SU399719A1 - DEVICE FOR MEASURING ANGLES - Google Patents

Description

one

The invention relates to electrical measuring equipment, in particular to devices for measuring angles between the leads of precision wire potentiometers.

In factories producing precision wire potentiometers of the PTP and PLP types, the technological process involves the control of the angles between the leads, which is carried out manually using optical dividing heads and ohmmeters.

However, such control has low labor productivity; characterized by the subjectivity of the measurement process, depending on the qualifications of the operator, the degree of fatigue and other reasons (lighting, ohmmeter location, etc.), frequent discrepancy between the measurement results of the same angle for the same checked potentiometer, insufficient measurement accuracy and an increase in time with an increase in its accuracy due to repeated rechecking of the positions of the points of beginning and end of readings.

The purpose of the invention is to increase the accuracy and speed of the device. For this, the proposed device for measuring angles between the leads of precision wire potentiometers contains an electromechanical assembly.

the angular displacement of the engine of the potentiometer under test, as well as a number of electronic units. These include a block for analyzing the change in the resistance value between the engine and the potentiometer terminals through a level equal to about half the resistance value of one turn; the unit specifying the specified resistance value; software control unit; invoice block

electrical impulses; a display unit for measuring results in digital form and a control unit for a stepper electric motor of an electromechanical unit for the angular displacement of the slider of a tested potentiometer,

the axis of the checked potentiometer is fixed in the clamp of the electromechanical assembly, the electrical leads of the checked potentiometer and the leads of the resistance setting block are connected to the block for analyzing the change in the resistance value between the slider and the potentiometer leads. The output of the unit for analyzing the change in values is connected to the program control unit, to the outputs of which the electrical counting unit is connected

pulses and a control unit of a stepper motor, connected via a precision wave mechanical gearbox with the above-mentioned clamp of an electromechanical assembly, and the output of an electric pulse counting unit

connected to the input of the display unit result

tat measurements in digital form (in the form of a digital scoreboard).

The unit for analyzing the change in resistance between the slider and the terminals of the calibrated potentiometer, through a level equal to approximately the zero value of the resistance of one turn, contains a measuring lustar current composed of resistors, one of which is the part of the resistance between the slider and this output of the scanned a potentiometer, and a blocking generator, the secondary winding of an impulse transformer through which the diode is connected to the internal diagonal of the specified bridge, and the output of the blocking A generator is connected to one of the inputs of the software control unit.

The nrogram control unit contains a generator of rectangular clock pulses with a 500 Hz following frequency, connected via an electronic key with units of electric NMR pulse counting and stepping motor control, and an automatic control system with the specified key but a given program, which includes a trigger trigger, triggr comaid imnul1; ow, trigger of not-ready measurements, trigger of all-simultaneous cycles, trigger of the main cycle, electronic key, separate delay nodes, respectively, 120, 350, 350 and 120 ms and the node of the reverse of the conclusions of the tested potentiometer. The output of the trigger is controlled with the input of the first electronic key, and the six inputs of the trigger are respectively controlled with the Start and Reset buttons and the outputs of the second electronic key, the delay node for 120 ms, the other delay node for 120 ms, and the delay node for 350 ms In particular, the output of the blocking generator a of the block is connected via a trigger of command impulses to one of the inputs of the second electronic key, the switching input of which is connected to the output of the trigger of measurement preparation, the two inputs of which are connected respectively knonkoy "Reset parallel to spike counting reset unit imnulvsov electrical nodes, and the input delay unit 120 msec.

FIG. 1 shows a block diagram of the device; in fig. 2 is a schematic diagram of the unit of analysis of the change in the resistance value between the engine and the conclusions of the tested heat meter, entering the device through a level equal to approximately half the resistance value of one turn; in fig. 3 — electric circuit of the tested potentiometer; in fig. 4 is a block diagram of the installation control unit included in the installation.

The device contains the following main components and blocks (Fig. 1).

The unit 1 sets the resistance value equal to approximately half the value of the resistance of one turn of the winding of the tested potentiometer of a given ton and

given nominal value of resistance. The block contains switches, a set of devices, by means of which any of the required indicated levels can be set, the value of the resistance of wire precision potentiometers of the PTP and PLP types for all their commemorative values from 200 ohm to 50 lump at a power of 1.2 and 5 W. Before starting the measurements, the switches are set to the positions corresponding to the nominal value and power of the noticiometer being tested. Essentially, this unit represents a well-known resistance shop.

