SU1442979A1 - Apparatus for program control of temperature - Google Patents

Abstract

The invention relates to the field of automatic control, in particular, to devices for software digital temperature control in electrothermal installations. The aim of the invention is to improve the accuracy and enhance the functionality of the device by organizing a multi-programmed temperature control with automatic control from start to stop of the device. The device contains a starting element, a control unit, the first and second counters, a reversible counter, blocks of memory and program input, a control: a frequency divider, a comparator, an algebraic adder, a linearizer, an analog-to-digital converter, a code converter, synchronization unit, pulse generator, timer, timer type, sensor, temperature, object. 2 hp f-ly, 2 ip. (L CZ

Description

The invention relates to devices for programmatically controlling the temperature of various technological processes, in particular for precision temperature control in electrothermal installations. new

The purpose of the invention is to increase the accuracy and enhance the functionality of the device.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 - functional block diagram.

The device contains a starting element 1, a control unit 2, a first counter 3, a memory block 4 and a program input block 5, a controlled frequency divider 6, a comparator 7, a linearizer 8, characteristics of a temperature sensor, a reversible counter 9, an analog-to-digital converter (AShch1) 10, an algebraic adder 1, a thyristor actuator 12, a heater 13, a temperature sensor 14, a technological object} 5, a synchronization unit 16, a generator of 17 pulses, a second counter 18., a timer 19 and a code converter 20.

Control unit 2 consists of RS flip-flop 21-, element 22 and D-flip-flop 23, with the S input of trigger 21 being the second input of control unit 2, the R input of RS flip-flop 21 being the first input and input of element 22 - the fourth input, and the R-input of the D-flip-flop 23 - the third input of the control unit 2. The output of the RS flip-flop 21 is the third output, the first flip-flop of the D-flip-flop 23 is the first one, and the direct output of the D-flip-flop 23 is the second output of the control unit 2

The device works as follows.

Before starting operation, the program of temperature control (number of control cycles, the duration of each cycle, the speed and direction of temperature change in the cycle, the maximum temperature of the cycle)

When the device is switched to the operating mode, the D-flip-flop 23 of the control unit 2 is set to a hook, and the first counter 3 of the task set

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grams - to the initial state (installation chains are not shown). In this case, the information about the first cycle of the program appears on the output of memory block 4.

From the trigger element 1, a single pulse arrives at the first input of the control unit 2, setting the RS flip-flop 21 to one. The high level from the first output of the control unit 2, arriving at the input of the element And 22, includes a synchronization unit 16 that outputs pulses with the frequency of the protracted network.

15 From the outputs of memory block 4, information is received on the first cycle of the program: the code for the rate of temperature change from the first output to the first input of the controlled frequency divider b,

20 code of the maximum temperature from the second output - to the first input of the comparator 7, the code of the exposure time of this temperature from the third output - to the first input of the timer I9.

25 Since the B-trigger 23 of the control unit 2 is in the zero state, a high level from the second output of the control unit 2 is supplied to the controlled frequency divider 6 and

30 includes it. A pulse from the output of the synchronization unit 16, tied to the beginning of the mains voltage half-period, starts the generator 17 of pulses,

The pulses from the output of the generator 17 are fed to the input of the controlled frequency divider 6, from the output of which to the counter input of the reversible counter 9 pulses are transmitted with a frequency determined by the code of the rate of temperature change specified from the block, 4 memories. The code from the output of the counter 9 is fed to the second input of the comparator 7. To the first input of the comparator 7, the set temperature code is supplied from

45 blocks of 4 ladies. The control signals from the second and third outputs of the comparator 7, arriving at the inputs of changing the counting direction of the reversing counter 9, set the ramp up or decreasing temperature mode depending on the ratio of codes at the inputs of the comparator 7

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40

If the temperature rises, the contents of counter 9 increase until the counter code 9 is less than the code received at the first input of the comparator 7, the output code of the reversible counter 9, corresponding to: the current temperature value at a given time, goes to the first input of the algebraic adder 11. The output of the temperature sensor 14 converted by the ADC 10 into a digital code and linearized in the luteator is fed to the second input of the latter. The differential signal from the output of the algebraic adder 11 is fed ie the input transducer 20 codes, which, depending on the desired temperature change law generates the code on the output conductive doing the information input of the second counter 18.

The leading edge of the pulse from the output of the synchronization unit 16 this code each half-period of the mains voltage is written to the second counter 18. From the generator 17 output, the pulses arriving at the counting input of the second counter 18 increase its content until an overflow pulse occurs. The overflow pulse from the output of the second counter 18 includes in each half-period a thyristor actuator 12, which sets the power of the heater 13. The temperature of the technological object 15 increases until the codes at the inputs of the algebraic adder 11 do not match, i.e. the signal from the temperature sensor (converted to code and linearized) becomes equal to the output code of the reversible counter 9. At this point, the overflow pulse of the counter 18 appears at the very end of each half-period of the mains voltage, and the minimum power is applied to the heater 13.

