SU613267A1 - Method of measuring parameters of rc- and lc-circuits - Google Patents

Description

The invention relates to the field of electrical measuring equipment and is intended to automate the measurement of the parameters of two-element C- and -, circuits.

The known method of element-by-element tolerance control or, based on a method of comparing transients, arising three connections of measuring circuits composed of series-connected controlled RK or Ck circuit and sample element to a constant voltage source, co-control one element or / to K-circuit carried out by means of a tolerant assessment of the voltage of the transition process at a certain point in time, and the control of another by means of a tolerant assessment of the allocated interval from the beginning of the transition to achieve a transient voltage value predetermined reference voltage.

The disadvantage of the known measurement method is the low accuracy of measurement, rhenium.

The closest technical solution to the invention is a method of automatically measuring inductance and loss angle of coils, according to which, in order to measure parameters separately, according to the cosine law, the voltage module on the compensating element simultaneously with the change of its phase 2 changes.

The disadvantages of this method are the complexity and low accuracy of the measurement process, due to the need to isolate the components from the uncompleted difference, proportional to the inductance and the angle of coil losses, respectively, and the effect is proportional to the values of these components on potentiometers, potentiometers, one of which functional.

The purpose of the invention is to simplify the process of measurement and increase accuracy.

The goal is achieved by the fact that

by applying a periodic effect to the measuring circuit and receiving an informative signal at its output, which is a composition of periodic voltage | yamonal and triangular pulses, it is proposed to compensate the component of the informative signal, which modulates the amplitude by the input action, coinciding in fof | fix the value of the compensating voltage

successively at the moments of coincidence of the beginning and end of the calibrated time interval, specified during each loluperiod of the input action, symmetrically with respect to the middle of the half period, with the moments

the transition of the uncompensated difference through the zero level and, according to these values, determine the parameters of the RC, / L-chains.

On fig. 1 shows a block diagram of a device, | real, with the proposed method; in fig. 2 — time diagrams of its operation (a — the detection at the output of the generator of a periodic input action, b — the voltage at the output of the driver, c — the voltage at the output of the Meip.H body block, g — the voltage at the output of the differential zero-o.rgan, d - voltage output of a logic element).

The device contains a generator .1. Periodic input (Impact, parallel connected to the input of the measuring unit 2 and the input of the scaling node 3. Another output of the generator / through the driver 4 is connected to the input of the logic element 5. The outputs of the measuring unit 2 l scaling node connected to the inputs of a potential null organ 6 connected to another input of logic element 5, the output of which is connected to the input of control unit 7. The output of the latter is connected to the control input of the scaling node of its 3 and. with inputs and converter 8 codes, the outputs of which are connected to digital indicators 9 and 10.

The output / signal of the generator 1 is a periodic input, for example, alternating rectangular voltage with amplitude ± and frequency / o I / To (Fig. 2 a is fed to the input of measurement | rItel unit 2. The signal at the output of the latter (Fig. 2 b) is a composition of periodic rectangular and triangular voltage pulses and in each half-period of the input action is described by the following expression (for example, when measuring parameters of a sequential / L-circuit):

i;, (/ ± Z: | f - 2 - -i (L ... L.

In a parallel channel with a scaling node of 3 forms. A compensating voltage is inserted:

and, ia,

where f, i is the discretely variable transfer coefficient of the scaling node 3.

Differential zero-organ 6 emits pulses at the moments of transition by the difference of voltages at its inputs:

L.

DU (0- ± (f + -) -2 -p (, - /

1- -bf ,. 4 through the zero level.

Shaper 4 during each half period forms time stamps (Fig. 26), equidistant from the middle of each half period, for example, for the interval

At, TO is, denoting time intervals, measured from the beginning of each half period:

Thats

5 / ,, + D /

four

The control unit 7 changes the transmission coefficient | l until the moment of transition of the uncompensated difference Af / (/) through the zero level coincides in series with the output pulses of the driver 4, i.e. with the beginning of the center c the end of the specified interval 2D /. The specified points correspond to the system of equations:

 T

BUT ,

l

: 0

z: 7a

H-2. (

Substituting into the system the expressions for / i, / 2 and solving it with respect to L, we get:

  R

-. 0

Y

4A “

In the instants of the short matches, the logic element (Fig. 2e) 5 outputs signals to the control unit 7, according to which codes corresponding to | x and | i are fixed in the code converter 8. Then, in the converter 5 of the codes, the operations of summation and subtraction of the codes are performed and the results are output on the digital indicators 9 and 10.

The use of the proposed method makes it possible to separately measure the parameters of RC and / L circuits when performing only one linear adjustment of the compensating parameter, which simplifies the measurement process and improves its accuracy.

Claims (2)

1. Certificate of author No. 385239, cl. G 01 R 27/02, 1971. 2. Author's certificate number 230295, cl. G 01 R 27/26, 1967. H