JP2009036740A - Weight-measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure weight, using a digital load cell having a different rating instead of a digital load cell that is determined as being abnormal, when a digital load cell in respective digital load cells is abnormal, in a weight-measuring device that uses a plurality of digital load cells. <P>SOLUTION: In the weight-measuring device for measuring the weight of one object to be measured where load action points are located at a plurality of locations using a plurality of digital load cells, provided corresponding to the action points of the loads, the weight using a new digital load cell having a different rating can be used in place of the digital load cell determined as being abnormal, when a digital load cell in the respective digital load cells is determined as being abnormal, presupposing that each of the plurality of digital load cells is appropriately connected. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The invention of this application relates to a weight measuring device using a plurality of digital load cells.

For example, in an automatic scale such as a hopper scale, a packer scale, or a truck scale, a weight detection means such as a digital load cell is provided at an appropriate portion of a plurality of load application points on a weighing container or a weighing platform, and each of the plurality of weight detection means is provided. By integrating the detected values with a weight generator, the weight of the object to be weighed (the total weight including the weight of the load in the case of a truck scale) is measured (so-called multi-load cell method) (See Patent Literature 1, Patent Literature 2, Patent Literature 3, etc.)
In the case of a weight measuring apparatus adopting such a multi-load cell system, each of the plurality of load cells has recently been provided with an amplifier or an A in the load cell unit main body from the viewpoint of measurement accuracy, temperature compensation, anti-noise performance, and the like. Digital type load cells incorporating / D converters, microcomputers and the like have been increasingly used, and all of these digital load cells of course have the same rating.

JP 2003-28707 A JP 2002-243562 A JP 2006-112986 A

  However, in the case of a weight measuring device configured using a plurality of digital load cells as described above, it is necessary to determine what digital load cell is abnormal when an abnormality occurs.

  When it is possible to grasp what digital load cell is abnormal, it is necessary to replace the digital load cell with a normal one. However, depending on the situation on the user side, there is a digital load cell with the same rating to be replaced. In such a case, the weight measurement cannot be continued as it is.

  The invention of this application was made to solve such a problem, and on the premise that each of the plurality of digital load cells is appropriately connected and installed, while determining whether each of the digital load cells is abnormal, It is an object of the present invention to provide a weight measuring apparatus capable of measuring weight using a digital load cell having a different rating instead of a digital load cell determined to be abnormal.

  In order to achieve the object, the invention of this application includes the following problem solving means.

(1) Invention of Claim 1 This invention measures the weight of one measuring object in which the point of action of a load exists in a plurality of places using a plurality of digital load cells provided corresponding to the point of action of the load. In the weight measuring device thus configured, it is determined that any one of the digital load cells is abnormal on the assumption that each of the plurality of digital load cells is appropriately connected. In this case, it is possible to measure the weight using a digital load cell with a different rating instead of the digital load cell determined to be abnormal.

  According to such a configuration, the abnormality of each digital load cell is appropriately determined on the assumption that each of the plurality of digital load cells is properly connected.

  If any of the digital load cells is determined to be abnormal, weight measurement can be performed using a normal digital load cell with a different rating instead of the digital load cell.

  Therefore, even when there is no digital load cell with the same rating due to circumstances at that time, measurement can be continued using a new digital load cell with a different rating, which is very convenient.

(2) The invention of claim 2 This invention comprises weight value conversion means for converting the digit value of the count data of each digital load cell into a weight value of a predetermined unit in the configuration of the invention of claim 1 above, It is characterized in that the final weight value is calculated by converting the digit value of the count data of the digital load cell into a weight value of a predetermined unit and integrating the digit values.

  As described above, when the rating of the digital load cell is different, the digit value of the output count data is also different. For this reason, in order to eliminate the measurement error caused by this, for example, digit values between digital load cells having different ratings are converted into weight values in a predetermined unit such as kg, and then an accurate weight value is calculated.

(3) Invention of Claim 3 In this invention, in the configuration of the invention of Claim 1 or 2, the measurement ability of the digital load cell having the lowest measurement accuracy in the plurality of digital load cells is used as the measurement ability of the weight measuring device. It is characterized by having made it correspond.

  As described above, it should be noted that when using a plurality of digital load cells having different ratings, the measurement accuracy of each digital load cell is different. Therefore, in this case, the accuracy of the digital load cell having the lower measurement accuracy is set as the accuracy of the scale.

  As a result, a scale with the above configuration that uses digital load cells with different ratings is effective as long as the digital load cell with lower measurement accuracy and lower weight does not violate the capacity required for the scale. Can be used for.

