SU1352371A2 - Digital tachometer - Google Patents

Abstract

This invention relates to measuring angular velocities. The purpose of the invention is to expand the upper limit of measurement and reduce the dynamic error. The device contains a contactor 1, an electric motor 2, a raster sensor 3 of angular displacements, a comparator 4, a control circuit 5, a period quantization device 6, a microcomputer 7, a coincidence circuit 8, a trigger 9, an address counter 10, read only memory II, a code- converter 12 voltage, frequency divider 13, register 14, computing device 15, trigger switch 16, query register 17, and direct memory access controller 18. The introduction of new elements and the formation of new connections between the elements of the device allows one to record information about one period of the informative signal from the code of the period quantization device 6 and the code from the output of the buffer register 14 to the operative memory of the microcomputer 7 for each comparator signal 4. 1 hp . f-ly, 3 pcs.

Description

The invention relates to a measurement technique, in particular, to means of measuring angular velocities, and may find application in mechanical engineering and instrument making.

The aim of the invention is to expand the upper limit of measurements and reduce the dynamic error

Figure 1 presents the structural diagram of the proposed digital tachometer; figure 2 - block diagram of the register of requests; FIG. 3 is a temporary chart of the operation of the register. owls

The digital tachometer contains contactor 1, electric motor 2, raster sensor 3 angular displacements, comparator 4, control circuit 5, period quantization device 6, micro, computer 7, coincidence circuit 8, first trigger 9, address counter 10, read-only memory ROM) 1 converter 12 code - voltage (PKN), controlled frequency divider 13, buffer register 14, computing device 15, trigger switch 16, query register 17 and direct access controller 18, to memory.

The contactor I, with the second output, connects to the trigger switch, the output of which is connected to the control circuit 5 and the microcomputer 7, and the first output to the electric motor 2, the shaft of which is connected to the modulator axis of the raster sensor 3 of angular displacements, having two exit. The main informative output of sensor 3 (sin-signal output) is connected to one of the inputs of the comparator 4, the output of which is connected to the main input (second) of the control circuit 5 and to the counting input of the query register 17. The output of the raster sensor 3 (the output of the cos signal) is connected to the trigger switch 16 and to the first input of the control circuit 5. The first output of the control circuit is its informative output and is connected to one of the inputs of the period quantization device 6, to the input of which the second output (reference signal output) of the control circuit 5 is connected. The period quantization device 6 is connected to one of the microcomputer inputs as well as to one of the inputs of the computing device 15, the output of which is connected to the second input of the buffer register 14, the first input of which is connected to the first

,

ten

523712

control output 1 of control circuit 5. In addition, the second inputs of the microcomputer 7, the computing device 15, as well as the code input of the frequency divider 13 being charged are connected to the output of the buffer register 14. The second input of the controlled frequency divider 13, as well as the counter input W of the address are connected to the output of the matching circuit 8, one the input of which is connected to the second output of the control circuit 5, and the second input of the coincidence circuit 8 is connected to the output of the first flip-flop 9, the inputs connected to the third and fourth outputs of the control circuit 5.

The output of the controlled frequency divider 13 is connected to the third input of the control circuit 5. The address counter 10, the ROM I1 and PKN 12 are connected in series, and the overhead of the latter is connected to the second input of the comparator 4.

The register of 17 requests consists of three triggers: the second 19, the third 20 and the fourth trigger 21, the R-inputs of which are connected to three in15

20

25

the top outputs (RDP O, RPD1, RPD2) of the controller 18 of the direct memory access, and the direct outputs (ZPDO, ZPD1, ZPD2) of the trigger 19, 20 and 21 are connected to three control inputs of the controller 18 of the direct memory access . The counting input of the second flip-flop 19. is connected to the output of the comparator 4 connected to the third input of the control circuit 5, and its inverse output is connected to the counting input of the third flip-flop 20, the inverse output of which is connected to the counting input of the fourth flip-flop 21. Information ( D-inputs) and installation (S-inputs) of the flip-flops 19, 20 and 21 are combined and connected to the source of level l.

