JP2012233772A - Weighing control method for powder mass weighing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measurement control method for a powder mass measuring device.SOLUTION: A powder mass measuring device of the present invention comprises the steps of: calculating a unit feed amount by sampling a fed-back measurement value; and performing determination of measurement value after the measurement. The step of performing determination of measurement comprises the steps of: determining whether or not a measurement error of the measurement value from a set value of mass falls into a predetermined determination value range; and determining whether or not past records at low and medium speeds are within a reference time range. When the measurement error and the past records at the low and medium speeds are within the reference time and determination value range, the measurement values before the determination of quantity, before drop, and at the drop are stored and updated as the next measurement values before the determination of quantity, before the drop, and at the drop, respectively. When the measurement error and the past records at the low and medium speeds are out of the determination range and the reference time range, the next measurement values before the determination of quantity, before the drop, and at the drop are calculated and applied as the measurement values before the determination of quantity, before the drop, and at the drop, respectively at the start of the next measurement.

Description

  The present invention relates to a weighing control method for a powder mass measuring device, and more specifically, a method for automatically adjusting and autonomously controlling a powder mass measuring device that cuts and measures powder from a powder container (hopper) or the like. About.

  In order to supply powder having a different mass setting value every time and a plurality of times of measurement from a powder container or the like, a powder mass measuring device that cuts and measures powder from the powder container is used. In general, as a control method of the powder mass measuring device, as shown in Patent Document 1 and Patent Document 2, before quantification for switching the cutting speed, a drop or the like is set in advance, and the cutting speed of the cutting machine is set. A two-speed method for driving a cutting machine to switch from a high speed to a low speed, or a pre-quantification, a pre-fall, a drop set in advance in the order of high speed, medium speed, and low speed as shown in Patent Document 3. For example, there is a three-speed method for driving the cutting machine so as to switch the cutting speed. Further, as another control method of the powder mass measuring device, there is a speed change method for calculating the cutting speed of the cutting machine from the mass deviation as shown in Patent Document 4.

JP 2001-124618 A JP-A-11-152102 JP 2001-158537 A Japanese Patent Application Laid-Open No. 5-296818 Japanese Unexamined Patent Publication No. 7-012628

  In general, in a powder mass measuring device in which the mass setting value changes every time and multiple times of measurement, the amount of cut-out (unit feed amount) per second of the powder is determined by the cutting machine of the powder mass measuring device. It greatly depends not only on the speed but also on the height and density of the powder surface in the powder container and the physical properties of the powder. Therefore, if the powder surface height or density rises due to the change of the mass setting value due to the change of the production type of powder or the change of the situation in the powder container, the unit feed amount even if the output of the same speed amount Rises. In the methods shown in Patent Document 1, Patent Document 2, and Patent Document 3, when the powder surface height and density increase, the unit feed amount also increases even if the output is the same speed amount, and is set in advance. Before quantification, before the drop, the drop might not be appropriate. Therefore, as a result, it is not possible to secure a sufficient shift time interval, and it is easy to overweight. On the other hand, if the cut-off speed is reduced and the unit feed amount is lowered, insufficient weighing occurs or the measuring time is unnecessarily extended, so that the production efficiency is lowered. In such cases or when cutting out powder for the first time, it is necessary to re-adjust the control parameters such as speed, pre-quantification, before drop, drop, etc. by engineers and skilled workers each time, and the equipment operation rate also decreases. . Furthermore, in the method shown in Patent Document 2, an engineer or a skilled worker is required to take into account the mass setting value, the ability and structure of the cutting machine, etc., for weighing time with a wide time range of about ten seconds to several tens of minutes. Adjustments are often made by a person for several hours.

  Further, in the method disclosed in Patent Document 4, the cutting speed is gradually lowered, and the cutting machine is driven at a very low cutting speed and stopped at the mass set value. Therefore, the measurement time is extended and the production efficiency is poor. There was a problem.

  Patent Document 5 discloses a powder mass measuring device that creates a data table corresponding to a unit feed amount by actual measurement and performs control so as to obtain a cutting speed corresponding to a change in the unit feed amount based on the data table. Have been described. However, in the powder mass measuring apparatus described in Patent Document 5, it takes time to create a data table by actually measuring a head or a unit feed amount at several speeds in an initial stage.

