JPS6071416A - Control method for continuous quantitative supply operation - Google Patents

Abstract

PURPOSE:To enable at all times the optimum amount of intial operation to be set by conducting simulated operation and thereby previously obtaining a characteristic of an operation amount to a supply amount when powdered substance in a hopper scale is continuously and quantitatively supplied, using a discharge feeder. CONSTITUTION:An amount of powdered substance in a hopper scale 1 is detected by a load cell 3, and the optimum amount of operation is evaluated in a measurement controller 4 based on the detected value. The output is applied to a discharge feeder 2 for continuous quantitative supply. In this instance, an amount of intial operation is applied in order to prevent rising of supply start of the discharge feeder 2 from being delayed. Simulated operation is conducted before actual operation. A supply amount at each amount of divided operation obtained by dividing a full span of the operation amount into plural sections is measured and plotted. A characteristic of the operation amount to the supply amount is obtained employing linear approtimation among the plots. Thereafter, an operation amount corresponding to a set continuous supply amount is estimated based on the aforesaid characteristic to provide the amount of intial operation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a continuous quantitative supply operation control method in digital metering control.

Continuous quantitative supply operation is performed by controlling the discharge feeder according to the amount of powder or granules in the hopper. Figure 1 shows hopper scale (1)
, the arrangement relationship of the discharge feeder (2), the load cell (3), and the weighing controller (4) is shown. In I), an appropriate operation amount is calculated and applied to the discharge feeder (2) to drive it.

The operation amount F(l is calculated by converting the set continuous supply amount to R[kg/
If hl, the following control algorithm is used.

F(t)=K(△wt+4−Sat△W i )・・・・・・
・(2) - O t; Elapsed time from the start of discharge (s) Wt; Particle body appearance in the hopper scale in seconds (kg) Wo
; Amount of powder and granular material in the hopper scale at the start of discharge (kl?) K; Proportionality constant T; Integral time constant As is clear from these equations, the metering controller (4) is PL
It is an adjustment system, and can be adjusted to the optimum control state by changing the proportional constant K and the integral time constant T. By the way, the proportionality constant K and the integral time constant T are generally adjusted under steady state conditions, and as a matter of course, transient phenomena are not in the optimal state, especially when the I control system is involved. Therefore, the problem of start-up delay occurs when starting supply.

The present invention deals with this problem of start-up delay, and the initial operation amount F is adjusted in accordance with the set continuous supply amount R (kg/b).

The feature is that this is determined and given to the discharge feeder as an initial condition, and the initial operation amount F is considered to be difficult. This decision is to be solved by conducting a preliminary simulation operation. This will be explained in detail below based on examples.

Initial operation amount F in place of equation (2) above. The relationship between the amount W of powder and granular material in the hopper scale and the manipulated variable F(t), taking into account, can be expressed as follows. Initial repetition amount F. is the set continuous supply amount R (kg
/h), but if it is too small, “
It does not eliminate the rise delay, and conversely, if it is too large, it will lead to the hunting phenomenon, so it is necessary to select a fairly accurate value. By the way, the continuous supply amount R (kg/h
) and the amount of repetition F. The relationship between the two is normally different each time depending on the abrasive properties such as the specific gravity and particle size of the supplied powder and granules, and the characteristics of the discharge feeder during the time when the amount of operation is received and the material is actually supplied from the discharge feeder. It is difficult to predict this relationship.

Therefore, in the present invention, a simulation operation is performed in advance to grasp the relationship between the operation amount and the supply amount, and a specific method thereof is shown in the graph of FIG. That is, the full span of the manipulated variable F is divided into 11 equal parts, and each of the 11 equally divided manipulated variables F, , F2
. . . Each supply amount R, , R2 . . . 1R) 1 at Fn was measured, plotted, and the plots were connected with a straight line to show the relationship between the manipulated variable and the supply amount.

To measure each supply amount R,, R2...Rn, the respective operation amounts F,', F2...Fn are output and outputted to the discharge feeder, and the layer thickness is stabilized for a time t. After seconds have elapsed, sample the powder weight Wlo, W2o...WIlo indicated by the load cell, and sample again after t seconds, W, t,
L't...Wllt is calculated using the following equation.

600 Rn=-1"=(Wno-Wnt)--(4)(n
=1.2.・River...n) The solid line in FIG. 2 is the operation amount-supply amount characteristic diagram obtained in this simulation operation.

In other words, the relationship between the manipulated variable and the supply amount according to the present invention is determined by dividing the total manipulated variable into several stages, performing simulation operation at each stage, and measuring each supply amount. The amount is plotted and these plot points are connected with a straight line.The relationship between the operation amount and the supply amount other than the plot points is obtained by linear approximation.For example, to illustrate the set continuous supply amount R, Rn-, Rn If Rx is between
...(5) It can be calculated as follows. The continuous supply amount R is between any plots, for example Rm-, ≦R'<Rm.

The general formula for the case is shown as F　o　=　F　II+　-1+-”　X　R-R'.

-4゜■F,・・・・・・(6) becomes.

In addition, although the actual manipulated variable-supply rate characteristic is shown in Figure 2 as a broken ship, the difference from the solid line, which is the simulated operating characteristic, decreases as the number of manipulated variable stages increases, and as the number of manipulated variable stages increases, As long as the value is adjusted and set to a level that does not pose a problem in practical use, it will not cause any problems with the roof.

As mentioned above, the present invention uses a discharge feeder to continuously supply a fixed amount of powder or granular material in a hopper scale, and the system is composed of a PI control system and includes one control system, so that the initial supply from the feeder is This causes a startup delay problem,
In order to solve this problem, in addition to adding an initial operation amount separately, in order to determine the initial repetition rate according to the set continuous supply rate, a simulation operation is performed before the supply operation to determine the fabrication rate - supply rate characteristic in advance. Even when a different supply amount is set, it is possible to always set the optimum initial operation amount and realize continuous fixed amount supply without any start-up delay.

[Brief explanation of drawings]

In the drawings, FIG. 1 is a block diagram of the embodiment, and FIG. 2 is a graph for explaining its operation. (1) Hopper scale (2) Discharge feeder (3) Load cell (4) Metering controller applicant Shinko Electric Co., Ltd. Agent Patent Attorney Haru Saifuji Yako 1 KL Kishi (￥f1

Claims (1)

[Claims] 1. Detect the amount of powder in the Hompa scale with a load cell, calculate the optimal operation amount in the metering controller based on the detected value, add it to the discharge feeder, and start supplying the discharge feeder for continuous quantitative supply. In order to prevent the start-up delay, an initial manipulated variable is added, and the full span of the manipulated variable is divided into multiple segments by simulation operation before actual operation, and the supply amount for each divided manipulated variable is measured and plotted.
A continuous constant supply operation control characterized in that linear approximation between the plots is performed to obtain the manipulated variable-supply amount characteristic, and based on this characteristic, the manipulated variable corresponding to the set continuous supply amount is determined and set as the initial manipulated variable. Method.