JP2013167594A - Method for driving hopper gate in combination balance, and combination balance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption of a stepping motor which drives opening/closing of a hopper gate of a combination balance.SOLUTION: The torque of a stepping motor 17 in driving opening/closing of a hopper gate 12 is measured in advance according to the pulse number. On the basis of the measured torque, a driving current value of the stepping motor 17 required for driving opening/closing of the hopper gate 12 is obtained according to the pulse number. When driving opening/closing of the hopper gate 12, the driving current of the stepping motor 17 is controlled to the obtained driving current value, and according to the torque required for driving opening/closing of the hopper gate 12, the driving current of stepping motor 17 is changed.

Description

  The present invention relates to a method for driving a hopper gate in a combination weigher including a hopper gate that is opened and closed by a stepping motor, and a combination weigher using the method.

  A combination weigher having a hopper gate that holds and discharges an object to be weighed is widely used in the field of weighing and packaging various products. An air cylinder, a motor, or the like is used as a drive source for the hopper gate. In particular, the stepping motor is suitably used as a hopper gate drive source because of its small size and easy digital control.

  In general, a combination weigher includes a plurality of weighing hoppers for measuring the weight of an input weighing object, and a plurality of supply hoppers for supplying the weighing objects to the weighing hoppers. Each of the plurality of weighing hoppers and the plurality of supply hoppers is provided with a hopper gate for holding and discharging the object to be weighed, and the hopper gate is opened and closed by a stepping motor. For example, in a 10-head combination weigher composed of 10 weighing hoppers, a total of 20 stepping motors are required together with 10 supply hoppers. For this reason, in order to reduce the power consumption of the combination weigher, it is effective to reduce the current consumption of the stepping motor.

  For example, in Patent Documents 1 and 2, the driving current of the stepping motor when the hopper gate is held in the closed state is I1, the driving current of the stepping motor when the hopper gate is held in the open state is I2, and the hopper gate is The drive current of the stepping motor is controlled so that 0 ≦ I1 <I2 <I3, where I3 is the drive current of the stepping motor in the case of opening driving or closing driving.

  As a result, the drive current I2 when the hopper gate is held open is made smaller than the drive current I3 of the stepping motor when the hopper gate is opened or closed, and the power consumption of the stepping motor is reduced. .

JP 2010-38687 A JP 2011-120353 A

  When opening and closing the hopper gate, the required torque varies depending on the opening and closing position of the hopper gate. However, in Patent Documents 1 and 2, the driving current of the stepping motor when opening and closing the hopper gate is controlled to a constant value. This constant value is the maximum value of the drive current required to operate the hopper gate from the closed position (or open position) to the open position (or close position). Therefore, during the opening / closing operation of the hopper gate, the maximum driving current continues to flow to the stepping motor regardless of the required torque changing depending on the opening / closing position of the hopper gate, causing unnecessary power consumption. There is.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a method for driving a hopper gate and a combination weigher in a combination weigher with reduced power consumption.

  In order to achieve the above object, the present invention is configured as follows.

  (1) The hopper gate driving method in the combination weigher of the present invention includes: a hopper that holds and discharges an object to be weighed; a hopper gate that is provided at the discharge port of the hopper; and the hopper gate that rotates according to a pulse. A method for driving the hopper gate in a combination weigher comprising a stepping motor that opens and closes, the first step of measuring the torque of the stepping motor when the hopper gate is driven to open and close according to the number of pulses, Based on the torque measured according to the number of pulses in the first step, a second step for obtaining a driving current value of the stepping motor necessary for opening and closing the hopper gate according to the number of pulses; The drive current is controlled to a drive current value corresponding to the number of pulses obtained in the second step, and the previous And a third step of opening and closing the hopper gate.

  According to the hopper gate driving method in the combination weigher of the present invention, the torque of the stepping motor when the hopper gate is driven to open / close is measured in advance according to the number of pulses, and the hopper gate is driven to open / close based on the measured torque data. The driving current value of the stepping motor required to perform this operation is obtained according to the number of pulses and controlled to this obtained driving current value, so that the driving current of the stepping motor varies depending on the torque required to open / close the hopper gate. Can be made. Therefore, the power consumption of the stepping motor can be reduced as compared with the conventional example in which the maximum driving current required to open / close the hopper gate is always supplied to open / close the stepping motor. A combination weigher having a large number of hopper gates is particularly effective because it can reduce the power consumption of a large number of stepping motors.