The unit for measuring the resistance value of the tested potentiometer 2 (Fig. 2). Block 1 and the potentiometer under test are connected to this unit; 3. The purpose of the unit is the issuance of electrical imiuls in

 the moment of damage when the engine of the potentiometer with its angular displacement takes positivity, at which the resistance between its engine and this (any) output of the checked potentiometer abruptly passes through a level equal to approximately one half of the resistance of one turn. The angular displacement of the potentiometer slider is carried out in discrete steps, each of which

equal to one angular minute; the time of one step and the next pause is 2 ms. With the angular displacement of the potentiometer slider, the resistance between the slider and the terminals of the die gauge changes in steps. The analysis time with the beginning of each stunenki does not exceed 100 microseconds. Therefore, an electrical impulse signaling the passage of a specified level of 0.5 magnitude with the resistance of one turn, at the output of this block, but is much earlier than the next step movement of the slider occurs. This emphasizes the high guaranteed performance of the systems for analyzing the core of the specified resistance.

Block 2 consists of known nodes, but is not standard. It includes a measuring bridge of a constant current composed of resistors 4, 5, 6, 7; the shoulders of this measuring bridge are additionally included

a resistor 8, which is one of the resistors of the resistance box (the block considered earlier), and the winding of the tested potentiometer, which is conventionally depicted as a non-temporary resistor 9. Terminal 10

A constant-magnitude constant injection of the measuring bridge is set; a blocking generator containing a transistor 11, a resistor 12 and a capacitor 13 in the emitter value, resistors 14 n 15 in the circuit

base displacement, resistor 16 and pulse traction transformer 17 included in the collector circuit of the transistor, with the secondary winding of the pulse transformer through diode 18 connected to the measuring diagonal

the bridge. Capacitor 19 is separable and at the same time freestanding for blocking geerator. The capacitor 20, the resistor 21 and DIOD1 22 are the elements forming the output circuit of the block under consideration. A stabilized DC supply voltage is applied to terminal 23. Terminal 24 is the output terminal of the blocking generator and block 2 as a whole. FIG. 2, the winding of the tested potentiometer 9 is connected to the circuit by two ends - terminal 25 of the output of one end of the potentiometer and terminal 26 of the slider output. Terminal 27 of the dual potentiometer and terminal 28 of the midpoint point output are free (connection to the circuit of one or another terminal 25, 27 or 28 is automatically generated, i.e., finding the reference points when measuring angles takes place using a two-terminal connection circuit of the tested potentiometer). The diode 29 is one of the elements of the feedback circuit of the blocking generator. Terminal 30 is input to this block through the reverse of this blocking oscillator. By terminals 24 and 30, the block in question is connected to the program control block 31.

Since the measuring bridge and the blocking generator are known, their operation is not considered. It is only necessary to point out that with a given resistance value of resistor 8, which is set by switches before starting measurements in block 1, and with varying resistance value 9 (between the slider and the output of the measured potentiometer), the blocking generator is automatically excited when the balance occurs measuring bridge. At these times, a single voltage pulse with a duration of 15 microsec appears each time at the output terminal 24, indicating that at a given time the resistance between the slider and the output of the potentiometer to be tested abruptly changed, the level of resistance 0.5 of one turn passed . In general, the blocking generator would have to generate sustained oscillations at its own frequency, but in this case, returning block 2 to its original state, in which transistor 11 is locked, would have to move the engine of the potentiometer away from the point of origin of self-oscillations. And when checking low-resistance potentiometers, approximately from 500 ohms and below, it would be difficult to break auto-oscillations in general. To exclude the subsequent auto-oscillations after the first pulse, a feedback circuit is introduced, one of the elements of which, as mentioned above, is diode 29. When the first pulse occurs, the blocking generator, which is fed from terminal 24 to the program control unit, triggers on its leading edge command pulses, which is included as an integral part of the specified block, while the output of this trigger is connected to terminal 30. The trigger when tilting its output

through the diode 29 it shunts the transistor 11 of the blocking oscillator, preventing the subsequent generation of auto-scrollers. By virtue of what has been said, only a single pulse appears at output terminal 24.

