SU943665A1 - Program control device - Google Patents

Description

(B) DEVICE FOR PROGRAM REGULATION

The invention relates to software automatic control of the parameters of various technological processes, in particular, the temperature during the drying of capillary porous building materials, and can be used in various industries, such as the building materials industry. A device for temperature control is known, comprising a heater, an actuator, amplifiers, a temperature sensor, a comparison unit, differentiation units, a temperature setpoint device, an adder and a power sensor. The operation of the device is based on comparing the temperature of an object with a given one and controlling the error signal of the operation of the executive device. In addition, the device contains an additional channel for regulating the power of the heater. The disadvantage of the device is its high accuracy; which is associated with the use of analog quantities in the specification and comparison, as well as with the differentiation of analog quantities. It is also known to have a temperature control device comprising a thermocouple, a comparison unit, a setting unit, a switching unit, a constant voltage source, a switch, a heater, an amplifier, a multivibrator. The operation of the device consists in comparing the sensor and setpoint signals and controlling the error signal with the thyristor key. In addition, there is an additional channel that ensures the operation of the device in a steady state, controlled by a thyristor switch using a pulse sequence with a constant duty cycle 2. The drawback of the device is the low accuracy due to the ana. the denial form of representation of the signals, and the relative complexity due to the presence of two control devices.

The closest in technical essence to the present invention is a device for software control containing a pulse generator connected to a memory unit and a switching element that is connected to an actuating unit controlling the heater operation, a temperature sensor connected to another input of the memory unit and comparison elements, to the other input of which the program master is connected, and the output is connected directly to the execution unit and through the delay element to the memory unit whose output is dinene with another input switching element. The reference element compares the setpoint parameter settings of the setter with the actual value from the sensor. The executive unit switches on or off and on or off the power of the heater. The generator, the memory block and the switching element provide a programmed temperature change, and the commands corresponding to the program change points are supplied to the memory block from the delay element Z.

i The disadvantage of this device

is a relatively small execution accuracy of a program associated with the use of analogue setpoints and a reference element.

The aim of the invention is to increase the accuracy of the device.

The goal is achieved in that the device contains analog-digital and digital-analog converters, and the software master is designed as a pulse distributor connected to OR elements, the output of one of which is connected to the input of the memory block and the input of the delay element connected by the outputs with the corresponding inputs of the comparison element, the inputs of the other OR elements are connected to the inputs of the switching element, and the temperature sensor is connected via an analog-to-digital converter to the comparison element whose output go through a digital-to-analog converter connected to the second input of the execution unit.

The introduction of a digital-to-analog converter (D / A converter), an analog-to-digital converter (A / D converter), and the indicated compounds can significantly increase the program flow.

Figure 1 shows the block diagram of the device; figure 2 is a graph of the adjustable parameter (temperature)

The device contains a pulse generator 1, connected to the input of the software setpoint generator 2, which can be made in the form of a pulse distributor 3, to the outputs of which are connected the elements OR, 5,6. The outputs of the elements and 5 are connected to the inputs of the switching element 7, which can be made as an RS flip-flop, the output of the element OR 6 is connected to the memory block 8 and the delay elements 9, the temperature sensor 10 is connected to the analog-to-digital converter (ADC) 11. The outputs of the memory block 8, the A / D converter 11 and the delay element 9 are connected to the comparison element 12, the outputs of which are connected via a digital-to-analog converter (D / A converter) 13 to the input of the execution unit I, which can be implemented as a key 15. the adder 16 and the voltage source 17- The output of the switching element 7 is connected to another input of the execution unit 1, and the output of the execution unit I is connected to the heater 18 located together with the sensor 10 in the control object 1

The operation of the device is based on approximation of the program by the acceleration (heating) and deceleration (cooling) sections of the control object 19.

The device works as follows.

Claims (2)

i In the initial state at the output of the switching element 7 - O, the key 15 is open, i.e. the heater 18 is turned off, the reference element 12 is locked, the output voltage of the DAC 13 is zero. The first pulse of the generator 1 sets the distributor 3 to the state when the signal that sets the switching element appears at the output of the element OR 4. This opens the key $ 1 and the voltage of the source 17 is applied to the heater 18. The output value increases with time. At time t, preceding the approximation node (moment t, a pulse appears at the output of the element OR 6. This pulse from the memory block 8 extracts the code N directly proportional to the value of the parameter at point A. After a time determined by the delay element 9 and comparing the code from the memory block 8, the comparison of the N code and the Mule code corresponding to the actual value of the parameter at time t is allowed.An element of comparison 12 determines not only the magnitude of the difference NN, but U its sign. J three options are possible (point a). In this case, the output voltage of the D / A converter 13 is zero and the heater is fed to the source 17 for the heater, i.e. the program goes through section a-b (Fig. 2) .0 (point a), In this case, the voltage at the output of the DAC 13 is denoted by the magnitude, for example, by the sign, proportionally to the difference between the codes, and the parameter differences at the points a. The resulting voltage at the output of the adder 16 decreases and the program goes through section a-b. the voltage supplied to the heater 18 is proportional to the temperature difference at the points a and a, and the interval t2-t is fixed, t at the time t parameter adjustment will come to approximate Node. . fL-N.n70 (dot). In this case, the voltage at the output of the DAC 13 is positive in sign, and in magnitude it is proportional to the temperature difference at the points a and a. For the reasons stated above, at time t, the adjustable parameter will be at points-5. At the same time point (t2), a pulse appears at the output of the element OR 5 which sets the switching element 7 to O, thereby stopping the supply of voltage to the heater 18, i.e. the program goes along the cooling curve (-c points), and at time t, the pulse appearing t is a pulse, with the output of the element OR C, again sets the switching element 7 to 1. It is necessary to withstand the time interval for exact program correction for all nodes, the approximation of a node type is the same. This condition is ensured by the appropriate connection of the outputs of the distributor 3 to the elements OR j and 5. By increasing the number of points like point a, you can adjust the program 9, which means 5 more than once, thereby increasing the accuracy of the program. The proposed device, which has significantly broader possibilities in terms of the variety of programs implemented, makes it possible to significantly improve the program execution accuracy, which in general is a number of processors (drying processes of capillary-porous building materials, diffusion processes, growing single crystals). affects the quality (percentage yield) of products. A software control device comprising a pulse generator, a software driver, a switching element, to the output of which a heater is connected through the execution unit, a delay unit, a comparison element and a temperature sensor, which, in order to improve the accuracy of the device, includes analog-to-digital and digital-to-analog converters, and the software setter is designed as a distributor and pulses connected to OR elements, the output of one of which is connected the input of the memory unit and the input of the delay element connected by the outputs with the corresponding inputs of the comparison element, the inputs of the other elements OR.connected to the inputs of the switching element, and the temperature sensor is connected via an analog-digital converter to the comparison element whose output is through a digital-analog converter connected to the second input of the executive unit. Sources of information taken into account in the examination 1. The author's certificate of the USSR If 365691, cl. G 05 D 23/19, 1973. 2. USSR author's certificate H-398933, cl. G 05 D 23/19, 19733. USSR author's certificate No. 483660, cl. G 05 O 23 / 1S, 1975 (prototype). Tt ti fr it t, c Fm.g