SU550570A1 - The device for eddy current testing of steel cables - Google Patents

Description

digital indicator, and the output of the signal processing unit and the second input of the code comparison unit are connected to the inputs of the output unit.

The drawing shows the block diagram of the device for the eddy current testing of steel cables.

The device comprises a generator 1, an eddy current converter-2, channels 3 and 4 of measurement of quadrature signal components, a phase shifter 5, a control unit 6, first and second keys 7 and 8, and first and second output blocks 9 and 10.

Generator 1 is connected to converter 2, which is connected via channels I to channels 3 and 4. Generator 1 is also connected to reference input 12 of channel 3 without phase shift and to reference input 12 of channel 4 through a phase shifter 5. Control unit 6 is connected to control to the inputs 13 and 14 of channel 3 and channel 4. The outputs of channel 3 and

4 are connected via keys 7 and 8 with output blocks 9 and 10.

Channels 3 and 4 are made in the form of serially connected blocks: block 15 (16) comparison, block 17 (18) multiplication, integrator 19 (20), converter 21 (22) voltage-code and digital divider 23 (24), the output of which connected to the auxiliary input 25 (26) of the comparison unit 15. The control inputs of the integrator 19 (20) and the converter 21 (22) are connected respectively to the control inputs 13 and 14 of channel 3 (4). The reference inputs of the block 17 (18) and the digital divider 23 (24) are connected to the reference inputs 12 of channel 3 (4).

The output units 9 and 10 have the same construction and each is made as a serial connection of the signal processing unit 27 (28), the code comparison unit 29 (30) and the digital display 31 (32). The input unit 27 (28) and the second input unit 29 (30) are connected respectively to the inputs 33 and 34 of the output unit 9 (10).

The signal from generator 1 is fed to converter 2, which is connected to the-signal inputs 11 of channels 3 and 4, as well as to the reference inputs 12 of channels 3 and 4. The reference input 12 of channel 3 is connected to generator 1 directly, i.e. without phase shift (amplitude normalizer 35 can be switched on in the reference circuit). The reference input 12 of the channel 4 is connected to the generator 1 through the phase shifter

5 (normalizer can also be included)

36 amplitudes). A control unit 6, connected via control inputs 13 and 14 to each of the channels 3 and 4, controls the signal conversion system. The output signal of channel 3 (4) is fed to the key 7 (8). In the calibration mode, the signal enters the input 33 of the output unit 9 (10). In the measurement mode - to the input 34.

When the flaw detector is put into operation, generator 1 feeds converter 2 with alternating current. The signals of converter 2 through the signal inputs enter the channel 3 (4) on the signal input of the comparison unit 15 (16), and the additional input 25 (26) of which supplies a signal from the digital splitter 23 (24).

The input signal and output signal of the digital divider 23 (24) is fed to block 17 (18) multiplication. In the case when in-phase and quadrature with generator voltage 1, the output voltage of digital divider 23 (24) does not fully compensate for the in-phase quadrature with generator voltage 1; electoral frequencies on the input of block 17 (18) The umpolation of the signal contains an in-phase (quadrature) signal with a generator voltage of 1 component. Through the reference input 12, drips 3 (4) to the input of block 17 (18) of the multiplication are received the reference signals from generator 1 (in-phase and quadrature components of the frequency at which the measurement is made). This results in the output of block 17 (18) of multiplying the constant component, the sign of which is uniquely determined by the sign of the compensation error, and the level is proportional to the magnitude of this error. The output voltages of the multiplication blocks 17 and 18 affect the input of the integrator 19 (20), which is controlled by the control unit 6. Block 6 generates integrator control pulses equal in duration to the period of the measurement frequency, which is fed to its input from generator 1. Output coupler and integrator 19 (20) is a sequence of rectangular pulses of constant duration, the amplitude of which is proportional to the product of multiplied voltages. The output voltage of the integrator 19 (20) is maintained for a certain period of time after the end of the integration cycle, normalized by the control unit 6. The output signal of the integrator 19 (20) is fed to the converter 21 (22) voltage code. Depending on the sign of the voltage of the integrator 19 (20), the converter 21 (22) generates a compensating sawtooth of one or another polarity and the filling pulses of a defined time interval. The operation of the converter 21 (22) is clocked by the control unit 6 via the control input 14 of the drip 3 (4) and synchronized with the operation of the integrator 19 (20). If there is a mismatch error, the output of integrator 19 (20) will be a signal and, therefore, the output signal of converter 21 (22) will change. The equilibrium position will be observed only in the case when the output voltage of the integrator 19 (20) will be the threshold voltage of the converter 21 (22).

Claims (2)

Thus, the compensation system behaves like an astatic control system. The state of the digital voltage divider 23 (24), which displays the value of the compensating voltage in a binary-decimal code, is compared with the value of the code written in the data circuit of block 27 (28) of the output block 9 (10), where the signal comes from the output channel 3 (4) via key 7 (8) and input 33. This signal characterizes the unworn portion of the rope. The measurement process of wear and tear is carried out in two cycles. In the ivy cycle, the key 7 (8) is closed through the input 33 of the output unit 9 (10) to the input of the unit 27 (28) and the measurement is carried out on the reference section of the measured cable. In the second cycle, the key 7 (8) is closed through the input 34 of the output unit 9 (10) to the unit 29 (30) comparing the IRP codes measuring the working part of the steel caiat. Claim 1. Device for vortex monitoring of steel ropes, comprising a generator, an eddy current converter connected to it, a phase shifter, two parallel channels for measuring quadrature components, signal inputs connected to the converter, and the reference inputs of the first channel directly, and the second channel through the phase shifter with the output of the generator, and the first output unit, from the fact that, in order to improve the control accuracy, it is equipped with a control unit connected between the output of the generator torus and the control channel inputs, the second output unit and two switches through which each output unit connected to the output of its dripping. 2. A device according to claim I, characterized in that each channel is made up of serially connected Comparing, multiplying, integrator, voltage-code converter, digital voltage divider, the output of which is connected to the second input of the comparator, control inputs of the integrator and the voltage-code converter is connected to the control inputs of the channel, the reference inputs of the multiplication unit and the digital divider connected to the reference input of the channel. 3. The device according to paragraphs. 1 and 2, characterized in that each output unit is made in the form of a sequentially connected signal processing unit, a code comparison unit and a digital indicator, and the input of the signal processing unit and the second input of the code comparison unit are connected to the inputs of the output unit. Sources of information taken into account in the examination: 1.B. S. Gerasimov, A. 3. Chapaevsky “Mine lifting installations abroad, Moscow, TsNIZIugol, 1972, pp. 25-26. 2. The patent of the USSR 352481, M. Kl.2 G 01N 27/86, 12.06.69.