  Further, since the driving current of the stepping motor is controlled according to the required torque, it is not necessary to use a CPU having a high processing speed or a plurality of CPUs as a control CPU, compared to a configuration in which the pulse interval is time-controlled. The cost of the combination weigher can be reduced.

  (2) In a preferred embodiment of the present invention, in the second step, the torque measurement data measured according to the number of pulses in the first step is used as original measurement data, and the original measurement data is converted into the number of pulses. On the other hand, the measurement data moved in a direction with a small number of pulses and a direction with a large number of pulses are used as first and second movement measurement data, and the original measurement data and the first and second movement measurement data. The stepping motor drive current value required to open / close the hopper gate is determined according to the number of pulses based on at least the first and second movement measurement data.

  The plurality of pulses may not be the same in the direction in which the number of pulses is small and in the direction in which the number of pulses is large. That is, the first and second movement measurement data have different movement amounts from the original measurement data. Also good.

  In the hopper gate, for example, during assembly, individual differences occur due to variations in the mounting angle of the link mechanism that transmits the rotational power of the stepping motor to the hopper gate to the motor shaft. In this embodiment, the measurement data of the torque of the stepping motor measured in step 1 is shifted from the number of pulses. In this embodiment, the measurement data measured in the first step is used as the original measurement data, and the original measurement data is converted into the number of pulses. On the other hand, since the driving current value of the stepping motor required to open and close the hopper gate is obtained based on the first and second movement measurement data respectively moved in the direction with a small number of pulses and the direction with a large number of pulses. The effects of individual differences can be corrected.

  (3) In another embodiment of the present invention, in the second step, the stepping motor is driven at the start of the transition from the closed position to the open position of the hopper gate and at the start of the transition from the open position to the closed position. Correct and increase the current value.

  According to this embodiment, the driving current value of the stepping motor is increased at the start of the transition from the closed position of the hopper gate to the open position and at the start of the transition from the open position to the closed position, so that the hopper gate is in the closed position or the open position. The hopper gate can be operated by overcoming its inertia, and the step-out at the start can be prevented.

   (4) A combination weigher according to the present invention includes a hopper that holds and discharges an object to be weighed, a hopper gate provided at a discharge port of the hopper, and a stepping motor that rotates according to a pulse to drive the hopper gate to open and close A storage unit that stores information related to the driving current of the stepping motor that is required to open and close the hopper gate, and the stepping motor based on the information stored in the storage unit. And a control unit that controls the driving current according to the number of pulses, and the information stored in the storage unit is obtained based on a torque of the stepping motor that is measured in advance when the hopper gate is opened and closed. Information.

  According to the combination weigher of the present invention, the torque of the stepping motor when the hopper gate is driven to open / close is measured in advance, and information on the driving current of the stepping motor necessary to open / close the hopper gate obtained based on the measurement data is obtained. Since the driving current of the stepping motor is controlled based on the stored information, the driving current of the stepping motor can be changed according to the torque required to open / close the hopper gate. Therefore, the power consumption of the stepping motor can be reduced as compared with the conventional example in which the maximum driving current required to open / close the hopper gate is always supplied to open / close the stepping motor. A combination weigher having a large number of hopper gates is particularly effective because it can reduce the power consumption of a large number of stepping motors.

  Further, since the driving current of the stepping motor is controlled according to the required torque, it is not necessary to use a CPU having a high processing speed or a plurality of CPUs as a control CPU, compared to a configuration in which the pulse interval is time-controlled. The cost of the combination weigher can be reduced.

   (5) In a preferred embodiment of the present invention, the information stored in the storage unit includes the number of pulses and a driving current value of the stepping motor corresponding to the number of pulses.

  According to this embodiment, the driving current of the stepping motor can be controlled according to the number of pulses based on the information stored in the storage unit.

  According to the present invention, since the driving current of the stepping motor is changed according to the torque required to open / close the hopper gate, the maximum driving current required to open / close the hopper gate is always supplied to open / close the stepping motor. The power consumption of the stepping motor can be reduced compared to the conventional example of driving.

  Further, since the driving current of the stepping motor is controlled according to the required torque, it is not necessary to use a CPU having a high processing speed or a plurality of CPUs as a control CPU, compared to a configuration in which the pulse interval is time-controlled. The cost of the combination weigher can be reduced.

