SU885884A2 - Device for checking frequency change rate - Google Patents

Description

(54) DEVICE TO CONTROL THE SPEED CHANGE OF FREQUENCY

I

The invention relates to a control measuring technique. In particular, to low-inertia devices for controlling rotational speed and acceleration, and can be used in automatic control and monitoring systems in which information is presented in frequency form.

According to the main author. St. No. 811156, there is a known device for controlling the rate of change in frequency, comprising a speed sensor, an input driver, a control unit, a counter, a period code processing unit, a conjugator, an output driver, and a reference frequency generator, the period code processing unit consisting of an encoder, a multiplication unit, block period difference and comparison block l3

A disadvantage of this device is that it has low noise immunity in the conditions of external noise, as well as during short-term interruptions of the signals from the speed sensor, caused, for example, by breaks or short circuits in the sensor or its circuits. In these cases, the loss of one or several signals from the speed sensor can lead to a sequence of input signals that occurs during the emergency operation of the object being monitored, and therefore the device can generate a false output signal.

The purpose of the invention is to improve noise immunity.

The goal is achieved by the fact that a device for controlling the rate of change in frequency, containing serially connected speed sensor, input driver, and control unit, the first, third and second outputs of which are connected respectively to the first and second inputs of the counter and the first input of the main conjunctor, generator the reference frequency, the output of which is connected to the third input of the counter, the output of which is connected through the code processing unit to the second input of the main conjunctor, the output of which is connected With the first input of the output driver, two comparison blocks, two co-linkers, two disjunctors and a blocker pulse shaper were added, the counter output being connected to the first inputs of the additional disjunctors via the first comparison block. and directly with the input of the second comparison unit, the first output of which is connected to the third input of the main conjunctor, the second output of the second comparison unit is connected to. the second input of the first disjunctor, the output of which is connected to the first input of the first additional conjunctor, the second input of which is connected to the second output of the control unit, and the first input of the second additional conjunctor. the second input of which is connected to the output of the code processing unit, and the output of the second input of the second disjunctor, the third input of which is connected to the output of the first conjunctor through the driver of the blocking pulses, the output of the second disjunctor is connected to the second input of the driver of the output signals.

Fig. 1 is a block diagram of a device for controlling the rate of change of frequency; in fig. 2 a possible variant of the device, in FIG. 3 - 5 - diagrams ,. on his work.

The device includes a speed sensor G / driver 2 input signals, a control unit 3, a counter 4, a period code processing unit 5, conjunctors 6-8, an output driver 9, a reference frequency generator 10, comparison units 11 and 12, disjointrs 13 and 14, the driver 15 blocking pulses,:

I

The device works as follows.

The signal from sensor 1, which corresponds to the beginning of period T, goes to shaper 2, which produces a pulse, at the leading edge of which block 3 starts up. At the first output of block 3, there are prohibitions of the pulse, and at the second output - allowing. The impulse of the first output of block 3 pod858844

the first input of the counter 4 and prohibits the flow of signals from the generator 10 to the counter 4.

After the end of the pulse, a control pulse appears at the second output of unit 3 at its third output, which is fed to the second input of counter 4. At the trailing edge of this pulse, the counter 4 and unit 3 are reset. At the same time, at the first output of block 3, the enabling signal appears and the signals of generator 10 begin to fill in counter 4. In the last 5, codes of numbers are formed, information about which is fed to the inputs of block 5 of processing the period code and blocks 11-12 of comparison.

R the moment of arrival of the next signal sensor 1, corresponding to the end of the period T, and the beginning of the period, in the counter 4 a number is formed that is proportional to the length of the period network TJ, in block 5 bu. The result of the period code processing is obtained.

In this case, the pulse of the first output of block 3 prohibits the flow of signals from the generator 10 to the counter 4. The opening pulse of the second output 3 of block 3 is fed to the input of conjunctor b and the inputs of conjunctors 7 and 8,

The following options for device operation are possible.

