SU1594500A1 - Programmable temperature control - Google Patents

Abstract

The invention relates to control devices and controls, namely to precision temperature controllers with a programmed temperature setting. The purpose of the invention is to improve the accuracy of the regulator in a wider range of control temperatures. The software controller contains a setpoint and a temperature sensor, the outputs of which are connected to the input of the reference element, connected to the inputs of the differentiator and the linear amplifier connected to the input of the adder connected to the input of the actuator, as well as the integrator and two scaling amplifiers. A new regulator is the use of two scaling amplifiers, the input of the first of which is connected to the output of the differentiator, and the output to the input of the adder connected by another input to the output of the second scaling amplifier connected to the input of the integrator. The control input of the first scaling amplifier is connected to the output of the temperature sensor, and the control input of the second scaling amplifier to the output of the reference element, to which the integrator's input is also connected. 1 il.

Description

The invention relates to devices for controlling and controlling the temperature of electrical resistance furnaces having a final warm inertia, namely, precision temperature controllers with a programmed temperature setting, and can be used in semiconductor electronics to control the technological processes of thermo-processing semiconductor materials.

The purpose of the invention is to improve the accuracy of the regulator in a wider range of control temperatures.

The drawing is a diagram of a software temperature regulator.

A software temperature controller contains a software temperature setting device 1, a temperature sensor 2 for converting temperature into an electrical signal, a reference element 3, a differentiator 4, a first scaling amplifier 5, a linear amplifier 6, an integrator 7, a second scaling amplifier 8, an adder 9 and an actuator 10 ,

. The program temperature controller operates as follows.

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When the regulator is turned on, the difference between the signals from setpoint 1 and temperature sensor 2 is usually large, therefore element 3 of comparison, performed on the amplifier, works in limiting mode, since the jero section is linear, working due to the need for a large factor the gain is only a few percent: of the total (maximum) operating temperature range of the regulator. Thus, although the difference between the signals from the setpoint 1 and sensor 2 decreases with the approach of the temperature of the electric furnace to the set point, the output signal of the reference element 3 at the beginning (when 1 the difference of the signals of preset 1 and sensor 2 of the temperature is large) It is equal to the maximum (positive or negative) output-: voltage that is transmitted by the black: linear amplifier 6 and the adder 9 to the actuator 10, thereby providing the maximum power to the control object. Differentiator 4 does not function, since the signal at its input does not change. The voltage at the control input of the second scaling amplifier 8 (which is a DC amplifier with a controlled voltage gain factor —and can be performed, for example, on a multiplier), supplied from the reference element 3, is maximal, as a result of which it is. usi. laziness is minimal. Therefore, although the maximum signal is supplied to the input of the integrator 7 from the comparison element 3, due to the minimum gain factor of the second scaling amplifier 8, the integrator 7 is practically disconnected from the adder 9 and does not affect the operation of the regulator. The control object is heated with full power. When the temperature of the electric furnace approaches the predetermined difference between the signals from setpoint 1 and sensor 2. The temperature decreases so that the comparison element 3 goes out of the limit and starts working in the linear amplification mode j, its output signal starts to decrease proportionally (in absolute value). A decrease in the voltage at the comparison element 3 connected to the output of the input of the second scaling amplifier 8 causes an increase in its gain factor.

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This leads to the smooth inclusion of the integrator 7 in the operation of the PID controller. Differentiator 4 also begins to function, as the output signal of reference element 3 began to vary. The whole operation of the PID controller starts near the predetermined temperature when the reference element 3 comes out of the limitation and starts operating in the linear amplification mode. Since while the comparison element 3 was operating in the limiting mode, a maximum signal was applied from its output to the input of the integrator 7, a decrease in the signal at the output of the comparison element 3 and, as a result, an increase in the gain of the second scaling amplifier 8 causes the input of the adder 9 from the output of the integrator 7 through the second scaling amplifier 8 pos, blunts the signal, which reduces the power supplied to the object of regulation. This signal increases smoothly with a decrease in the signal at the output of element 3 of the comparison, which does not cause an oscillatory process. Differentiator 4 has the same inhibitory effect on the temperature rise process. The output signal of the adder 9 through the actuator 10 considerably limits the power supplied to the regulation object. This greatly slows down the rate of increase of temperature when approaching a given temperature value. Therefore, the output mode - at a given temperature - occurs without. overshoot, asi 1to the bottom. In the course of further work, the PID controller functions as usual, ensuring the required accuracy of controlling the temperature of the object. At the same time, the accuracy of maintaining the temperature of the object by the proposed program temperature controller is higher in a wider range of adjustment temperatures due to the operation of the first scaling amplifier 5 (which is An amplifier with an p-ostro inrgo current with a controlled voltage gain factor and can be performed, for example, on a multiplier). At the temperature of the dynamic tuning of the PID controller, the gain of the first scaling amplifier 5 is set equal to one, therefore at this temperature it does not affect the operation

.PID controller and does not change the accuracy of temperature control. Setting the temperature of an electric furnace other than Ta leads to a change in voltage on the control input 3 of the first scalable amplifier 5 connected to sensor 2 (or setpoint 1) and proportional to its gain, which leads to a proportional change in the differentiator signal applied to the adder 9 4. The coefficient of proportionality is chosen experimentally for a particular type of object of regulation.

