SU470827A1 - Graphic reading device - Google Patents

Description

one

The invention relates to the field of automation and computer technology, in particular, to devices for reading graphic information.

Graphic information reading devices are known that comprise a tablet made in the form of a system of two mutually perpendicular coordinate buses connected to the interrogation switch, a coordinate remover, a control unit connected to the coordinate registers, an analog-to-digital converter, and AND and OR logic elements.

A disadvantage of the known devices is that they do not provide the required accuracy of determining the coordinates, due to the two-layer structure of the working field of the tablet.

The purpose of the invention is to eliminate this drawback, i.e., to improve the accuracy of determining the coordinates.

The goal is achieved by the fact that the device contains a multiplying unit, the inputs of which are connected to number registers, memory blocks and, via a delay line, to control units, and the output is connected to the Y coordinate register; the sign bit of one of the number registers is connected to the output of the phase discriminator.

FIG. 1 shows a general view of the tablet with

coordinate tires; in fig. 2 is a block diagram of the device.

The block diagram of the device consists of a tablet 1 with two systems, mutually alternating, their coordinate buses 2, located in the same plane in one layer at an angle to each other, the switch 3 polling pulses, the remover 4 coordinates with the start button 5 mounted in it, the unit b control, register 7 coordinates X, register coordinates Y 8, the element "OR 9, phase discriminator 10, analog-digital converter 11, amplifier 12, key block 13, including keys 14 and 15, registers 16 and 17 numbers, memory blocks 18 and 19, the multiplying unit 20 and whether delay 21.

The principle of measuring coordinates using a tablet is as follows.

One X coordinate is determined by calculating the vertical coordinate tires with the addition of a correction (in Fig. 1, this is either the segment CA or GK for different positions of the stripper) depending on the distance of the stripper tip to the left, and subtracting the constructive correction.

To measure the Y coordinate, consider two cases: the puller is located between the tires and the puller is located to the right of both tires. (Let the coordinate be determined first for point A). The magnitudes of the puller signal, induced from the vertical (segment CA) and inclined (segment AE) tires, determine the quince values of these segments, but the value AE-in easily determines segment AD, because the angle between the perpendiculars to the tires, represented by yush; by them the distance of the tips of the puller to the tires is equal to the given angle a. Obviously, AD b / cosa. The OSD triangle is easily determined from the OSD triangle, which is equal to the desired coordinate Y, increased by a segment — an imaginary continuation of the vertical tire to the intersection with the inclined one. The OH interval is a constant value (embedded in the instrument design) and can easily be subtracted from the final measurement result. So -CD a + blcosa,. , OS - a-ctga ± 6COseca, tg аtg whence the coordinate Y - a-ctgy. -f-b-coseca-C With a structurally given angle a, the values of ctga, coseca and c are pto ny and are easily taken into account in the computing unit. When the puller points are located at point B, to the right of both tires (vertical and inclined), from consideration of triangles BKF and OGK, find Y a - ctg - 6. cosec a - C, where and are the distances of point B to the corresponding tires. The cases for points A and B are easily distinguished electrically when using a magnetic puller. At point A, the signals from vertical and inclined shea may differ in signs due to the different orientation of the magnetic field when interrogating these tires, and at point B, the signals have the same signs. This condition determines the sign of the term. The device works in the following way. When the puller is pressed at the selected point of the image, the start button 5 closes, after which the control unit 6 outputs interrogation signals to the switch 3 and the X coordinate register 7, thereby calculating the vertical coordinate tires to the puller points. When excited by the corresponding bus of the puller coil, a signal of a certain polarity is applied to it, fed to the analog-to-digital converter 11 and the phase discriminator 10. This same signal, entering block 6 through the element "OR 9, stops the flow of pulses on the higher bits of register 7, the x coordinate is fixed to a number, which is the “coarse coordinate reading”). Passing the analog-to-digital converter 11, the signal from puller 4 is converted into a code proportional to the distance a of the puller from the vertical bus. This code, via key 14, controlled from the switch, goes to the storage register of the number a and to the lower bits of register 7 of the x coordinate. Together with the number of vertical bus counts previously recorded in the high bits of the register 7, this code constitutes the final value of the x coordinate. The next polling pulse excites the ramp bus, and the second signal induced in the puller stops the polling pulses in the control unit 6 and, having passed the analog-digital converter 11 and the key 15, goes to the register of the number b determining the distance ue puller inclined to the tire. In the case of a negative inductive signal, the status of the "1." After the second induced pulse arrives at control unit 6, this block generates a signal that sets the Y coordinates in the reverse code to number 8 (constructive correction), and through delay line 21 triggers multiplication unit 20, which produces products a-ctga and b -the flow and their transfer to the register 8 coordinates Y, operating in the mode of summation. As a result, a ctg a ± b-cosec-C expression, representing the exact value of the Y coordinate, is calculated on the register. The values of the ctga and coseccs values are stored in memory blocks 18 and 19, respectively. containing a tablet made in the form of two systems of mutually alternating coordinate buses, a coordinate remover connected to a phase discriminator whose output is connected to the OR element, and through an amplifier to an analog-to-digital converter connected to the input of the unit keys, a control unit connected to the coordinate registers and Y, with a polling pulse switch, the outputs of which are connected to the coordinate buses and a key block, with the element "OR through the start button - with the coordinate remover, number registers connected to the key block, memory blocks TI and delay line, characterized in that, in order to improve the accuracy of determining the coordinates, it contains a multiplying unit, the inputs of which are connected to number registers, memory blocks and through a delay line to a control unit, and the output is connected to a register Y coordinates; at the same time, the sign bit of one of the number registers is connected to the output of the phase discriminator.

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