The bi-directional input-output of the direct access controller 18 to the memory is connected to the fourth input of the microcomputer 7.

The device operates in two cycles. In the first cycle, the periods of the information signal from the output of sensor 3 are quantized and information is stored in the microcomputer 7 RAM. Quantization begins upon receipt of a signal from circuit 6 simultaneously with the start of the electric motor 2. The trigger counter switch 16 counts the number of periods at the second output of the raster sensor 3. Overflow pulse, scoring313

The trigger switch 16 arrives at the control circuit 5 and stops the quantization of the periods of the sensor signal 3, and also enters the microcomputer 7, and gives the command to process the information, calculate the angular velocity values, the dynamic moment, i.e. permission to start the second measure.

The first cycle of the digital tachometer.

Informative sine wave signal from the second output of the sensor 3

enters one of the inputs of the comparator 4, where it is unevenly quantized in order to convert the sinusoid slope, which changes with a change in the measured speed, into the frequency of the pulses. This improves the resolution of the digital tachometer. The voltage from the output of sensor 3 is compared with the output voltage of PKN 12 using a comparator 4. The voltage levels of PKN correspond to the values of the signal U sin i / 7/9 j i.e.

and

eleven

) i / 9; U, and „-31p T // 9

etc. Output codes PKN, providing the values of U, and are set using the ROM 11. Address inputs ROM

connected to the counter 10 of the address. To implement a continuous quantization of the signal from the output of the comparator 4 to the input of the counter 10 of the address, digital positive feedback is initiated via the control circuit 5. When each level of VCP coincides with the voltage at the output of the comparator 4, an impulse appears, i.e. converts the slope of the sinusoidal signal to frequency. This sequence of pulses goes to the second input of the circuit 45 p RI ° Yes to the device 15-, where the control 5 is calculated and, its passage is fed to the period quantization device 6, and the first input of the control circuit 5 from the second output of the sensor 3 is fed rectangular, shifted relative to U, by J / 2,3ro, dp is necessary to distinguish between quarters of the U signal period. In addition, the voltage drop across the output of the comparator 4 is formed by the former.

is

2 i ...

the code is being written.

50

55

corresponding to Z j, to the buffer register 14. Each new pulse, which is fed from the first output of the control circuit 5 to the input of the quantization unit 6, clocks the buffer register 14, and the Z value (the last clock cycle) from its output goes to the second the input of the computing device 15 for calculating at the resolution of those that go to the control circuit 5, in the capacity Z j ,, is fed to the microcomputer 7

depending on the value of U Un, cos and controls the operation of the trigger 9. The latter is set to

0

five

|| II

After opening the coincidence circuit 8, and the pulses from the reference frequency generator included in the control circuit 5, from its second output go to the address counter 10. Each impulse passed through the circuit 8 sets the counter 10 to a new sos, and the trigger 9 - to the state. Thus, the closure of the feedback circuit is multiplied. informative signal 18 times. The periods of this signal are quantized with the reference frequency f (j (the second output is a circuit O

5. we are 5 controls) in the period quantization scheme 6, and the codes are fed to microcomputer 7 ,. as well as to the computing device 15, in which the determination of the resolution of the sensor 3 is carried out on the basis of information on the dynamic characteristics of the measurement object. The selection algorithm Z is represented by the relation

Z. Yes

where Z j - the value of the resolution in the subsequent cycle J

Z. - the value of the resolving method Q. ownership - preceding tact; .

K t wholesale

0

five

N

t.

where NT- is the i-ro period code; N 2000.