The purpose of the software control unit 31 is to follow the conditions specified before the start of change (measurement of the operating angle, technological angle or angle

between the middle and terminal pins of the tested potential meter, automatically control the sequence of actions and the interaction of individual units and blocks of the device.

The process of measurement and, accordingly, the operation of individual UNITS and installation units are divided into three stages, which are considered at the same time as the working angle at which: the average output of the potential to be tested is not connected to the measuring circuit.

First stage. At this stage, we can call the preparatory t (see the electric circuit of the tested potentiometer (3), in which a is indicated the working angle of the potentiometer slider 32, which is fixed in the installation, from a random position indicated in the drawing, by letter, letter a. In the L positions and with the slider of the potentiometer, with its continuous step-by-step movement, the points pass at which the resistance between the slider 32 and the clamp 27 of the potentiometer hopping pecheholit through the level 0.5 of the magnitude of the resistance of one coil. From the moment of the passage of the engines of life (or point) b, which is indicated by the current of current 2, the time begins, which is always constant and set at the setting once for all tomina. values, check potentiometers, and is equal to 120 msec; during this time, the tilt-positioning slider from position b is interchanged to the position d that is all-further than position r, and stops. The position of d depends only on the specified delay and can be changed in some preliminaries.

Second phase. In the dashyum stage, the potentiometer slider 32 from position d starts angular step-over sweeping in the direction opposite to the arrow .4. In position with. where oppsanlip hopping occurs