FIG. 1 is a schematic configuration diagram of a combination weigher according to an embodiment of the present invention. FIG. 2 is a block diagram showing a schematic configuration of the hopper gate driving mechanism of FIG. FIG. 3 is a diagram showing the relationship between the torque of the stepping motor measured in advance and the number of pulses. FIG. 4 is a diagram showing the measurement data of FIG. 3 and the driving current of the stepping motor calculated from the measurement data. FIG. 5 is a diagram showing a table stored in the memory of the combination weigher of FIG. FIG. 6 is a diagram for explaining processing of measurement data according to another embodiment of the present invention. FIG. 7 is a diagram for explaining processing of measurement data according to still another embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram showing a schematic configuration of a combination weigher according to an embodiment of the present invention.

  The combination weigher 1 of this embodiment includes a main feeder 3 that vibrates a conical top cone 2 disposed at the upper center of the center, and radially disperses the objects to be weighed on the top cone 2. A plurality of linear feeder pans 5 arranged in a circle around each of them are vibrated to provide a plurality of linear feeders 6 for conveying the objects to be weighed and distributed from the top cone 2, and corresponding linear feeder pans 5. The plurality of supply hoppers 4 to which the objects to be weighed are supplied from the respective linear feeder pans 5, the plurality of weighing hoppers 7 for respectively weighing the objects to be weighed supplied from the respective supply hoppers 4, and the hoppers 4 and 7 A plurality of link mechanisms 13 for opening and closing the hopper gate 12, and a collecting chute 8 for receiving an object to be weighed from each weighing hopper 7 and discharging it to a packaging machine (not shown) below. A plurality of frames 10 for supporting the body 9, and a base 11 supporting the frame 10.

  In the combination weigher 1, an object to be weighed is supplied onto a top cone 2 from a supply path (not shown) provided above, and the top cone 2 conveys the object to be weighed to each linear feeder pan 5. Each linear feeder pan 5 supplies an object to be weighed to each supply hopper 4 by vibration. The supply hopper 4 holds the supplied weighing object, opens the hopper gate 12 at a predetermined timing, and supplies the weighing object to the weighing hopper 7. The weighing hopper 7 holds and weighs the object to be weighed received from the supply hopper 4. A control unit (not shown) obtains a combination of the weighing hoppers 7 such that the sum of the weighing values of the respective weighing hoppers 7 is larger than the preset target weight and is closest to the target weight, and selects the combination. The hopper gate 12 of the weighing hopper 7 thus opened is opened to discharge the object to be weighed. The hopper gates 12 of the supply hopper 4 and the weighing hopper 7 are opened and closed by a hopper gate driving mechanism shown in FIG.

  FIG. 2 is a block diagram showing a schematic configuration of the hopper gate driving mechanism.

  The rotation of the hopper gate drive mechanism of this embodiment is controlled by the control device 14, the power supply 15, a drive unit (driver) 16 that receives a control signal from the control device 14 and power from the power supply 15, and the drive unit 16. The stepping motor 17, the above-described link mechanism 13 that is attached to the motor shaft (rotary shaft) of the stepping motor 17 and transmits the rotation force of the stepping motor 17, and the above-described link mechanism 13 that opens and closes by the driving force transmitted from the link mechanism 13. And a hopper gate 12.

  The control device 14 includes a CPU 18 and a memory (storage unit) 19. The CPU 18 outputs a current control signal for controlling a driving pulse and a driving current to the driving unit 16. The memory 19 stores table data, operation programs, and the like for controlling the drive current of the stepping motor 17 described later.

  The pulse output from the control device 14 to the drive unit 16 is a pulse signal for driving the stepping motor 17, and every time one pulse is input, the stepping motor 17 has one step angle. In form, it rotates by 0.9 degrees.

  Therefore, in this embodiment, the motor shaft of the stepping motor 17 rotates once by 400 pulses. The rotation of the stepping motor 17 is connected to the hopper gate 12 by the link mechanism 13, and a series of operations for opening and closing the hopper gate 12 is performed when the motor shaft of the stepping motor 17 rotates once. The torque required to open / close the hopper gate 12 is not constant and varies depending on the opening / closing position of the hopper gate 12.

  In this embodiment, in order to save power in the combination weigher, the drive current of the stepping motor 17 that drives the hopper gate 12 to open and close is reduced as much as possible.

