JPH091223A - Loop controller - Google Patents

Abstract

PURPOSE: To provide a stable loop controller, by which the disturbance of elevating/lowering rollers is compensated. CONSTITUTION: A position detector 16 for detecting the present position of elevating/lowering rollers 13 and a amplifier 17 for adjusting a feedback quantity are installed. Further, a function arithmetic circuit 18 for finding the change quantity of loop length by the position of the elevating/lowering rollers and a differentiation circuit 19 for finding a change quantity per the unit time of the loop length are installed. A speed compensation quantity to the change of the elevating/lowering rollers is found, and the found speed compensation quantity is given as a compensation quantity to the speed command of a motor 4 for driving rolls.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loop control device in equipment for producing surface-treated steel sheets.

[0002]

2. Description of the Related Art A conventional loop controller is based on the Hitachi review (V
ol.65 No. 2 [1983-2]) P73 to P74 is applied, and there are rolls 1 and 2 for forming a loop as shown in FIG. The rolls are provided with electric motors 3 and 4 for driving. Further, it is composed of a loop detector 10 for detecting the loop amount. Normally, a speed command device 6 that targets a speed command 5 as a reference of equipment so that the peripheral speeds of the rolls 1 and 2 are constant
The speed control circuit (ASR) 7,
It is controlled by 8.

Consider the case where the strip is being fed from roll 1 to roll 2, with roll 1 being the reference roll for speed. In order to make a constant loop between the rolls 1 and 2, a loop command 9 for giving a reference loop amount,
A loop control circuit 12 calculates a deviation of a signal of an amplifier 11 which adjusts a feedback amount from the loop detector 10 and gives it as a speed correction amount of the electric motor 4 to perform loop control.

[0004]

In a facility for producing a surface-treated steel sheet, when an elevating roller for changing the position of a fulcrum forming a loop is installed between rolls forming a loop in order to avoid scratches and the like due to strip welds. There is.

While the elevating roller is operating and the fulcrum position of the loop is being changed, the loop length is changed and acts as a disturbance of the loop control, which makes the loop control unstable. When there is a strip heat treatment device such as an oven between the loops, there is a problem that the slip contacts the upper or lower part of the oven when the loop control becomes unstable. Further, in order to improve the thermal efficiency of the oven, it is necessary to narrow the strip passage space of the processing device, and the position of the loop bottom point is kept constant and the loop shape is not changed even while the lifting roller is operating. Is required for loop control.

An object of the present invention is to provide a stable loop control device even when the position of the loop fulcrum is changed by the elevating roller and acts as a disturbance.

[0007]

In order to achieve the above object, the present invention obtains a change amount of a loop length from a change amount of a lift roller in order to compensate an influence of a change amount of a lift roller on a loop. The loop control device has an arithmetic circuit and a differentiating circuit for converting the amount of change in the obtained loop length into the amount of speed compensation.

[0008]

Since the present invention is configured as described above, the amount of change in the loop length per constant time can be obtained by providing an arithmetic circuit for obtaining the amount of change in the loop length from the amount of change in the lift roller. Also, if the amount of change in the loop length per fixed time is known, this value can be divided by the fixed time to obtain the amount of speed compensation due to the change of the lifting roller, and this can be compensated for in loop control. A stable loop control can be obtained with.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 (a) shows an embodiment of coating equipment. Between the bridle rolls 1 and 2 that move the strip, the coating roll 14 is adjusted, and the strip contact angle of the coating roll 14 is adjusted and the strip welded portion comes into contact with the coating roll 14 when the strip welded portion passes the coating roll 14. It consists of a lifting roller 13 for avoiding heat and an oven 15 machine for heating and drying the coated strip.

A speed control circuit (ASR) 7, 8 is a command given from a speed command device 6 for targeting a speed command 5 which is a speed reference of equipment, and a bridle driving electric motor 3,
4 is controlled.

The strip is fed from the bridle roll 1 to the bridle roll 2, and in order to form a constant loop between the rolls 1 and 2, a standard loop amount determined based on the shape of the oven is given. Loop command 9 for detecting the loop amount, a loop detector 10 for detecting the loop amount, and a speed correction amount calculated by the loop control circuit 12 based on the deviation of the signal of the amplifier 11 for adjusting the feedback amount, and applied to the motor 4. We are in control.

