JPH0890038A - Looper tension control method of metal strip - Google Patents

Abstract

PURPOSE: To secure the stable looper tension at abnormal time by switching the looper tension control from tension control mode to electric current control mode in the case abnormality is generated in tension measured value. CONSTITUTION: A metal strip S is introduced into a deflector roll 11 and is in a looper. At normal case, a speed controller 14 and electric current controller 15 are sequentially controlled by the control signal ΔT of a tension controller 13 so as to keep a tension of the strip S is constant. When a abnormal discrimating device 21 discriminates the signal of tension meter 12 of defector roll 11 as breakage, a switching relay 22 is actuated to turn contacts 22a, 22c to ON and contacts 22b, 22d to OFF and then the output of tension controller 13 is interrupted. A tension setting value Ts is inputted in a tension/electric current transforming device 23, an electric current command value Is* is outputted to an electric current controller 15 as a new electric command. By this method, the secondary breakage in looper is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a looper tension control method for a metal strip in a continuous processing line equipped with a looper such as a continuous annealing equipment.

[0002]

2. Description of the Related Art For example, in a continuous annealing equipment, a continuous processing line such as a plating line, a pickling device, etc.,
A looper as shown in FIG. 4 is provided for continuously passing the metal strip. That is, the inlet looper 2 is provided on the upstream side of the continuous processing apparatus 1 such as continuous annealing equipment.
Further, output loopers 3 are provided on the downstream side.

A plurality of rolls 4a, 4b, 5a, 5b are vertically arranged on the entrance looper 2 and the exit looper 3, respectively, and a metal strip S is sequentially wound around these rolls 4a, 4b, 5a, 5b. The lower rolls 4b and 5b are fixed (hereinafter referred to as fixed rolls), and the upper rolls 4a and 5b are fixed.
The carriage a can be integrally lifted and lowered by the carriages 6 and 7 (hereinafter referred to as a movable roll). In the figure, 8 is a drum for moving up and down the carriages 6 and 7 via wires 9, 10 is a bridle roll, and 11 is a deflector roll.

With the above construction, the fixed rolls 4b and 5b and the movable rolls 4a and 5a are controlled by rotating the drum 8 and controlling the elevation of the carriages 6 and 7.
Since the distance between and can be changed, the storage amount of the metal strip S can be controlled. by this,
For example, it is possible to continuously feed the metal strip S to the continuous processing apparatus 1 even during welding or when stopping the threading from the entry side for cutting.

By the way, the case of controlling the tension of the looper used in such a continuous processing apparatus 1 will be described with reference to FIG. FIG. 5 shows an example of only the entrance looper 2. That is, the tension measurement value T _R of the metal strip S detected by the tension meter 12 attached to the deflector roll 11 is input to the tension control device 13, and the tension deviation ΔT is calculated by comparison with the tension set value T _S. Input to the device 14 and compare and calculate with the line speed setting value V _S to obtain the current command value I
_It is input to the current control device 15 as _S. Then, by controlling the control power supply device 16, the carriage lifting motor 17 is controlled. The drum 8 is rotated by the carriage lifting motor 17, the winding amount of the wire 9 is controlled, and the tension of the metal strip S in the looper 2 is kept constant.

The rotation speed of the carriage lifting / lowering motor 17 is detected by the pulse transmitter 18 and fed back to the input side of the speed control device 14, and a part of the output value of the speed control device 14 is drooping compensation circuit 19. Is compared with the droop set value D _S, and the deviation value is fed back to the input side, whereby drooping compensation is performed. Further, the output current from the control power supply device 16 is detected by the current detector 20 and fed back to the input side of the current control device 15.

[0007]

However, in the continuous processing line in which the looper tension control is performed as described above, at a non-steady state such as when the metal strip S breaks or when the tension meter 12 becomes abnormal. Even so,
There is a drawback in that the usual tension control in the system is continuously performed, which causes the following problems. Especially in the case of the number of strands is large looper, when tension measured value T _R such at break occurs is decreased, despite the tension there plate at most in the looper is ensured,
The tension of the metal strip S in the looper is increased to become over tension. In addition, if fragments of the metal strip S are scattered and placed on the tensiometer 12, the tensiometer will be affected by its own weight and impact.
Since the measured value of 12 increases, the control system operates to control the tension in the looper to decrease, which causes a problem such as sagging of the plate in the looper. It is difficult to install another tension meter inside the looper, and the tension inside the looper is controlled by the tension meter installed outside the looper and close to the looper. In such a non-steady state, there is a problem that the tension inside the looper does not match the tension measurement value of the controlled object.

The present invention solves the problems of the prior art as described above, and provides a method capable of performing stable looper tension control of a metal strip even when the measured tension value is unsteady. The purpose is to provide.

[0009]

SUMMARY OF THE INVENTION The present invention detects the presence or absence of an abnormality in the controlled tension measurement value in a continuous processing line in which the looper tension of a metal strip is controlled using a tensiometer, and the tension measurement value is detected. When there is an abnormality in the looper tension control, the looper tension control is switched from the tension control mode to the current control mode.