TT onT

But the above ratio in the computing device. 15 occurs; an extrapolation of the sensor resolution and 3 angular displacements based on the known resolution value of the preceding clock, and also on the basis of information carried by code N. After entering code N from the output of quantizer 6

n RI ° Yes to device 15-, where it is calculated

2 i ...

the code is being written.

corresponding to Z j, to the buffer register 14. Each new pulse, which is fed from the first output of the control circuit 5 to the input of the quantization unit 6, clocks the buffer register 14, and the Z value (the last clock cycle) from its output goes to the second the input of the computing device 15 for calculating the resolution Z j ,, is fed to the microcomputer 7

for further information processing, as well as to the second input of a controlled frequency divider 13.

Divider 3 is constructed tad, which, depending on the control code coming in from the output of the buffer register 14,, the divider gives j pulses. In this way, the resolution of the device is changed.

To reduce the exchange time T. between the device 6 quantization ne ™. By the period of time, the buffer register 14 and the microcomputer 7 RAM are additionally entered into the tachometer controller 18 of the direct memory access.

The function of the generator of the signaling of the ZPDO, ZDSHCH, ZSHCH2 signals for the correct operation of the controller 18 of the direct memory access is performed by the request register 17 () о The timing diagram of the work of the query register i 7 is shown in FIG. 3

When a pulse arrives from the output of the comparator 4 on its front, the NepeAHeivry is set to one state trigger 19, thus forming a direct access request signal (ZPDO) on the zero channel of the controller 18, the last on the output of the RPD generates a flat access signal -a, on which a direct access request (EITA) of the zero channel of the controller 18 is removed (the trigger 19 by the R input enters), at the same time the controller 18 of the direct memory access forms the fourth input of the micro- roAvAm all necessary signals the low byte code N,., 0--7 in the RAM of the microcomputer 7, then a direct access request is made, (ЗПД1) on the first channel of the controller 18 "While the trigger 19 is set to zero, on its inverse output is formed a positive front that sets trigger one to 20.

The direct access request signal (ЗПД1) is fed to the corresponding input of the controller 18 The latter generates a direct access enable signal (РПД1) on the first channel, which removes the direct access request (ППД1), generates the control signals necessary for dd1 I correct recording. code N, 8-15 in the RAM of the microcomputer 7 and generates a direct access request (ЗПД2) on its second channel, B the result of the high byte, 8-15 with you 523716.

the progress of the period quantization device 6 enters the RAM of the microcomputer 7. Controller 18 generates a direct access enable signal (RPD2) via the second channel5 which removes the RFP2 signal and transmits the AID code byte from the output of the buffer register 14 to the microevm RAM 7.

Thus, information is written about one period of the informative signal from the output of the period quantizing device 6 and the ADF code from the output of the buffer register 1.4 to the RAM of microcomputer 7 for each output signal of comparator 4.

0

15

0

five

0

0

five

0

five

Claims (1)

1. Digital tachometer on avt. No. 11518885 characterized by the fact that, in order to expand the upper measuring range and reduce the dynamic error, a query register and a direct memory access controller are added to it, with the count input of the query register connected to the output of a comparator connected to the third L input circuit control, and directly the outputs of the query register are connected to three control inputs of the direct memory access controller, three inverse; the output of which is connected to the three inverse inputs of the register of requests, 5 bidirectional input-output control-. The direct memory access linker is connected to the fourth microcomputer input 2. A tachometer according to claim 6, characterized in that the request register consists of three triggers, the R inputs of which are connected to the three inverse outputs of the direct memory access controller, and The outputs of these triggers are connected to the three control inputs of the direct memory access controller, the counting input of the second trigger is connected to the output of the comparator connected to the third input of the control circuit, and its inverse output is connected to the counting input of the third trigger, inverse the output of which is connected to the counting input of the fourth trigger, the information and installation inputs of the second, third and fourth triggers are combined and connected to the level source J logical). zplo Fi. Compiled by J. Murcuko Editor I. Rybchenko Tehred A. Kravchuk Proofreader M. Maksimishinets Order 5560/43 Circulation 776 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4