JP2016153803A - Indicator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an indicator that reduces human and economic burdens in investigating the cause why the accurate weight is not displayed on the indicator.SOLUTION: An indicator estimates the cause of a defect by using a load signal immediately before an object to be measured is loaded on a load detector, and a load signal immediately after the object to be measured is removed from the load detector.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an indicator provided in a weighing system configured to display the weight of an object to be measured based on a load signal from a load detector.

  In many weighing systems having a load detector that detects the load of a platform that uses a vehicle or the like as an object to be measured, an indicator that processes the load signal output from the load detector and displays the weight of the object to be measured. (For example, Patent Document 1).

JP-A-5-322637

  In such an indicator, there is a case in which an accurate weight of the object to be measured is not displayed due to various causes. For example, an accurate load signal is not input to the indicator due to a failure of the load detector, or a part of the connection line between the load detector and the indicator is broken, or exists near the connection line. Such inconvenience may occur due to noise mixed from the noise source being superimposed on the load signal.

  Conventionally, when such a malfunction occurs in the weighing system, the worker has installed a cause investigation device and conducted an investigation based on the cause investigation information obtained by performing signal processing on the cause investigation signal. For this reason, installation of causal investigation equipment and cable wiring have been indispensable for investigating the cause.

  In addition, if a defect appears regularly or regularly, the time required for investigating the cause may be relatively short. However, if the defect appearance timing is irregular, the weight displayed on the indicator and the information for investigating the cause We have to wait for the appearance of a problem while continuing to monitor.

  Therefore, the worker must purchase and possess the cause investigation equipment and spend time on the cause investigation equipment installation, cable wiring, monitoring the weight displayed on the indicator and the cause investigation information. The economic and human burden was very large.

  Here, the cause investigation device is a device having a signal processing / display function. For example, an electronic computer or an oscilloscope. The cause investigation signal is a signal useful for investigating the cause of the fact that the accurate weight is not displayed on the indicator. As long as it includes at least a load signal output from the load detector, for example, a voltage signal indicating a voltage applied to the load detector, a temperature signal indicating the environmental temperature of the weighing system, or the like may be included. The case where the defect appearance timing is irregular is, for example, the case where a defect appears by superimposing noise whose generation timing is indefinite on the load signal.

  The present invention has been made in view of the above points, and reduces the human and economic burden when investigating the cause of a failure in which the exact weight of an object to be weighed is not displayed on the indicator. With the goal.

  As described in claim 1, the indicator of the present invention is an indicator that displays the weight of an object to be measured based on at least the load signal output from the load detector, and is information for investigating the cause. Are stored in synchronism with each other.

  Since the cause investigation information is stored in synchronization with the information storage unit, the cause investigation information can be analyzed at any time without having to continue monitoring the weight displayed by the indicator in real time. Can be investigated and the human and economic burden is greatly reduced.

  As described in claim 2, in the indicator of the present invention, the information storage unit is configured so that the cause investigation information can be stored, transferred, or duplicated on a removable medium.

  Since causal investigation information can be taken out without cabling, it is not necessary to perform wiring work only for investigating the cause of malfunction. Because it is possible to investigate at any place and time, use a large or high-speed causal investigation device that is unsuitable for carrying from the viewpoint of size and cost, etc., when you want to end the investigation of the cause of failure early. It is also possible to have engineers with many experiences and skills conduct surveys at offices. Even if the storage capacity of the information storage unit is relatively small, large-capacity data can be acquired without omission by medium replacement or overwrite storage. In other words, the human and economic burden is reduced by the investigation time / artificial reduction or the reduction of the storage capacity.

  As described in the third aspect of the present invention, the indicator of the present invention includes an information selection unit that selects cause investigation information stored in the information storage unit.

  If only cause investigation information necessary for failure cause analysis is selected, the amount of information to be stored is reduced. Further, for example, when a measuring system including the indicator is operated in an environment in which temperature management is carefully performed, it is not necessary to select temperature information unnecessary for investigating the cause of the malfunction. Therefore, if temperature information is not selected, the capacity of information to be stored can be reduced.

  If the information capacity to be stored is small, there is an economic advantage because the information storage section can be reduced in capacity, and there are also human and economic advantages because the time and labor required for information analysis are reduced.

  As described in the fourth aspect of the present invention, the indicator of the present invention includes a failure cause estimation unit that analyzes the cause investigation information stored in the information storage unit and estimates the cause of the failure.