  In addition, there are a wide variety of weighing requirements in the industrial field, which may require a degree of meshing such as less powder, just more, and more than the mass set value. There is a need to weigh.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a cutting machine for cutting powder supplied from a supply container into a measuring container, and the cutting machine is operated at a high speed, a medium speed, or a low speed. A method for controlling a powder mass measuring device comprising: a drive unit for driving at a cutting speed; and a weighing unit that feeds back the mass of the powder cut out to the weighing container as a measured value. The measurement value fed back from the sample is sampled at a predetermined sampling period, and based on the sampling, the unit feed amount for each of the high speed, medium speed, and low speed cut-out speeds is calculated, and the measurement determination is made after the measurement is completed. The step of executing the weighing determination includes a determination value range in which a weighing error of the weighing value from a mass set value is determined within a predetermined range. And a step of determining whether or not the actual speed of the low-speed state is within a predetermined range centered on a reference time that is a period including at least three sampling cycles. Determining whether it is within a defined reference time range, and determining whether a medium speed time result indicating an actual duration of a medium speed state is within the reference time range, When it is determined that the measurement error is within the determination value range, and the small speed time result and the medium speed time result are within the reference time range, before the determination, before the drop, Before the next quantification, before the next head drop, and the next head, and it is determined that the measurement error is not within the judgment value range, or the small speed time result or the medium speed time result is the reference time. If it is determined that it is not within the range, the next head is calculated based on the head calculated at the previous measurement and the head correction value in the current measurement calculated by correcting the measurement error to be small. Based on the unit feed amount at the time, the reference time, the medium speed unit feed amount, and the head ratio, the time before the next head is calculated so as to bring the small speed time result closer to the reference time. Based on the unit feed amount, the reference time, the high-speed unit feed amount, and the head ratio, by calculating before the next quantification so as to bring the medium speed time result closer to the reference time, the calculated next quantification The method is characterized in that the previous, previous head, and next head are applied as the pre-quantity, before head, and head, respectively, at the start of the next measurement.

According to a second aspect of the present invention, in the method of the first aspect, at the start of the medium speed measurement, a ratio between the high speed time record in the previous measurement and the high speed time record in the current measurement is set to a predetermined large value. Further comprising determining whether it is within the range of the fast time performance ratio;
If it is determined that it is out of the range of the high speed time results ratio range, it is based on the ratio between the high speed time results at the previous measurement and the high speed time results at the previous measurement and the high speed time results at the previous measurement. The latest before the current head is calculated and the calculated latest head before the current head is updated as before the current head, and the latest small speed unit feed amount obtained for each sampling is measured in advance during the small speed measurement. Based on the actual head drop after a low-speed stop and the head correction value calculated in the previous measurement, the latest head is calculated for each sampling, and the calculated latest head is updated as a head in the current measurement. To do.

  According to the present invention, even if the unit feed amount greatly changes while the output of the same speed amount is changed due to the change of the mass set value by switching the production type of powder or the situation change in the powder container, each measurement Every time before the next quantification, before the drop, before the drop is calculated and the optimum measurement result is always pursued, readjustment by an engineer or a skilled worker is unnecessary.

  According to the present invention, the pre-next head drop and pre-quantitative calculation are performed so that the low speed time result and the medium speed time result are within the reference time range for each measurement, so that a conservative cutting speed for avoiding overweighing Compared with the weighing method in the above and the weighing method that changes the head before quantification, before the head, or the head each time, the measuring efficiency is improved.

  According to the present invention, since the next head and the latest head during measurement are calculated so that the measurement error falls within the determination value range for each measurement, an accurate measurement result can be obtained.

  According to the present invention, if a plurality of commands are output from the sequence management unit using a communication module, a multi-point input / output module, or the like in the PLC, the powder mass measurement control method of the present invention can be performed with several tens of powder masses. It is possible to correspond to a weighing device. As a result, it is not necessary to change and readjust the control parameters by technicians or skilled workers for each unit, greatly reducing the adjustment work time of powder mass measuring devices from one to several tens. Stable weighing is always possible in a short time.

It is a figure which shows the whole structure for controlling the powder mass measuring apparatus which concerns on this invention. It is a graph which shows the time-mass correlation during the powder supply operation | movement of the powder mass measuring apparatus which concerns on this invention. It is a graph which shows the relationship between the feed amount of powder, and a sampling period. It is a flowchart for determining next head, before next head, and before next fixed amount.

  Hereinafter, a control method of the powder mass measuring apparatus according to the first embodiment of the present invention will be described. FIG. 1 shows an overall configuration for controlling a powder mass measuring apparatus according to the present invention. FIG. 1 shows a terminal PC1, a PLC 10, and a powder mass measuring device 20. As shown in FIG. 1, the PLC 10 includes a storage unit 11 that stores various data, an arithmetic processing unit 12 that executes arithmetic processing to be described later, a control unit 13 for controlling the powder mass measuring device 20, The powder mass weighing device 20 includes a sequence management unit 14, and includes a drive unit 21 connected to a cutting machine 24, an electronic balance, and the like, and measures the mass of the powder supplied to the weighing container 25. A portion 22 and a supply container 23 storing powder are provided. In FIG. 1, the screw type cutting machine 24 is shown, but the invention is not limited to this, and in the present invention, a cutting machine 24 having any mechanism capable of speed control can be used.

