SU947842A1 - Temperature regulator - Google Patents

Description

The invention relates to thermostatting (temperature control).

Known regulator, temperature, comprising a temperature sensor connected in parallel to the three operational amplifiers whose outputs are sub shreds ⁵ to the inputs of the block generating the control signal output coupled to an input of the thyristor actuator. This and similar _{] (J-type} temperature controllers have two or more control levels. With each step, the power supplied to the heating element decreases, which provides a smoother ₁₅ approach to the set temperature [ij.

However, due to the discreteness of regulation of the power supplied to the heater, the overshoot remains quite large. 20

Closest to the proposed technical essence is a proportional temperature controller containing a temperature sensor.

a DC amplifier, a nullorgan, a sawtooth voltage generator, a synchronizing pulse shaper, a coincidence element, a control pulse shaper, and a control element connected to the heating element. In this thermostat, the signal from the temperature sensor is amplified by a DC amplifier. The amplified signal is fed to the input of the zero-organ, to the second input of which a sawtooth voltage generator is connected, and the output is connected to one of the inputs of the coincidence element. The synchronizer pulse generator is connected to the second input of the coincidence element, and the output of the coincidence element is connected to the control pulse generator, the output of which is connected to the input of the regulating element) ^].

The proportional temperature controller described allows, as it approaches the set temperature, to smoothly reduce the power supplied to the heating element and thereby significantly reduce overshoot, but does not provide high accuracy of regulation.

The purpose of the invention is to improve the accuracy of the device.

This goal is achieved by the fact that in the device for controlling the temperature, comprising a temperature adjuster, a clock generator and a series-connected temperature sensor, an amplifier, a comparator, a control pulse generator, a control element and a 15 heater, a subtractor, a memory block, a clock generator and a digital -analog converter, the control input of which is connected to the _20th output of the clock generator, the first output - with the first input of the subtractor , the second output - with the second input of the comparator, the output connected to the control input of the memory unit ₂₅ , and the output of the temperature setter is connected to the second output of the subtractor.

In FIG. 1 is a functional diagram of the device for regulation of temperature ₃₀ Nia; in FIG. 2 - time diagrams of his work.

The temperature control device (Fig. 1) includes a temperature setter 1, a subtractor 2, a memory unit 3, a clock generator 4 of ³⁵ ow, a digital-to-analog converter 5, a comparator b, a driver of control pulses 7, a clock generator 8, a control element 9 , heater 10., temperature sensor 11, amplifier 12.

A device for controlling the temperature is as follows.

The moment of switching control device digital-analog pre-forming 5 ⁴⁵ is reset and its first output is set to zero code value input to the first input of a subtractor 2. The second input of subtraction ⁵⁰ of Tell 2 code is present, the value of which corresponds to a predetermined set point adjuster 1 temperature. At the same time, a difference code is generated at the 'output of subtractor 2, the value of which is maximum ⁵⁵ and corresponds to the difference between the counts specified by the setter 1 and zero from the output of the digital-to-analog converter 5. This difference code is recorded in the memory block 3 by the installation pulse generated in the initial one, formed in the block 3 memory at the initial 5 moment of switching on the control device. The pulse width of the installation in the original digital-to-analog Converter 5 and the memory unit 3 is selected a slightly longer duration of transients that occur when you turn on the control device. From the output of the memory unit 3, the recorded difference code is supplied to the control input of the generator 4 clock pulses. The repetition period of clock pulses (figa) at the output of the generator 4 depends on the value of the code at the control input and at the maximum value of this code is determined by the condition

F _, .. T min 2PT where min is the minimum period of the following clock pulses;

T is the period of supply voltage to the heater;

N - digit capacity of the digital-to-analog converter (maximum number of steps at the output of the digital-to-analog converter).

Shaper 8 pulses generates a sequence of clock pulses (Fig.2B) with a repetition period T / 2, formed at the moment of transition through zero voltage supplying the heater 10. When the heater 10 is supplied with a voltage of 50 Hz, the repetition period of the clock pulses will be 10 ms.

Each clock pulse, arriving at the control input of the digital-to-analog converter 5, sets the latter to the zero (initial) state, and at the end of the clock pulse at the first output of the digital-to-analog converter 5, an increasing code is generated with the clock frequency determined by the clock generator 4, and the second output increases with the same clock frequency, the step voltage (Fig. 2B - 1), supplied to the second input of the comparator 6 (Fig. 1). At the first input of the comparator 6 there is a signal amplified by the amplifier 12 from the temperature sensor 5 947842 6 ka 11 (Figs. 2c - 2). Comparator 6 compares two input signals and, at the moment of their equality, generates a pulse at its output (Fig. 2d) · received at the 5th input of the driver 7 of control pulses (Fig. 1), which generates a control signal (Fig. 2d) to open the control element 9 (FIG.

