SU847033A1 - Comparator for checking stroke measures - Google Patents

Description

(54) COMPARATOR FOR THE TESTING OF BAR MEASURES

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The invention relates to a measurement technique and can be used to calibrate both linear and angular stroke measures.

Known apparatus for calibration of action bar containing exemplary and believed emuyu dashed steps comprising photoelectric and electromechanical Coordinate Scanning Devices channels and the information processing units. In these devices, the difference in position of the strokes of the exemplary and calibrated measures is converted into a time interval filled with counting pulses C1.

The accuracy of the conversion in the described devices is limited by the scanning speed. Low scan speed limits comparing performance.

The closest to the invention to the technical essence is a comparator for calibration of stroke measures, containing an exemplary measure, channels of an exemplary and verifiable measure, each of which includes a serially connected transmitting television tube with a single-line deflection system having a scanning current generator, an amplifier

the signal of the television tube and the demodulator, and the channel of the measure to be tuned also includes the trigger and conjunctor 2.

However, all signal transformations in the described device are carried out by analog elements, the instability of the parameters and characteristics of which leads to an error of measurement, and the need for a systematic adjustment of its sensitivity limits the speed.

The purpose of the invention is to increase the comparability and speed of the comparator.

This goal is achieved by the fact that the comparator is equipped with four threshold elements with a pulse output, a reversible counter block,

A 20 register, a differentiating circuit and a code-converter converter, demodulators are made according to the synchronous detector circuit, the synchronizing input of which is connected to

25 by the output of the scanning current generator in the model measure channel, the output of the synchronous detector is connected to the inputs of two parallel-connected threshold elements, the outputs of the threshold elements are connected, respectively,

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The inputs of the summation and subtraction of the counting unit, the output of the counting unit are connected to the input of the code-voltage converter, the output of the code-voltage converter is connected to the deflection system of the television | Channel tube of the exemplary measure, in the channel of the measure being measured the output of the synchronous detector is connected to the inputs two parallel-connected threshold elements, the outputs of the threshold elements are connected to the corresponding separate trigger inputs, one of the trigger outputs through a differentiating circuit is connected to the input of a conjunctor in Ora konyunktora input connected to the output model measures channel counting unit and an output coupled to an input register (

This goal is also achieved by the fact that the register erase bus is connected to the second trigger output.

The drawing shows a block diagram of a comparator.

Light sources 1.1 and 1.2 illuminate sample measure 2 in the form of periodic transparent and opaque areas and tangent measure 3, mechanically interconnected so that synchronous movement of the measures in the direction shown in the drawing by an arrow is provided. The step of measure 2 is chosen equal to the step of measure 3, or - an integer number of times smaller than the last step. The images of measures 2 and 3 are projected by optical systems 4.1 and 4.2 onto photo cathodes of transmitting television tubes 5 and b, equipped with single-line deflecting systems with deflecting coils 7 and 8 in the channel of the exemplary measure and coil 9 of the channel of the measure being measured. In each channel, the signal outputs of the television tubes 5 and 6 are connected to the inputs of amplifiers 10 and 11, respectively. Scanning current generator 12 is connected to coils 7 and 9, as well as to the reference inputs of synchronous detectors 13 and 14, the signal inputs of which are connected to the outputs of amplifiers 10 and 11, respectively. The outputs of synchronous detectors 13 and 1 are connected to two threshold elements 15.16 and 17.18, respectively, made according to the balanced diode-regenerative voltage comparator based on a blocking generator and having a pulse output. and to the subtractive inputs of the correspondingly reversible counting block 19, the output of which is connected to the converter code-voltage (PKN) 20, the output of which is connected to the keetush 8.

Nodes 1.1,2,4.1,5,7,8,10,13,15,16 19- and 20 form a measuring gauge.

The outputs of the threshold elements 17 and 18 are connected to the corresponding inputs of the trigger 21 with separate inputs, the output of which is connected through the differentiating circuit 22 and the conjuncer 23 to the input of the register 24. To the second input of the conjunctor 23 a signal is output from the output of the counting unit 19, and the erase bus of the register 24 is connected with the second trigger output 21. The output signal of the register 24 is fed to the indicator; one or two digital printing devices (CPUs) (not shown in the drawing).

Nodes 1.2,3,4,2,6,9,11,14,17,18 and 21-24 form the measuring channel of the measure to be measured.

