RU1768938C - Linear-displacement meter - Google Patents

Abstract

The invention relates to automation and measurement technology, and in particular to devices in systems for automatically monitoring and adjusting the thickness of a strip in rolling mills. The aim of the invention is to expand the dynamic range of the measured thicknesses. The essence of the device for measuring linear displacements comprises a generator whose paraphase outputs are connected to two opposite terminals of the differential inductive displacement sensor, the output of which is connected to the first input of the subtractor, the second input of which is connected to the output of the digital-analog converter, the signal input of which is connected to the output of the subtraction circuit, the output of the subtractor through an amplifier is connected to the input of the detector, the control input of which is connected to one of the outputs generator. A code shift circuit and a switch are introduced into the device, the inputs of which are connected to the generator outputs, the output of the switch is connected to the first input of the subtraction circuit, the second input of which is connected to the output of the sensor, the control input of the switch being connected to the control output of the code shift circuit, the inputs of which are connected with the outputs of the setter, and the outputs are said with the inputs of the digital-to-analog converter. 2 ill. Yo

Description

The invention relates to automation and measurement technology, and in particular to devices in automatic belt control and regulation systems in a rolling mill. Displacement measuring devices are known comprising a differential inductive displacement transducer included in a bridge circuit and a rectifier connected to the output of this circuit.

A disadvantage of the known devices is the low measurement accuracy.

The closest in technical essence to the claimed device is

a prototype pouCTBJ for measuring displacement, comprising: a generator; differential inductive sensor, amplifier, detector, f; 13 moving block, subtraction circuit, digital-to-analog converter, master, voltage divider, key and adder.

The sensor is powered by a generator with paraphase outputs. Two antiphase signals are input to the subtraction circuit. The first signal from: the output of the differential inductive sensor is proportional to the controlled value. The setpoint is set by the master

O 00 YU SO 00

tape thickness. This value is converted into an analog signal by a digital-to-analog converter and fed to the second input of the subtraction circuit.

A signal proportional to the difference between the specified thickness value and its measured value is output from the subtraction circuit to the input of the amplifier and then through the detector to the output of the device. The reference voltage for the digital-to-analog converter is formed of three signals. The first signal is proportional to one of the sensor supply voltage phases. The phase shifting unit compensates for phase shifts in the communication line between the sensor and the secondary device. A signal from the amplifier output is fed to the subtracting input of the adder for constant correction of nonlinearity in the entire range of measured thicknesses. When the senior bit of the setter is turned on in the upper section of the dynamic range of measured thicknesses, a part of the signal is proportional to the other phase of the sensor supply voltage to the second summing input , a weighted change in the reference voltage at the input of the digital-to-analog converter occurs. The degree of reduction is determined by the divider.

The disadvantage of the prototype is a narrow range of measured thicknesses, almost equal to half of the entire measuring stroke (movement) of the sensor, this is due to the fact that the differential inductive sensor is made of two identical windings located on the same axis so that the movement of the plunger made of magnetic material , within the measuring stroke causes a change in the inductance of the windings by an equal amount, but of the opposite sign, i.e. plunger - has a position corresponding to the zero output signal of the sensor (position of the electrical neutral). The phase of the output voltage of the sensor changes when the plunger crosses the neutral, the phase of the reference voltage of the digital-to-analog converter is rigidly connected to the supply voltage of the sensor, therefore, it is possible to compensate the output voltage of the sensor from the output of the digital-to-analog voltage only on one of the sensor travel half .

Thus, the device can operate only on half of the entire measuring movement of the sensor.

The purpose of the invention is to expand the range of controlled movements.

Figure 1 presents a block diagram of a device; Figure 2 is an exemplary embodiment of a code shift scheme.

The device comprises a generator with paraphase outputs 1, a differential inductive sensor 2, a first subtraction unit 3, an amplifier 4, a detector 5, a digital-to-analog converter b, a control unit 7, a second block

Subtract 0, switch 9, code shift circuit 10.

The paraphase outputs of the generator 1 are connected to the inputs of the differential inductive sensor 2 and to two inputs

5 of the switch 9. The output of the differential inductive sensor 2 is connected to the second input of the first subtraction unit 3 and the second input of the second subtraction unit 8, the first input of which is connected to the output

0 switch 9. The third input of the switch 9 is connected to the control output of the code shift circuit 10, the inputs of which are connected to the outputs of the control unit of the controlled parameter 7, and its outputs are connected to the inputs 5 of the digital-to-analog converter 6. The output of the second subtraction unit 8 is connected to the signal input digital-to-analog Converter 6, the output of which is connected to the first input of the first block subtract 0 or 3. The output of the first block of subtraction 3 is connected to the input 4, the output of which is connected to the detector 5, the control input of which is connected to one of the output generator.

