JPH0685906B2 - Coating amount control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a coating amount control method suitable for use in a coating amount control device, which improves controllability of the coating amount at the start of coating.

<Prior Art> An outline of a coating control device will be described with reference to FIG. Reference numeral 1 is a base paper roll, 2 is a base paper pulled out for coating, and 3 is a take-up roll of a paper 2 which has been coated on both sides.

Reference numeral 4 is a first coating means for applying a paint to one surface of the paper 2, 5 is a first B / M meter for measuring the moisture content and the weight of the paper before coating, 6
Is a first dryer for drying the paper that has passed through the coating means 4.

7 is a second for applying paint to the other surface of the paper 2 that has passed through the dryer 6
A coating means, 8 is a second B / M meter for measuring the moisture content and weight of the paper before coating, and 9 is a second dryer for drying the paper which has passed through the coating means 4.

A third B / M meter 10 measures the moisture content and the weight of the paper 2 that has passed through the second dryer 9.

Reference numeral 11 is a measured value calculation means, which is the first, second, and third B / M meters 5,8,1.
The measured values M ₁ , M ₂ and M _{3 of 0} are input, the difference between the measured value on the downstream side and the measured value on the upstream side is calculated, and the coating amount measured value PV11 by the first coating means 4 and the dryer 6 are calculated. Moisture content measured value PV ₁₂ on the output side, coating amount measured value PV ₂₁ by the second coating means 7 and dryer 9
Output PV ₂₂ of the measured moisture content on the output side. The coating amount and the water content are controlled to the target set values based on these measured values.

FIG. 4 is an enlarged view of the coating means 7. The applicator roll 15 whose lower part is dipped in the paint 14 in the fan ten 13 is operated upward with respect to the paper 2 run by the backing roll 12. In contact with each other, the paint is adhered to the paper through the applicator roll, and a part of the adhered paint is scraped off by the blade 16 to control the coating amount. Reference numeral 17 is an actuator for operating the angle of the flade.

The moisture content is controlled by manipulating the amount of hot air supplied to each dryer.

An example of the control loop of the coating amount control at the time of coating start in the coating amount control device having such a structure will be described with reference to FIG.

18 is a coating rate of controllers, at the start applied via measurements PV ₂₁ and setter 19 are given through the changeover switch 20 from the set value PV ₂₁ or the multiplier 21 by the arithmetic measurement value calculating means 11 The control output MV ₂₁ calculated by controlling the deviation from the set value PV ₂₁ ′ of is output and the actuator 17 is driven.

22 is a speed sensor, the measured value PV ₃ is given to a function calculator 23 selected by the brand, for increasing the period coating amount set value until the speed reaches a steady value in a predetermined functional relationship. The coefficient k is transmitted and supplied to the multiplier 21.

The multiplier 24 multiplies the coefficient k and the set value SV ₂₁ by the set value SV.
₂₁ 'is transmitted to the changeover switch 21.

A sequence device 24 receives a sequence command ST generated at the start of coating and an applicator roll touch signal AR and transmits a drive signal to the changeover switch 21 and the controller 18, and sets the changeover switch 21 to the initial state as shown in the figure. Switch to the set value SV ₂₁ ′, and when the coating speed reaches the steady speed set value SV ₃ , switch to the steady state and set the steady set value SV.
Control to select V21.

Figure 6 is shows the change in SV ₂₁ 'in the period of time t ₁ from a coating start time t ₀ until steady speed, setting a proper coating amount by coating speed is achieved .

<Problems to be Solved by the Invention> With such a configuration, the set value can be corrected by changing the speed at the start of coating, but at the start of coating, the operation amount and the coating amount of the coating means are changed depending on the speed. There is a phenomenon that the relationship is interfered, it is difficult to make the coating amount follow the set value SV ₂₁ 'unless the operation output is changed according to the speed, and manual intervention of the operator is required.
There's a problem.

An object of the present invention is to provide a coating amount control method capable of eliminating the phenomenon that the relationship between the manipulated variable and the coating amount at the time of start interferes depending on the speed.

<Means for Solving Problems> In the present invention which achieves such an object, the deviation between the measured value (PV ₂₁ ) of the coating amount sensor and the coating amount setting value (SV ₂₁ ′) at the start is controlled. The operation end of the coating machine is controlled by the calculated operation output (MV ₂₁ ), and the above-mentioned speed is supported according to the brand until the coating base paper speed at the start of coating reaches the steady value (SV ₃ ). In a coating amount control method having a function of multiplying the above-mentioned coating amount setting value by a coefficient (k), the first operation output ΔWa after a lapse of a _first waiting time (T ₁ ) from the start of coating. = Ka (PV ₂₁ −SV ₂₁ ′) is transmitted by the control calculation, and after the first waiting time (T ₁ ) has elapsed and the second waiting time (T ₂ ) has further elapsed From the sampled value P, I feedback control operation output ΔWb = 100 {(En-En-1) + En / T} / PB (where E n is the control deviation in the nth control cycle, T
Is a time constant, PB is a proportional band) and is repeated at every constant control cycle until the control deviation is within the allowable range. When the measured value of the coating amount sensor reaches a predetermined limit value, And a third step of performing an operation output ΔWc = −Kc (Sn−Sn−1) of the feedforward control for compensating for interference (where Sn is the speed in the n-th control cycle). The second step and the third step are executed in parallel until the value reaches the value, and after the speed reaches the steady value, the second step is performed until the control deviation of the coating amount falls within an allowable range. Is characterized by continuing.

