SU930761A1 - Device for control of operating mode of heavy-current glow discharge set - Google Patents

Description

(54) DEVICE FOR REGULATING THE OPERATION MODE OF INSTALLATION OF HIGH-CURRENT GLOWING

one

The invention relates to electrical engineering and can be used to control the electrical and thermal conditions of a plant in which parts are heated and heat treated using a high-current glow discharge.

A device for automatic control and monitoring of the start-up period and the heat treatment process using a glow discharge, containing an arc frequency detection unit associated with the discharge chamber, a software controller connected to an adjustable power supply, and a controller for the processing mode are known. In the initial processing period, the voltage of the power source rises according to the program set by the software controller. When an arc discharge occurs, the power source is turned off for a time sufficient to deionize the discharge gap. Depending on the frequency of the arcing, the program may remain at the reached level, return to the previous step or to the initial state. At the end of the program

The software controller is turned off, and further processing can be done manually or automatically using the processing mode controller f1.

The disadvantage of this device is that the program flow depends only on the frequency of arcing and does not take into account the rate of change of temperature of the parts, which, as the frequency of arcing decreases, may exceed the limit values at which deformations of parts occur.

Claims (2)

The closest to the invention to the technical essence is a device for controlling the installation mode of a glowing glow containing a differential amplifier, the inputs of which are connected to the setpoint sensor and the temperature sensor, and the output through the second differential amplifier is connected to the input of the current regulator, and the output of the sensor temperature through the amplifier is connected to the second input of the second differential amplifier. In addition, the current regulator is provided with an additional input for connection, for example. 3 to the high-speed switch, which gives out pulses in the event of arc discharges. This device allows products to be heated to a predetermined temperature at a rate not exceeding a predetermined value of 2. The disadvantage of this device is that a differentiator is used to determine the rate of temperature change, which grows very slowly () during the initial processing period. . A device for differentiating variable values is difficult to implement. In addition, differential devices are very sensitive to interference. The aim of the invention is to simplify the circuit and increase the noise immunity of the device. To achieve this goal, the device contains an integrator connected by an input to the output of a differential amplifier, and an output to the first input of the comparison unit, the second input connected to the output of the temperature sensor, and the output to the input of the logic unit, the first output of which is connected to the second input of the second differential amplifier, and the second - with the control input of the integrator. . FIG. 1 is a block diagram of the device; in fig. 2 - time characteristics; in fig. 3 - the characteristic input and output logic unit. The device contained a differential 1 (1), the inputs of which are connected to the outputs of the setpoint 2 and the temperature sensor 3, and the output to the first input of the second differential amplifier 4 connected to the input of the current regulator 5, connected in series to the integrator 6, which is connected with the output of the differential amplifier I, the comparison unit 7 whose second input is connected to the output of the temperature sensor 3, and the logic block 8 connected by the first output to the second input of the differential amplifier 4, and the second to the control input dy integral torus 6. The operation is as follows. In the initial state, the output of the current regulator 5 sets a zero signal or a signal corresponding to some initial value of the discharge current. Since the mismatch between the set and the actual temperature is large, a constant signal will be set at the output of the differential amplifier 1 corresponding to the saturation voltage of the amplifier. This signal, arriving at the input of the integrator 6, causes a linear increase of its output signal and y at a speed corresponding to a given value of the heating rate, which is determined by the settings of the regulator. At the same time, the output of the regulator 5, made in the form of a PI controller with a long integration time, under the influence of the output signal of the differential amplifier 4 will also increase, causing the products to heat up. If at time ts signal U.J. proportional to the temperature of the products will become greater than the signal UtjCUg O), which will happen when the heating rate of parts exceeds the specified value, then the first output of the logic unit 8 will receive a 1Gd signal, 1X-which, entering the input of the second differential amplifier, will cause a decrease in its output signal and a decrease in the rate of increase or decrease in the output signal of the current regulator 5. In the initial processing period, due to the high frequency of arc discharge, the heating rate can be much lower given the maximum speed, resulting in a signal Uy will be much larger than the signal U. In this case, until the signals U c and U rj are equal, the products can be heated at a speed greater than the specified one. To avoid this, logic block 8 is designed so that when the signal Uj- is exceeded, at the output of the comparison circuit of a given value and η c (time point tj), the signal 1} outX2-2 appears on its second output, arriving at the control input of integrator 6, reduces the rate of increase of signal 1 (or changes the sign of speed) until the output signal of the comparison circuit Uj is reduced to a value of 1) 2 (time point is 12). Thus, uncontrollable rate of change of temperature of parts is possible only when the difference signals. which can be done enough. small. The pattern of change of the signal U l in this case is shown in fig. 2. When the preset temperature is reached, the signal from the output of amplifier 1 will become equal to O, which causes the termination of the growth of the signal from the output of the integrator. The device allows to limit the heating rate, without resorting to the operation of signal differentiation, proportional to temperature, which increases the noise immunity. Apparatus of the Invention A device for controlling the mode of operation of a nightglow-discharge unit, comprising a differential amplifier, the inputs of which are connected to a sensor and a temperature setting device, and an output to a first input of a second differential amplifier, the output of which is connected to an input of a current regulator of the installation, that in order to increase noise immunity, the device contains an integrator connected by an input to the output of a differential amplifier, and vi {by a move - to 9 6 the first input of the comparator unit, the second input which is connected to the output of the temperature sensor, and the output to the input of the logic unit connected with the first output to the second input of the second differential amplifier, and the second output to the controlling input of the integrator. Sources of information taken into account during the examination 1. Swiss patent N 349283, cl. 21 h 16/60, 1963. 2. USSR author's certificate M 753373, cl. H 05 B 7/16, 1976. j-7 % / GC IV UftiK.1 Fke.