The comparator works as follows. :

Into an exemplary channel, the generator current 12 flowing through the coil 1 g causes the image of measure 2 to be scanned by the electron beam of tube 5, the output of which is amplified by amplifier 10 and demodulated by a synchronous detector 13. When the phase of the output signal of amplifier 10 coincides with the voltage of the generator 12 at the output of the synchronous detector 13, a positive voltage is generated, which excites the threshold element 15, "generating a pulse voltage. These pulses are fed to the summing input of the counting unit 19, where they are recorded. With each registered pulse at the output of the PCN 20, a constant voltage increases in steps, which in turn generates a step-up current in the coil 8. The magnetic field of the coil 8 quantizes the scanning center along the photocathode of the television tube 5 until the time point when the signal component with the scanning frequency at the input of the synchronous detector 13 becomes equal to zero, after which the threshold element 15 stops generating pulses that accumulate in the counting unit 19 is terminated, which leads to the termination of quantization of the scanning electron beam of the television tube 5.

When overshooting (or under the influence of a pulse noise), when the counting unit 19 has registered excess pulses, the input signal of the synchronous detector 13 becomes anti-phase voltage of the generator 12, and a negative voltage appears at the input of the demodulator 13, exciting threshold element 16. The pulses of the latter act The subtracting input of the counting unit 19 reduces the number of pulses registered in it, which leads to quantization of the scanning electron beam of the tube 5 in the opposite direction until the voltage is and the output of the synchronous detector 13 will not again become zero and the threshold element 16 will not stop the generation of pulses. .

Moving measure 2 leads to an accumulation of pulses in the counting unit 19, at which a zero voltage is continuously maintained at the output of the synchronous detector 13. With this current position of measure 2 corresponds to the current value of the number of pulses accumulated by the counting block 19. The capacitance of the counting unit 19 is chosen to be 1000 pulses, while the arrival of each pulse into the counting unit causes the electron beam to be quantized by 0.001 steps in the image of the measure on the photocathode of the television tube 5, and the thousandth pulse causes the counting to overflow, and block 19 to the initial state that / occurs when moving measure 2 by one step. At the same time, the output voltage of the PCN 20 abruptly drops to zero, and the electron beam abruptly moves 1 step in the direction opposite to the movement of the image of measure 2 while maintaining the output voltage of the synchronous detector 13 is equal to zero, and tracking the movement of measure 2 continues as described above.

Thus, in the channel of an exemplary measure, there is the following compensation transformation of the magnitude of the movement of measure 2 into a digital code with interpolation of the step of the exemplary measure.

In the channel of measure 3 being checked, the electron beam of the television tube 6 is scanned by the magnetic field of coil 9. The operation of nodes 1,3, 4,6, 9,11,14 17 and 18 is similar to the work of the corresponding channel nodes with an exemplary measure.

When the image of the stroke of the moving measure 3 enters the scan zone, a positive voltage appears at the input of the synchronous detector 14, which, when moving the measure 3, increases until the stroke boundary coincides with the middle of the scan zone, after which the voltage at the output of the synchronous detector 14 falls and passes through a zero value when the middle of the stroke passes through the middle of the scanning zone. Upon further movement of measure 3, the negative voltage at the output of the inetr detector 14 reaches the maximum value at the point in time when the second stroke boundary coincides with the middle of the scanning zone, after which the negative voltage drops and becomes equal to zero after the stroke image leaves the zone scan.

When a positive voltage appears at the output of the synchronous detector 14, a threshold element 17 is excited, the output pulses of which output the trigger 21 from the initial state, which leads to erasing the previously registered information in the register 24. The smallest negative voltage threshold element 17 stops the generation of pulses

0, but threshold element 18 is turned on, which returns trigger 21 to its original state. Upon the exit of the stroke of measure 3 from the scanning zone, the threshold element 18 also stops its operation, but the trigger 21 remains in the initial state until it enters the scanning zone of the next stroke of measure 3, after which the above described process repeats. When returning the trigger 21 to the initial state

0, a short pulse is generated from the output signal of its differentiating circuit 22, which is allowed to be transmitted from the output of the counting unit 19 through the conjunctor 23 to the register 24 of the code information on the position of the stroke of measure 3.

If measure 3 is made exactly, then one and the other will be recorded on the digital indicator and in the CPU.

Q same number. Deviation of the stroke position from its expected exact position causes a corresponding decrease or increase in the displayed and recorded number.

, With an exemplary measure step of 2 mm and a capacitance of the counting unit of 19,100 pulses, a pulse price of 0.0001 mm can be obtained.

As an exemplary measure 2, it is possible to use a raster interface of the wife or an interference pattern from a coherent light source. Television tubes can also be applied with electrostatic deflection of the electron beam.

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Claims (2)

1. USSR author's certificate number 188023, cl. G 01 B 11/02, 1966. 2. Polonik B.C. Television automatic devices. M., Holy Hour, 1974, p. 130-137 (prototype).