  FIG. 2 is a graph showing a time-mass correlation during the powder supply operation of the powder mass measuring apparatus according to the present invention. The powder weighing operation of the present invention will be briefly described with reference to FIG. The autonomous weighing control method according to the present invention will be described later. Before quantification, before head, and head are values based on the mass set value, and below, the mass obtained by subtracting the head, before head, and before quantification from the mass set value is the small speed switching point, medium Let it be a speed change point and a high speed change point.

  When a measurement start command is output from the sequence management unit 14 in the PLC 10, the control unit 13 of the PLC 10 outputs a high-speed driving signal indicating a high-speed cutting speed to the driving unit 21 of the powder mass measuring device 20. In response to the input high speed drive signal, the drive unit 21 starts the cutting operation by the cutting machine 24 by driving the cutting machine 24 at a high speed cutting speed. The cutting machine 24 cuts out the powder supplied from the supply container 23 during the cutting operation and supplies the powder to the weighing container 25 on the weighing unit 22. The measuring unit 22 measures the current mass of the powder supplied to the measuring container 25 and feeds back the measured value to the PLC 10. The arithmetic processing unit 12 of the PLC 10 calculates the next drop, before the next drop, before the next drop, before the next quantification, etc., which will be described later, based on the fed back measurement values.

  FIG. 2 shows the cutting speed of the drive unit 21 and the measurement value of the measurement unit 22. As shown in FIG. 2, when weighing is started after setting the mass set value, the cut-out speed of the drive unit 21 suddenly rises and is driven in a high speed state, and the measured value increases accordingly. . When the measured value reaches the high speed speed switching point, the control unit 13 outputs a medium speed driving signal to the driving unit 21 in order to switch the cutting speed of the driving unit 21 from the high speed to the medium speed. The drive unit 21 drives the cutting machine 24 at a medium cutting speed in response to the input medium speed driving signal. It is shown in FIG. 2 that the cut-out speed suddenly falls from the high speed to the medium speed, and the measured value slightly increases immediately after switching and then increases more gradually than at the high speed. Note that the fluctuation of the measured value immediately after the switching is caused by the bounce of the balance of the weighing unit 22 due to the change from the high speed to the medium speed and the amount of powder cut out from the cutting machine 24 suddenly decreases. . When the measured value reaches the medium speed switching point, the control unit 13 outputs a small speed driving signal to the driving unit 21 in order to switch the cutting speed of the driving unit 21 from the medium speed to the small speed. The drive unit 21 drives the cutting machine 24 at a low speed cutting speed in response to the input low speed driving signal. FIG. 2 shows that the cut-out speed has been switched from medium speed to low speed. When the low speed state is continued and the measured value reaches the low speed speed switching point, the control unit 13 stops outputting the low speed drive signal in order to stop the driving of the drive unit 21. The fluctuation of the measured value after the stop of driving is caused by the bounce of the balance of the measuring unit 22 by the powder cut out due to the response delay when the cutting machine is stopped and the powder dropped in the air after stopping at a low speed. After a predetermined time has elapsed, as will be described later, it is determined whether the weighing error from the mass set value is within the judgment value range, and whether the low speed time result and the medium speed time result are within the reference time range. The weighing determination is executed, and before the next quantification, before the next falling, and the next falling are determined based on the result of the weighing determination. The high speed time results, medium speed time results, and low speed time results indicating the actual durations of the high speed state, the medium speed state, and the low speed state are measured by the PLC 10 and recorded in the storage unit 11. .

  Next, the unit feed amount according to the present invention will be described. In the present invention, by sampling the measurement value fed back from the measuring unit 22 at each predetermined period from the high speed to the medium speed, from the medium speed to the low speed, and from the low speed to the stop, the high speed, A unit feed amount that is an average feed amount of powder per second is calculated for each cutting speed of medium speed and low speed.

In the following, the current measurement is the current measurement, the previous measurement is the previous measurement, and the measurement value at the (n + 1) th sampling is increased from the measurement value at the nth sampling in the current measurement. Is the current increase, the increase from the measurement value at the mth sampling to the measurement value at the (m + 1) th sampling when the (m + 1) sampling was performed in the previous measurement is the previous increase, Assuming that the unit feed amount calculated at the (m + 1) th sampling is the previous unit feed amount (assuming that n ≧ 1, m ≧ 1), the unit feed amount at the (n + 1) th sampling is expressed by ) To calculate.
(Unit feed amount) = (Previous increase + Current increase + Previous unit feed amount) / (Sampling cycle * 3) (Formula 1)

The unit feed amount shown in (Formula 1) is calculated for each cutting speed of high speed, medium speed, and low speed. Each unit feed amount for each cutting speed of high speed, medium speed, and low speed is constantly calculated and updated for each sampling during the current measurement. If the previous measurement has not been performed, such as when measuring for the first time, the unit feed amount for each speed is calculated by sampling six times or more at each speed, for example, during automatic adjustment described later.