  For example, by analyzing the information corresponding to the load signal, it is always necessary to adjust to the minus side or the plus side every time zero adjustment is performed to zero the weight when the object is not placed on the platform. If this tendency is found, it is estimated that a load detector failure may have occurred.

  Since the cause of failure estimated by the cause-of-failure estimation unit can be referenced, there is no need to dispatch engineers with a lot of knowledge or to spend a lot of time on investigations to identify the cause of failure, which has human and economic advantages. .

  By adopting the present invention, it is possible to provide an indicator capable of reducing the human and economic burden when investigating the cause of a failure in which the exact weight of an object to be weighed is not displayed.

Configuration diagram of a weighing system equipped with an indicator of the present invention Table showing patterns that appear in the cause investigation information A graph showing the relationship between time information and weighted information of cause investigation information Graph showing the relationship between load information and temperature information in the cause investigation information Graph showing the load information of the cause investigation information immediately before and after weighing Flow chart showing operation of failure cause estimation unit

  As shown in FIG. 1, a weighing system includes a scale 1 and an indicator 2. The scale 1 includes a platform 10 and an analog load cell 11 as a load detector that detects the weight of an object to be weighed placed on the platform 10. The indicator 2 includes a CPU 20 that processes a load signal and displays a weight, an AD converter 21 that performs A / D conversion on the input signal, a power supply unit 22 that supplies a voltage to be applied to the load cell 11, and a weighing unit. A temperature monitoring unit 23 that is a temperature sensor that monitors the environmental temperature of the system, a memory 24 that stores an operation program of the CPU 20, and an operation display unit 25 that is a man-machine interface are provided.

  The indicator 2 operates in the same manner as the conventional indicator 2 with respect to the weight display, and is configured to display the weight of the object to be measured based on the load signal output from the load cell 11. The operation will be described. When an operation key such as a power switch (not shown) provided in the operation display unit 25 is operated to start the weighing system, the operation program stored in the memory 24 is executed by the CPU 20. A predetermined voltage is applied to the load cell 11 by the power supply unit 22 that has received a command from. When an object to be weighed is placed on the platform 10 of the scale 1, a load signal corresponding to the object to be weighed is input from the load cell 11 to the indicator 2. The load signal is sampled at a predetermined interval by the AD conversion unit 21 that has received a command from the CPU 20, is A / D converted, and is input to the CPU 20 as load information.

  The CPU 20 executes a weight calculation program, which is one of the operation programs stored in the memory 24, calculates the weight according to the load signal, and then calculates the weight based on the temperature information acquired from the temperature monitoring unit 23. The weight of the object to be weighed is displayed on the touch panel type liquid crystal panel provided in the operation display unit 25 by correcting and driving a drive circuit (not shown).

<First embodiment>
The indicator 2 is synchronized with cause investigation information, which is information obtained by performing signal processing on the cause investigation signal, which is a signal useful for investigating the cause when a problem that the normal weight cannot be displayed in the weighing system occurs. And an information storage unit that stores information and an information selection unit that selects information stored in the information storage unit.

  The information storage unit includes a peripheral circuit such as a drive circuit 27 that reads / writes cause investigation information for a USB memory that is an example of a medium that can be inserted into and removed from the indicator 2 and a control unit that controls the peripheral circuit. The information selection unit includes a peripheral circuit (not shown) such as a drive circuit of the liquid crystal panel and a control unit that controls the peripheral circuit. These control units are functional blocks that are formed in the indicator 2 when a program that embodies the corresponding function is executed by the CPU 20. The information storage unit and the information selection unit are activated / stopped according to the operation of the operation display unit 25.

  The information selection unit displays on the liquid crystal panel provided in the operation display unit 25 an information selection screen in which information names of information useful for failure cause investigation are arranged in a list format or a matrix format. Information useful for investigating the cause of the malfunction includes at least information (for example, load information and temperature information) used by the CPU 20 for calculating the weight display, and includes, for example, sensing voltage information and time information.

  When the net applied voltage to the load cell 11 is lower than the normally assumed voltage drop, the correct weight may not be shown. Therefore, sensing voltage information is used when identifying such a cause. Is useful. This is because the time information can determine the time when the trouble occurs, and is useful, for example, for identifying a noise source of noise occurring at a predetermined time.

