JPS5943733A - Control method for constant feed ware - Google Patents

Abstract

PURPOSE:To improve accuracy of discharging a specified quantity of flow by a method wherein a control signal of a discharging device is controlled in such a way as discharging capacity of the discharging device is set to substantially a certain constant in response to the weight of the discharged item. CONSTITUTION:For example, when the first screw feeder is to be controlled, CPU11 chekcs (a-1) if the operation is in a supplying period and when it is in the discharging period, the newest weight signal Wk is read from A/D converter 10 at (a-2). Then, a discharging quantity of feeder per unit time is calculated in response to a difference between the newest weight Wk read at the a-2 and the previously read weight, the discharging quantity is compared with the desired flow rate F, a control signal for the motor 6 is varied at (a-3) in such a way as the actual discharging quantity approaches the desired flow rate F, and then the operation process passes through the other routine and returns to the (a-1). In the step (a-5), the applied voltage is calculated to output the digital signal. In this way, the control signal to the motor 6 is varied in sequence in response to the weight and the variation in current is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling constant feedware discharging at a constant rate.

Conventionally, constant feedware is weighing device (1)
A weighing hopper (2) supported through the weighing hopper (2), a first screw feeder (3) mounted as a discharge device on the bottom of the weighing hopper (2), and a weighing hopper (2).
) is supplied with discharged material to the second screw feeder (4).
) and the motors (6) (7) of the second screw feeder (3) (4) via the motor control device (5) based on the weighing signal from the weighing device (1). It is composed of a control device main body (8) for controlling. and,
When the weight W of the discharged material in the needle hopper (2) is between the upper limit set value Wυ and the lower limit set value wL as shown in FIG. Stop replenishing the weighing hopper (2) from the feeder (4),
The motor control device ( 5), the rotational speed of the motor (6) of the first screw feeder (3) is controlled by the rA1 node (hereinafter, this period will be referred to as the discharge interval α0). However, the following timetable 1. During the period from 1o to 1o, the accurate discharge amount per unit time cannot be determined from the weighing signal of the weighing device (1), so the first screw feeder (3
) The control based on the decreasing change ζ in the meter weight phase is temporarily interrupted at time Ll-. The weight W reaches the lower limit set value wLf [
Time 1. ), and the control device main body (8>) controls the second screw feeder (4) via the motor control device (5) so that almost constant flow rate replenishment is performed from the second screw feeder (4) to the 51M hopper (2). Start driving the feeder (4).This state is at time L when the weight iw reaches the upper limit setting value WU.
This continues until U, and after the completion of replenishment, the fluctuation of the weighing weight A due to the input of the discharged material becomes stable at time t. The control state of the first screw feeder (3) is also returned to the original state.

Note that the time [, to [. Because the flow rate control cannot be performed during the replenishment period (I) 1 for the reasons mentioned above, the conventional control device main body (8) will control the discharge flow rate appropriately when the replenishment period 1j (former I) begins. Motor control device (5
) of the first screw feeder (3) via the motor (
6), for example, at time t while maintaining the driving state at time [1,].

1, therefore, the accuracy of the discharge flow rate during the replenishment period (I) is worse than that during the discharge period (Ir), and the accuracy of the discharge flow rate from the discharge period σ0 to the replenishment period (I) is worse than the discharge period (Ir). The current situation is that it is worse than Nosoi 1.

The present invention was made by focusing on the fact that there is a nearly constant tendency between the weight of the material to be discharged in the weighing hopper and the discharge capacity of the discharging device attached to the weighing hopper,
The weight of the discharged material in the weighing hopper reaches the lower limit set value.
Then, in response to the decrease in weight, the control signal to the discharge device is controlled so that the weight is discharged from the course hopper at a constant flow, and when the weight falls to the lower limit set value, the second limit is set. The replenishment of the pruned material to the weighing hopper is continued at a nearly constant rate until the weight is reached, and this replenishment period is based on the preset discharge capacity according to the change in the discharge capacity of the discharge device in response to the change in the position. It is characterized in that it sequentially calculates from the compensation characteristics according to the weight and level in the weighing hopper and outputs it to the discharge device.

Hereinafter, specific embodiments of the present invention will be described based on FIGS. 8 to 7.

Figure 8 shows the relationship between the weight of the discharged material in the weighing hopper (2) and the discharge capacity of the first screw feeder (3).
Measurements were made for the following raw materials (a), (b), and (c).
The rotational speed of the motor (6) is constant. As can be seen from FIG. S, the discharge capacity of all three raw materials (a), (0), and (c) tends to improve as the weight w increases. Therefore, as in the past, the time jL(1,)
When the motor (6) is rotated in the driving state, the replenishment period (1
), the flow rate tends to gradually increase, and the overall control accuracy deteriorates.

FIG. 4 shows - during the replenishment period ([) of the control method of the present invention.
Give an example. As shown in Figure 8, the weighing hopper (2
) The discharge capacity of the first screw feeder (3) increases as the weight W of the discharged material increases, so ff
The purpose is to lower the voltage applied to the motor (6) as 1ilW increases. In other words, the lower limit setting value wL
The voltage V1. applied to the motor (6) required to discharge the target flow NF at V1. The applied voltage V11 required to discharge the target half amount F at the second limit setting value WU is determined and set in advance from the relationship diagram in FIG. 3 and the characteristics of the motor (6), and the lower limit setting value WL and the applied voltage are ■Intersection A with 1 and 1 and upper limit setting value W. Find the line segment (C) that connects the intersection point B with the applied voltage ■6, and find the occasional heavy paper W in Sodefune period l1lJ (1): WK
The applied voltage vK to the motor (6) is determined from the intersection of the line segment (C) and the line segment (C), and the applied voltage to the motor (6) is calculated from V6 to V along the line segment (C). The aim is to make gradual changes toward the future.

