JP6242233B2 - Weighing device - Google Patents

Description

  The present invention relates to various weighing devices that measure the weight of an object to be weighed, such as a platform scale, a track scale, and a combination weigher, and more particularly to a technique for detecting an abnormality of a weighing device.

  Conventionally, as a technique for detecting an abnormality of the weighing device, during the operation of the weighing device, the variation amount of the zero point weight value is calculated, and when the calculated variation amount of the zero point weight value is out of a predetermined range, What determines that an abnormality has occurred in the weighing device (see Patent Document 1), or notifies that it is abnormal when the weight value immediately after turning on the weighing device is out of a predetermined range near the zero point ( Patent Document 2).

JP-A-2005-147920 JP-A-55-22141

  In the above abnormality detection, when the fluctuation amount of the zero point weight during the operation is out of the predetermined range, or when the weight value immediately after turning on the power is out of the predetermined range near the zero point, it is determined as abnormal. However, most of the fluctuations in the zero point weight occur not only when the weighing device is turned on, but also during the power-off period when the weighing device is turned on. In some cases.

  That is, in the weighing device, during the operation stop period that is a power-off period, for example, the weighing unit may be cleaned, the maintenance inspection is performed, or the weighing device may be moved for layout change. In such a case, for example, if you forget to lock the load sensor and the cleaning work method is not appropriate and an excessive load is accidentally applied to the weighing unit, the zero point of the load sensor becomes an abnormal value, or Even if the value does not reach an abnormal value, the zero point may fluctuate greatly, and the value may be accumulated during the operation suspension period.

  Further, while the temperature and humidity are appropriately managed by the air conditioning system during the operation period, the air conditioning system is stopped during the operation suspension period, and the ambient temperature of the weighing device may decrease. When the load sensor of the weighing device is a strain gauge type load cell, when the temperature of the load cell decreases during the operation suspension period, moisture in the air taken into the case containing the load cell is condensed, and chlorine contained in the moisture, Strain gauge corrosion and insulation failure may progress due to sulfur compounds, etc., and the amount of zero fluctuation may increase.

  On the other hand, during the operation period when the power is on, the supply of the object to be weighed to the weighing unit is inappropriate and an excessive impact load is applied to the weighing unit, or the load level is not so excessive. A relatively large load is repeatedly applied, and even if it is not determined that the zero point is abnormal with a single impact load, the zero point weight value may become abnormal due to accumulation of relatively large zero point fluctuations.

  In this way, most of the large zero-point fluctuation may occur during an operation suspension period that is a power-off period, or may occur during an operation period that is a power-on period.

  For this reason, as in Patent Documents 1 and 2, even if an abnormality in the zero point weight is detected during the power-on period, it is only known that the zero point weight is out of the predetermined range at the time of detection. It is not possible to grasp whether the main cause of the error occurred during the operation period or during the operation stop period. Therefore, when an abnormality occurs, it is not easy to investigate the cause, and it takes time to take a countermeasure.

  For example, when the zero point weight fluctuates greatly due to inadequate cleaning work during the operation stop period, and when the zero point fluctuation amount is outside the predetermined range and an abnormality is detected during the operation period, the cause is Suppose that it is due to excessive impact load due to improper supply of objects to be weighed rarely or due to continuous overload during operation, and supply of objects to be measured during operation If only the behavior of time is traced, a great deal of time is wasted investigating the cause.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to be able to detect an abnormality of a weighing device and to easily investigate the cause of the abnormality.