5 The code shift circuit (see FIG. 2) may consist of the high-order transmission circuit 11, the digital comparator 12, the code reversal circuit 13. The outputs of the setter 7 are connected to the inputs of the digital comparator

0 12, the outputs of which are connected to the control inputs of the code reversal circuit 13. The first output of the digital comparator 12 is connected to the input of the switch 9. The second output of the digital comparator 12 is connected

5 with the control input of the high-order pass-through circuit 11, the output of which is connected to the high-order input of the code-reversal circuit 13, the remaining inputs of which are connected to the corresponding outputs

0 of the master 7. The two senior outputs of the master 7 are connected to two inputs of the high-pass circuit 11.

The outputs of the circuit 13 of the code 13 are connected to the inputs of the digital-to-analog converter 5.

The device operates as follows.

The setter 7 sets a predetermined thickness of the tape. Code corresponding to a given thickness through a code shift scheme

10, to the inputs of the digital-to-analog converter 6, and after conversion to an analog signal, it is supplied to the first input of the first subtraction unit 3. The signal from the output of the differential inductive sensor 2 is fed to the second input of the unit 3. The sensor is powered from the generator 1 with paraphase outputs.

A signal equal to the difference between the set thickness value and the measured value, from the output of the first subtraction unit 3, is fed to the input of the amplifier 4 and then through the detector 5 to the output for use in the mill control system in rolling mills in order to obtain a specified thickness tolerance.

The reference voltage for the digital-to-analog converter 6 is generated from two signals Us and Us. One of the signals Us is proportional to one of the supply voltages of the sensor Ui or U2 depending on the signal at the control output of the code shift circuit 10. The second signal from is the output of the sensor, which, when added to the signal Us, changes the value of the reference voltage at the input and, accordingly, at the output of the digital-to-analog converter 6 over the entire range of measured displacements to correct the non-linearity of the sensor characteristics.

Fig. 3 shows the relative positioning of the codes over the entire range of measured values.

The displacement sensor in the range is Khnom, 0, Khnom, (Fig. 3a), while the measured thickness is in the range 0, Khnom, 2XNom (Fig. 36).

The code at the output of the code setter 7 varies in the range of O, N, 2N (Fig. 3S). The code at the output of the code shift circuit in the range of sensor movements from -Xnom to 0 is Q N - p, and in the range of sensor movements from 0 to Xnom it is Q p - N, i.e. over the entire range of movements varies in the range of N, O, N (Fig. Zg). The voltage at the output of the digital-to-analog converter U4 is proportional to Q (Fig. 3C), and the voltage at the output of the sensor Us also changes adequately. Thus, the voltage Us is always compensated by the equal voltage UA, so that the output voltage is Ј 0.

Voltage U4 Us Q ySi ± Us Q fh., Where / 3i, the scale factors of the second subtraction block are 8 for the signals Us and Us.

Voltage boost Us Q fh. determines the degree of continuous change in the value of the reference voltage in the range of displacements necessary for linearizing the characteristics of the sensor.

The digital comparator 12 generates at its two outputs two signals with N (signal

work in the first half of the measuring range of movement) and p N (signal of operation, respectively, in the second half of the measuring range of movements). High-Pass Circuit 11

passes a signal to the output when a code is dialed at the dial that is exactly half the range of N.

If N p 2N, at the control input of the high-pass circuit 11

there is a signal prohibiting the passage of the high-order code to the input of the circuit 13 code. With the code p 2N, this prohibition signal is cleared, but the high-order bit of the dialed setter 2N code is sent to

high-order input N of the circuit 13 of the code 13. In this case, the circuit of the code 13 in the presence of a signal at the first control input p N (in the first half of the measuring range of movements)

converts the input code to an additional one, and if there is a signal at the second control input, p N issues the input code to its output in the direct code, but shifted by N (see Figs. Sv and Zr).

Thus, the introduction of a shear scheme

code and the switch allows you to work in the entire range of movements of the differential inductive sensor-Khnom, 0. Khnom, providing the ability to linearize the characteristics of the inductive sensor.

Claims (1)

SUMMARY OF THE INVENTION Linear Measuring Device displacements, comprising a generator, the phase outputs of which are connected to the inputs of the differential inductive sensor, the first subtraction unit, the amplifier and the detector are connected in series. the control input of which is connected to one of the outputs of the generator, a digital-to-analog converter, the output of which is connected to the first input of the first subtraction unit, the second input of which is connected with the output of the differential inductive sensor, a second subtraction unit, the output of which is connected to the signal input of the digital-to-analog converter, and a sensor of the controlled parameter, which, in order to expand the range of controlled movements, is equipped with a code shift circuit and a switch, two the input of which is connected to the outputs of the generator, the third input is connected to the control outputs of the code shift circuit, the output is connected to the first input of the second subtraction unit, the second input of which is connected to the output of differential inductive sensor input circuit the code shift is connected to the outputs of the master of the controlled parameter, and its outputs are connected to the inputs of the digital-to-analog converter. five, i R 2 / V / Y -X Katz R ABOUT X KSM Ј AND Q-- A; -b /ABOUT / v -  P ± N - $ FIG. 2 PSLO BNNS p.t / nzheta sensor measurable thickness gn setter Q b-L  cxeNK code WITH shear C „