Thus, in this control loop, support is produced; The temperature of the process object 15 equal to the code of the reversible counter 9. As the content of the reversible counter 9 increases, the temperature of the process object 15 also increases. At the same time, the linearizer 8 provides a linear change in the output signal of the temperature sensor 14 over the entire temperature range, and the code converter 20 change the power supplied to the heater 13 depending on the value of the output code of the subtractor, i.e. establish a certain law of approximation

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temperature tehnolop-gcheskogo ob7zekta 5 to given.

At the moment of coincidence of the codes at the inputs of the comparator 7, a high level appears at its first output, which goes to the quarter input of the control unit 2 and sets the D-flip-flop 23 to the unit through the AND 22 element.

10 Thus, the controlled frequency divider 6 is turned off by a low level from the first output of the control unit 2 and. . reversing counter 9 stops. High level from first exit

15 of the comparator 7 is also fed to the trigger input of the timer 19, the code from the output of the interval interval Ereme is written to it. They are constantly set on the unit 4 of the iTM, and the timer has gone off.

20 At the input of the timer 19, the pulses are received from the output of block 1b of synchronization. Timer 19 in accordance with the code. gyupt} hv1 1 # 1 at its input from the rear of an interval of time, counts down the holding time of a given temperature.

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0

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After processing the specified interval .Byperm vyderlsk.and constant temperature at the output of the timer 19 appears impulse, on the third input is reset.1 In trigger 23 of the control unit 2. The low level at the first input of the control unit 2 switches the first counter 3, which sets the address of the next command (next cycle) of the program. If in the next cycle the heating mode of the process object 15 continues, the process continues in the manner described.

If cooling mode starts, then the code at the first input of the comparator 7 is less than the code at the second input. The signals at the first and second inputs of the comparator 7 put the reversible counter 9 into subtraction mode. The pulses from the output of the controlled divider frequency b reduce the content of the reversing counter 9. The output code of the counter 9 is fed to the second input of the algebraic adder 11, the first input of which receives a signal from the temperature sensor 14 .. The code at the second input of the algebraic adder 11 is smaller, therefore the output code of the algebraic adder 11 switches the code converter 20 in a manner that

The third input of the second counter 18 receives a code that turns off the thyristor actuator 12 and the heater 13. The technological object 15 and with it the temperature sensor 14 begins to cool. The code at the second input of the algebraic adder 11 decreases. If it becomes less than the code at its first input, then the heater 13 turns on and raises the temperature of the tenological object 15. This ensures the cooling speed of the technological object 15

When on both inputs of the commuter 7 the values of the codes coincide, the high level at its first output is anal. As described, it disables the controlled frequency amplifier, i.e. the cooling mode ends and timer 19 is on, i.e. the temperature begins to decrease 1, then the next cycle is passed,

Claims (3)

Invention Formula 1, A device for software temperature control, containing a temperature sensor, an algebraic adder, a tactile thyristor executive element connected to a heater, mounted on a techno-lop-gait object, a starting element connected to the first input of the control unit, the first output of which is connected with a counter input of the counter connected by an output to the input of the cycle setting of the temperature control program of the memory unit, the information input of which is connected to the output of the input unit of the control program the controller, the output of the rate of change of the temperature of the memory unit is connected to the input of the controlled frequency divider, the output of the temperature level setting with the comparator input, the output of the end of the heat treatment program with the second input of the control unit, the output of the controlled / frequency divider is connected to the counting input A reversible counter connected by an output to the second input of the comparator is also a code converter, characterized in that, in order to improve the accuracy and enhance the functionality of the device, it is entered into it, synchronization unit, pulse generator, second counter and timer, and the output of the adder is connected to the input of the code converter, the output of which is connected to the specifying input of the second counter, the output of which is connected to the input of the thyristor actuator, the synchronization input of the second counter is connected to the output of the synchronization unit, the synchronization input of the pulse generator and the synchronization code of the timer, the counting input of the second counter connected to the output of the pulse generator and the input of the reference signal of the controlled frequency divider, the stop input of which is connected to the second. To the output of the control unit, the third TYPE of which is connected to the first input of the synchronization unit, the third input of the control unit of the connection IeH to the output of the timer, the driver input of which is connected to the output of the time interval maintenance of the memory unit, which triggers the timer input is connected to the fourth input of the control unit k with the first output of the comparator, the second and third outputs of which are connected respectively to the inputs of changing the counting direction of the reversible counter, the second input of the synchronization unit network with phase conductor, yield reversible counter is connected to the second input of the adder, 2, The device according to p. 15 of a tl of icu; This is because the control unit contains an ftS-trigger, the output of which is connected to the first input of the element AND, the output of which is connected to the synchronizing input of the D-trigger, the RS-trngger twist input being the second, the set input - RS-flip-flop — the first one, zeroed the D-flip-flop input, the third, and the second input of the AND element — the fourth output of the control unit; the inverse D-flip-flop output is the first, its first code output, the RS-flip-flop output - one third of them by the outputs of the control unit; the installation input of the D-trigger is connected to the output of the source nick level signal 3. The device according to claim 1, which is based on the fact that an analog-to-digital converter has been entered into it, the output of a temperature sensor characteristic connected to the linearizer input, and the analog-digital converter output of the linearizer of the digital converter Temperature sensor ki - with the first one with the output of the temperature sensor, the input of the algebraic adder. Jig, 1 Figg