Figure 5 shows a main body (8
) and its surrounding configuration, (9) is the load cell in the weighing device (1), α1 is the N-width converter, and αη is the CPU
.

0■ is a memory in which the execution program of the CPU θ sword is written, and 03α4 is an r〆A converter that converts the control signal output from the CPU αυ into analog and applies it to the motors (6) and (7). Note that the CPU (b) receives the upper and lower limit set values Wυ, WL, the target flow rate F, and the applied mpressure V1. and ■. The setting values corresponding to J)l and I)+
+ or set jl.

Figure 6 shows the control routine for the first screw feeder (3) by CPLJ (lυ).This routine ship's control routine (CPLI) (+υ is first checked to see if it is in the replenishment period (I) (, a-1 :) Yes, if the discharge period (11) is the latest weight itwK from the converter (III)
Read [a-2], then read the latest weight wK and nl read in [a-2], and read the past weight X read in the same way.
The discharge amount of the first screw feeder (3) per unit time is determined from the difference with V, and this is compared with the target flow rate F, and the motor (6) is adjusted so that the actual discharge amount approaches the target flow rate F. ) changes the control signal to (a-8) [,, then passes through other routines to (a-1) i. , When it is determined that it is the supply period (I) in (a-1), read the heavy nails at that time as in 1la-2J [a = 4], and then (
From the WK read in step a-4) and the line segment (C) in FIG. 4, in step [a-5], for example, the applied voltage VK is calculated as follows and output as a digital signal.

(Wg WL) : (wK-;w,-) = (V
L ``u): (V, ÷ VK) In this way, even during the replenishment period (1), the control signal phase to the motor (6) changes sequentially according to the weight W, so the replenishment time is lower than before. 1) The flow rate fluctuation in the former I) is improved.

In the above example, whether (a-5) is executed at short time intervals or not, this is determined by the upper and lower limit setting values WU and Wl as shown in FIG.
For example, set values for Wl and W2 are set between , and the replenishment period (
Enter I) at time 1. The period J from 1 to the time when it is detected that the weight itw matches W drive the motor (6) in the state (7, time L)
1 to the time when it is detected that the weight j1w matches w2 [
During the period up to t2, the motor (6) is driven in the state obtained by substituting wK2W into the equation [a-5), and the motor (6) is driven at time t2.
to time t. The period N until Wg "" W2 is (a-
Even if the motor (6) is driven in the state obtained by substituting into the equation 5), better meteor control than before can be achieved. It should be noted that, although here, there are two setting values, wl and w2, the number of setting values may be one or more.

In C, a-8) of the above embodiment, the weight W per unit time
The instantaneous meteor control was used to control the amount of water that is reduced so that it reaches the target flow rate each time, but it is also possible to control the total discharge amount from the start of discharge so that it approaches the integral value of the target flow rate. The same is true.

As explained above, according to the control method of the present invention, even during the replenishment period, the control signal of the ejection device is controlled to correspond to the amount of material to be ejected in the hopper, so that the ejection capacity of the ejection device remains almost constant. Since it can be controlled, the accuracy of constant flow discharge is improved compared to conventional methods.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of constant feedware, Fig. 2 is an explanatory diagram of a conventional control method, Figs. 8 to 7 show specific examples of the control method of the present invention, and Fig. 3 Relationship diagram between weight and discharge capacity, Figure 4 is an explanatory diagram of control signal calculation,
FIG. 5 is a configuration diagram of the main body of the control device and its surroundings, FIG. 6 is a flowchart of the main part of FIG. 5, and FIG. 7 is an explanatory diagram of the embodiment 1112. (2)... ;tl turtle * collar 1 (3)... 1st screw feeder [discharge device], (8)... control device main body, θυ... CPLJ 1 (2)...・Memory, C
I)...Discharge period, (1)...Replenishment period agent
Yoshi Morimoto Hironori Gi &! 186-4sai-9-hi (Fig. 5, β, Fig. 7)

Claims (1)

[Claims] 1. Control to the discharge device so that a constant amount is discharged from the weighing hopper in response to a decrease in the weight until the weight of the discharged material in the weighing hopper reaches a lower limit set value. The signal is controlled, and when the weight falls to the lower limit set value, a nearly constant amount of the discharged material is continued to be replenished to the weighing hopper until the upper limit set value is reached, and this replenishment period ζ is in response to the weight change. A constant feedware control method that sequentially calculates a discharge capacity compensation characteristic set in advance according to a change in discharge capacity of a discharge device according to a weight level in a weighing hopper and outputs the result to the discharge device. 2. A patent claim characterized in that the discharge capacity compensation characteristic is an approximate characteristic designated by two control signals to the discharge device at a lower limit set value and an upper limit set value of the weight of the discharged material in the weighing hopper. A method for controlling constant feedware according to item 1.