SU1325532A1 - Information readout device - Google Patents

Abstract

The invention relates to automation and computing and can be used, for example, to read codes from optically contrasting media. In order to increase the reliability of reading information in the device, the process of reading information is strobed. In addition, the device contains logic elements, triggers, a counter, and a decoder, providing the selection of clock pulses, counting them, and blocking the device after reading is finished or when a failure is detected. This system is triggered by a pulse generated when reading the first service code symbol on the storage medium. 1 il. with 1C SP ate with N3

Description

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The invention relates to automation and computer technology and can be used, for example, to read codes from optically contrasting media.

The purpose of the invention is to improve the accuracy of the device.

The drawing shows the functional diagram of the device.

The device contains a scanning unit 1, the first trigger 2, the first driver 3 information pulses, the first element AND-NOT 4, the element NOT 5, the second driver 6 information pulses, the second element AND-NOT 7, the second trigger 8, the third element AND - NOT 9 , the first counter 10, the fourth element AND-NOT 11, the generator 12 clock pulses, the element And 13, the first decoder 14, the third trigger 15, the second counter 16, the shift register 17, the driver 18 reset pulses, the fourth trigger 19, the fifth element And - NOT 20, the second decoder 21.

The device works as follows.

The reset pulse generator 18, when energized, generates a negative pulse and initializes the triggers 15 and 8, the counter 16 and the register 17. The information carrier with the code is oriented and fixed using appropriate mechanisms (not shown) so that the beam of the block 1 moved strictly along the code. At the moment when the scanner starts moving, a pulse is sent from the control circuit of its movement (not shown) to the input of the trigger 8, which transfers it to the state "1. The signal from trigger 8 permits the passage of signals from block 1 through shaper 3 and through the element NOT: 5, block 6 and the element AND-NO 4 and 7 to the input S of the trigger 15 only at the time of direct reading of the code, thereby increasing the noise immunity of this circuit.

The code printed on the carrier must begin with a pad having a reflective surface 1 bit wide in the code. This site is the key to start the code. Then the code should go in the form of alternating reflected and non-reflecting sections depending on what information the current code bit carries: reflective — if one, and non-reflective — if zero, and the width of all bits should be the same.

When a key appears, the beam from block 1, reflected from the surface, goes to the receiver of block 1, in which the illuminated light signal is converted into an electrical one, the shape of which will repeat the form of the code. The formers 3 and 6 generate pulses on the fronts of this signal, which zero the counter 10 and, via elements 11 and 13, the trigger 19. In addition, on the fronts of the signal, trigger 2 sets the information at the input of the register 17.

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The first input pulse sets the trigger 15 to the state "1" and thereby ensures the passage of clock pulses from the generator 12 to the decoder 21, adding one bit to the code key, the counting input of the counter 10, and the first counting pulse resets the trigger 8 to the state “O”, thereby ensuring the next launch of the scheme only when it is transferred to the state “1” at the beginning of the movement of the block.

The counter 10 and the deflector 14 provide for resetting the flip-flop 19 to the state "1" with some delay after the front of the input signal, thereby ensuring the noise immunity and reliability of the read information. When a single front is formed by the trigger 19, the counter 16 and the register 17 have at their inputs clock signals, according to which they change their state. The register shifts to the right 0 of the information set at the input by trigger 8, and the counter reads the clock signals.

The trigger 19 is reset to zero or a pulse from the edges of the input signal (when there is a change of information bits), or after a certain time interval defined by the information bit width, the speed of the block 1 and the oscillator frequency 12 (when the adjacent code bits contain the same information).

Thus, a circuit including a counter 10, a decalphator 14, a trigger 19 and an element 13 generates a clock signal for each code element. Counter 16 counts the number of these clock signals, and thus the number of code elements.

In order to stop the circuit after reading a given number of bits of information and thereby eliminate the possibility of reading "unnecessary and, therefore, false information, counter 16 through the decoder 2 resets the trigger 15 to" O, thus 0 stops the flow of clock pulses to the counter input 10 and in register 17 there remains information recorded up to this point.

The counter 16 is also reset by the signal from the decoder 21 through the element 20. All elements of the circuit are brought to the initial state and now the reading process can be started only with a new pass of the block 1.

Reversal of the scanner does not affect the operation of the circuit, since the trigger 8 must be cocked by the turn-on signal of the block 1, rather than reversal. The change in the number of possible bits of the read information is carried out by the appropriate connection of the outputs.

By gating the reading process of the code, as well as tracking the number of read bits of information in the device, the read accuracy is increased.

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Claims (1)

Apparatus for reading information comprising a scanning unit connected to the inputs of the first information pulse generator, the HE element and the first trigger input R, the element output is NOT connected to the second pulse driver input and the first trigger element S, the inputs of which are connected respectively to the outputs of the first and second drivers of information pulses, and the output is connected to the first input of the second element AND- NOT and to the input R of the first counter, the second input of the second ele I-NOT is connected to the output of the second trigger, and the output is connected to the input S of the third trigger, the reset pulse shaper connected to the inputs R1 of the second and third triggers and the input R of the shift register, the third AND-NOT element, whose inputs are connected respectively to the outputs clock generator and the third trigger, and the output with the input R2 of the second trigger and the counting input of the first counter, the information outputs of which are connected to the corresponding inputs of the first decoder, and you four the overflow stroke is connected to the first input of the And element, the fourth trigger, whose inputs S and R are connected respectively to the outputs of the first controller and the element I. And the output with the synchronous input of the shift register, the input S of the second trigger is the control input of the device, the outputs of the shift register - outputs of the device, characterized in that, in order to increase the accuracy of the device, it contains the fourth AND element - NOT, the fifth AND-NOT element, the second counter and the second counter, whose information inputs are connected according to control input is connected to r the first input of the fourth AND element — NOT and the third trigger output, and the outputs are connected respectively to the first input of the fifth IS – N element and to the R2 input of the third trigger; the counting input of the second counter is connected with the output of the fourth trigger 20, and the input R with the output of the fifth AND element — NOT, the second input of the fourth AND element — is NOT connected to the output of the first AND-NOT element, the second input of the fifth AND element is not connected to the reset pulse shaper .