  For this reason, when one hopper gate 12 is driven to open and close, the torque applied to the motor shaft of the stepping motor 17 is measured in advance using a torque meter.

  FIG. 3 is a diagram showing the relationship between the torque applied to the motor shaft of the stepping motor 17 measured in advance and the number of pulses corresponding to the open / close position of the hopper gate 12.

  The torque measurement data in FIG. 3 is obtained by rotating the motor shaft of the stepping motor 17 every 9 degrees, that is, every 10 pulses, and measuring the torque necessary for the link mechanism 13 to move with the torque measuring device. .

  In the stepping motor 17 of this embodiment, a series of opening / closing operations of the hopper gate 12 is performed by rotating the motor shaft by 360 degrees, that is, by one rotation with 400 pulses as described above. Therefore, in FIG. 3, the pulse number 0 and the pulse number 400 correspond to the fully closed position of the hopper gate 12, and the pulse number 200 corresponds to the fully open position of the hopper gate 12.

  In FIG. 3, the measured torque corresponding to the number of pulses 201 to 400 at which the hopper gate 12 shifts from the fully open position to the fully closed position, that is, the measured torque corresponding to the closing operation of the hopper gate 12 is indicated by its absolute value. .

  Since a proportional relationship is established between the torque applied to the motor shaft of the stepping motor 17 and the drive current of the stepping motor 17, the torque applied to the motor shaft of the stepping motor 17 measured as described above is used. Find the proportionality constant.

  Therefore, the minimum drive current required to open the hopper gate 12 from the fully closed position to the fully open position is measured, and the minimum drive current required to close the hopper gate 12 from the fully open position to the fully closed position is measured. measure.

As shown in FIG. 3, the measured torque becomes maximum at around 120 pulses as shown in FIG. 3 in which the hopper gate 12 is opened from the fully closed position to the fully opened position. _Set to ₁ . Further, the minimum drive current required to change the hopper gate 12 from the fully closed position to the fully open position, that is, the maximum drive current among the drive currents required to change the hopper gate 12 from the fully closed position to the fully open position is measured. Assuming that the measured value is I ₁ , the proportional constant α ₁ between the torque of the stepping motor 17 and the drive current of the stepping motor 17 in the interval of 0 to 200 pulses is
α ₁ = I ₁ / T ₁
It becomes.

Further, in the section of the number of pulses 201 to 400 in which the hopper gate 12 is closed from the fully open position to the fully closed position, as shown in FIG. 3, the measured torque becomes the maximum around the number of pulses 280 as shown in FIG. The torque is the same T ₁ as described above. The minimum required drive current measured hopper gate 12 from the fully open position to the fully closed position and the measured value I _2. In this embodiment, the link mechanism 13 is provided with a spring for urging the hopper gate 12 in the closing direction. Therefore, in the closing operation for moving the hopper gate 12 from the fully open position to the fully closed position, the urging force of the spring is used. Therefore, the measured value I ₂ becomes smaller than the measured value I ₁ when the hopper gate 12 is opened from the fully closed position to the fully opened position. The proportional constant α ₂ between the torque of the motor shaft of the stepping motor 17 and the drive current of the stepping motor 17 at this time is
α ₂ = I ₂ / T ₁
It becomes.

Therefore, in the section of 0 to 200 pulses from the fully closed position to the fully open position of the hopper gate 12, the measured torque T and the proportional constant α _{1 are used} as the drive current of the stepping motor 17 required to open the hopper gate 12. Thus, the drive current Id of the stepping motor 17 corresponding to the number of pulses can be calculated according to the following equation.

Id = α ₁ × T (1)
Similarly, in the section of the pulse number 201 to 400 from the fully open position to the fully closed position of the hopper gate 12, the measured torque T and the proportional constant α are used as the drive current of the stepping motor 17 necessary for closing the hopper gate 12. ₂ , the drive current Id of the stepping motor 17 corresponding to the number of pulses can be calculated according to the following equation.

Id = α ₂ × T (2)
FIG. 4 shows the relationship between the drive current of the stepping motor 17 and the number of pulses calculated every 10 pulses based on the proportional constants α ₁ and α ₂ and the measured torque applied to the motor shaft of the stepping motor 17. FIG.

  In FIG. 4, the torque of FIG. 3 measured in advance is indicated by a broken line, and the drive current of the stepping motor 17 calculated as described above is indicated by a solid line.

