SU1730537A1 - Device for measuring diameter of a product - Google Patents

Abstract

This invention relates to a measurement technique. The aim of the invention is to improve the measurement accuracy by compensating for the scatter and changes in the parameters of the photodetectors. A device for measuring the diameter of products contains optically coupled illuminator 1, on the optical axis of which the measured product 2, standard 3, lens 4, diaphragm 5 and discrete photodetector b are installed, made in the form of two lines of photodetectors symmetrically located with respect to the optical axis of the illuminator, On which the shadow images of the edges of the product 2 are projected. The polling generator 7 generates M polling cycles of the first and second lines of photo detectors of a discrete photodetector 6. After the polling cycles, the amplitudes are digitized The beats of the measured signals of photodetectors in the amplitude-digital conversion unit 8 are entered into numbers in the calculation unit 9. Between the two input cycles, the current amplitudes are accumulated with previously accumulated for subsequent averaging. After averaging, arrays of numbers describing the output signals of the first and second lines of the photodetectors of the discrete photodetector 6. are subjected to median filtering, where sample drops due to scatter of the parameters of the photoreceivers are excluded. Next, in block 9 of the calculations, the differences in the brightness of the images on the first and second lines of the photodetectors of the discrete photodetector b are selected, from which the product diameter is determined. 4 hp f-ly, 5 ill. YO XI CO O SP with XI

Description

The invention relates to a measurement technique and can be used to measure the diameter of products.

The aim of the invention is to improve the measurement accuracy by compensating for the scatter and changes in the parameters of the photodetectors.

Fig, 1 shows a functional diagram of the device; in fig. 2-4 are structural diagrams of the first, second and third embodiments of the amplitude-digital converter unit, respectively; in fig. 5 is a block diagram of a computing unit.

A device for measuring the diameter of products contains optically coupled illuminator 1, on the optical axis of which the measured product 2, standard 3, lens 4, diaphragm 5 and discrete photodetector 6 are installed, made in the form of two lines of photodetectors, which are symmetrically located relative to the optical axis of illuminator 1, 1 7 polling, the first and second outputs of which are connected to the inputs of the first and second lines of photo receivers of the discrete photodetector 6, respectively, the amplitude-digital conversion unit 8 (ADC), the first and second The inputs of which are connected to the outputs of the first and second lines of the photodetectors of the discrete photodetector b, respectively, block 9 calculations, the first input and the first output of which are connected by a bi-directional bus to the third output and the input of the interrogation generator 7, the second input and the second output are connected bi-directionally to the bus the output and the third input of the ADC block 8, the signaling block 10, the input of which is connected to the third output of the calculation block 9, the command block 11, the output of which is connected to the third input of the calculation block 9.

In the first embodiment, ADC block 8 (FIG. 2) contains first and second amplifiers 12, whose inputs are the first and second inputs of the ADC block 8, respectively, the first and second comparators 13, the first inputs of which are connected respectively to the outputs of the first and second amplifiers 12 The outputs are the output of the ADC block 8, the digital-to-analog converter 14 (D / A converter), whose inputs are the third care of the ADC block 8, the output is connected to the second inputs of the first and second comparators 13.

In the second variant, the ADC block 8 (FIG. 3) comprises the first and second amplifiers 15, whose inputs are the first and second inputs of the ADC block 8, respectively, the first and second analog-to-digital converters 16, the first inputs of which

respectively, with the outputs of the first and second amplifiers 15, the second inputs are the third input of the ADC block 8, the outputs are the output of the ADC block 8. In the third embodiment, ADC block 8 (FIG. 4) comprises first and second amplifiers 17, whose inputs are the first and second inputs of the ADC block 8, a switch 18, the first and second inputs of which are connected to the outputs of the first and second amplifiers 15, respectively, A / D converter 19, the first input of which is connected to the output of switch 18, the output is the output of ADC unit 8, the third input of switch 18 and the second input of A / D converter 19 is the third input of ADC block 8.

Calculation block 9 (FIG. 5) contains a clock generator 20, calculator 21, memory block 22, interface 23, timer 24, restart circuit 25, the input of which is connected to the first output of timer 24, output to the first input of calculator 21, the second the input of which is connected with the output of the clock generator 20, the input and the second output of the timer 24, the third input and output of the calculator 21, the input and output of the memory block 22, the first input and the first output of the interface 22 are connected with each other and with the first input and the first output block 9 calculations bidirectional tires, the second input and the second output of the interface 23 with bidirectional buses are connected to the second input and second output of the computation unit 9, the third associated bus interface input 23 to the third input computing unit 9, a third output bus coupled to a third output unit 9 calculations.