  FIG. 3 is a graph showing the relationship between the amount of powder feed and the sampling period. As shown in FIG. 3 (a), when the cutting of the powder starts, the unit feed amount suddenly rises, and after the lapse of DZT, the unit feed amount of the powder stabilizes and pulsates. Is cut out. Here, DZT is a measurement waiting time provided in advance in order to execute accurate sampling in consideration of fluctuation of the measurement value at the time of switching the clipping speed as described above. In the present invention, in order to calculate an accurate unit feed amount, sampling is started after the lapse of DZT so as not to include the cutout amount during the DZT period in which the cutout amount is unstable. The sampling is executed for each high speed, medium speed, and low speed cut-out speeds after the DZT has elapsed and until each cut-out speed is switched. Further, FIG. 3A shows that sampling is executed in each section delimited by the sampling timing, and an increase in the measured value is obtained for each sampling. In this way, the unit feed amount is obtained as in (Equation 1) using the increase obtained for each sampling.

  In the first sampling immediately after the lapse of DZT, since the measurement value is affected by the above-described blur, an accurate unit feed amount is often not obtained. Therefore, in order to accurately obtain the unit feed amount, it is necessary to calculate the unit feed amount using the increase in the second and subsequent samplings, and considering the current increase and the previous increase shown in (Equation 1), 3 It is preferable to perform sampling more than once.

  The sampling period of sampling in the present invention is preferably set to 1/3 or more of the pulsation period of the cutting machine 24 at a low speed. If there is no pulsation in the amount of powder cut in the cutting machine 24, there is no problem, but if there is pulsation, there is a variation in the amount of powder increase in each sampling period, and there is a case where an accurate unit feed amount cannot be calculated. . Therefore, in order to accurately calculate the unit feed amount, it is necessary to perform sampling at a sampling period in which the influence of the pulsation of the amount of powder cut out by the cutting machine 24 is absorbed.

  FIG. 3A further shows the relationship between the sampling pulsation period and the sampling period when the sampling period is 1/3 or more of the sampling pulsation period when the sampling speed is small, and FIG. The relationship between the pulsation period and the sampling period in the case of 1/3 or less of the pulsation period of cutout at a low speed is shown. The cutting-out speed of the powder mass measuring device is assumed to be small. 3 (a) and 3 (b) show an increase 1 that is an increase from the measurement value at the first sampling with respect to the measurement value at the second sampling, and 2 for the measurement value at the third sampling. An increase 2 that is an increase from the measurement value at the time of the second sampling, ..., an increase 4 that is an increase from the measurement value at the time of the fourth sampling with respect to the measurement value at the time of the fifth sampling is shown. As is apparent from FIG. 3B, the amount of increase varies with each sampling. As shown in FIG. 3A, when the sampling period is set to 1/3 or more of the pulsation period, the convex portion of the pulsation waveform is surely present within the range of the sampling period for each sampling period. The unit feed amount that absorbs the influence of the pulsation of the cutting machine 24 can be calculated.

Next, the reference time according to the present invention will be described. In the present invention, a reference time is provided as a reference for the time during which the medium speed state and the low speed state are continued. The reference time is n, where n is the number of times sampling is performed.
(Reference time) = DZT + (sampling period) * n (Formula 2)
Is calculated by In order to calculate an accurate unit feed amount, it is preferable to sample three times or more for the reason described above, that is, n ≧ 3.

  The automatic adjustment of the powder mass measuring apparatus according to the present invention will be described. Automatic adjustment can be performed when powders are manufactured for the first time using a powder mass measuring device, or when the bulk density is 1/2 or less, 2 or more times, or the powder shape is significantly different. It is executed to initialize various control parameters related to the weighing control of the powder mass measuring device when the switching is performed. After the initial setting is made by the automatic adjustment, a powder weighing operation in which autonomous weighing control is performed is executed.

  When the terminal PC1 outputs main initial setting data such as the maximum weighing, the sampling cycle, the maximum speed that can be cut out, and the minimum speed to the PLC 10, the storage unit 11 of the PLC 10 stores and sets the initial setting data. Thereafter, when the sequence management unit 14 in the PLC 10 outputs a command for causing the automatic adjustment operation to be performed to the control unit 13, the control unit 13 of the PLC 10 outputs a drive signal including the speed amount to output the powder mass measuring device 20. The automatic adjustment operation is started by driving the driving unit 21. The drive unit 21 cuts out the powder supplied from the supply container 23 while changing the cutting speed of the cutting machine 24 in the order of high speed, medium speed, and low speed based on the drive signal. The cut powder is supplied to the weighing container 25. The measuring unit 22 measures the mass of the powder supplied to the measuring container 25 and outputs the measured value to the PLC 10. The arithmetic processing unit 12 of the PLC 10 calculates automatic adjustment data, which will be described later, based on the input measurement value. After a series of operations, the control unit 13 stops outputting the drive signal, and the automatic adjustment operation ends. Thereafter, the storage unit 11 of the PLC 10 stores and sets the calculated automatic adjustment data.

