SU1674087A1 - Temperature controller - Google Patents

Abstract

The invention relates to automation, in particular to devices for temperature control, and can be used in thermophysical instrument making, as well as in other areas. The aim of the invention is to improve the accuracy of the device. The device for temperature control contains a temperature sensor 1, included in the shoulder of the measuring bridge 2, the key 14, the adder 16, the temperature sensor 3 connected to the first input and the comparator input 12 connected to the output of the generator a sawtooth voltage 4, an input connected to an output of a pulsed power supply 6 and an input of a pulse shaper 5, as well as a thyristor power amplifier 7, consisting of an optocoupler 8, a current-limiting resistor 9, a rectifier 10 and a triac 1 1, the input of the thyristor power amplifier 7 is connected to the output of the comparator 12, a heater 13 is connected to the output circuit of the thyristor power amplifier 7, a control pulse shaper 17, made in the form of serially connected power amplifier and a shorter shortened front and rear edges of the pulses, made in the form of two waiting multivibrators 19, 20 and adder 21 on the cell 2 AND-NOT, as well as the sample and storage unit 15 connected between the output of the measuring bridge 2 and the second input of the adder 16, and the importer sov 5 configured as a frequency divider 10, which is connected to the output of the power amplifier input control pulse shaper 17, and the output of the shortened by rising and falling edge pulses is connected to the control input of the sampling unit and a storage 15. The 2-yl.

Description

The invention relates to automation, in particular to devices for temperature control, and can be used in thermophysical instrument making, as well as in other areas,

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

FIG. 1 is a block diagram of a device for temperature control: FIG. 2 is a diagram of his work.

The device for temperature control includes a temperature sensor 1 included in the shoulder of the measuring bridge 2, a temperature setting device 3, a sawtooth voltage generator 4, a pulse shaper 5, a power supply pulse unit 6, a thyristor power amplifier 7 consisting of a line 8, a current limiting regulator torus 9, rectifier 10 and triac 11. comparator 12. heater 13, key 14, sampling and storage unit 15, adder 16 and control pulse shaper 17, made in the form of series-connected power amplifier 18, bodies 19 are shortened on the leading and trailing edges of the pulses on the two waiting multivibrators 19 and 20 and on the adder 21 on the cell 2I – NO.

The device works as follows.

A sinusoidal signal with a frequency of 50 Hz (Fig. 2a) is fed to the input of a pulsed power supply unit 6, where 100 Hz clock pulses are formed (Fig. 26), and the leading edge of these pulses strictly coincides with transitions through the zero voltage. These clock pulses are fed to the input of the sawtooth 4 generator and to the input of the driver 5 pulses. From the output of the sawtooth generator, a signal is removed (Fig. 2e) whose amplitude is proportional to the accuracy of temperature maintenance and is fed to the input of the comparator 12

From the output of the pulse generator 5 to the input of the control pulse generator 17, a pulse sequence (Fig. 2c) is received, from which, by delaying the leading and trailing edges, control pulses (Fig. 2d) are formed by block 15. This same pulse sequence (Fig. 2c), amplified in power, controls key 14, i.e., pulse voltage is generated from the mains voltage (Fig. 2a) (Figs. 26, c. d, e), synchronized with each other and zero crossing voltage, while the temperature memorization cycles

and the operation of the heater 13 is separated in time.

On the measuring bridge 2. one of the arms of which includes the sensor 1. receives powerful pulses (Fig. 2c). From the output of the bridge 2, the pulses, whose amplitude is proportional to the current temperature in the thermostatically controlled volume, arrive at the input of block 15. The command to memorize comes with a delay relative to the information pulse from the bridge, this eliminates the influence of transients and memorizing the real value of the current temperature

After the block of sampling and storage, the circuit switches to the operating mode on direct current.

The DC signal from the output of the sampling and storage unit 15 is fed to the adder 16. where it is compared with the voltage of the temperature setting unit 3 (Fig. 2e). At the output of block 16, a slowly varying relative to zero level is obtained by voltage D U Uz - LU. where Di is the error voltage; Uz is the set point voltage; UT is the voltage proportional to the current temperature of the thermostatically controlled volume.

Voltage D U is added to the sawtooth voltage (Fig. 2e) on the resistive adder and the resulting signal (Fig. 2g) controls the operation of the comparator 12. The switching of the comparator occurs strictly synchronously with the transitions through the zero voltage. Since the comparator controls the operation of the thyristor power amplifier 7, the heater 13 switches with zero voltage on it, without causing interference and without affecting the accuracy of temperature maintenance. The input of the thyristor amplifier 7 receives a width-modulated signal (Fig. 2c) controlling the operation of the heater 13, and the power released by the heater depends on the number of network pulses arriving at the heater for each elementary control cycle of 100 ms.

Claims (1)

Invention Formula A temperature control device containing a temperature sensor included in the measuring bridge, the diagonal of the power supply includes a switch, an adder, the first input of which is connected to the temperature setpoint, and the output includes a comparator input connected also to the output of the sawtooth generator, connected with the output of the switching power supply unit and the input of the pulse former, as well as a thyristor power amplifier, connected to the output of the comparator, the output circuit of the thyristor power amplifier includes En heater, characterized in that, in order to increase the accuracy of the device, it contains a control pulse shaper, made in the form of a series-connected power amplifier and shaper shortened on the leading and trailing edges pulses, as well as a sampling-storage unit, connected between the output of the measuring bridge and the second input of the adder, the driver of the pulses made in the form of a frequency divider, the output of which is connected to the input of the amplifier of the driver of the control pulse generator, and the output of the driver of shortened on the front and rear edges The pulses are connected to the control input of the sampling and storage unit.  t Phage 2