<Operation> In the first step, first, the operation output is performed, and the operation end of the coating machine is placed in the feedback controllable area. In the second step, when the control deviation of the coating amount is large by feedback control, an operation output for compensating for this is provided. In the third step, the relationship between the operation amount and the coating amount is interfered by the speed at the start of coating, and therefore the operation output is performed by the feedforward control for decoupling the influence of the speed. This reduces the amount of wasted paper at the start of coating.

<Example> An example of the present invention will be described with reference to FIG. Description of the same elements as those described in FIG. 5 will be omitted, and description of the characteristic portion will be added. DCS is the controller side, P
Indicates the process side. In the control apparatus, 25 is a feed forward computing means inputs the measured value PV ₃ of coating weight measurements PV21 and speed sensor, is activated at the start of the coating machine in the sequence of signals the controller 24. This calculation means includes a coating amount limit monitoring unit 251 and a calculation unit 252.
The output signal MVf is guided to the adding means 26 and added to the operation output MV ₂₁ of the controller 18.

The feedforward calculating means 25 is controlled so as to emit a feedforward output signal until the speed reaches the target value after the coating amount reaches the limit value.

FIG. 2 is a flow chart showing the procedure of the operation, and the block B of the chain line is the part for realizing the feedforward operation peculiar to the present invention.

First, after the initial condition is satisfied, when the touch of the applicator roll is confirmed, the timer T ₁ is started in step 1 and a certain waiting time is set, and then in step 2, the first operation output, ΔWa = Ka (PV ₂₁ −SV ₂₁ ′ Transmitted by control calculation of controller 18.

At the same time, the timer T2 is started in step 3, and when the deviation is large after a certain waiting time, the effective sample value P, I feedback control is set as ΔWb = 100 {(En-En _-1 ) + En / T} / PB The control calculation is performed until the deviation falls within the allowable range at every constant control cycle. Here, En is the deviation, PB is the proportional band, and the set value is SV ₂₁ ′.

Furthermore, the measured PV value ₂₁ of the coating amount is monitored in step 4, and the feedforward signal is not calculated until the predetermined limit value is reached. The signal ΔWc = −kc (Sn−Sn ₋₁ ) is calculated, added to the output signal of the previous calculation cycle, and transmitted to the addition means 25 as MV ₄ . Where S is speed. The control by this calculation and the sample value control are executed in parallel until the speed reaches the target value.

When the speed reaches the target value, it is checked whether the coating amount deviation is within the allowable range, and if it is outside the allowable range, the sample value PI control is continued. Shift to the general feedback coating amount control.

The embodiment described above is an example of control on the coating means 7 side, but the present invention can be similarly applied to the coating means 4 side.

<Effects of the Invention> As described above, according to the present invention, it is possible to appropriately compensate for the excess of the operation output to the coating actuator due to the speed change at the start of coating by the feedforward signal, and to start coating. It is possible to improve the controllability of the coating amount control in, and contribute to the burden on the operator, the reduction of waste paper, and the saving of energy.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a flow chart diagram showing a signal processing procedure, FIG. 3 is a conceptual diagram of a coating machine control device, and FIG. 4 is an enlarged view of coating means. , FIG. 5 is a block diagram showing an example of a conventional technique, and FIG. 6 is an operation explanatory diagram thereof. 11 …… Measured value calculation means, 17 …… Actuator, 18 ……
Controller, 19 …… Coating amount setting device, 20 …… Changeover switch, 21
...... Multiplier, 22 ...... Speed sensor, 23 …… Function calculation means, 24 …… Sequence control device, 25 …… Feedforward calculation means, 26 …… Addition means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuaki Hashimoto, Inventor No. 3 Aomori Yachi, Kawara Wood, Aomori Prefecture No. Yokogawa Electric Co., Ltd. (72) Inventor Kazushi Takano 2-9-32, Nakamachi, Musashino-shi, Tokyo Yokogawa Electric Co., Ltd. (56) Reference JP 62-201668 (JP, A)

Claims (1)

[Claims] 1. The operating end of the coating machine is controlled by an operation output (MV ₂₁ ) which is calculated by controlling the deviation between the measured value (PV ₂₁ ) of the coating amount sensor and the coating amount set value (SV ₂₁ ') at the start. To control
Until the coating base paper speed at the start of coating reaches the steady value (SV ₃ ), the coating amount has the function of multiplying the above-mentioned coating amount setting value by the coefficient (k) corresponding to the above speed according to the brand. In the control method, a first step in which a first operation output ΔWa = Ka (PV ₂₁ −SV ₂₁ ′) is transmitted by a control calculation after a lapse of a _first waiting time (T ₁ ) from the start of coating. Then, after the elapse of the first waiting time (T ₁ ), and further after the elapse of the second waiting time (T ₂ ), the sampled value P, I feedback control operation output ΔWb = 100 {(En−En -1) + En / T} / PB (where En is the control deviation in the nth control cycle, T
Is a time constant, PB is a proportional band) and is repeated at every constant control cycle until the control deviation is within the allowable range. When the measured value of the coating amount sensor reaches a predetermined limit value, And a third step of performing an operation output ΔWc = −kc (Sn−Sn−1) (where Sn is the speed in the nth control cycle) for compensating for interference, and the speed is the steady state. The second step and the third step are executed in parallel until the value reaches the value, and after the speed reaches the steady value, the second step is performed until the control deviation of the coating amount falls within an allowable range. A coating amount control method characterized by continuing with.