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

(1) A weighing device according to the present invention includes a weighing device for measuring the weight of an object to be weighed, and is capable of measuring a zero point weight value, which is a weight value in a state where there is no object to be weighed in the weighing device.
Zero point weight value calculating means for calculating a zero point weight value at a time in the vicinity of the time when the power is turned on during a power on period in which the power of the weighing device is turned on;
Zero point weight value calculating means for calculating a zero point weight value at a time point after the vicinity time point when the power source is turned on during the power on period, as a zero point weight value other than when the power source is turned on;
Storage means for storing the zero point weight value when the power is turned on;
The same power supply the zero weight value at power-on in the on period and the power-on time zero point variation calculating means for calculating a zero point fluctuation amount in the power-on time which is a difference between the zero point weight value other than the power-on Prepared ,
The zero-point weight value calculating means for calculating a zero-point weight value at a time point after the vicinity time point when the power source is turned on in the power-on period as a zero-point weight value other than when the power source is turned on. The zero point weight value near the time point when the power is turned off is calculated as the zero point weight value when the power is turned off.
The storage means stores the calculated zero point weight value at the time of power-off,
The power-on period zero point fluctuation amount calculating means calculates a difference between the zero point weight value when the power is turned on and the zero point weight value when the power is off in the same power-on period as the zero-point fluctuation amount during the power-on period. To do.

  The time near the time when the power is turned on is a time near the time including the time when the power is turned on, for example, the time when the power is turned on, or after the power is turned on, It may be when manual zero adjustment or automatic zero adjustment is performed for the first time, or after the power is turned on, the absolute value of the measured weight value is below the predetermined weight value near the zero point for the first time. It may be a point in time.

  The time point after the neighboring time point when the power is turned on in the power-on period means a time point later than the neighboring time point in the same power-on period, and the zero point weight value is the power-on time. This is a time point later than the neighboring time point calculated as the zero point weight value of time, for example, a time point when the power is turned off in the same power-on period.

According to the weighing device of the present invention, the zero-point weight value at the time of power-on is calculated and stored, and the power-on which is the zero-point weight value at a time later than the zero-point weight value at the time of power-on in the same power-on period. Zero point weight value other than the hour is calculated, and the zero point fluctuation during the power-on period is the difference between the zero-point weight value when the power is turned on in the same power-on period and the zero point weight value after the power-on other than when the power is turned on Since the amount is calculated, if an excessive zero fluctuation occurs, the zero fluctuation is the power-on period from the time the power is turned on to a time other than the time when the power is turned on, that is, the operation of the weighing device. It becomes possible to grasp that this occurred during the period, and it becomes easier to investigate the cause of the excessive zero point variation compared to the conventional example.
In addition, when excessive zero point fluctuation occurs, the zero point fluctuation is caused during the power-on period from power-on to power-off, that is, during the operation period of the weighing device. As a result, it is possible to grasp the cause of the excessive zero fluctuation compared to the conventional example.

(2) The weighing device of the present invention includes a measuring device for measuring the weight of an object to be weighed, and is capable of measuring a zero point weight value, which is a weight value in a state where there is no object to be weighed in the measuring device.
Zero point weight value calculating means for calculating a zero point weight value at a time in the vicinity of a time point when the power is turned off during a power on period in which the power of the weighing device is turned on;
Zero point weight value calculating means for calculating a zero point weight value at a time in the vicinity of the time when the power is turned on in the next power on period after the power source is turned off in the power on period as a zero point weight value at the time of power on. When,
Storage means for storing the zero point weight value when the power is off;
A power source that calculates a difference between the zero point weight value when the power is turned off stored in the storage means and the zero point weight value when the power is turned on during the next power on period as a zero point fluctuation amount during the same power off period Off period zero point fluctuation amount calculating means.

  The time near the time when the power is turned off is a time near the time including the time when the power is turned off, for example, the time when the power is turned off, or before the power is turned off. It may be the last time manual zero adjustment or automatic zero adjustment is performed, or the absolute value of the weight value measured before the power is turned off is the predetermined weight value near the zero point. It is good also as the time when it became the following.

  According to the weighing device of the present invention, the zero point weight value when the power is turned off is calculated and stored, and the zero point weight value when the power is turned on in the next power on period is calculated. Since the zero point fluctuation amount during the same power off period, which is the difference from the zero point weight value at the time of power on during the power on period, is calculated, if an excessive zero fluctuation occurs, the zero point fluctuation is , It is possible to grasp that it occurred during the power-off period, that is, during the operation suspension period of the weighing device, and it becomes easier to investigate the cause of the excessive zero-point fluctuation compared to the conventional example. .

  As a preferred embodiment of the present invention, the configuration of the present invention (1) and the configuration of the present invention (2) may be combined.