  1 to 4 show the configuration and operation of a weight measuring apparatus using a plurality of digital load cells according to the preferred embodiment of the invention of this application.

(Features of the device)
The weight measuring apparatus according to this embodiment includes (a) a function for detecting that a load acting on a plurality of digital load cells has become an unbalanced load, and (b) an output value of each of the plurality of digital load cells. The deviation of the weight detection value indicated based on the above is calculated and recorded in a predetermined data memory, and when the calculated deviation is larger than the predetermined reference value, the failure of the digital load cell is judged and displayed. (C) a function capable of measuring the weight using a normal digital load cell with a different rating in place of the digital load cell when the failed digital load cell is found. Configured.

(Configuration of device application example)
As described above, the weight measuring device can be applied to various automatic scales such as a hopper scale, a packer scale, and a track scale. In this embodiment, for example, as shown in FIG. The four side walls of the weighing container (hopper) 1 are connected between the upper and lower connecting members of the latching tools 2a to 2d and the hanging tools 3a to 3d, and the load cell (straining body) portion is weighed. The first to fourth digital load cells 4a to 4d configured so that the load of the container 1 and the object to be weighed in the weighing container 1 is applied, and the first to fourth digital load cells 4a to 4d. A supporting frame 5 that supports the weighing container 1 in a suspended state, and a limit switch LS required to prevent the weighing container 1 from descending when the hanging tools 3a to 3d are cut. It is configured as a hopper scale consisting of a stopper member 6a~6d provided.

(Configuration of first to fourth digital load cells 4a to 4d)
The first to fourth digital load cells 4a to 4 are each provided with a predetermined output of a strain-generating body LC and an analog strain output from a strain gauge provided in the strain-generating body LC in a cassette-type main body casing that can be suspended. A voltage amplifier A that amplifies the signal to the level, and an analog / digital converter A / that converts the analog output amplified to a predetermined level by the voltage amplifier A into a digital signal corresponding to the applied load value by sampling with a predetermined sampling pulse. D, the digital load signal from the analog / digital converter A / D is input via the input side interface circuit I / O, and the load characteristics (linearity, hysteresis characteristics, etc.) based on the shape of the strain body LC, etc. Microcomputer unit CPU that performs correction and temperature compensation, external weight generation of corrected load detection value from microcomputer unit CPU It has from incorporating module structure together each of the output side interface circuit I / O to be output (such as the configuration personal computer PC / Programmable Logic Controller PLC) 10 location.

Each of the first to fourth digital load cells 4a to 4d individually has an identification number (digital code No.) including the relationship with the mounting positions at the four front, rear, left and right positions of the weighing container 1, and will be described later. The normal / abnormal state of each of the digital load cells 4a, 4b, 4c, 4d can be grasped from the digital display screen portion of the indicator DISP ₁ of the weight generating apparatus 10 to be operated.

  When any one of the first to fourth digital load cells 4a to 4d is found to be abnormal (failed), the digital load cell itself or the main body casing of the digital load cell is stored. The module structure (LC, A, A / D, I / O, CPU, I / O) that has the same rating (or a different rating if there is no same rating) may be used.・ The measurement can be continued by exchanging with later.

(Configuration of weight generator 10)
On the other hand, the weight generation device 10 includes an interface circuit I / O corresponding to the outputs of the first to fourth digital load cells 4a to 4d and the first to first input signals inputted via the input interface circuit I / O. The weight indicator DSP ₁ that integrates and displays the weight detection values of the four digital load cells 4a to 4d and calculates the weight detection values (digit values) of the first to fourth digital load cells 4a to 4d, respectively. The load acting on the first to fourth digital load cells 4a to 4d, which should be essentially equal based on the detected output values of the first to fourth digital load cells 4a to 4d, is an unbalanced load. The alarm sound generator B is driven to generate a warning sound, and the detected output values (decodes) of the first to fourth digital load cells 4a to 4d are determined. It calculates a deviation of the weight measurement value indicated by the JIT value) may be recorded in the deviation data memory M _1, the first to the fourth digital load cell 4a~4d each abnormality based on the same deviation data (fault) When the judgment sound is displayed and the alarm sound generator B is driven as necessary to cause the operator to generate a warning sound and the abnormal (failed) digital load cell is found, a different rating is used instead of the digital load cell. Stores (registers) the arithmetic processing unit 10a having a measurement program for measuring the weight using a normal digital load cell, the status display unit DISP _2, and the number and identification number of the preliminarily digital load cells 4a to 4d. And a memory M ₂ that is connected to the memory M ₂ .