In the coating equipment, in order to avoid the strip welded portion from the coating roll, the welded portion detector 20 detects the welded portion, the signals of the pulse generator 25 are integrated from the detection timing, and the roll diameter of the bridle roll 1 and Roll 1
The tracking circuit 21 tracks the welded portion based on the number of rotations per rotation, the welded portion raises the raising / lowering roller at a position before the raising / lowering roller 13, and descends at the timing when the welding point passes the raising / lowering roller. Let For this reason,
The fulcrum position of the loop and the loop length change, and the strip vibrates. With conventional equipment, loop control absorbs the vibration of the strip, and it took time for the strip to stabilize.
In the equipment of the embodiment, in order to obtain a constant loop amount even when the lifting roller is in operation, a position detector 16 for detecting the current position of the lifting roller 13 and an amplifier 17 for adjusting the feedback amount are provided, and the lifting roller is further provided. A function calculation circuit 18 for calculating the change amount of the loop length depending on the position of 13 and a differentiating circuit 19 for calculating the change amount of the loop length per unit time are provided to calculate the speed compensation amount for the change of the lifting roller. , The speed command of the electric motor 4 for driving the bridle roll 2 is given as a compensation amount.

The details will be described below with reference to FIG.

The loop amount D in the steady state is the weight W (kg / m) per unit area of the strip and the tension T (kg) of the set value.
And the fulcrum distance S (m).

S: Constant determined by equipment W: Calculated from preset thickness, width and specific gravity T: Operator set value

[0017]

## EQU1 ## D = WS ^ 2 / 8T (Equation 1) Since the bridle roll 2 controls the loop amount D to always be constant, the tension T is constant in a steady state.

The strip length L at this time is

[0019]

[Equation 2] L = S + 8D ^ 2 / 3S (Equation 2)

When the position of the elevating roller 13 changes by H, the loop amount D becomes D0, and D0 at this time is

[0021]

## EQU3 ## D0 = D (1-H / 4D) (Equation 3)

Therefore, if a correction is made so that D0 → D during a transition, a constant loop amount D can be obtained. Here, assuming that the change amount of H is ΔH, the change amount of D is ΔD, and the change amount of L is ΔL, when ΔH occurs, ΔD is obtained from Equation 3, and from Equation 2 from ΔD to Δ
D is obtained by adding L as a correction amount per constant time,
By performing a speed correction of ΔV by setting / dt · ΔL → ΔV, the loop amount can be kept at a constant position even during a transition (while the lifting roller 13 is operating).

[0023]

According to the present invention, not only can a stable loop control device be provided by compensating for the disturbance of the lifting roller, but in the equipment with an oven as in the embodiment, the strip position is stable, so that the oven The strip passage space can be narrowed, the effect of increasing the thermal efficiency of the oven can be obtained, and the strip can be prevented from hitting the oven so that the product can be prevented from being scratched and the product quality and yield can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of a painting facility.

FIG. 2 is an explanatory diagram showing conventional loop control.

[Explanation of symbols]

1-2 ... Roll, 3-4 ... Electric motor, 5 ... Speed command, 6 ...
Speed command device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Suzuki 3-2-1, Saiwaicho, Hitachi-shi, Ibaraki Hitachi Engineering Co., Ltd.

Claims (2)

[Claims] 1. In a facility for producing a surface-treated steel sheet, in a loop control device for controlling a certain slack by an electric motor and a loop detector in the process of surface treatment, an elevating and lowering device for changing the position of a strip in a loop. When there is a roller, in order to compensate the influence of the change amount of the elevating roller on the loop, an arithmetic circuit that obtains the change amount of the loop length from the change amount of the elevating roller and the calculated change amount of the loop length are used for speed compensation. A loop control device having a differentiating circuit for converting into a quantity. 2. A loop controller according to claim 1, comprising a detector for detecting the connection of the strip and a circuit for tracking the connection.