The device works as follows.

When the power is turned on, the illuminator 1 directs a weakly converging beam of light to the product 2 and the standard 3, the shadow images of which by the lens 4 are projected through the diaphragm 5 onto the first line of photodetectors of the discrete photodetector 6

- their left edges, on the second line of photodetectors of a discrete photodetector b

-rights. The degree of divergence of the light beam of the illuminator 1 is chosen such that when the product 2 moves during the manufacturing process along the optical axis of the device, the dimensions of its image in the plane of the photodetector lines of the discrete photodetector 6 do not change. The light that forms the shadow image of the product 2 and the reference 3 passes through the diaphragm 5. At the same time, the rays scattered and refracted in the product 2 are almost completely filtered by the diaphragm 5. Also, when the power is turned on, a reset signal is generated in the calculator 21, which initializes the calculator 21 and the interface 23. Further, according to the signals of the clock generator 20, the calculator 21 begins to execute the program contained in the ROM of the memory unit 22. The program commands test the block 9 calculations in the following sequence: RAM test, ROM test, interface test, interrupt test. Next, the measuring channel of the device is tested: the commands of the computing unit 9 in the polling generator 7 generate a sequence of polling phase pulses of the first and second photodetector lines of the discrete photodetector 6, 50% of whose output signals (if the illuminator 1 has normal power and correct alignment of the optical elements of the device) are close to saturation.

In ADC block 8, under control of calculation block 9, the output signals of the first and second lines of photo detectors of a discrete photodetector 6 are digitized. The latter are successively entered from block 8 of ADCs into block 9 of calculations, where 50% of normal amplitudes of light signals are detected at the outputs of both lines photo-receivers of discrete photo-receiver b, while the computing unit 9 via the interface 23 issues to the display unit 10 commands for which the latter generates a short sound signal, lights the light signal normally and operation proceeds to measuring the diameter of the main program (product); the presence of only dark signals, while the computing unit 9 via the interface 23 and the display unit 10 produces an intermittent sound signal, accompanies it with a similar light signal, which indicate either the need to replace the glow lamp in the illuminator 1, or the need to adjust the optical elements; The absence of signals at the output of one of the photodetector lines of the discrete photodetector 6, while the calculation unit 9 via the interface 23 and the display unit 10 generates a continuous sound signal, lights all the digital displays and one of the numbers 10-17 on the digital display unit of the display 10. The last of the indicated display modes signals the presence of a fault in the device. The figures together with the commas on the display unit 10 are indicative of failures in the following tests: 10 - the RAM test was incorrectly passed; 12 - ROM; 13 interface 23; 14 - interrupts; 15 - there are no signals at the output of the first line of photodetectors of a discrete photodetector 6; 16 - at the output of the second line of photodetectors of a discrete photodetector 6; 17 - there are no signals at the outputs of the first and second lines of photo detectors of a discrete photodetector 6. The main program for measuring the diameter of a product includes loading the timer 24, m polling cycles of the first and second lines of photo detectors of a discrete photodetector 6, digitizing and inputting amplitudes of the measured signals of photo receivers into the RAM of block 22 the memory of the computing unit 9 through the ADC block 8; Between the two input cycles, the current amplitudes are added to the previously accumulated amplitudes

averaging. After polling and averaging an array of numbers at, at, describing the output signals of the first and second lines of photo detectors of a discrete photodetector 6, they are subjected to median filtering, during which the arrays bi, bt are obtained, and the counts of the photodetectors are eliminated. Next, the subroutine for extracting the brightness of images on the first and second lines of the photodetectors of the discrete photodetector b is performed, the first 1+ K photodetector located on the first edge of the image is determined from the conditions

 I 1;

Ln-to-Ml 0.35M, (1)

with.

five

0

where K const 10 is a number exceeding the maximum number of photodetectors located on differences in brightness;

I +5

m 2 bj / 10

The last I-K photodetector located at the analyzed image edge is determined from the conditions I-K I + K: I-M I 0.35 M, (2)

{.

