input of the first oscillator 1, from whose output the pulses through the open first key 5 enter the input of the first counter of 13 pulses, the counter of 13 pulses counts the number N of periods t of the frequency of the first autogenerator 1 set in the first decoder 17. At the same time, the formation of the first time interval occurs), where t tp + / it, t is the period of the frequency of the oscillator 1 with the connected LC circuit 3 BEFORE the measurements start; B t is the increment of the frequency period of the first auto-oscillator 1 with the connected measuring LC circuit 3, due to the change in the inductance of the sensor when measuring a non-electric quantity, for example, displacement; k is the frequency instability coefficient of the first oscillator 1. At the same time, the received time interval T is filled with the pulses of the second oscillator 2. For this, the pulses from the second oscillator 2 are fed through the third key 7 to the input of the third counter 15 pulses and are counted by them) 593570 where t. the period of the frequency of the second oscillator 2 with the connected reference LC circuit k before the start of measurements, k is the frequency instability coefficient of the second oscillator 2. After the formation of the time interval T from the output of the first-. The decoder 17 receives a command O to the second input of the control unit 21, which closes the control keys 5,7,9 i11 and opens the control keys 6,8,10,12, while the LC circuit 3 is connected via the sixth key 10 to the input the second oscillator 2, and the LC circuit 4 through the key 12 is connected to the input of the first oscillator 1. The pulses from the output of the oscillator 2 through the second key 6 is fed to the input of the second counter 1 pulses. A pulse counter 1k counts the number Ml of the periods t of the frequency of the oscillator 2 with the connected LC-circuit 3, thus forming the second time interval T2 + k). At the same time, the time interval T is filled with pulses with a period t-j, the frequency of the oscillator 1 with the reference LC circuit connected 4. The number of pulses is Ta. , -tjU -K,) and-whether taking into account expressions (2), (3), C) d-N-1 71- f tt if From expression (6) it follows that the number u.,. N3 pulses of instability are not affected by the generator, since t, 2 t2 ZrcVlj C, where the parameters of the circuit 3; L С - parameters of the circuit i, then N3N-1-p (7) 2. Li, C, C con5t, he are dependent on the measured non-electric quantity Мз п1 ,. (8) 5 ц 06 where n is the coefficient for converting the measured value into the number of pulses. The signal corresponding to the number of pulses NJ is fed from the output of the controlled key 8 to the input of the subtracting unit 20. The second counter of pulses 1 stops when it reaches the number recorded in the third counter of 15 pulses, which is recorded by the element 19 of coincidence of codes, the signal from the output of which goes to the first input of control unit 21. At the command of the control unit 21, the keys are closed 6,8,10,12 and the keys are opened 5,7,8,11, i.e. the device returns to its original state. In subtraction unit 20, the number of N is subtracted from the number of pulses N3, corresponding to the number of periods of the frequency of the oscillator 1 with the connected LC circuit 3 before the measurements start. The resulting number N. proportional to the measured non-electric value, counted with the sign of the counter of 16 pulses, converted to the decimal code by the decoder 18 and fixed by the indicator 22. Thus, the dependence of the number of pulses in the counter 16 on the measured electrical value is linear. the used additional control eNfctx keys 9-12, allowing in one measurement cycle to connect autogenerators 1.2 to measuring 3 and reference LC circuits in such a way that each of the autogenerators alternately plays the role of measuring and "reference", provides an exception - i influence neither on the duration of the formed time intervals of parasitic frequency care of oscillators 1, 2. Due to this, no less than twice the accuracy is achieved. Claims An apparatus for measuring non-electrical quantities, comprising first and second oscillators, measuring and reference LC circuits, first, second, third, and fourth keys, first