SU1488864A1 - Device for determining prespecified level of controlled parameter - Google Patents

Description

The invention relates to devices for automatic control of the signal level and forecasting the time to reach a critical level of the input signal in automated process control systems. The aim of the invention is to increase the information content of the device. For this purpose, the device containing the sensor 1, the threshold blocks 2 and 3, the block 4 of the reversing counting and time indication, the signaling unit 5, the level setting unit 6, the analog switch 7, the counter 8, the controlled divider 9, the shaper 10 short pulses and the trigger 1 1, an analog switch 12, a short pulse shaper 13, an AND 14 element, an OR 15 element, a selector 16, and a zero decoder 17 are introduced. The device allows you to monitor the reduction of the input signal level and predict the time to reach both the maximum and minimum levels of the monitored parameter. 4 il.

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The invention relates to devices for automatic control of the signal level and prediction of the time to reach a critical level of the input signal in automated systems for controlling process control.

The aim of the invention is to increase the information content of the device.

FIG. Figure 1 shows the structure of the device; in fig. 2 block diagram of the reversive account and time indication; in fig. 3 and 4 are graphs illustrating the operation of the device.

A device for detecting a predetermined level of a monitored parameter contains a level 1 sensor, threshold blocks 2 and 3, a block 4 for reverse counting and time indication, an alarm block 5, a level setting block 6, an analog switch 7, a counter 8, a controlled divider 9, a driver 10 short pulses , trigger 11, analog switch 12, shaper 13 short pulses, element AND 14, element OR 15, selector 16, decoder 17 zero.

The block 14 of the reverse counting and time indication comprises a generator 18, a delay element 19, an OR element 20, a summing 21 and a subtracting 22 counters, and an indication unit 23.

The device works as follows.

In block 6 tasks! levels are stored N intermediate levels of the monitored parameter 8, which through analog switches 7 and 1 2 arrive as reference signals to the inputs of threshold blocks 2 and 3, respectively. Analog switches 7 and 12 are controlled by a code from the output of counter 8, and at code 1, analog switch 7 switches to threshold block 3 Ι-th level P, and analog switch 1 2 switches to threshold block 2 (1 + 1) -y level P _{1 + 1} . The number of switched levels in the block is 6 N = 2 ^m , where Ng is the number of digits of the counter 8. The difference between the values of any two adjacent levels ύΗ = Ρ [ _{+ ί} - P 1 = constG and the digit capacity of the counter t is chosen from the condition

5 them ⁺ АБ = 8 _{М ((КС} , where 8 _MIN

and 8. - limit values of

the parameter to be rotated.

The value of the Ιth level is determined from the expression

^p , - ^Τί11 ·

In the initial state, the level of the controlled parameter 8 is minimal.

The code at the output of counter 8 is zero. In this case, the threshold unit 3 receives the level P _o , and the threshold unit 2 receives the level P ,. The decoder 17 zero prohibits the operation of block 4 of the reversing counting and time indication and holds the trigger 1 Gv state, which provides on the selector 1 6 switching information from the inverse output of the counter 8 to the input of the controlled divider 9, thus, the controlled divider 9 sets the division factor K I * where I * is the inverse code value at the inverse output of the counter 8. In this case, the counter 8, controlled from the output of the trigger 11, is transferred to the summing state of the pulses arriving at its input. Since the threshold unit P _o ^ 3 is applied to the threshold unit 3, when the device is turned on, the threshold unit 3 is activated and a signal corresponding to the logic zero level appears at its output. The shaper 10 short pulses forms at the output a pulse when the signal at its input changes from a logic zero level to a logic one level. Thus, the operation of the threshold unit 3 in the initial state does not change the state of the device.

A change in the level of the monitored parameter leads to a corresponding change in the analog signal at the output of sensor 1. When the analog signal reaches 3, the value of P is triggered by the threshold unit 2, the output of which changes from the level of the logical unit to the logic level zero. In this case, the short pulse shaper 13 generates a pulse, which confirms the state of the trigger I1 and is summed up in the counter 8. The new code value on the direct output of the counter 8 switches the analog switches 7 and 12, which connect the corresponding levels of the reference signals to the outputs of the threshold blocks 2 and 3 (on

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threshold unit 3 P ₁₅ and on threshold unit 2 P ₂ ).

The inverse code I * of the inverse output of the counter 8 through the selector 16 enters as a division factor to the controlled divider 9. Since the first output of the counter 8 is set to a code different from zero, the output signal from the decoder Ι7 of zero allows the operation of the 4 reverse counting and indication unit of time. From the output of the controlled divider 9 to the input of the block 4 of the reverse counting and time indication, pulses begin to flow, the number of which is proportional to the current time with

5 mix

where R. is the nearest expected value1 + 1

the level of the controlled parameter.