In automatic adjustment, automatic adjustment data including standard high-speed unit feed amount, standard medium-speed unit feed amount, standard low-speed unit feed amount, slope ratio, and before the next quantification at the time of automatic adjustment, before the next head, and next head can get. The standard high-speed unit feed amount, the standard medium-speed unit feed amount, and the standard low-speed unit feed amount are unit feed amounts that become reference values when the cutting-out speed of the cutting machine is high speed, medium speed, and low speed, respectively. It is. These automatic adjustment data are calculated by the following (Expression 3) to (Expression 9).
(Standard high-speed unit feed amount) = (Last high-speed unit feed amount) (Formula 3)
(Standard medium speed unit feed amount) = (Recent medium speed unit feed amount) (Formula 4)
(Standard slow speed unit feed amount) = (Recent slow speed unit feed amount) (Formula 5)
Here, the most recent high-speed unit feed amount, the most recent medium-speed unit feed amount, and the most recent small-speed unit feed amount are respectively the large speed finally obtained using (Equation 1) during automatic adjustment. The unit feed amount, the medium speed unit feed amount, and the small speed unit feed amount.

The actual feed drop of the powder after stopping at a low speed (the sum of the mass of the powder cut out by the response delay when the cutting machine stops and the mass of the powder falling in the air after stopping at a low speed) If the value divided by is the slope ratio, the slope ratio is calculated using (Equation 6) below.
(Inclination ratio) = (Actual drop) / (Standard small speed unit feed amount) (Formula 6)
Here, the slope ratio is a value that includes the safety factor, and the head ratio before the next quantification at the time of automatic adjustment, before the next head, and the next head before the initial next quantification, before the initial next head, and the initial next head, The initial next head before quantification, the initial next head drop, and the initial next head drop are calculated using the following (Equation 7) to (Equation 9), respectively.
(Before initial measurement) = (Standard high speed unit feed amount) * (Drop ratio) (Formula 7)
(Before initial next drop) = (Reference medium speed unit feed amount) * (Drop ratio) (Formula 8)
(Initial next head drop) = (Reference small speed unit feed amount) * (Tilt ratio) (Formula 9)
In addition, when a lot of stitches is required in the measurement results, the stitch rate may be subtracted from the slope ratio of the second term on the right side of (Equation 9).

  Next, the autonomous weighing control method of the powder mass weighing device according to the present invention will be described. In this autonomous weighing control method, in the first measurement after the above-mentioned automatic adjustment, the high-speed speed obtained by subtracting the initial next head before the initial next quantification, the initial next head, and the initial next head calculated in the automatic adjustment from the mass set value, respectively. The cut-out speed is switched at the switching point, the medium speed speed switching point, and the low speed speed switching point, and before the next quantification, before the next head, and the next head are calculated based on a calculation method and measurement determination described later. At the start of the second measurement, the high speed switching point and medium speed are applied by applying the previous head, before the next head, before the next head, and the next head, which were calculated in the previous weighing, as the pre-quantity, before head, and head, respectively. A switching point and a low speed switching point are calculated. The cut-out speed is switched at each calculated speed switching point, and based on the calculation method and measurement determination described later, the pre-next quantification, the pre-next head, and the next head are calculated. By repeating such an operation, the weighing accuracy and the weighing efficiency become better each time weighing is repeated.

  Hereinafter, the calculation method before the next head, before the next head, and before the next quantification will be described. The next measurement after the current measurement will be the next measurement.

The next drop is calculated using the following (Equation 10).
(Next head) = (head) + (head correction value) (Equation 10)
Here, (head) in (Expression 10) corresponds to the next head calculated using (Expression 10) at the time of the previous measurement. Further, when the measurement error is within the range of the determination value described later, the head correction value is 0, and when the measurement error is outside the range of the determination value, the following (Expression 11) and (Expression 12) A head correction value is calculated. When the weighing error is zero or more,
(Drop compensation value) = (Weighing error) * OCR (Equation 11)
When the weighing error is negative,
(Drop compensation value) = (Weighing error) * NCR (Formula 12)
And OCR is a plus-time FS (flyset: head value) correction ratio, and NCR is a minus-time FS correction ratio, which are appropriately determined and can be preferably less than 1. By applying the next head calculated using (Equation 10) to (Equation 12) as a head at the start of the next measurement, the low speed speed switching point is calculated. By appropriately setting the OCR and NCR, the next measurement error can be reduced, and the measurement error can be gradually reduced every time the number of measurement is repeated.

