SU1488763A1 - Temperature controller - Google Patents

Description

The invention relates to devices for temperature control according to the program nd can be used to control temperature pe2

press of heating devices. The purpose of the invention is to improve the accuracy of regulation. The device for temperature control contains temperature setting unit 1, · transducers' 2 and 3 object temperature and heater-to-voltage temperature, comparison units 4 and 5, memory blocks 6 and 7, PWM 8, power amplifier 9, driver 10 control pulses and comparator 11 that displays the "Device Ready" mode. The device allows to smoothly turn on the heater to the minimum power and to produce heating taking into account the dynamic parameters of the heater.

2 Il.

8 C „, 1488763

The invention relates to devices for temperature control according to the program and can be used to control the temperature $.

the mode of heating devices used both for production and technological purposes, and for scientific research.

The purpose of the invention is to improve the accuracy of temperature control in a given interval.

FIG. 1 shows a device for temperature control; in fig. 2 - diagrams of his work. 15

The device for temperature (FIG. 1) contains a temperature setting device 1, a measuring transducer 2 of an object temperature into voltage, a measuring transducer 3 temperature of a heater into a voltage, first 4 and second 5 comparison units, first 6 and second 7. memory blocks, pulse width modulator (NIM) 8, power amplifier 9, driver 10 25

control pulses and comparator 11.

The device works as follows.

Object temperature and temperature. 30 heater is converted to signals in the form of voltages and ₂ and and _? . converters 2 and 3, respectively, these signals arrive at blocks 4 and 5 of the comparison (Fig. 1), where 35 comparisons take place and ^ mismatch signals are generated and ₄ and ₆ . At the moment of time (Fig. 2a), the device turns on, the temperature setpoint device 1 generates a signal at the output of 40 as a voltage, and. Moreover, the temperature setting is carried out by a digital code, which is converted in accordance with the temperature setter characteristic recorded in the converter '45 of a given number 1-1 (Fig. 1), into a new one, and with the help of a DAC 1-2 generates a voltage and ₄ ( figa).

Thus, a linear characteristic of the setpoint temperature is performed. The setpoint voltage C <is compared with the voltage and _r and the unbalance signal Cf converts the pulse-width modulator (PWM) 8 to the maximum on-duty ratio (fig.2b). Since c. the time of switching on the device at the output of blocks 6 and 7 of the voltage memory ϋ ₆ and and ₇ are equal to zero (FIG. 2g), amplifier 9

33 ⁴

power generates at the output the supply voltage of the heater C, thereby smoothly turning on the heater, the starting currents are reduced and the reliability of the device increases.

With increasing temperature of the heater, the voltage υ _χ and and ₅ grows at the output of converter 2 and 3 ^ the comparison unit 5 performs a continuous comparison of voltages and _b and _s (fig.2e) and at the time from the falling edge of the PWM signal 8 driver 10 on the second output (Fig.2d) produces a control pulse C ^ _o , recording the output state of the comparison unit 5 5 to the output of memory block 7. An increase in voltage and ₇ causes an increase in the supply voltage of the heater C ^, which, in turn, causes an increase in the rate of rise of the temperature of the heater and thus the output of block 9 is set to 1C _Mo1X .

At time point C ₃ from the leading edge of the pulse, the driver 10 is pulse and ₈ records the current state of the output of the converter 3 to the output of memory block 6, at this point the voltage and. ₅ = ϋ ₆ and at the output of the comparator, the voltage drops to zero (Figure 2e). As the temperature of the heater increases, so does the voltage and _h increase, which causes an increase in the voltage Ts _? when υ ₉ = const.

At the time from the trailing edge of the pulse, a write pulse is generated and, _o (fig.2d), which captures the current voltage value at the output of memory block 7 (fig.2g). Thus, at the output of block 7, the voltage C ^ is formed, which is proportional to the rate of rise of the temperature of the heater during active activation of the heater with pulse-width control.

Voltage and _{7 is} fed to the input of unit 4 of the comparison, where the comparison of the voltages and ", and ₂ and and ₇ according to the expression

and, - and ₄ - and ₈ = o, (P

those.

and <= and _r + and ₀ (2)

As soon as the temperature of the object approaches the set point, it is executed

expression (2), and at the output of the comparison unit voltage is exceeded. and ₄ , which reduces the duty cycle of switching on PWM 8, the rate of increase of the heater temperature decreases, while the time during which the heating rate changes occurs decreases. All this leads to the fact that the voltage and ₇ at the output of the memory unit 7 decreases (Fig. 2g), which causes a decrease in the voltage value (Fig. 2c). As a result, the voltage and, tends to

and ₇ - "0, a and _z =>. The voltage and _{7 are} fed to the input of the comparator 11, where it is compared with the reference voltage and _pores (Fig. 1), and as soon as ₇ "0 and a = ₁ , the comparator 11 (Fig. 2h) triggers and a signal appears at ₂ about the output "Device readiness", indicating that the object has reached a predetermined temperature level.

Due to the fact that the device 25

It operates in a wide range of temperatures, depending on the set temperature, a correction occurs and _9} leading to the exclusion of emissions for overshoot and an increase in the accuracy of maintaining the temperature at a given level.

Claims (1)

Claim Thames Control Device perature containing serially connected measuring transform 1488763 an object temperature to voltage detector, a first comparison unit, a control unit and a power amplifier, as well as a heater-to-voltage temperature measuring transducer, a second reference unit and a temperature setter, characterized in that the device contains two memory blocks and driver of control pulses, while the control unit is made in the form of a pulse-width modulator, 15 and the power amplifier - with the ability to change the transmission coefficient, and the output of the setter The temperature is connected to the second input of the first comparison unit and to the correction input of the minimum transfer ratio of the power amplifier; output with information input of the second memory block, output connected with the third input of the first comparison element and input of the transmission coefficient control of the power amplifier, output One pulse-width modulator is connected to the input of a driver for control pulses, the outputs of which are connected to the control inputs for overwriting memory blocks. 1488763 P "S ---- ---- c? and? ---- V ί / g ^ ^ν ι and ^C ΠΠΠΠΠΠΙ ^Y Chl G, - - - e * III 1 1 1 1 1 _τ ι [/ *, I 0 ¹⁰ 1 1 1 1 1 1 1 1 _τ R 1 ~ * _c ^υ №4№ | - * —V—, / FIG. 2