  In this case, when an excessive zero-point fluctuation occurs, the zero-point fluctuation occurs during the power-on period, that is, during the operation period of the weighing device, or the power-off period, that is, the measurement It is possible to determine whether the error occurred during the operation stop period of the apparatus, and it becomes easier to investigate the cause of the excessive zero point fluctuation as compared with the conventional example.

( 3 ) In a preferred embodiment of the weighing device according to (1 ), the zero point weight value at a time point after the time point near the time point at which the power source is turned on in the power on period is set to a zero point weight value other than when the power source is turned on. The zero-point weight value calculating means for calculating the value is a weight value at the time of zero-point adjustment during the power-on period, and is calculated as a zero-point weight value at the time of zero-point adjustment. The amount calculation means calculates a difference between the zero point weight value when the power is turned on and the zero point weight value when the zero point is adjusted in the same power on period as the zero point fluctuation amount during the power on period.

  The zero point adjustment may be manual zero point adjustment or automatic zero point adjustment.

  According to this embodiment, the zero-point weight value at the time of power-on is calculated, and the zero-point weight value at the time of zero-point adjustment, which is the zero-point weight value at the time when the zero-point adjustment is performed, is The calculated zero point fluctuation amount during the power-on period, which is the difference between the zero-point weight value at the time of power-on and the zero-point weight value at the time of zero adjustment in the same power-on period, is calculated. In such a case, it becomes possible to grasp that the zero point fluctuation has occurred during the power-on period from the power-on to the subsequent zero-point adjustment, that is, during the operation period of the weighing device, As a result, it becomes easier to investigate the cause of the excessive zero point variation as compared with the conventional example.

( 4 ) In a preferred embodiment of the weighing device of the present invention, the zero point fluctuation amount during the power on period or the power off period calculated by the power on period zero point fluctuation amount calculating means or the power off period zero point fluctuation amount calculating means. Output means for outputting the zero point fluctuation amount.

  The output means may be a display output, an audio output, a print output, or a combination of them.

According to this embodiment, since the zero point fluctuation amount during the operation period that is the power on period or the zero point fluctuation amount during the operation stop period that is the power off period is output, the operator outputs the zero point fluctuation amount that is output. Based on the above, it is possible to easily grasp whether or not an excessive zero point fluctuation has occurred, that is, whether or not there is an abnormality.
( 5 ) In another embodiment of the weighing device of the present invention, the zero point fluctuation amount or the power off period during the power on period calculated by the power on period zero point fluctuation amount calculating means or the power off period zero point fluctuation amount calculating means. A determination means for determining the presence or absence of an abnormality based on the zero point fluctuation amount in the center is provided.

  According to this embodiment, since the presence or absence of an abnormality during the operation period or the operation suspension period is determined by the determination unit, the operator does not need to determine the presence or absence of the abnormality based on the zero point fluctuation amount.

( 6 ) In the embodiment of the above ( 5 ), the determination means may determine the presence / absence of the abnormality by comparing the zero point fluctuation amount with a predetermined allowable value.

  According to this embodiment, when an excessive zero point fluctuation exceeding the allowable value occurs, it can be determined that there is an abnormality.

( 7 ) In the embodiment of the above ( 5 ) or ( 6 ), the determination means may determine the presence / absence of an abnormality based on an evaluation value calculated based on the zero point fluctuation amount.

  As the evaluation value calculated based on the zero point fluctuation amount, for example, an integrated value or an average value of zero point fluctuation amounts during a plurality of power-on periods, an integrated value or an average value of zero point fluctuation amounts during a plurality of power-off periods, The zero point fluctuation amount per unit time during the power-on period, or the zero point fluctuation amount per unit time during the power-off period, and the like may be determined based on a plurality of evaluation values. .

  According to this embodiment, since the presence / absence of abnormality is determined based on the evaluation value calculated based on the zero point fluctuation amount, it is determined not only whether there is abnormality but also abnormal by using an appropriate evaluation value. Sometimes it is easy to identify the cause of the abnormality.