the transition of the value of the resistance over the level of 0.5 resistance of one turn, the engine stops, which lasts 120 ms (this time is not strictly regulated): during this time, the end leads of the tested potentiometer are switched, i.e., to the measurement circuit (block 2) The output of terminal 27 is connected to terminal 25 and all resistance of the potentiometer under test is turned on between the engine and terminal 25. The third stage. During this stage, the slider 32 and its step angular displacement in the same direction, i.e. opposite to the arrow A, and from position c moves to position g and stop, at position g there is an abrupt change in resistance value through level 0.5 of resistance one coil. The positions of g W. e are similar in their meaning to the positions of s and 6. The number of steps when moving the slider from point c to g is equal to the number of angular minutes between them. The need for the engine to pass the position of the first stage with the stop in position d and the reverse movement is determined by the following considerations: first, the potentiometer slider should only come to one side from conclusions 27 and 25, in this case the reference points can be either points with V.g or points b and e, since the angle between them is equal to the angle between terminals 27 and 25, i.e. angle a; secondly, despite the presence in the installation of precision mechanical assemblies and parts, mechanical backlashes are inevitable, increasing with time as they wear out, and therefore when moving the potentiometer slider from position d to position c, at the second stage all mechanical backlashes that could worsen angle measurement accuracy. All of the above manipulations are carried out automatically using the software control unit in question, the block diagram of which is shown in FIG. 4. Block 31 contains the following nodes. The generator of rectangular clock (split) pulses 32 with a frequency of 500 Hz. The output of this generator through the electronic key 33 is connected to the inputs of the electric pulse counting unit 34 (Fig. 1) and the reverse unit of the control unit of the stepper motor 35. The switching voltage to the electronic key 33 is supplied from the output of the control trigger 35 (Fig. 4), which has the input circuits to which the manual start button 36 is connected, the output of the delay node 37 (for 120 ms) (the same output is connected to one of the trigger inputs of the command pulses 38 and the measurement preparation trigger 39), the output of the delay node 40 (for 350 ms), electronic key 4 1 and one of the trigger inputs of the main loop 42; the output of the delay node 43 (120 ms), the manual reset button 44 and one of the trigger inputs of command pulses 38, measurement preparation trigger 39, main cycle trigger 42 and auxiliary cycles trigger 45. The output of measurement preparation trigger 39 is connected to the control key input 41. Another input of the same key is connected to the trigger output of co-mandal pulses 38 and one of the trigger inputs 45 of auxiliary cycles. The output of this trigger is connected to the inputs of the delay node 37 and the delay node 46 (for 350 ms). The output of the delay node 46 is connected to the input of the delay node 40 and to the switching input of the reverse node of the stepper motor control unit 35, not shown in FIG. 4. One of the outputs of the trigger of the main cycle 42 is connected to the input of the delay unit 43, and the other output of the same trigger is connected to the input of the node of the reverse 47 ends of the tested potentiometer and the reset of (automatic) counting nodes of the electric pulse counting unit 34, not shown in the diagram ; The output of the manual reset button 44 is connected to the same length. The outputs of the reversal assembly 47 of the ends of the tested potentiometer are the contacts of the electromechanical relay entering it, through which the tested potentiometer is connected to the circuit of the analysis unit (2) for measuring the resistance value of the tested potentiometer. One of the trigger inputs of the commanding pulses 38 is connected to the output terminal 24 of the indicating unit 2 (Fig. 2), and the output of this trigger is connected to the terminal 30 of the unit, this circuit, as mentioned above, is feedback to the blocking generator block 2, providing only a single pulse from the blocking generator. All described links between nodes and blocks reflect functional links between them, which means that the diagrams do not contain inevitable isolation circuits and other elements that do not reflect functional links. The control unit of the schagovym motor 35 is not described, since it is a standard that is widely known and commercially available (such as BU-2-64 developed by ENIMS - Experimental Research Institute of machine tools). The stepper motor 48 is a standard and commercially available type of SD-4. It is controlled by a six-step scheme with a step angle of 1.5 °. The presentation wave mechanical gear 49 is made according to a known scheme. Its reduction factor is 90. (With a stepper angular displacement of a stepper motor of 1.5 °, i.e. 90 angular minutes, and with a reduction ratio of 90 of the specified precision mechanical wave gear HjaroBoe, the angular displacement of the slider of the tested potentiometer is carried out with a resolution of one angular minute) The electric pulse counting unit 34 consists of standard counting points (scaling circuits with decoders); nodes 50, 51, 52, and 53 have a counting module equal to ten, and node 54 has a counting module equal to scatter. The counting modules are combined in such a way that the product of the first two modules (nodes 50 and 54) was equal to sixty — the number of minutes in one angle degree, and the remaining nodes corresponding to 51, 52, 53 recalculated units, tens and hundreds of degrees. . The schematic diagrams of these counting points are standard and widely known, so there is no description of them. The measurement indication display unit in digital form 55 (digital display) is standard-5 assembled on IN-1 gas discharge indicator lamps according to the usual connection schemes to diode decoder buses of the above-mentioned counting nodes. The operation of the device is as follows. After fixing the tested potentiometer in the collet clamp of the installation mechanical head by pressing the button "Reset 44, all 15 counting nodes of the electric pulse counting unit are reset (zeroes in all digits are set on the digital display) and nodes 35, 38, 39, 42, 45 In this case, the electronic switches 33 and 41 are closed and the pulses from the generator 32 non-20 arrive at the inputs of the electric pulse counting unit 34 and the control unit of the stepping motor 35. The stepping motor 48 is then decelerated, and to unit 2 the tested sweat The potentiometer 3 is connected 25 (Fig. 3) with pins 26 and 27. By pressing the Start 36 button (Fig. 4), a pulse is applied to the input of control trigger 35, which, turning over, turns off the key 33, and the pulses from the generator 32 begin to enter 30 the electric pulse counting unit and the reverse unit of the stepper motor control unit. The rotation of the stepper motor begins, and through the precision wave reducer 35 this rotation is transmitted to the slider of the tested potentiometer, which begins to mix in the direction of the arrow L (Fig. 3). At the transition of the slider 32 through position b in block 2 (Fig. 2), a pulse appears at its output terminal 2440, which (Fig. 4) arriving at the input of the flip-flop 38, tilts it, as a result of which the flip-flop 45 tilts the output of which is delayed by the delay nodes 37 and 46 (at the same time, a pulse is applied to the terminal 30 to disrupt the further generation of the blocking generator at node 2). The stepping motor continues to rotate, moving the potentiometer slider 32 to position d (see Fig. 3), since the key 3350 remains open, and the key 41 is closed. After 120 ms, a pulse appears at the output of the delay node 37, under the action of which the flip-flop 39 tilts, the flip-flops55 35 and 38 reset, the key 41 opens and the key 33 closes. The stepper motor stops and the slider of the tested potentiometer stops at position d. This ends the first stage of operation60 of the device. After 230 ms, after the delay node 37 triggers (or 350 ms after the delay nodes 37 and 46 marked above), a 65 10 pulse appears at the output of the delay node 46, which charges the delay node 40 with a dwell time of 350 ms and simultaneously arrives at the switching the input of the node of the reverse control unit stepper motor. In this case, the control inputs of the stepping motor are switched, i.e., preparations are made for its turning in the reverse direction. After 350 ms from the moment of charging the delay node 40, a pulse appears at its output, which, tilting the control trigger 35, opens the key 33. The pulses from the generator 32 begin to flow through the public key 33 to the inputs of the stepping motor control units and the electric pulse counting. The engine starts to rotate in the opposite direction by moving the potentiometer slider (Fig. 3) from point d in the direction opposite to arrow L. At its displacement, the potentiometer slider passes position c; at the moment of passing this position, block 2 is triggered as described, and an electrical impulse appears at terminal 24 (Fig. 4), which overturns trigger 38. A pulse from the output of this trigger passes through the previously open key 41 and simultaneously enters the trigger inputs 35 and 42, returning to the initial state the trigger 35 and overturning the trigger 42. In this case the key 33 is closed, the stepping motor stops and the potentiometer slider stops at position c, the reverse end node 47 of the tested potentiometer is triggered, connected to the measuring circuit of outputs 25 and 26, in the electric pulse counting unit all counting nodes are set to zero. This completes the second stage of operation of the device, 120 ms after the arrest of the delay node 43 (Fig. 4), and this time is necessary for reliable operation of the node 47 of the reverse of the ends of the tested potentiometer, an output appears at the output of this delay node, which, overturning the trigger 35 opens the key 33. The step of measuring the operating angle begins. The pulses from the generator 32 through the open key 33 arrive simultaneously to the inputs of the electric pulse counting and stepping motor control units. The stepping motor starts to rotate, moving the slider in the same direction, i.e., in the direction opposite to arrow L, from position c to position g by preventing any backlash in the gearbox and the potentiometer to be checked, which were all previously chosen and the direction of rotation was changed. As mentioned above, each electric pulse from generator 32 at the output of key 33 corresponds to one angular minute of the angular displacement of the slider of the potentiometer under test; The electric impulse counting unit counts the engine slips as it moves from position c to position g. When it reaches the position g, i.e. when it rotates and a and the angle c, equal to approximately or