If the program has a drastic change in the specified temperature value during its testing, for example, downwards (to switch to a lower temperature), then in the event of a large difference in signals from the setpoint 1 and the temperature sensor 2, the element. 3 comparisons again go into the restriction mode and at its output a maximum (negative or positive) constant signal appears. Because of this, the coefficient

the state corresponding to a higher temperature, its output signal and the output signal of differentiator 4 supplied to the adder 9 have a braking effect on the rate of decrease in the temperature of the electric furnace by supplying some power for heating to it, the regulator begins to function and asymptotically from above temperature at a given level without overshoot. With this inclusion. integrator 7 proceeds smoothly

15 by gradually increasing the gain of the second scaling amplifier 8, which does not cause an oscillatory process. The gain of the first scaling amplifier 5 varies in proportion to the temperature, which leads to a proportional change in the magnitude of the signal transmitted from the output of differentiator 4 to the input of sum 25 of the mat 9, and an increase in the accuracy of the temperature maintained by the regulator. If the programmed temperature change does not lead to the transition element. 3 comparisons to the limiting mode (non-amplification of the second scaling amplifier — 30 large temperature change), then the switch 8 becomes minimal and it offers a program regulator

. Temperatures work like an ordinary PID controller.

significantly weakens the signal from the output of the integrator 7, which is fed to the input of the adder 9. Thus, the integrator 7 is practically turned off from the operation of the PID controller. Differentiator 4 also ceases to function, since the signal on its input does not change. At the input of the adder 9, only the output signal of the linear amplifier 6 is received. This leads to the fact that the power supply is interrupted on the control object and its passive rise occurs. During the cooling process, when the comparison element 3 leaves the restriction mode, the operation of the program temperature controller again becomes similar to that described. Amplification factor35

Claims (1)

Image formula A software temperature controller containing a setpoint adjuster and a temperature sensor connected to the inputs of the JQ comparison element, connected to the inputs of the differentiator, integrator and linear amplifier, the output connected to the input of an adder connected in series with the executive unit: that, in order to increase the point-. the regulator, it contains included between the outputs of the differentiator and the integrator and the corresponding inputs of the second scaling amplifier 50 D adder linear scaling 8 increases, which is why the incoming amplifiers, the control inputs of the adder 9, start to receive a signal rk connected respectively in the cany-from the output of the integrator 7. Begins; le differentiator with sensor output the state corresponding to a higher temperature, then its output signal and the output signal of differentiator 4 supplied to the adder 9 have a braking effect on the rate of temperature decrease of the electric furnace by supplying some power for heating to it, the PID regulator starts functioning and asymptotically from above temperature at a given level without overshoot. In this case, the inclusion of the integrator 7 is carried out smoothly. by gradually increasing the gain of the second scaling amplifier 8, which does not cause an oscillatory process. The gain of the first scaling amplifier 5 varies in proportion to the temperature, which leads to a proportional change in the magnitude of the signal transmitted from the output of the differentiator 4 to the input of the adder 9, and an increase in the accuracy of the temperature maintained by the regulator. If the programmed temperature change does not lead to the transition element. 3 comparisons to limit mode (not 35 Image formula A software temperature controller containing a setpoint adjuster and a temperature sensor connected to the inputs of the comparison element connected to the outputs of the differentiator, integrator and linear amplifier, the output connected to the input of an adder connected in series with the actuator: In order to improve the accuracy of the regulator, it contains included between the outputs of the differentiator and the integrator and the corresponding inputs function differentiator 4. Since integrator 7 has retained its temperature, in the integrator channel - it is from the output of the reference element. Compiled by L. Pentsova Editor 0. Head of Tekhred P. Oliynyk Proofreader L. Bezkid Order 2828 Circulation 656 VNIIPI State Committee for Inventions and Discoveries at the State Committee for Science and Technology CQCP 113035, Moscow, Zh-35, Raushsk. About. 4/5 Production and publishing combine Patent, g, Uzhgorod, ul, Gagarin, 101 Subscription