  As a preferred embodiment of the present invention, when the configuration of the present invention of (1) and the configuration of the present invention of (2) are provided together, the evaluation value calculated based on the zero point fluctuation amount For example, the ratio between the zero fluctuation amount during the power on period and the zero fluctuation amount during the power off period, the difference between the zero fluctuation amount during the power on period and the zero fluctuation amount during the power off period may be used. Good.

( 8 ) In any one of the above embodiments ( 5 ) to ( 7 ), when the determination unit determines that an abnormality has occurred, a notification unit that notifies the abnormality is provided.

The notifying means may be shared by the output means of the above embodiment ( 4 ).

  According to this embodiment, when it is determined that there is an abnormality, the fact is notified, so that the operator can easily grasp that an abnormality has occurred and can investigate the cause of the abnormality.

( 9 ) In a preferred embodiment of the measuring device of the present invention, the time measuring means for measuring the date and time to generate date and time data, the date and time data by the time measuring means corresponding to the time near the time when the power is turned on, and the Date and time data storage means for storing date and time data of at least one of the date and time data corresponding to a time near the time when the power is turned off.

 According to this embodiment, the date / time data at the time corresponding to the zero-point weight value at the time of power-on and the date / time data at least one of the date / time data corresponding to the zero-point weight value at the time of power-off are stored. When fluctuations occur, it is easy to grasp which power-on period or which power-off period the zero-point fluctuation has occurred.

( 10 ) In the embodiment of ( 9 ), the date / time data of the date / time data storage means is associated with the zero point fluctuation amount during the power-on period or the zero point fluctuation amount during the power-off period. Display means for displaying.

The display means may also be used as the output means in the above embodiment ( 4 ).

  According to this embodiment, at least one of the date / time data corresponding to the zero-point weight value at the time of power-on and the date / time data corresponding to the zero-point weight value at the time of power-off is changed to zero-point fluctuation during the power-on period. Display in correspondence with the amount of zero or the amount of zero fluctuation during the power-off period, so that when there is an excessive zero-point fluctuation, the zero-point fluctuation occurred in any power-on period or any power-off period It is possible to visually confirm whether it is a thing, and it becomes easy to investigate the cause of excessive zero point fluctuation.

  According to the present invention, when an excessive zero point fluctuation occurs, the zero point fluctuation occurs during an operation period that is a power-on period, or during an operation stop period that is a power-off period. Therefore, it becomes easier to investigate the cause of the excessive zero fluctuation compared to the conventional example.

FIG. 1 is a block diagram of a weighing device according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the power-off period and the power-on period. FIG. 3 is a flowchart for explaining the operation. FIG. 4 is a flowchart of the process following FIG. FIG. 5 is a diagram showing a display example of the zero point fluctuation amount during the operation period and the zero point fluctuation amount during the operation stop period.

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

  FIG. 1 is a block diagram of a weighing device 1 according to an embodiment of the present invention.

  The weighing device 1 of this embodiment is, for example, a platform scale, and includes a weighing device 2 and an indicator 3.

  The weighing device 2 includes, for example, a strain gauge type load cell LC as a load sensor that supports a weighing table (not shown).

  The indicator 3 includes a power supply circuit 12 that supplies power to the load cell LC, an operational amplifier 4 that amplifies the analog load signal output from the load cell LC, and converts the analog load signal from the operational amplifier 4 into a digital load signal. An A / D converter 5, a CPU 6 for calculating a weight value, a zero point weight value, and a zero point fluctuation amount described later based on the digital load signal from the A / D converter 5, and storage means As a memory 7, an input unit 8 having a key switch for inputting setting data and an operation command, and a display unit 9 as an output means for displaying and outputting a weight value, a zero point fluctuation amount described later, and the like. .

  The memory 7 includes a ROM in which an arithmetic program and the like are stored, an EEPROM in which setting values, a span coefficient K, and the like are stored, a static RAM that is backed up by a battery 10, and the like. The static RAM stores a zero point weight value, a zero point fluctuation amount, and the like during an operation period and an operation suspension period described later.

  In addition, the battery 10 backs up the power supply of the real-time clock element 11 as time measuring means for outputting current date / time data as date / time data.