Before the next drop is calculated using the following (Formula 13).
(Before the next drop) = (Before the next calculated drop) + (Correction value before the next drop) (Formula 13)
The next calculation head and the next head correction value are calculated using the following (Formula 14) and (Formula 15), respectively.
(Before next calculation head) = ((Small speed unit feed amount) * (Reference time) + (Medium speed unit feed amount)) * (Drop ratio) * (Estimated head coefficient) (Formula 14)
(Correction value before the next drop) = (reference time−actual speed at small speed) * (low speed unit feed amount) / (correction coefficient before the drop) (Formula 15)

  Here, the assumed head time coefficient is a constant that is appropriately determined assuming that the powder is in space immediately after switching of the cutting speed, and the pre-head correction coefficient is represented by (Equation 15) (reference time− This is a constant determined in advance in order to adjust the value of (actual speed actual time) * (small speed unit feed amount) as appropriate. The medium speed change point is calculated by applying before the next drop calculated using (Expression 13) to (Expression 15) as the before drop at the start of the next measurement.

  As shown in (Equation 14) and (Equation 15), since the reference time is used to calculate the next calculated head and the correction value before the next head, the small speed time result in the next measurement is used as a reference. The time before the next drop is calculated so as to approach the time.

Before the next quantification, it is calculated using (Equation 16) below.
(Before next quantification) = (Before next calculation quantification) + (Correction value before next quantification) (Formula 16)
The calculation value before the next calculation and the correction value before the next calculation are calculated using the following (Equation 17) and (Equation 18), respectively.
(Before next calculation quantification) = ((medium speed unit feed amount) * (reference time) + (high speed unit feed amount)) * (head ratio) * (head expected time coefficient) (Formula 17)
(Correction value before next determination) = (reference time−medium speed actual time) * (medium speed unit feed amount) / (correction coefficient before determination) (Equation 18)

  Here, the pre-quantification correction coefficient is a constant determined in advance to appropriately adjust the value of (reference time−medium speed actual time) * (medium speed unit feed amount) shown in (Equation 18). The high speed speed switching point is calculated by applying the pre-quantity calculation calculated using (Expression 16) to (Expression 18) as the pre-quantification at the start of the next measurement.

  As shown in (Equation 17) and (Equation 18), since the reference time is used to calculate the next calculation quantification value and the next quantification correction value, the medium speed time result in the next measurement is used as a reference. The next before quantification is calculated so as to approach the time.

  Next, the measurement determination according to the present invention will be described. In the present invention, a judgment value range within a predetermined range is set, and at the time of weighing determination, the calculation error between the final measurement value at the end of measurement and the set mass value is within the determination value range. It is determined whether or not. In addition, a reference time range determined within a predetermined range is set with the reference time calculated using (Equation 2) as the central value, and the small speed time result and the medium speed time result are set in the reference time range at the time of measurement determination. It is determined whether it is within.

  FIG. 4 is a flowchart for determining the next drop, before the next drop, and before the next quantification at the time of measurement determination. As shown in FIG. 4, when it is determined in step 401 that the measurement error is within the determination value range, the process proceeds to step 402. If it is determined in step 402 that the low speed time record is within the reference time range, the process proceeds to step 403. If it is determined in step 403 that the medium-speed time record is within the reference time range, the process proceeds to step 404. Through steps 401 to 403, it is indicated that the measurement error, the low speed time result, and the medium speed time result are within the judgment value range or the reference time range. , Before the head, and the head are stored and updated as before the next quantification, before the next head, and the next head. When it is determined that the weighing error is not within the determination value range, the small speed time result is not within the reference time range, or the medium speed time result is not within the reference time range, the step Proceed to 405. The measurement error, low-speed time record, or medium-speed time record is not within the judgment value range or the reference time range, and the measurement error, low-speed time record, or medium-speed time record is not an appropriate value. Therefore, in step 405, the above-mentioned (Equation 10) to (Equation 19) are used to calculate the previous head before the next quantification, before the next head, and the next head, and to calculate the calculated head before the next time, before the next head, and the next head. At the start of the next measurement, each speed change point at the next measurement is calculated by applying the pre-quantification, before the drop, and the drop, respectively.

  By performing the weighing determination as described above, and calculating the next head, before the next head, and before the next quantification as described above, the small speed time result and the medium speed time result become the reference time each time the measurement is repeated. The weighing error decreases with each approach and weighing. If the measurement error, small-speed time record, and medium-speed time record are acceptable values, the measurement error before measurement, before drop, and drop are memorized and updated so that the values are maintained. If the actual value of the small speed time or the medium speed time is not acceptable, the next head, before the next head, and before the next quantification are calculated so that the value approaches the judgment value and the reference time. It is applied as a head before quantification, before head, and head.