35 1. The result of processing the code in block 5 does not meet the requirements of the normal operation of the controlled object. In this case, from the output of block 5 to the input of conjunctor 6 will be served

40 opening signal (signal from Avariya), and from another output blocks 5 to the input of conjunctor 7 - a closing signal.

1-1. At counter 4, a number is formed that will be

more than the trigger threshold of block 11, but less than the trigger threshold of block 12. In this case, one output of block 11 will have an opening signal, and there will be no opening signals at its other output and output of block 12. Therefore, the disjunctor 13 and the conjunctors 7 and 8 will be closed, the driver 15 will not start, all three inputs of the disjunctor 14 will have no opening signals and it will not generate a signal for the initial installation of the driver 9.

Since on all three inputs of the conjunctor 6 there will be opening signals, it will form a pulse, which will be written into the shaper 9 logical 1.

1-2. If the counter 4 generates a number less than the thresholds for the operation of blocks 11 and 12, there will be a closing signal at one output of block 11, an opening signal at its other output, and no opening signal at the output of block 12. Therefore, conjunctors 6 and 7 will be closed, and the disjunctor 13 and conjunctor 8 will be open and the output impulse of the conjunctor 8 will start the driver 15, the signal of which, having passed through the disjunctor 14, will go to the installation input of the former 9, will set this driver to its initial state and block its counting input at time C; 5d 2

1-3. If TTj |, jjj, jTO, the number in counter 4 will be greater than the trigger thresholds of blocks 11 and 12. In this case, one output of block 11 and output b: r1ka 12 will have opening signals, the other output of block 11 will have no opening signal . In this case, the opening signal at the output of the unit 12 in Vits until the end of the period T; , and having passed through disjunctor 19, will set shaper 9 to its initial state.

At the moment of arrival of the pulse from the second output of the block 3 to the conjunctor 8, the driver 15 starts up, while the counting input of the driver 9 will be blocked for the time Trp.

2. The result of processing the code in block 5 corresponds to the requirements of the normal operation of the controlled object. With this, from one output of block 5 to the input of conjunctor 6, a closing signal is given, and from its other output to the input of conjunctor 7, an opening signal.

In this case, regardless of the condition in which blocks 11 and 12 are located, conjunctor 7 generates a pulse, which, having passed through disjunctor 14, sets shaper 9 to its initial state.

In the same way as in the cases of 1-2 and 1-3, with T 7 Tu, op 1, the driver 15 starts and counts

the input of the imaging unit 9 will be blocked for the time of TGsd.

In all the cases considered after the end of the pulse on the second

At the output of block 3, a control signal appears at its third output, which is fed to the input of counter 4. At the trailing edge of this pulse, the counter 4 is set and

block 3 to its original state. From this moment, a new cycle of monitoring the rotation parameters will begin.

If situation 1-1 repeats on the second monitoring cycle, the second logic 1 is recorded in driver 9 and it produces an output signal.

If one of the situations is repeated in which the trigger signal from the conjunctor 8 is sent to the driver 15, the output pulse of the driver -15 will last for 2Grd from the moment of the last start and thus will again

secured counting lock

input shaper 9 at the time of the TC. 2 T ,,,.

FIG. 2 presents one of the possible options for the implementation of the proposed device. In this device, the role of the control unit 3 is to execute the shift register and trigger, the period code processing unit 5 consists of the encoder 16, for which the toggle block is used, the number multiplying unit 17, the period difference block 18 implemented on the countdown counter, comparison unit 19. The output driver 9 consists of a counter 20 and an output amplifier 21, the reference frequency generator 10 is a multivibrator.

Comparison unit 11 consists of conjunctor 22 and trigger 23, and comparator unit 12 consists of conjunctor 24 and trigger 25. At the same time, the response thresholds of comparator blocks 11 and 12 are provided by connecting the inputs of conjunctors 22 and 24 to the outputs of counter 4. Correcting the 15 blocking pulses on key 26, RC circuit 27 and Schmidt trigger, 28.