II

exactly an angle of 330 °, a pulse tilting the flip-flop 38 appears on the terminal 24 (Fig. 4), as a result of which the flip-flop 35 returns to its initial state through the open key 41 by closing the key 33. Pulsing from the generator 32 to the control units of the scap motor and the counting of the electrical impulses ceases. The potentiometer slider stops at position g, and the digital display shows the fixed value of the working angle k, expressed in angular degrees and minutes, for example 329 ° 27. This ends the third stage of the device operation.

When checking other angles (technological angle, the angle between the middle and terminal pins of the potentiometer), the installation works in a similar way. The circuit of connecting the leads of the potentiometer under test to the measuring part of the device circuit changes.

The maximum test time for a single potentiometer using the proposed device is 70 seconds. The testing time is the shorter the closer the random position of the slider 32 (Fig. 3) of the potentiometer is from pin 27 when the potentiometer is checked in advance in the device.

12

Subject invention

A device for measuring the angles between the leads of precision wire potentiometers, containing an electric pulse counting unit, the output of which is connected to a measurement results indication unit, characterized in that, in order to improve the accuracy and speed of the device, a software control unit is inserted into it, the first output of which is connected to the input of the electric pulse counting unit, connected in series by a stepper motor, the input of which is connected to the output of the control unit of a scap motor, and a precision wave A new mechanical gearbox, kinematically connected with a tested potentiometer, a resistance setting unit and a measurement analysis unit measuring the potentiometer to be tested, the first input of which is connected to the output of the potentiometer to be tested, the second input is connected to the resistance setting unit, and the output is connected to the input of the unit software control,

the first output of which is connected to the input of the control unit of the stepper motor, and the second output to the input of the potentiometer under test.

thirty

L

l you

25 28 L 2b

five

f

/

27

grew up

(9 1.