[0010]

[Operation] According to the present invention, when a metal strip breaks in the looper or an abnormality occurs in the tensiometer, a breaking signal or a tensiometer abnormality signal corresponding to those phenomena is output. Since the looper tension control is switched from the tension control mode to the current control mode by the signal of, the stable tension in the looper can be secured.

[0011]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic diagram showing an embodiment when the method of the present invention is applied to an entrance looper. In the figure, the same members as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted. In the figure, reference numeral 21 denotes a non-steady-state determination device for detecting and determining an unsteady state such as breakage, to which a measured tension value T _R and a set tension value T _S are input. Reference numeral 22 is a tension control / current control mode switching relay that operates according to the output signal from the non-steady-state determination device 21, and has four contacts 22a, 22b, 22c, 22d.
It has.

Reference numeral 23 denotes a tension / current converter for converting the tension set value T _S input via the contact 22a into a current, and a current command value I _S ^* (A) according to the tension set value T _S (kgf). It functions as a current control mode by converting to. Reference numeral 24 is a ratio setter for setting the ratio constant k, and has a function of applying a static tension lower than the tension during operation during non-steady state to adjust to an optimum tension. Reference numeral 25 is a first ramp generator that prevents a problem due to a sudden control response by changing the output stepwise according to the input even if the input value switches in steps, and the signal is current control. Provided on the input side of the device 15.

A second ramp generator 26 has a function similar to that of the first ramp generator 25. The normal drooping set value D _S is supplied via the contact 22b and the drooping set value D _S is supplied via the contact 22c. The maximum set value D _MS is input, and its output signal is given to the drooping compensation circuit 19. The remaining contacts 22d are connected to the tension controller 13 and the speed controller 14 respectively.
Incorporated between and.

Therefore, when the normal looper tension control is normal, it is in the tension control mode, the contacts 22a and 22c are off and the contacts 22b and 22d are on, and the speed control is performed by the control signal ΔT from the tension controller 13. The device 14 and the current control device 15 are sequentially controlled. Then, when the occurrence of breakage is detected by the non-steady-state determination device 21, the tension control / current control mode switching relay 22 operates to switch to the current control mode, and the contact 22
a, at the same time contact 22b Turning on 22c, 22 d are turned off, and inputs the tension setting value T _S to the tension / current converter 23 as well as blocking the output of tension controller 13. And
The tension / current converter 23 outputs the current command value I _S ^* to the current controller 15 as a new current command.

On the other hand, the drooping compensation circuit 19 has a normal drooping set value D _S to a drooping maximum set value D.
_Switch to _MS . As a result, the drooping amount can be increased and the speed command from the speed control device 14 can be made dull, so that the control system can be a circuit in the current control mode. Fig. 2 shows the change over time in the conventional example in which the tension control mode was continued at the time of detecting the breakage. From this figure, it is likely that a secondary breakage easily occurs due to the influence of a large change in the tension measurement value. You can see. On the other hand, FIG. 3 shows an example of the present invention in which the current control mode is switched to when a break occurs, but it is possible to secure a stable tension in the looper regardless of a large change in the tensiometer, and it is possible to secure the tension in the looper. The next fracture could be prevented.

In the above-mentioned embodiment, the case of detecting the breakage has been described, but the present invention is not limited to this, and the same action and effect can be obtained even when an abnormality occurs in the tensiometer. . It goes without saying that the invention can be applied not only to the entrance looper but also to the exit looper.

[0017]

As described above, according to the present invention,
Since the looper tension control is switched from the tension control mode to the current control mode when the tension control of the metal strip in the looper is unsteady, it is possible to secure a stable tension in the looper. Next breakage can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing a looper tension control system of the present invention.

FIG. 2 is a characteristic diagram showing a change over time in a conventional example in which a tension control mode is continued when breakage occurs.

FIG. 3 is a characteristic diagram showing changes with time in an example of the present invention in which the current control mode is switched to when a break occurs.

FIG. 4 is a schematic diagram of a conventional continuous processing line.

FIG. 5 is a block diagram showing a conventional looper tension control system.

[Explanation of symbols]

 1 Continuous processing device 2 Inlet side looper 3 Outlet side looper 4a, 5a Movable roll 4b, 5b Fixed roll 6,7 Carriage 8 Drum 9 Wire 10 Bridle roll 11 Deflector roll 12 Tensiometer 13 Tension controller 14 Speed controller 15 Current control Device 16 Control power supply device 17 Carriage lifting motor 18 Pulse generator 19 Drooping compensation circuit 20 Current detector 21 Non-steady-time judgment device 22 Tension control / current control mode switching relay 22a, 22b, 22c, 22d contact 23 Tension / current Converter 24 Ratio setter 25 First ramp generator 26 Second ramp generator S Metal strip

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Claims (1)

[Claims] 1. A continuous processing line in which a looper tension of a metal strip is controlled by using a tensiometer, detects whether or not there is an abnormality in the tension measurement value being controlled, and when there is an abnormality in the tension measurement value, the measurement is performed. A looper tension control method for a metal strip, characterized in that the looper tension control is switched from a tension control mode to a current control mode.