  Here, the load information, temperature information, and sensing voltage information are the load signal output from the load cell 11, the temperature signal output from the temperature monitoring unit 23, and the net applied voltage to the load cell 11 in consideration of the voltage drop. It is a digital value obtained by AD-converting a certain sensing voltage. The time information is digital information output from the clock circuit 26 provided in the indicator 2.

  When the information name on the information selection screen is touched, the information selection unit changes (inverts, emphasizes, flashes, etc.) the display mode so that the information name is selected. When the selected information name is touched again, the display mode is restored so that it can be seen that the selected information name is not selected. When the confirmation key arranged on the information selection screen is operated, the information storage unit is instructed to store the selected information.

  The information storage unit is configured to store each of them in the USB memory in synchronization when a plurality of types of cause investigation information are selected by the information selection unit. When load information, temperature information, and sensing voltage information are selected by the information selection unit, the information storage unit considers the load signal output from the load cell 11, the temperature signal output from the temperature monitoring unit 23, and the voltage drop. The sensing voltage that is the net applied voltage to the load cell 11 is acquired by controlling the AD converter 21 as load information, temperature information, and sensing voltage information as digital information, and these are synchronized with each other including time information. And store it in the USB memory.

  An example of the cause investigation information stored in the USB memory by the information storage unit in this way is shown in Table 1. As shown in Table 1, the information storage unit includes time information in the year / month / day column and time column, load signal in the load information column, sensing voltage information in the sensing voltage information column, temperature information in the temperature information column, Each is memorized in synchronization.

  The load information, sensing voltage information, and temperature information in Table 1 are digital values when stored in the USB memory. When displayed on the liquid crystal panel, the load information, sensing voltage information, and temperature information are generally based on a predetermined arithmetic expression by the CPU 20. It is converted into a unit and displayed. For example, if it is load information, it is converted into gram notation and displayed. However, storing in the USB memory is not limited to this. That is, the information storage unit may store the cause investigation information in terms of a general unit, for example, an SI basic unit, instead of the digital value.

  Although the cause investigation information sampled every second is stored in Table 1, it is an example in the present embodiment, and the sampling period of the present invention is not limited to one second. For example, the information selection screen displayed by the information selection unit may be provided with a cycle designation frame, and the information storage unit may store the cause investigation information at the sampling cycle designated in the frame.

  When the remaining capacity for recording the cause investigation information decreases, the information storage unit notifies the operator via the operation display unit 25 and prompts the operator to replace the USB memory. The cause investigation information during the replacement of the USB memory is temporarily stored in the memory 24, and the cause investigation information temporarily stored in the USB memory after the replacement is transferred and stored. Since it is comprised in this way, it can memorize | store reliably, without missing cause investigation information. The cause investigation information during the replacement of the USB memory may not be temporarily stored in the memory 24, and the cause investigation information may not be acquired.

<Second embodiment>
In the description of the second embodiment, the same parts as those of the first embodiment are denoted by the same reference numerals. The same applies to the following embodiments. The information storage unit of the second embodiment is configured to store cause investigation information in the memory 24. Then, in response to an operation on the operation display unit 25, the cause investigation information is transferred or copied to a medium. The information storage unit may be configured to notify that the cause investigation information is to be transferred or copied to the USB memory when the capacity for storing the cause investigation information cannot be sufficiently secured in the memory 24. .

  Here, the difference between transfer and duplication will be described. The former is to delete cause investigation information that has been written to the medium from the memory 24, and is useful, for example, when the capacity of the memory 24 is not sufficient. The latter is what remains in the memory 24 even after the cause investigation information is written on the medium, and is useful when the cause investigation information is written on a plurality of media.

<Third embodiment>
The indicator 2 of the third embodiment includes a failure cause estimation unit that analyzes cause investigation information stored in the information storage unit and estimates the cause of the failure. The failure cause estimation unit is embodied in the indicator 2 by the CPU 20 that executes the operation program. The failure cause estimation unit is activated / stopped in accordance with the operation of the operation display unit 25.

  A pattern that appears in the cause investigation information when various trouble causes occur is stored in the memory 24. The failure cause estimation unit is configured to collate the analysis result based on the cause investigation information with the pattern to identify the cause of the failure and to instruct the operation display unit 25 to display the failure cause on the liquid crystal panel. .

  FIG. 2 shows the pattern stored in the memory 24 in tabular form. The failure cause estimation unit compares the analysis result of the cause investigation information stored in the memory 24 with each pattern, and if there is a matching pattern, the failure cause estimation unit estimates that a failure of the pattern has occurred, and a corresponding solution. Is informed.