  Further, during the cutting operation, acceleration or deceleration can be applied to the high speed, medium speed, and low speed cutting speeds, and the accelerated / decelerated cutting speed can be reset to the original speed amount. In the present invention, the reference unit feed amount at each speed is compared with the current unit feed amount, and when the unit feed amount is smaller than the predetermined acceleration feed determination value for the second continuous speed during one metering operation. The speed output is accelerated, and the speed output is decelerated when the unit feed amount is larger than the predetermined deceleration feed determination value for the second speed continuously during one weighing operation. For the acceleration and deceleration, the unit feed amount falls below a predetermined acceleration reset value at the second continuous speed at the subsequent cutting speed including the next weighing, or the unit feed amount is a predetermined deceleration reset at the second speed continuous. It is reset when the value is exceeded. Note that the acceleration amount and the deceleration amount can be set individually for high speed, medium speed, and low speed.

  Hereinafter, a control method of the powder mass measuring apparatus according to the second embodiment of the present invention will be described. The weighing control method of the powder mass measuring device according to the second embodiment of the present invention calculates the next head, before the next head, and before the next quantification by the weight control method according to the first embodiment, and also during the current weighing. Based on the change of the measurement value, the latest before and the head are calculated, and the head and the head determined at the start of the current measurement are updated with the calculated previous head and the head. Thereby, even if the unit feed amount changes abruptly during measurement this time, it can respond with high sensitivity. In the following, the latest head and head calculated during the current measurement are defined as the latest head and the latest head, respectively.

At the start of medium-speed measurement, the arithmetic processing unit 12 determines that the ratio of the high-speed time record in the previous measurement and the high-speed time record in the current measurement is out of the predetermined high-speed time record ratio range. In this case, the value before the latest head is calculated using the following (Equation 19).
(Before the latest head) = (Before the head) * (Adjusted ratio before the head) (Formula 19)
Here, (before head) in (Formula 19) corresponds to before the next head calculated using (Formula 13) at the time of previous weighing. If the high-speed time record in the previous measurement is the previous high-speed time record and the high-speed time record in the current measurement is the current high-speed record, the pre-head correction ratio is calculated using the following (Equation 20). .
(Correction ratio before head) = (previous high speed time result / current high speed time result) (Formula 20)
Here, in order to increase the value before the latest head shown in (Equation 19), a predetermined addition coefficient may be added to the pre-head correction ratio shown in (Equation 20).

  When the previous head is calculated using (Equation 19), the head before the head determined at the start of the current measurement is updated by the calculated head before the head, and the head before the head is the head before the current head. When the calculation processing unit 12 determines that the ratio of the previous high speed time result and the current high speed time result is within the predetermined high speed time result ratio range at the start of medium speed measurement, the current measurement starts. The head before the head decided at times is used as it is.

At the start of medium-speed measurement, the arithmetic processing unit 12 determines that the ratio of the high-speed time record in the previous measurement and the high-speed time record in the current measurement is out of the predetermined high-speed time record ratio range. In this case, the latest head is calculated for each sampling using the following (Equation 21) and (Equation 22) during the small-speed measurement.
(Latest head) = (Latest head) + (Head correction value / Head correction coefficient) (Formula 21)
(Latest calculated head) = (head ratio) * (small speed unit feed amount) (Formula 22)

  Here, the small speed unit feed amount shown in (Equation 22) is the latest small speed unit feed amount that is calculated and updated one after another for each sampling during the current measurement. Moreover, the head correction coefficient calculates the latest calculated head that seems to be the optimum value in (Equation 22), but in order to eliminate the measurement error, it uses (Equation 11) and (Equation 12) from the measurement error during the previous measurement. It is a coefficient of about 1.55 for adjusting the calculated head correction value to eliminate the measurement error offset. Furthermore, the head correction value used in (Equation 21) is the head correction value calculated during the previous measurement. When a lot of stitches is required in the measurement results, the stitch rate may be subtracted from the head ratio shown in (Equation 22).

  When the latest head is calculated using (Equation 21), the head determined at the start of the current measurement is updated with the calculated latest head. Since the latest head is calculated and updated one after another for each sampling, the head corresponding to the latest small-speed unit feed amount becomes the head during the current measurement. When the calculation processing unit 12 determines that the ratio of the previous high speed time result and the current high speed time result is within the predetermined high speed time result ratio range at the start of medium speed measurement, the current measurement starts. The head determined at times is used as is.

  As for the pre-quantification at the time of the current measurement, the pre-quantification determined at the start of the current measurement is used as it is. As described above, by calculating and updating the latest head and the latest head, it is possible to respond with high sensitivity even if the unit feed amount changes suddenly during the current measurement.

  The automatic adjustment and measurement control method of the present invention can be widely used in a powder mass measurement apparatus that cuts out powder from a powder container or the like and measures it in an industrial field or the like. Further, although the present invention has been described by taking the three-speed system of high speed, medium speed, and small speed as an example, the present invention can also be applied to a two-speed system including high speed and small speed. Furthermore, if a plurality of commands are output from the sequence management unit using a plurality of communication modules, multi-point input / output modules, etc. in the PLC, the powder mass measurement control method of the present invention can be applied to dozens of powder mass measurements. Applicable to the device.