i + 5

whereM bJ / 10- j i - 5

Similarly, in the bi array there is a second edge of the image belonging to item 2 (the first difference in brightness is created by the edge of the pattern 3). Next, the photodetectors of the bi array belonging to the third and fourth image brightness differences, which are created respectively by the second subject edges of the product 2 and the reference 3, are determined. The processing of the amplitudes of the photodetector signals located on the first edge of the image is as follows: determining the average signalnd level at the edge of the image: Bi- (M) / 2 + M; determination of the average change in the signals of neighboring photodetectors belonging to the first difference of brightness:

bi- (bi - K-bi + K) / (2 K);

determining the number of photodetector I, having a signal amplitude closest to the average level of the difference EY, but lower in absolute value: bi Vd; Ibi-Bil bi; (3)

determining the distance from the beginning of the first line of photodetectors of a discrete photodetector 6 to the middle of the first edge of the image (first edge of the standard 3):

 + T (Bi -bi) / bi T-l + b, (4)

where T is the period of the line of photodetectors;

e - correction of the position of the image edge taking into account the linear approximation of the photodetector signals belonging to the considered image brightness difference.

Next, the distance from the beginning of the first line of photodetectors of a discrete photodetector 6 to the middle of the second image edge (first edge of product 2) S2, the distance from the beginning of the second line of photodetectors of a discrete photodetector 6 to the middle of the third edge of image (second edge of standard 3) , from the beginning of the second line of photodetectors of the discrete photodetector 6 to the middle of the fourth edge of the image (second edge of the product 2) S4. The last block of the main program determines the diameter of item 2 taking into account the systematic and random errors of the device, since along with simultaneously obtained Si, ..., S4 counts in block 9 of calculations, Lo is used - the size of the standard 3 read into calculator 21 from block 22 memory

D U-S2 + + S3.

(five)

Expression (5) is used in view of the fact that the first and second lines of photodetectors of the discrete photodetector 6 are interrogated towards each other. Then, the measured diameter D is output from the calculation unit 9 on the display of the display unit 10, the position of the ten-day switches of the command unit 11-Do is read into the calculation unit 9 and a comparison is made. If Do + Е D (е 15 microns is the permissible deviation of the diameter of products 2) through the interface 23 to the external control bus

0

five

objects are issued from the calculator 21 command to slow down the stretching of the product 2; if DO - e D - a command is issued to the control bus of external objects - to accelerate the pulling of product 2; if D0 - - e D Do + E - a command is issued - the diameter is normal, and the corresponding light comes on in display unit 10. Next, the difference between the current readings of the edges of the Si.i reference standard is analyzed; Ss.i and readings of the edges of the Si standard, 3h, obtained during the first pass of the main program for measuring the diameter of the product 2.

If none of the inequalities holds

Ai lSi-Si, i I So

A2 3z-3z, 1 I So, (6)

HC

{:

This is an unconditional transition to

the beginning of the main program (So - the maximum permissible deviation of the reference along any edge of the standard). If at least one of the inequalities (6) is fulfilled, then the indicator Deviation of the reference lamp lights up on the display unit 10, the digits of the display unit 10 of the display are alternately displayed: D, Df, Yes, the unconditional transition to the beginning of the main program for measuring the diameter of the product 2 is performed . Digitization

output signals of the first and second lines of photodetectors, discrete photodetector 6 in the main measurement mode is performed under the control of the same subroutine as in the test mode, and for

the first embodiment of the block 8 ADC (Fig. 2) consists of the following operations: issuing from the block 9 calculations to the DAC 14 a reference voltage code, starting through the generator 7 interrogating the read cycle of the first and second

lines of photodetectors of a discrete photodetector 6, the output signals of which are amplified by the first and second amplifiers 12, are compared with the reference voltage in the first and second comparators 13,

digital outputs of which for each photodetector via interface 23 are recorded in memory block 22 of calculation block 9; sync signals for receiving data in memory block 22 are generated in

polling generator 7 synchronously with phase pulses of polling of the first and second lines of photodetectors of a discrete photodetector 6; These sync signals are received in memory block 22 and interface

23 to implement control functions (end of polling cycles of photodetector lines), gating data transmission. Then the cycle of polling the first and second lines of photodetectors repeats.