<Pattern 1>
When the shield of the cable that conducts the load signal is insufficient, the sensing voltage information is stable, but noise having a commercial power source as a noise source may be superimposed on the load information. Such a state is stored as pattern 1 in the table shown in FIG. FIG. 3 is a graph showing the relationship between time information and load information in such a case. The failure cause estimation unit is configured to analyze the periodicity from the relationship between the time information of the cause investigation information and the load information when the sensing voltage information is stable at a substantially constant value. When the periodicity has a periodicity of 50 Hz or 60 Hz similar to the frequency of the commercial power supply as shown in the graph of FIG. 3, the failure cause estimating unit shields the cable that conducts the load signal as the cause of the phenomenon. The solution of pattern 1 is displayed on the liquid crystal panel via the operation display unit 25 by estimating that the amount is insufficient.

<Pattern 3>
When the temperature characteristic of the load cell 11 or the temperature characteristic of the AD converter 21 is abnormal, even if the sensing voltage is stable, the temperature changes several times during a predetermined time (at least in a certain day). Load information (preferably load information in a state where the object to be weighed is not on the stage 10), temperature information, and the like. The existence position of the graph showing the relationship may deviate from a predetermined range. Such a state is stored as pattern 3 in FIG. FIG. 4 is a graph showing the relationship between load information and temperature information in such a case, and this relationship is expressed by a linear function.

  When the sensing voltage information is stable at a substantially constant value, the failure cause estimation unit determines the relationship between the temperature information and the load information whose value falls within a preset range during a preset time. The linear function shown is configured to be obtained. If the temperature characteristics of the load cell 11 or the AD conversion unit 21 are normal, the slope of the linear function falls within a preset predetermined range (hatched area in FIG. 4). When it is located outside the predetermined range shown in the graph of FIG. 4, it is estimated that the cause of the phenomenon is a temperature characteristic abnormality of the load cell or the AD conversion unit, and the liquid crystal panel solves the pattern 3 via the operation display unit 25. Display a solution.

<Pattern 4>
The power supply unit 22 steps down the voltage obtained from the commercial power supply to a predetermined voltage, stabilizes it, and applies it to the load cell 11. Therefore, the sensing voltage hardly fluctuates due to the influence of the weight of the object to be weighed or the temperature. That is, when the sensing voltage is unstable, there is a high possibility that some trouble has occurred in the power supply unit 22. Such a state is stored as pattern 4 in FIG. When the sensing voltage information is unstable, the failure cause estimation unit estimates that the cause of the phenomenon is that some abnormality has occurred in the power supply unit 22, and solves the pattern 4 on the liquid crystal panel via the operation display unit 25. Display a solution.

<Pattern 5>
When the scale 1 is a truck scale in which the vehicle is an object to be weighed and the platform is installed by digging a pit, a stopper is provided so that the platform 10 does not collide with the frame body when the vehicle gets on and off. If a load spilled from the vehicle during weighing is caught in this stopper, the value immediately after weighing will not return to the value immediately before weighing. Such a state is stored as pattern 5 in FIG. FIG. 5 is a graph showing load information immediately before and after weighing in such a case.

  The failure cause estimation unit compares the load information immediately before and after weighing when the temperature information and sensing voltage information are stable.If the latter value does not return to the former value, the cause of the phenomenon occurs. It is estimated that a foreign object is caught, and the solution for the pattern 5 is displayed on the liquid crystal panel via the operation display unit 25.

  Here, the failure cause estimation unit has a period in which the value of the load information is equal to or greater than a predetermined threshold value, and after that, there is a period during which the load information does not vary substantially for a predetermined time period, and then decreases from the predetermined value. If there is a period that does not vary substantially for a preset time with the measured value, it is determined that weighing has been performed, and the value of the load information before the threshold value is exceeded is set to the value immediately before weighing, and is reduced from the predetermined value. The above estimation is performed using the measured value as the value immediately after the measurement.

<Pattern 6>
When the platform 10 is installed outdoors, it may be affected by rainfall or snowfall. In view of this, the indicator 2 is equipped with a zero tracking function for displaying a measured value as having no influence of rainfall or snowfall. With this function, when the change amount of the load information is a value that is less than or equal to the zero tracking range (when the measurement method is applied, it is less than half of the scale), the indicator 2 determines that the change has not occurred. It is configured to display.