  The present invention operates using a PLC among control controllers used in the industrial field, but can also be realized by an electronic input / output control device of another control controller such as a sequencer, industrial instrument, DCS, or microcomputer.

In the following, the current measurement is the current measurement, the previous measurement is the previous measurement, and the measurement value at the (n + 1) th sampling is increased from the measurement value at the nth sampling in the current measurement. Is the current increase, the increase from the measurement value at the mth sampling to the measurement value at the (m + 1) th sampling when the (m + 1) sampling was performed in the previous measurement is the previous increase, Assuming that the unit feed amount calculated at the (m + 1) th sampling is the previous unit feed amount (assuming that n ≧ 1, m ≧ 1), the unit feed amount at the (n + 1) th sampling is expressed by ) To calculate.
(Unit feed amount) = (Previous increase + Current increase + Previous unit feed amount * Sampling cycle ) / (Sampling cycle * 3) (Formula 1)

According to a second aspect of the present invention, in the method of the first aspect, at the start of the medium speed measurement, a ratio between the high speed time record in the previous measurement and the high speed time record in the current measurement is set to a predetermined large value. Further comprising determining whether it is within a fast time performance ratio range ;
If it is determined that the ratio is out of the range of the high speed time actual ratio range, the difference between the high speed time actual in the previous measurement and the current high speed time in the previous measurement and the high speed time actual in the current measurement is calculated. Based on the ratio, calculate the latest before the current head, update the calculated previous head as the previous head at the time of the current measurement, and update the latest small speed unit feed amount obtained for each sampling during the low speed measurement. Based on the measured actual head after the small speed stop and the head correction value calculated in the previous measurement, the latest head is calculated for each sampling, and the calculated latest head is updated as a head in the current measurement , When it is determined that the ratio is within the range of the high speed time performance ratio range, the head before the head at the start of the current measurement is the head before the head at the time of the current measurement, and the head at the start of the current measurement is the head of the head at the time of the current measurement. characterized in that To.

Claims (2)

A cutting machine for cutting the powder supplied from the supply container into the measuring container, a driving unit for driving the cutting machine at a high speed, medium speed, or a low speed cutting speed, and being cut into the weighing container A method for controlling a powder mass measuring apparatus comprising a weighing unit that feeds back the mass of the powder as a measured value,
Sampling the measured value fed back from the weighing unit at a predetermined sampling period, and calculating a unit feed amount for each of the high speed, medium speed, and low speed based on the sampling; and
Performing weighing determination after completion of weighing,
The step of executing the weighing determination includes
Determining whether a measurement error of the measurement value from a mass set value is within a determination value range determined in a predetermined range;
It is determined whether or not the low speed time result indicating the actual duration time of the low speed state is within a reference time range defined by a predetermined range with a reference time that is a period including at least three sampling periods as a center value. A determining step;
Determining whether a medium speed time result indicating an actual duration of a medium speed state is within the reference time range;
When it is determined that the measurement error is within the determination value range, and the low-speed time record and the medium-speed time record are within the reference time range, before quantification, before drop, and drop Is stored and updated before the next quantification, before the next drop, and as the next drop,
When it is determined that the measurement error is not within the determination value range, or the small speed time record or the medium speed time record is not within the reference time range,
Calculate the next head based on the head calculated at the previous measurement and the head correction value in the current measurement calculated by correcting to reduce the measurement error,
Based on the unit feed amount at the low speed, the reference time, the medium speed unit feed amount, and the head ratio, calculate the speed before the next head so as to bring the actual small speed time closer to the reference time,
Based on the unit feed amount at the medium speed and the reference time, the high speed unit feed amount, and the head ratio, by calculating the next before quantification so as to bring the medium speed time result closer to the reference time,
A method characterized in that the calculated before next quantification, before the next head drop, and the next head are applied as the pre-quantification, before head drop, and head, respectively, at the start of the next measurement. A step of determining whether or not the ratio of the high-speed time record in the previous measurement and the high-speed time record in the current measurement is within a predetermined high-speed time record ratio set at the start of medium-speed measurement; Including
If it is determined that it is out of the range of the high speed time results ratio range, it is based on the ratio between the high speed time results at the previous measurement and the high speed time results at the previous measurement and the high speed time results at the previous measurement. The latest before the current head is calculated and the calculated latest head before the current head is updated as before the current head, and the latest small speed unit feed amount obtained for each sampling is measured in advance during the small speed measurement. Based on the actual head drop after a low-speed stop and the head correction value calculated in the previous measurement, the latest head is calculated for each sampling, and the calculated latest head is updated as a head in the current measurement. how to.

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