discrete photodetector 6 for the next reference voltage, the results of two polling cycles are analyzed, the numbers of photodetectors, the amplitudes of which are enclosed between the generated reference voltages, are determined; for these photodetectors, the amplitude codes of the output signals are written into the array ai. The described cycle of polling and program analysis is repeated 2P times, where n is the resolution of the DAC 14. For the second embodiment of block 8 of the ADC (Fig. 3), digitization is carried out after one cycle of polling the first and second lines of photodetectors of the discrete photodetector b when their output the signals amplified in the first and second amplifiers 15 are fed to the inputs of the first and second analog-to-digital converters 16 (their control inputs are received from the computing unit 9, the strobe signals), where the amplitude codes of the output signals of the photodetectors are obtained Cove, which outputs to an analog-digital converter 16 through the interface 23 is recorded in the memory unit 22. For the third embodiment of block 8 of the ADC (Fig. 4), digitization is also performed during one cycle of polling the first and second lines of photo detectors of a discrete photoreceiver b when their output signals amplified in the first and second amplifiers 17 are alternately received through switch 18 Analog-to-digital converter input 19 (switching and gate signals generated at the interface 23 from the clock signals from the polling generator 7, Gd) are fed to the control inputs of the switch 18 and the analog-digital converter 19. The amplitude codes of the output signals of the photodetectors are formed, which, through the interface 23, are recorded in the memory block 22). At the beginning of the main cycle of the diameter measurement program from calculator 21, timer 24 is loaded, which (when it increases, which increases or stops the calculation cycle) generates pulses with a frequency specified by a loading constant. The first pulse of timer 24, which came into the restart circuit 25, causes the formation of a signal in it Interrupt entering the calculator 21. If the interrupt is prohibited at the given moment and the calculator 21 has not resumed its operation, then the second pulse of timer 24, which came into the restart circuit 25, the latter generates a Reset signal and the calculator 21 starts executing a program containing in the ROM of the memory unit 22, starting with the first command (test mode).

Claims (5)

Claim 1. Device for measuring the diameter of products containing optically coupled illuminator, lens and discrete photo 5 receiver, made in the form of the first line of photodetectors, control unit, the first output of which is connected to the input of the first line of photoelectric receivers of the discrete photodetector, computing unit, It is notable that, in order to increase the measurement accuracy, it is equipped with a standard located between the illuminator and the lens, the diaphragm located between the lens and the disk photoreceiver, m amplitude-digital conversion (ADC) block signaling and command unit, the photodetector is provided with a discrete second line of photodetectors situated 0 symmetrically to the first line of photodetectors relative to the optical axis of the illuminator, the computing unit is made with three inputs and three outputs, the control unit is designed as a polling generator with 5 three outputs and one input; the second output of the polling generator is connected to the input of the second line of photodetectors of the discrete photodetector; the third output and input are connected by a bi-directional bus to the first 0 input and the first output of the computing unit, the second input and the second output of the computing unit are connected by a bi-directional bus to the third input and output of the ADC unit, the third output is connected to the input of the signaling unit, the third input is to the output of the command unit, the first and second inputs of the ADC unit the respective outputs of the first and second lines of the photodetectors of the discrete photodetector are connected. 02. The apparatus of claim 1, wherein the ADC unit is made up of first and second amplifiers, whose inputs are the first and second inputs of the ADC unit, first and second, respectively. The 5 comparators, the first inputs of which are connected respectively to the outputs of the first and second amplifiers, the outputs are the output of an ADC unit, a digital-to-analog converter whose inputs are 0 with the third input of the ADC unit, the output is connected to the second inputs of the first and second comparators. 3. The device according to claim 1, characterized in that, in order to increase quickly, the ADC unit is designed as a first and second amplifiers whose inputs are respectively the first and second inputs of the ADC unit, the first and second analog-digital converters whose first inputs are associated respectively with the outputs of the first and second amplifiers, the second inputs are the third input of the ADC unit. the outputs are the output of the ADC block. 4. The device according to claim 1, characterized in that, for the purpose of simplification, the ADC unit is made in the form of first and second amplifiers, whose inputs are respectively the first and second inputs of the ADC unit, the switch, the first and second inputs of which The first and second amplifiers, the analog-to-digital converter, the first input of which is connected to the switch output, the output is the output of the ADC unit, the third input of the switch and the second input of the analog-digital converter are the third input of the ADC unit. 5. The device according to claim 1, wherein the computing unit is designed as a serially connected timer, restart and calculator circuit, a clock generator, the output of which is connected to the second input of the calculator, the memory block and the interface, the input and the second output timer, the third input and output of the computer, the input and output of the memory block, the first input and the first The interface output is interconnected by bidirectional buses and is the first input and the first output of the computing unit; the second input and the second output of the interface are bi-directional. buses and are the second input and the second output of the computing unit, the third input of the interface is the third input of the computing unit, the third output is the third output of the computing unit. 4Ј-t4 cd FIG. 2 17 "A c h ch I 18 - nineteen BUT l eight Figz