1) through which the heater + heater 10 is fed. At the end of the control signal, the regulating element 9 is closed and the passage of current through the heater 10 is stopped.

In addition, the pulse from the output 15 of the comparator 6 is supplied to the control input of the memory unit 3, by which the instantaneous value of the difference code corresponding to the difference between the values of the codes 20 of the set and actual temperatures is recorded during the corresponding synchronization period. As the actual temperature approaches the predetermined level increases stu- 25-step level voltage at which the input quantities occurs equality at the inputs of the comparator 6, which leads to an increase in the phase shift pulse at the output of the comparator ₃₀ in relative 6 The relative clock. In addition, an increase in the phase shift C> (Fig. 2d) as it approaches the set temperature is caused by a decrease in the steepness of the step voltage at the output of the digital-to-analog converter 5, which is a consequence of a decrease in the pulse repetition rate at the output of the 4-pulse generator. The decrease in the frequency of clock pulses occurs due to a decrease in the difference code supplied to the control input of the generator 4 clock pulses from the output of the memory unit 3. As you approach the set temperature, the value of the difference code tends to zero. In this case, the repetition period of clock pulses tends to the value of _t p - T so ^{1 m} ax = - 2N '

those. increases N times relative to.

¹ to the initial value '? mi η, therefore a maximum duration of ⁵⁵ The stresses increase stepwise zheniya output digital-to-analog converter 5 tends to lichineT ve / 2 t.e.k magnitude synchronization period.

An increase in the phase shift of the pulses at the output of the comparator 6 due to a decrease in the steepness of the step voltage at the output of the digital-to-analog converter 5 in combination with the usual phase control allows you to change the steepness of the temperature rise from the maximum at the initial moment of heating to the minimum steepness at the moment the temperature reaches the specified level, which Reduces warm-up time with minimal overshoot.

The use of a temperature control device with automatic control of the steepness of the temperature pulse in the assembly equipment of microelectronic production allows to reduce the time of assembly operations with high accuracy of maintaining the temperature conditions of the technological process.

Claims (2)

