SU1444436A1 - Arrangement for controlling multimotor d.c. drive of paper-making machine - Google Patents

Abstract

The invention relates to pulp and paper and woodworking industry and improves the quality of the paper web by reducing its obryshov and thickness, which is achieved by introducing a speed derivative control node, a digital-analog speed reference converter, a zero-level relay, and a shutdown relay with controllers entered. n keys that connect the outputs; n digital-to-analog converters of the speed of drive sections with zero bus. In the device, the digital circuit operates only in a small range of the error and turns off automatically when the operator intervenes to change the speed of the sections by the setting potentiometer of the analog controller. 1 il. 3 (L

Description

The invention relates to the manufacture of paper- and board-making machines (PM and CMM) and may find application in the control of multi-coupled electric drives.

The purpose of the invention is to improve the quality of the paper web by reducing its breaks and thickness,

The drawing shows a diagram of the device.

The device consists of the following components

The analog part consists of a motor 1, ..., 1, a thyristor converter 2 ,,,,., 2d, controllers 3, ,, .. and speeds 4,. .., 4., adders .. ,, 5 analogue controllers (AP) 6 ,,,,., 6 „and nodes 7.5 ,. 7j, assignments and memorizing speed ratios (potentiometers), tachogenerators 8,. .., 8у ,, converters 9.5, .., 9п speed sensors (alternator with resistor voltage divider).

The digital part includes i; digital switch (CPU) 10, digital-analog converter (D / A) 1 speed settings and digital-analog converters 12,, „, 12, 12“ speeds of the drive sections according to the number of sections of the PM, digital device 13, derived from multiplier 14, dryers .15 and 16, memory block 17, integrator 18, dw / dt control node 19, acting on keys 20 and 21, control signal zero relay 22, toggle switch 23, relay

24

24h shutdown interface

25 and display device 26 and communication 27 for connecting standard peripheral devices: a printing 28 and a displaying 29 devices

The device operates as follows.

The start of the electric PM drive is performed from CPU 1-0, which iiepes of DAC 1 issues tasks to analogue controllers 6 (, .., 6 "of paper machine sections. The same task from CPU via communication interface 25 is sent to multiplier I4 and digital adder 16 devices 13. Simultaneously information about the speed of sections from sensors

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3. The control node of the derivative dw / dt controls the magnitude of the derivative and affects the keys 20 and 21. In the starting state of the keys, the key is: 20 - on, 21 - off. For the digital device 3 to work, the toggle switch (Q2) 23 must be turned off (open circuit) and contacts

10 (Q3,, ..., аЗ „) 32 4, ..., 32 relays 24,,. . .

24 outage must be open,

five

0

five

five

0

0

0

At start-up, the multiplier 14, having received the setpoint signal N, multiplies the value by the coefficient K, which takes into account the individual characteristics of the section drive (reduction coefficient, etc.) The value of KN, each section is fed into the adder 15, from which the actual speed w is subtracted. The difference A.N. is stored in the memory block 17, since the key 20 is closed and 21 is closed,

In the steady state operation of the system of the BDM electric drive, the node 19 of the control for the derivative opens the keys 20 and closes the keys 21 by connecting the digital control. Here, the value AN j is used as a reference for the adder 16. The adder 1 6 performs algebraic addition operations of the quantities ANj - (N - w). The resulting value of bWp is supplied to the datagrator 18, which forms the control action NU. co-reversed digital control loop.

The keys 20 and 21 switch off the adder 16 and connect the memory block 17 to the adder 15 for the period of processing the control actions from the CPU 10 or the potentiometer 7, ..., 7 with analogue regulators 6j,. . ., 6., For this period, the digital device from the mode of the controller is transferred to the receiver mode of information about the change in the steady state mode of the section. Upon completion of all transients and upon reaching the new steady-state speed mode, the dw / dt control unit of the derivative switches the keys 20 and 215 thereby automatically turning on the digital

impulses through conversion

drivers, .., 31 code - number and interface 25 of communication also enters the adders 15 and 16 and the node 19 of the control of the derived digital device

adjustment.

The digital control is completely turned off by closing the toggle switch (Q2) 23 of the input signal circuit of the zero-level relay 22. With

signal Nn, equal to O, relay 22 generates signals for relays 24, ..., 24., disconnection, which by its contacts 32,. . ., 32 short-circuits the DAC 12 (, ..., 12 "sections, thereby allowing the digital control to be completely disconnected from the drive system. The zero signal level (Ni 0) is set using the PCC (7, ..., 7J.

A digital device circuitry provides output channels for connecting via standard interface 25 standard peripheral devices: teletype 28 and display 29. During operation of the paper machine, digital device 13 sends out to specified peripheral devices, and also receives commands to output information from them - Dialog mode.

At the same time, information about the target and actual speed of the sections is supplied to the display device 26.

Using the proposed device, measurement of the drive's rotational speed for adjustment and indication, calculation of the high resolution of the value for the slave analog controller, calculation of the correction effect based on the comparison of the digital reference with the actual value and integration of the deviation, conversion of the reference signals and correction to the analog form, their summation and memorization, and then input into the analog controller, indication of the set and actual speed values and the ratio of the speeds of the sections, registration of the length, area of output, electric drive operation time and its diagnostics, metering of electricity consumption, control of technological parameters, automatic switching from digital control to analog and vice versa, docking with a higher level automation system , as well as the possibility of independent operation of individual parts of the system.

In this way, the reliability of the control system of the electric motor machine BDM as a whole is increased by the availability of information and diagnostics of the operating modes of the electric drive, as well as the use of

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analog means for speed correction. At the same time, at the same mechanical equipment, to obtain products with a mini-fi weight of 5 square meters, to reduce the time for setting speeds after the machine stops and when changing the product mix, HS as a result, to increase productivity.

Claims (1)

Invention Formula The control device of a multi-motor electric permanent 15 current paper machine with five-dimensional converters, containing a digital speed controller, a digital switch connected to the communication interface buses, and an 20 tax controllers, nodes for setting and storing the speed with P.-1 adders, digital-analogue speed drive transducers for the drive section, code transducers — for example, for speed feedback circuits in analog controllers, code transducers — a number for a circuit x feedbacks on speed in a digital controller with impulse sensors, as well as display elements of speed modes and speed ratios associated with the communication interface of a digital controller, characterized in that 35 improving the quality of the paper web by reducing its obryshov and thickness, it is additionally equipped with a node for controlling the speed derivative, a D / A converter 40 speed settings, zero-level relays, n trip relays with entered controllable keys, through which the outputs of n digital-analogue speed converters are connected at 45 water sections, while the inputs of the speed derivative control unit are connected to address buses and communication interface data, The outputs are connected to the inputs of the corresponding contactless 5Q keys of the digital controller, the digital-analog converter of the speed reference is connected to the digital switch by the input, and its output is connected directly to the inputs 55 of all n analog controllers, a zero-level relay input through a key is connected to a digital controller, and its outputs are connected to data buses and communication interface addresses to which a 51.5 / 4 BP connect The inputs of the trip relay are also connected, and their outputs are connected to the controllable keys, the output of the first task node and the speed ratio storage is directly connected to the input of the first analog controller and to one of the inputs of the first summer adder of the second controller, the second input of the first summer adder is connected io out 366 The second node assigns and memorizes the speed ratio, and the output of the first adder is connected to the input of the second analog controller and to the first input of the (n-1) th adder, the second input of which is connected to the output of the nth task node and the output n 1 adder is connected to the input of the nth analog controller.