(Connection method of first to fourth digital load cells 4a to 4d and determination method of unbalanced load, failure, etc.)
Processing unit 10a of the weight generation unit 10, for example, as shown in step S ₁ to S ₈ of the flowchart of FIG. 3, first to a proper connection state of a fourth digital load cell 4a~4d each (connection Presence / absence), presence / absence of unbalanced load, presence / absence of abnormal cell (failed cell), and the like.

That is, the weight from the weighing by the power ON is started, first in step S _1, the first to fourth digital load cell 4a~4d whose number and identification number is pre Ji fit registered in the memory M ₂ The detection value (digit value) is input to the calculation unit.

In step S _2, based on whether there is a digit entry from the first to fourth digital load cell 4a~4d each in their respective digital load cell 4a~4d proper (actually) is connected to determine dolphin not, the process proceeds to the next step S ₄ in the case of there connected to all, if not connected even one or it is determined that no connection, the process proceeds to step S _8, above The alarm sound generator (such as a buzzer) B is driven to issue a warning to the operator.

First through if the procedure advances to Step S ₂ from Step S ₃ as each of the fourth digital load cell 4a~4d is properly connected, above the step S ₃ first to fourth digital load cell determines whether the weight detected value has stabilized from 4 a to 4 d (wait for stabilization), when the YES determination as stable made, the inclination degree of the weight value detected proceeds to step S ₄ (%) From this, it is determined whether or not there is an offset load (whether there is no offset of a predetermined percentage or more).

Then, as a result, when it is determined that there unbalanced load generates an alarm sound proceeds when similarly to Step S ₈ without connections described above.

  In this case, the reference value of the offset load can be arbitrarily set by the user, for example, with the indicator 10a on the weight generating device 10 side. For example, when the offset load is 10%, it exceeds 10%. At that time, a warning display is displayed on the screen of the indicator 10a and a warning sound is generated.

  In the example of two hopper scales 4a and 4b having different ratings as shown in FIGS. 1 and 4, for example, a warning is generated when 10%, that is, any of 4a and 4b exceeds 500 × 10 + 500 = 550 kg. Will do.

On the other hand, when no offset load non cause unbalanced load is directly proceeds to step S _5, recorded in the memory M ₁ The weight detection value at that time as a tentative normal detection value. Then, further in the subsequent step S _6, memory to the deviation value memory M ₁ calculates the deviation of the first to fourth digital load cell 4a~4d4 set of detection values, respectively the value to the base.

  In this case, the calculation of the deviation value is performed as follows, for example, as in the case of calculating the deviation value of the entrance examination.

Deviation value of each weight detection value = 10 × ((actual measurement value−average value) / standard deviation (σ) +50
Next, the deviation value of the weight detection value of each of the first to fourth digital load cells 4a to 4d is larger than a predetermined reference value (for example, set arbitrarily by the user in the range of 45 to 55). Or if it is less than or equal to the reference value, it is determined that there is no faulty cell, and the control for determining the failure etc. is terminated and the normal measurement control operation is performed. .

On the other hand, if there is greater than the deviation value as a the reference at any one hanging digital load cell of the first to fourth digital load cell 4 a to 4 d (45 to 55), the process proceeds to step S ₈ described above A warning sound is generated as a failure cell exists.

  In the above case, in the same configuration, the load of the weighing object is configured to act as a hanging load on the strain generating body portions of the digital load cells 4a to 4d, and the load cell portion is cut off. It is also possible to determine that an abnormality has occurred and generate a warning.

  As described above, when the load of the weighing object is configured to act as a hanging load on the strain generating bodies Lc, Lc... Of the digital load cells 4a to 4d, the load cell portion is not cut. Even in this case, the digital load cells 4a to 4d cannot detect an appropriate weight as in the above cases.

  Therefore, in such a case, if it is determined to be abnormal and a warning is generated in the same manner as described above, the limit switches LS, LS,. A failure cell can be found in advance.

  As a result, the operator grasps the digital load cell determined to be abnormal (failure) based on the identification number described above, replaces the digital load cell itself (or its circuit module part), and performs an appropriate weighing operation again. Can be migrated.

The deviation values (45 to 55) serving as the above reference can be set as desired by the user with the indicator DISP ₁ on the weight generating apparatus 10 side. The reason why the calculation formula of the deviation value is the same as that of the entrance examination is to make it as easy as possible for the user to use.

(Weight measurement using digital load cells with different ratings)
As described above, when it is determined that there is a failure and the digital load cell (or its circuit module portion) is to be replaced, if one with the same rating is prepared, it is preferable to use it.