This invention relates to thermostatic control (thermoregulation). A temperature controller is known, with a holding temperature sensor connected in parallel to three operational amplifiers, the outputs of which are connected to the inputs of a control signal generating unit, the output of which is connected to the input of a thyristor executive device. This and similar temperature controllers have two or more control steps. With each step, the power is reduced, supplied to the heating element, thus providing a smoother approach to a given temperature l. However, due to the discreteness of the regulation of the power supplied to the heater, the overshoot remains quite large. Closest to the proposed technical entity is a proportional temperature controller containing a temperature sensor. dc amplifier, nullorgan, sawtooth generator, clock generator, coincidence element, control pulse driver and control element connected to the heating element. In this thermostat, the signal from the temperature sensor is amplified by a DC amplifier. The amplified signal is fed to the input of the null organ, to the second input of which the sawtooth generator is connected, and the output is connected to one of the matching element. A synchronization pulse shaper is connected to the second input of the coincidence element, and the output of the coincidence element is connected to a control pulse shaper, the output of which is connected to the input of regulating element 2. The described proportional temperature controller allows smoothly reducing the power supplied to the heating element as it approaches the specified temperature 39 element and thereby significantly reduce the overshoot, however, does not provide a high accuracy of regulation. The purpose of the invention is to improve the accuracy of the device. The goal is achieved by the fact that a temperature control device, a clock generator and a serially connected temperature sensor, a comparator amplifier, a control pulse driver, a regulating element and a heater are inserted into a temperature control device, a serially connected subtractor, a memory generator of clock pulses and a digital-analog input are inserted the converter, the control input of which is connected with the output of the sync pulse generator, the first output - with the first input of the subtractor, in Ora output - to a second input of the comparator output connected to a control input of the memory, the output of the temperature set point is coupled to the second output of the subtractor. FIG. 1 is a functional diagram of a temperature control device; in fig. 2 - time diagrams of his work. The device for temperature control (Fig. 1) contains a temperature setting device 1, a subtractor 2, a memory block 3, a clock pulse generator A, a digital-to-analog converter 5, a comparator 6, a control pulse driver 7, a clock generator 8, a regulating element 9, a heater 10., temperature sensor 11, amplifier 12. A device for controlling the temperature of the circuit operates as follows. At the moment the control unit is turned on, the digital-to-analog converter 5 is reset and at its first output the zero value of the code arriving at the first input of the subtractor 2 is set. At the second input of the subtracting body 2 there is a code whose value corresponds to the temperature set by the setpoint 1. At the output of the subtractor 2, a differential code is formed, the value of which is maximum and corresponds to the difference of the quips given by setpoint 1 and the zero output of the digital-analog converter 5. This differential code is written to the memory unit 3 by the setting pulse to the original at the initial moment of switching on the control device. The duration of the pulse set to the initial digital-analog converter 5 and the memory block 3 is chosen to be somewhat longer than the duration of the transients that occur when the control device is turned on. From the output of memory block 3, the recorded difference code is fed to the control input of the generator of k clock pulses. The period of the clock pulses (Fig. 2a) and the output of the generator t depends on the code value at the control input and, at the maximum value of this code, is determined by the condition where min is the minimum clock time period; T is the period feeding the voltage heater; N is the size of the digital-to-analog converter (the maximum number of stages at the output of the digital-analog converter). The shaper 8 sync pulses generates a sequence of sync pulses of fig.2b) with a T / C following period, which is generated at the moment of passing through a voltage zero, supplying the heater 10 .. When the heater is powered by 10 voltage of 50 Hz, the sync pulse period will be 10 ms. Each clock pulse arriving at the control input of the D / A converter 5 sets the latter to the zero (initial) state, and at the end of the clock pulse, the first output of the D / A converter 5 produces an increase with the clock frequency determined by the clock pulse 4, the code and at the second output the step voltage increasing with the same clock frequency (Fig. 2c - 1), arriving at the second input of the comparator 6 (Fig. 1). At the first input of the comparator 6 there is a signal amplified by the amplifier 12 from the temperature sensor 11 (fig.2b - 2), the compressor 6 compares the two input signals and at the moment of their equality forms at its output a pulse (fig.2g) arriving at the input control pulse generator 7 (Fig. 1), generating a control signal (Fig. 2e) for opening the regulating element 9 (Fig. 1) through which the heater 10 is energized. At the end of the control signal, the regulating element 9 closes and the current flows through the heater 10 pr kraschaets. In addition, a pulse from the output of the comparator 6 is fed to the control input of the memory unit 3, which records the instantaneous value of the difference code corresponding to the difference between the values of the codes of the given and actual temperatures during the corresponding synchronization period. As the actual temperature approaches the specified level, the step voltage level increases, at which the input values at the inputs of the comparator 6 become equal, which leads to an increase in the phase shift of the pulse at the output of the comparator 6 relative to the sync pulse. In addition, an increase in the phase shift (fig.2g) as it approaches a predetermined temperature is caused by a decrease in the steepness slope at the output of the digital-to-analog converter 5, which is a consequence of a decrease in the pulse frequency at the generator output k clock pulses. A decrease in the frequency of clock pulses occurs due to a decrease in the value of the difference code fed to the control input of the clock generator from the output of memory block 3. As it approaches a predetermined temperature, the value of the delta code tends to zero. In this case, the period of the following clock pulses tends to a value of T I-max 2N, i.e. increases by N times in relation to the initial value of mip, Therefore, the maximum for -. The growth rate of the step voltage at the output of the digital-to-analog converter 5 tends to the value T / 2, i.e. the value of the synchronization period. Increasing the phase shift of the pulses at the output of the comparator 6 by reducing the steepness slope at the output of the digital-analog converter 5, in combination with the usual phase control, allows the temperature rise from the maximum at the initial warm-up time to the minimum slope and the temperature to reach the specified level, which reduces the warm-up time with minimal overshoot. The use of a device for temperature control with automatic control of the steepness of the increase in the temperature pulse in the assembly equipment of microelectronic production makes it possible to shorten the time of assembly operations with high accuracy in maintaining the temperature regimes of the technological process. Apparatus of the Invention A temperature control device comprising a temperature setter, a clock generator and a serially connected temperature sensor, an amplifier, a comparator, a control pulse generator, a regulating element and a heater, characterized in that, in order to improve the accuracy of the device, it comprises a series-connected reading device, unit a memory, a clock pulse generator and a digital-to-analog converter, the control input of which is connected to the output of the synchroimpulator pulses, the first output - with the first input of the subtractor, the second output with the second input of the comparator, the output connected to the control input of the memory unit, with the output of the temperature setpoint device connected to the second input of the subtractor. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 52593+, cl. G 05 D, 23/19,1975. . 2. USSR author's certificate number it91123, cl. G 05 O, 23/19, 197. (prototype). uz, 1 " ,BUT