  However, because of this function, if the amount of rainfall or precipitation is low and it continues to fall for a long time, the weighing value displayed on the indicator 2 will be displayed despite a lot of water and snow on the platform 10. It becomes zero. If the weighing of an object to be weighed is started in such a state, water or snow may fall from the platform 10 during weighing and the tare may change, and an accurate measured value may not be obtained. Such a state is stored as a pattern 6 in FIG.

  The failure cause estimation unit compares the load information immediately before and after weighing when the temperature information and sensing voltage information are stable.If the latter value is smaller than the former value, the cause of the phenomenon is listed. It is presumed that the amount of rain accumulated on the table or accumulated snow has fluctuated due to getting on / off of the object to be weighed, and the solution of the pattern 6 is displayed on the liquid crystal panel via the operation display unit 25.

  In addition, a rain gauge and a snow gauge are provided in the vicinity of the platform, and an information storage unit is configured to store signals (information) output from them as information for investigating the cause. The failure cause estimation unit may be configured to estimate whether or not the failure matches with 6. Furthermore, the communication unit connected to the information communication network such as the Internet or a telephone line is provided in the indicator 2, and the information storage unit is configured to store the rainfall / snowfall information announced by the Japan Meteorological Agency and the like acquired through the communication unit. The estimation may be performed in consideration of the rain / snow information.

  FIG. 6 is a flowchart when the failure cause estimation unit estimates a failure cause and notifies a corresponding solution. In step S <b> 1, when the operator touches a “probability cause estimation” button arranged on the operation screen (not shown) of the indicator 2 displayed on the liquid crystal panel of the operation display unit 25, the problem cause estimation unit is activated.

  In step S <b> 2, the failure cause estimating unit analyzes the cause investigation information and collates with the pattern stored in the memory 24. If a matching pattern is found in step S3, it is estimated that a problem has occurred due to the cause stored for the pattern. In step S <b> 4, the estimated cause solution is displayed on the liquid crystal panel via the operation display unit 25. In step S5, when the “cause estimation end” button arranged on the operation screen is touched, the failure cause estimation unit is stopped.

<Fourth embodiment>
As the period for recording the cause investigation information becomes longer, the capacity required for the recording increases. Further, as the cause investigation information increases, the time required for the analysis generally becomes longer. By the way, when analyzing periodic cause information such as pattern 1 in the table shown in FIG. 2, it is rare that the period is generally a long period such as a week unit. In many cases, the cause investigation information for several hours is sufficient. On the other hand, when an irregular period variation such as pattern 2 is found, it is often impossible to find it without analyzing cause investigation information recorded over a long period of about one week.

  Therefore, when recording the cause investigation information, the information storage unit records all the sampled data for a while after starting to record, and thereafter stores only the data that has exceeded the predetermined threshold. It is configured. Specifically, for example, the information selection screen displayed by the information selection unit includes a period for recording all the data and a frame for setting a threshold, and based on the period and the threshold specified in these frames, The information storage unit is configured to store cause investigation information.

  By adopting this configuration, it is possible to reduce the storage amount of cause investigation information without affecting the cause of failure.

<Other embodiments>
In the first to fourth embodiments, the analog load cell 11 is used as the load detector, but a digital load cell may be used. The medium for storing the cause investigation information in the information storage unit may be a CD-ROM or DVD other than the USB memory as long as it can store digital data and can be inserted into and removed from the indicator 2. . In this case, the information storage unit has a drive circuit corresponding to the employed medium.

  The information storage unit stores the cause investigation information in the USB memory, which is an example of a medium that can be inserted into and removed from the indicator 2, and transfers or copies the information from the memory 24. A drive corresponding to such a medium The circuit may be stored only in the memory 24 without having a circuit. In this case, the information storage unit does not necessarily have a medium drive circuit. Although the indicator 2 includes the information selection unit, all of the cause investigation information may always be stored.

1: Scale 2: Indicator 10: Platform 11: Load detector (load cell)
20: CPU
21: AD conversion unit 22: Power supply unit 23: Temperature monitoring unit 24: Memory 25: Operation display unit 26: Clock circuit 27: USB drive circuit

Claims (1)

An indicator for displaying the weight of the object to be weighed based on at least a load signal output from the load detector,
A failure cause estimation unit that analyzes cause investigation information and estimates the cause of the failure is provided.
The failure cause estimation unit uses the load signal immediately before the object to be placed on the load detector and the load signal immediately after the object to be measured is not placed on the load detector. An indicator characterized by estimating.

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