Estimated value of the forecast

’Max

1 * 1

^Ρ Ι * ι - ^R 1

corresponds to the expression 2 ^M - (1 + 1),

those. numerically equal to the inverse code I *. The pulse from the output of the shaper 13 short pulses through the element OR 15 is fed to the input of the block 4 of the reversing counting and time indication and enables the counting of pulses by the summing counter 21 coming from the output of the controlled divider 9. With a further increase in the monitored parameter of the threshold value P _{g, the} threshold block 2 is activated, at the output of the imaging unit 13, an impulse appears, which is summed up in the counter 8. This same impulse, acting on the input of the block 4 of the reverse counting and time indication, outputs into the signaling unit 5, subtracting the output 22, its counter value is a programmable time parameter maximum level 8, and translates unit 4 in the state that provides the next value calculating updated forecast. The controlled divider 9 receives the division factor corresponding to the new state of counter 8, and the next intermediate levels of the monitored parameter arrive at the inputs of threshold blocks 2 and 3.

When reducing the controlled parameter signal from the sensor 1 to CNI ⁵ zhaetsya level P _g, the threshold unit 3 passes to its original state, and the output signal is a C iemenya logic-zero level on

Yu level of logical units. With

This signal at the output of the short pulse shaper Yu sets trigger II to the state that switches the counter 8 to the subtraction mode of the input pulses, and the selector 16 to the state that provides the direct output of the counter 8 to the input of the controlled divider 9.

The same pulse is subtracted in the counter 8 and the division factor is fed to the input of the controlled divider 9.

Ρΐ-1 "8min

^P G *

G- "

25

thirty

where P ₁ _ ₁ - the nearest expected value of the level of the monitored parameter (Fig. 4). Taking into account expressions (I) and (2), the estimated value of the forecast time to reach the minimum level 5.

* - ^mn P _g ., - 5

^Ρ ΐ "

G- "

numerically equal to the code on the first output of the counter 8, equal to the value of 1-1,

35 where I - the previous value of the code at the output of the counter. The new code value on the direct output of counter 8 switches the analog switches 7 and 12 to the state providing connection to the input of the lower-level threshold unit, and the threshold unit 3 is activated and its output is set to a logic zero level, and to the input of the threshold unit 2 The device receives the level P _g , which does not change the state at the output of the threshold unit 2. In block 4 of the reversible counting and time indication, the predicted time for the minimum level to be reached is accumulated. Then the process repeats, and on the alarm unit 5, the state of the counter 8 is displayed, which allows to judge the level of the parameter being monitored, and in block 4

reverse counting and time indication the calculated value of the forecast is displayed, from which it is subtracted

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current real time, and the sign of the rate of change of the parameter, which corresponds to the state at the output of the trigger 11.

The estimated value of the forecast is accumulated in the summing counter 21, which is kept in the initial state by the signal from the output of the decoder 17 zero, coming through the element OR 20. The calculated value is overwritten into the subtractive counter 22 by the control signal from the output of the element 15, which is delayed on the element 1 9 delay and through the element OR 20 also brings the summing counter 21 to its original state. The pulses from the output of the generator 18, arriving at the input of the subtractive counter 22, allow you to make a correction to the forecast value for the current time. The display of the forecast time value and the sign of the parameter change rate is produced by the display unit 23.

Claims (1)

Claim A device for detecting a predetermined level of a monitored parameter, comprising a sensor whose output is connected to the first inputs of the first and second threshold blocks, the output of the first threshold block is connected to the input of the first short pulse shaper, the output of which is connected to the first, trigger input, the output of which is connected to the first input block reversing 'counting and display time, the first output of which is connected to the first input of a controlled divider, the output of which is connected to the second input of the block reverse accounting and ind time, the counter, the first output of which is connected to the first input of the alarm unit and the first the input of the first analog switch, the output of which is connected to the second input of the second threshold unit, the second output of the reversible counting and time indication unit is connected to the second input of the alarm unit, the level setting unit, the output of which is connected to the second input of the first analog switchboard, in contrast to the fact that, in order to increase the information content of the device, the second short pulse driver, the second analog switch, the AND element, the OR element, the zero decoder and the selector, the output of the level reference block are connected to it with the first input of the second analog • switch, the output of which is connected to the second input of the first threshold unit, the output of the second threshold unit is connected to the first input of the AND element and to the first input of the OR element, the output of which is POG is connected to the third input of the reversing account block. And the time indication and to the first input of the counter, the first output of which is connected to the first input of the selector, to the second input of the second analog switch and to the input of the zero decoder, the output of which is connected to the fourth input of the reversible counting unit and time display and to the second input element And, the output of which is connected to the second input of the trigger, the output of which is connected to the second input of the selector and to the second input of the counter, the second output of which is connected to the third input of the selector Ora, the output of which is connected to the second input of the controlled divider, the output of the first shaper of short pulses is connected to the second input element OR. • 1488866