  However, depending on the situation on the user side, there may be cases where there is no one with the same rating. In such a case, measurement cannot be continued with the conventional measuring apparatus.

  Therefore, in the arithmetic processing unit 10a of the weight generating apparatus 10 of this embodiment, in order to solve such a problem, an arithmetic operation that can continue weight measurement using digital load cells (or circuit modules thereof) having different ratings. It is configured with a program.

  For example, in the case of the hopper scale as shown in FIG. 1 above, if the first and second digital load cells 4a and 4b have different ratings as shown in FIG. become.

That is, as shown in FIG. 4, when a 1.0t container is placed on the weighing container 1, both the first and second digital load cells 4a and 4b have a load of 0.5t regardless of the rating. In general, the integrated value of the two count data is displayed on the weight indicator DISP ₁ in FIG.

  By the way, the count data of the first and second digital load cells 4a and 4b are normally output as follows.

Since the first digital load cell 4a has a rated capacity = 1t, a rated output 600,000, and a scale interval = 0.2 kg, the count value is 300,000 counts. The second digital load cell 4b has a rated capacity = Since 2t, rated output 1 million, and scale interval = 0.5kg, 0.5t, the count value is 250,000 counts.

  As described above, the digit value of the output count data differs depending on the rating of the digital load cell. For this reason, it is necessary to convert each digit value to, for example, kg which is a predetermined weight unit (of course, other weight units may be used depending on the country used), and to calculate an accurate weight value.

  Therefore, the calculation formula used in the actual weight generating apparatus 10 is as follows.

Digital load cell = (rated capacity) x (actual value) / (rated output) x (number of digital load cells)
1st digital load cell 4a = 1,000 (kg) x 300,000 (count) / 600,000 x 2 = 500 (kg)
Second digital load cell 4b = 2,000 (kg) x 250,000 (count) / 1 million x 2 = 500 (kg)
It should be noted here that the measurement accuracy of the first digital load cell 4a is different from that of the second digital load cell 4b. In this case, the accuracy of the digital load cell having the lower measurement accuracy is set as the accuracy of the scale.

  Therefore, unless the digital load cell with lower accuracy and lower weight violates the capacity that should be required for the scale, the scale using differently rated digital load cells 4a and 4b should be used effectively. Can do.

  As a result, even when there is no digital load cell with the same rating, the measurement can be continued using a digital load cell with a different rating, which is very convenient.

  The tolerance of an automatic weighing instrument (automatic scale) such as the hopper scale of this embodiment is determined as shown in the following table in the Japanese Industrial Standard (JISB7603-1986: 5. Performance-5.1 tolerance). It has been.

  In the above example, the rated capacity is 1 t and the scale is 0.5 kg, so that the static tolerance of class 1 in this table is satisfied. Therefore, the weight measuring device according to this embodiment can sufficiently cope with the law.

1 is a schematic diagram showing a hardware configuration of a weight measuring device according to a best embodiment of the invention of this application. It is a block diagram which shows the electric circuit structure of the same weight measuring apparatus. It is a flowchart which shows the determination operation | movement which determines the connection state of the digital load cell in the same weight measuring apparatus, an unbalanced load state, and a failure state. It is explanatory drawing at the time of measuring weight using the digital load cell of a different rating in the same weight measuring apparatus.

Explanation of symbols

1 is a weighing container, 2a to 2d are locking tools, 3a to 3d are hanging tools, 4a to 4d are first to fourth digital load cells, 10 is a weight generating device, 10a is an arithmetic processing unit, and DISP ₁ is weight. An indicator, DISP ₂ is a status display section, M ₁ is a deviation value data memory, and B is an alarm sound generator.

Claims (3)

  A weight measuring device configured to measure the weight of one weighing object having a plurality of load action points at a plurality of locations using a plurality of digital load cells provided corresponding to the load action points, Assuming that each of the plurality of digital load cells is properly connected, if any of the digital load cells is determined to be abnormal, the digital load cell is determined to be abnormal. A weight measuring device that enables weight measurement using digital load cells with different ratings.   By providing weight value conversion means for converting the digit value of the count data of each digital load cell into a weight value of a predetermined unit, by converting the digit value of the count data of each digital load cell into a weight value of a predetermined unit and integrating 2. The weight measuring apparatus according to claim 1, wherein a final weight value is calculated.   3. The weight measuring device according to claim 1, wherein the measuring capability of the digital load cell having the lowest measurement accuracy in the plurality of digital load cells is made to correspond to the measuring capability of the weight measuring device.

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