In FIG. 4, for every 10 pulses, the drive current is calculated by multiplying the maximum torque between them by a proportional constant α ₁ or α ₂ .

In this embodiment, correction values β ₁ and β ₂ are added to the above formulas (1) and (2), which are calculation formulas of the drive current Id in each section of the pulse number 0 to 200 and the pulse number 201 to 400. ing.

That is, the drive current Id in the interval of 0 to 200 pulses is calculated by the following equation:
Id = α ₁ × T + β ₁ (3)
The drive current Id in the interval of 201 to 400 pulses is calculated by the following formula.

Id = α ₂ × T + β ₂ (2)
The correction values β ₁ and β ₂ may be, for example, values of about several percent of (α ₁ × T) and (α ₂ × T).

  In this embodiment, the drive current value of the stepping motor 17 necessary for opening and closing the hopper gate 12 is calculated as described above, and the calculated drive current value of the stepping motor 17 is stored in the memory 19 of the combination weigher 1. A table is stored, and when the hopper gate 12 is driven to open and close, the driving current value of this table is read, and each stepping motor 17 is driven by the driving current value.

  FIG. 5 is a diagram showing an example of a table of the drive current value, and stores the torque of the motor shaft of the stepping motor 17 and the drive current value of the stepping motor 17 in a section of 1 to 400 pulses every 10 pulses. . The torque may be omitted.

The proportional constants α _1, α ₂ and the correction values β ₁ , β ₂ , or the drive current value stored in the memory 19 are obtained from an input / output device (not shown) such as a touch panel of the combination scale 1. For example, when the hopper is replaced with a new hopper, the driving current value corresponding to the new hopper may be changed.

  As described above, the torque applied to the motor shaft of the stepping motor 17 that opens and closes the hopper gate 12 is measured in advance according to the number of pulses, and the driving current of the stepping motor 17 corresponding to the measured torque is obtained and stored in the memory 19. When the hopper gate 12 is driven, the stepping motor 17 is driven with the driving current value read from the memory 19, so that the driving current can be changed according to the torque required to open and close the hopper gate 12. As a result, the power consumption of the stepping motor 17 can be reduced as compared with the conventional example in which the stepping motor 17 is driven to open and close by always passing the maximum drive current required to open and close the hopper gate 12.

  In a combination weigher having a large number of hopper gates 12, the power consumption of a large number of stepping motors 17 can be reduced, which is effective for so-called energy saving.

  Further, in the case of controlling the driving of a large number of stepping motors 17, in this embodiment, the driving current of the stepping motor 17 is controlled according to the required torque. Further, it is not necessary to use a high processing speed CPU or a plurality of CPUs, and the cost of the combination weigher can be reduced.

  In this embodiment, the torque of the stepping motor 17 is measured every 10 pulses and the driving current value of the stepping motor 17 is calculated. However, the present invention is not limited to 10 pulses, and the stepping motor 17 is not limited to every arbitrary number of pulses. And the drive current value of the stepping motor 17 may be calculated.

  In this embodiment, the torque of the stepping motor 17 when one hopper gate 12 is driven to open and close is measured in advance, the drive current value of the stepping motor 17 is calculated based on the measured torque data, and the calculated drive current is calculated. Although each stepping motor 17 is driven with a value, as another embodiment of the present invention, the torque of each stepping motor 17 that individually opens and closes each hopper gate 12 is measured, and based on the measured torque data, A driving current value may be calculated for each stepping motor 17 and driven.

(Embodiment 2)
In the above-described embodiment, the torque applied to the motor shaft of the stepping motor 17 that drives the hopper gate 12 to open and close is measured, and the driving current of the stepping motor 17 is calculated based on the measured value. Due to individual differences. For example, when the hopper gate is assembled, individual differences occur due to variations in the mounting angle of the link mechanism 13 to the motor shaft of the stepping motor 17.

  Due to this individual difference, the torque measurement data with respect to the number of pulses shown in FIG. 3 is about several pulses, in a direction with a small number of pulses (left direction in FIG. 3) or a direction with a large number of pulses (right direction in FIG. 3). Will slip.

  Therefore, in this embodiment, the following is performed in order to correct the influence of such individual differences.