Claims (1)

The device shown in FIG. 2, allows control of angular acceleration modulo (simultaneous control of positive and negative limit values of angular acceleration). Introduction to the known device of two units of comparison, two disjunctors, two recusers, blocking impulses with long-term TewC / rd 2 Tu ,, 1 / and corresponding connections, as well as the use of the accumulation principle of two successive Avarion signals , allows to completely exclude the device’s emergency response, caused by interference or interruption of the rotational speed sensor signals, when the device operates in the range of rotational speed, for which the condition uf) ShZH minds where and is satisfied ;,, and y, respectively imalna speed and the maximum rotation in the predetermined zone Meas. Expressing in the last condition the rotational speed through the period of rotation of the control object, we get hnin Cfmm TmiH Try, a. In FIG. 3-5 accept the following conventions: С, С, С - turnsal sensor signals; P, 112 I and l - interference. . At the same time, the newly introduced functional elements of the circuit and the communication block the output of the device when signals are applied to its input, the follow-up period of which does not correspond to the specified range of rotational speed control, thereby eliminating false alarms when exposed to high-frequency interference (Fig. 3, which is implemented by block 11, and the elimination of a spurious signal during short-term interruptions of the speed sensor signals, which is provided by block 12, as well as the expansion of a pulse that blocks the output of the device, to a value of 72 Tuu, d, which is necessary to eliminate a spurious signal with an accidental combination of noise (Fig. 4), when two adjacent periods, T and T, are divided into two interferences by Pu, and 112. At four intervals T T 2 , Tp ,, and Tp4, and, ,,,. X “,, irxatx48 In this case, at the time of the end of period T, block 11 generates a signal that prohibits the passage of the signal. Avariya of block 5, as well as a signal that allows the generator to start 15. 15 sets the former 9 to its initial state. At the end of the periods Tf, Tfil) the first output of block 11 will be the enabling signal (since, TP,) and false signals of Avariya of block 5 will be fed to the first input of the imaging unit 9. However, these signals will not trigger the device, because during the time Tr - d 2 T y - the first input of the imaging unit 9 will be blocked by the impulse of the imaging device 15. In addition, the output information imaging device 9 provides for the use of a storage device that allows generating the output signal only after two or more successive fuses are fed to the device input itic periods of rotation of the controlled object. Such an algorithm of the device operation is due to the need to prohibit the issuance of a false signal when a random disturbance appears in the AB interval of ne / h period. T (Fig. 5J, where, WT i TT - Tn + Tna T OJX-B in this case at the time of the end of period T ( 2 The signal from the block 5 to the counting input of the generator 9 will be allowed and the logical 1 may be recorded in the latter. However, at the end of the period, the information will be erased, since I TYfliyf will be set to its original state. Thus, in the proposed device for Rotation parameters control completely eliminates false alarms when the device is operating under conditions of noise and interruptions of the speed sensor signals. At the same time, the device operates in a relatively rotational speed range (jaiilo, 5) and provides a high fflwiQx speed of control. frequency change on the main bus number 811156, characterized in that, in order to increase noise immunity, it additionally includes two comparison units, two conjunctors, two diaunctors, and a blocking pulse shaper, the counter output being connected to the first inputs of disjunctors through the first comparison unit and directly to the second input of the comparison unit, the first output of which is connected to the third input of the main terminal junctor, the second output of the second unit of comparison is connected to the second input of the first disjunctor, the output of which is connected to the first input of the first additional conjunctor, the second input to torogo connected to 8588410 the second output of the control unit and the first input of the second additional conjunctor, the second input of which is connected to the output of the code processing unit, and the output to the second input of the second disjunctor, the third input of which is connected to the output of the first through the blocking pulse generator. conjuncer, the output of the second disjunkto10 RZ is connected to the second input of the driver of the high-voltage signals. Sources of information taken into account in the examination., 1. Copyright certificate of the USSR No. 8P156, 28.03.79.