SU1186498A1 - Device for monitoring press operation - Google Patents

Abstract

A DEVICE FOR MONITORING THE PRESS OPERATION, equipped with a press piston, containing an electric motor current sensor, the first memory element. the output of which is connected to a registering device, characterized in that, in order to increase the control accuracy, it is equipped with an adder, a second memory element, a calculator and an upper position sensor of the press box, the current sensor being connected to the first inputs of the adder and the second memory element, the output which is connected to the second input of the adder, the output of which is connected to the first input of the first memory element, the sensor of the upper position of the pressing area is connected to the input of the calculator, the first output of which is connected to the volt eye input of the second memory element, the second and third outputs are connected to respective other inputs of the adder, and the fourth output i is connected to the second input of the first memory element. (L cx o); cx

Description

The invention relates to the automation of technological processes of pressing building materials and can be used in the production of silicate bricks, ceramic tiles, etc.

The purpose of the invention is to improve the accuracy of control of the press.

FIG. 1 shows a block diagram of an apparatus for controlling a pressing mode; in fig. 2 is a schematic diagram of a calculator (position of a press piston); in fig. 3 and 4, are the time diagrams of the electric motor and device elements.

The device (Fig. 1) contains a press electric motor 1, a press current motor 2 sensor, memory elements 3 and 4, cy.viMBTOp 5, a recording current pressing device 6, a press piston upper position sensor 7 and a press piston 8 calculator 8 input 9 and output. 10-13. Current sensor 2 is made on the basis of a current transformer connected in one of the phases of electric motor 1 and rectifier. Sensor 7 of the upper position of the pressing piston is made on the basis of a kinematically synchronized with the movement of the pressing piston of the limit switch, the response time of which can be adjusted with the help of an adjusting resistance.

The calculator 8 of the position of the pressing port (Fig. 2) is made in the form of a generator 14 clock pulses, counters 15 and 16 pulses, decoders 17 and 18, logic elements AND 19, NOT-AND 20 and 21, and .IL 22.

The device works as follows.

At the moment of time preceding the start of pressing ti (Fig. 3), the current of the electric motor is caused by the idling mode (i.ti). The start of pressing corresponds to the time t2, the end is t.s. The pressing process is most fully characterized by the useful work of pressing, which can be determined with sufficient accuracy from the power (force) - time diagram. The pressing current is proportional to the pressing force. Consequently, the integral of the pressing current without taking into account the no-load current during pressing (ts-12) will characterize the useful work of pressing. In addition, depending on the modes and conditions of operation of the presses in each case, a certain type of control of the press operation is optimal - multi-position, continuous, single-position, i.e., control can be carried out over several press cycles type CMC-152, CM-816).

At the output of current sensor 2, a signal is generated that is proportional to the current of the motor 1 of the press (Fig. 3), which is fed to the information input of the memory element 3

and adder 5. At time ti (Fig. 3 and 4), at output 10 of calculator 8, a enable pulse is generated for recording the signal arriving at the information input of the element

5 3 memories (no-load current). A signal proportional to the no-load current of the electric motor from the output of the memory element 3 is fed to another information input of the su.mmator 5, where it is inverted and subtracted from the signal proportional to the total

0 current. At the moment of pressing, at output 11 of calculator 8, an integration resolution signal is generated.

After the expiration of three cycles of pressing (integration) at the output of the adder 5

 a resultant signal is generated, and output 12 of the calculator 8 is a recording enable signal for this signal, which is fed to the information input and the elements 4 of the memory. At the end of the recording of a new value

The pressing current Q in the memory element 4 at the output 13 of the calculator generates the initial installation signal of the integrating circuit of the adder 5. At time d, the output of the sensor 7 in each pressing cycle generates a signal of the initial installation of the calculator and at the same time input 9 carries out the initial installation of the counter 15 ( and decoder 17). The counter size 15 and the frequency of the rectangular pulses output from the generator 14 are selected taking into account the pressing time (0.7 s).

0 At outputs 10-13 of the calculator 8, control pulses are sequentially generated in accordance with the described algorithm (logical "O).

After pressing from the exit

the decoder 17 to the second input element AND 19 receives the signal "O, prohibiting the passage of clock pulses to the counting input of the counter 15. In this case, the counting of pulses in the counter 15 stops. The counter 15 is returned to the initial state by a pulse at input 9. Next, the process (the next pressing cycle) is repeated. A predetermined number of pressing (for example, three) at the corresponding output of the decoder 18 generates a signal arriving at the inputs of the elements NOT-AND 20 and 21. This signal is permitting for the control pulses produced by the decoder 17 to pass through the elements NOT-AND 20 and 21 These pulses are received respectively at the outputs 13 and 12 of the calculator 8

0 and further to the control inputs of the adder 5. Resetting the counter 16 is performed after counting a predetermined number of pressing cycles, when the corresponding output of the decoder 18 has a signal that is fed to the installation (P) input of the counter 16.

In the device for controlling the pressing mode, the sensor of the position of the pressing piston (the sensor of the position of the upper dead center

piston) is set to a point in time corresponding to time t | in each pressing cycle.

The device has a higher accuracy of control of the pressing mode due to synchronization of the operation of the engine current indicator with the working stroke of the pressing piston, as well as compensation of the no-load current and generation of a signal proportional to the useful work of pressing for the optimum number of pressing cycles.

The economic effect of using the device to control the pressing mode is achieved by improving the quality of the pressed products, as well as increasing the reliability of the pressing equipment due to the stabilization of the pressing force by better controlling the amount of filling of the pressed mass in the mold by the press operator who receives more accurate information on the pressing mode.

figure 2.

Claims (1)

DEVICE FOR MONITORING THE PRESS OPERATION, equipped with a press piston, comprising a motor current sensor, a first memory element, the output of which is connected to a recording device, characterized in that, in order to increase the control accuracy, it is equipped with an adder, a second memory element, a computer and an upper position sensor a press piston, the current sensor being connected to the first inputs of the adder and the second memory element, the output of which is connected to the second input of the adder, the output of which is connected to the first input of the first of the memory element, the upper position of the press piston is connected to the input of the calculator, the first output of which is connected to the second input of the second memory element, the second and third outputs are connected to the remaining corresponding inputs of the adder, and the fourth output _{β is} connected to the second input of the first memory element SB. l fig 1