  That is, as in the above-described embodiment, for one of the hopper gates 12, the torque applied to the motor shaft of the stepping motor 17 is measured to obtain measurement data similar to FIG. 3 indicated by the broken line in FIG. This measurement data is used as original measurement data, and then the original measurement data is moved in a direction (left direction) in which the number of pulses is small, for example, 10 pulses, as shown by a one-dot chain line in FIG. That is, it is moved back by 10 pulses to obtain the first movement measurement data, and the original measurement data is moved in the direction of increasing the number of pulses (right direction) as shown by the two-dot chain line in FIG. The second movement measurement data is obtained by advancing by the pulse.

  Among these measurement data, measurement data with the maximum torque in each pulse is extracted and used as extracted measurement data indicated by a solid line.

Based on the extracted measurement data, proportional constants α ₁ and α ₂ are calculated in the same manner as in the above-described embodiment, and in the same manner as in the above-described embodiment, the drive current of the stepping motor 17 is calculated and stored in the memory 19. Store as a table.

  Other configurations are the same as those of the above-described embodiment.

  In this embodiment, the first and second movement measurement data may be moved by different pulse numbers although the original measurement data has been moved by the same pulse number.

(Embodiment 3)
FIG. 7 is a diagram showing extracted measurement data corresponding to FIG. 6 according to still another embodiment of the present invention.

  In this embodiment, the extracted measurement data of FIG. 6 described above is corrected. At the start of the transition of the hopper gate 12 from the closed position to the open position and at the start of the transition from the open position to the closed position, for example, 20 The drive current value of the stepping motor 17 is corrected and increased by about the pulse. In this example, the torque is corrected to the same as the maximum torque, and the same as in the above-described embodiments based on the corrected extracted measurement data. Thus, the drive current value of the stepping motor 17 is obtained.

  As a result, when the transition from the closed position of the hopper gate 12 to the opening operation is started and when the transition from the opening position to the closing operation is started, the drive current value of the stepping motor 17 is increased, so that the hopper gate in the closed position or the opened position 12 can be operated by overcoming its inertia, and step-out at startup can be prevented.

  The combination weigher and the hopper gate driving method in the combination weigher according to the present invention are useful for suppressing power consumption.

1 Combination Weigher 4 Supply Hopper 7 Weighing Hopper 12 Hopper Gate 14 Control Device 17 Stepping Motor 18 CPU
19 Memory

Claims (5)

Driving the hopper gate in a combination weigher comprising a hopper that holds and discharges an object to be weighed, a hopper gate provided at a discharge port of the hopper, and a stepping motor that rotates in response to a pulse and drives the hopper gate to open and close A method,
A first step of measuring the torque of the stepping motor when the hopper gate is opened and closed in advance according to the number of pulses;
A second step of determining a driving current value of a stepping motor necessary for opening and closing the hopper gate according to the number of pulses based on the torque measured according to the number of pulses in the first step;
A third step of controlling the driving current of the stepping motor to a driving current value corresponding to the number of pulses obtained in the second step and driving the hopper gate to open and close;
A method for driving a hopper gate in a combination weigher. In the second step, the measurement data of the torque measured in accordance with the number of pulses in the first step is used as original measurement data, and the original measurement data is less than the number of pulses by a plurality of pulses. The measurement data moved in the direction and the direction with a large number of pulses are used as the first and second movement measurement data, and at least the first and second movement measurements among the original measurement data and the first and second movement measurement data. Based on the data, obtain the driving current value of the stepping motor necessary to open and close the hopper gate according to the number of pulses.
A method for driving a hopper gate in the combination weigher according to claim 1. In the second step, at the start of transition from the closed position of the hopper gate to the open position and at the start of transition from the open position to the closed position, the driving current value of the stepping motor is corrected and increased.
A method for driving a hopper gate in the combination weigher according to claim 1 or 2. A combination weigher comprising a hopper that holds and discharges an object to be weighed, a hopper gate provided at a discharge port of the hopper, and a stepping motor that rotates in response to a pulse to drive the hopper gate to open and close,
A storage unit that stores information related to the driving current of the stepping motor necessary for opening and closing the hopper gate, and the driving current of the stepping motor based on the information stored in the storage unit is set to the number of pulses. And a control unit that controls according to
The information stored in the storage unit is information obtained based on a torque of the stepping motor when the hopper gate measured in advance is opened and closed.
A combination weigher characterized by that. The information stored in the storage unit includes the number of pulses and the driving current value of the stepping motor corresponding to the number of pulses.
The combination weigher according to claim 4.

Images