  In the weighing device 1 of this embodiment, an abnormality can be detected based on the zero point fluctuation that is the fluctuation of the zero point weight value, and the zero point fluctuation is detected when the power is turned on to facilitate the investigation of the cause of the abnormality. It is possible to distinguish and grasp whether it is generated during a power-on period during which the power is on or during a power-off period when the power is not turned on.

  Here, first, the zero point weight value and zero point adjustment will be described.

  With the digital load signal Wad output from the A / D converter 5 in FIG. 1, the CPU 6 calculates the weight value Wn of the object to be weighed according to the following equation (1).

Wn = K · (Wad−Wi) −Wz (1)
K is a span coefficient, and Wi is an initial load value, which are stored in the non-volatile memories M _K and M _Wi constituting the memory 7, respectively. Wz is a zero point fluctuation value, and is stored in the nonvolatile memory M _Wz constituting the memory 7.

  Here, Wn representing the weight value of the object to be weighed is defined as the displayed weight value displayed on the display unit 9, and K · (Wad−Wi) calculated based on the measured digital load signal Wad is defined as the measured weight value. To do.

When the weighing device 1 is adjusted, the operator first puts the weighing table on the weighing device 1 into a no-load state without an object to be weighed and operates an initial load storage command switch (not shown) of the input unit 8. In the equation (1), the zero point fluctuation value Wz = 0 and the span coefficient K = 1 are set, and the value of the read digital load signal Wad is stored in the nonvolatile memory M _Wi as the initial load value Wi, and the display weight value Wn Becomes zero. This completes the initial load storage operation.

Next, the operator places a weight having a known load value of a rated load on the weighing table, displays the displayed weight value Wn at that time, and displays a span adjustment command switch (not shown) of the input unit 8. , The CPU 6 determines the value of the span coefficient K so that the displayed weight value Wn becomes the rated load value. The determined value of the span coefficient K is stored in the nonvolatile memory M _K. This ends the span adjustment operation.

  After this, when the value of the digital load signal Wad fluctuates from the time of span adjustment due to the zero point drift of the load sensor, etc., although the load is on the weighing platform, the display weight value Wn ≠ 0 is displayed.

  Regardless of whether the displayed weight value Wn is Wn = 0 or Wn ≠ 0, the value of the measured weight value K · (Wad−Wi) based on the digital load signal Wad when the weighing platform is unloaded. Is called the zero point weight value.

When the operator operates a zero adjustment command switch (not shown) of the input unit 8,
Wn + Wz → Wz (2)
If, variation of display weight value Wn is, is added to the zero-point variation value Wz (subtraction by the polarity of the Wn), together with the non-volatile memory M zero-point variation values stored in _Wz Wz is updated, (1) The displayed weight value Wn of the equation becomes zero, and zero adjustment is performed.
Performing the processing of equation (2) to set the display weight value Wn to 0 is called zero point adjustment.

  In the weighing device 1 according to this embodiment, the fluctuation amount of the zero-point weight value is calculated by distinguishing between the power-on period in which the power is on and the power-off period in which the power is off, and the calculated zero fluctuation amount Based on the above, the presence or absence of abnormality is determined.

FIG. 2A is a diagram for explaining calculation of the zero point fluctuation amount in the power-off period T _OFF , and FIG. 2B is a diagram for explaining calculation of the zero point fluctuation amount in the power-on period T _ON .

In order to calculate the zero point fluctuation amount in the power-off period T _OFF shown in FIG. 2A, the power-off time that is the zero-point weight value near the time point t1 when the power is turned off in the previous power-on period T _ON1 And a zero-point weight value at the time of power-on that is a zero-point weight value near the time point t2 when the power is turned on in the current power-on period T _ON2 . Then, in the current power-on period T _ON2, the zero point weight value at power-on is calculated, and zeros weight value at the time of power-on, the previous stored during power-off in the power-on period T _ON1 As the difference from the zero point weight value, the zero point fluctuation amount in the power-off period T _OFF is calculated.

In order to calculate the zero point fluctuation amount in the power-on period T _ON shown in FIG. 2B, the zero point at the time of power-on which is the zero-point weight value near the time point t3 when the power is turned on in the power-on period T _ON . The weight value and the zero point weight value when the power is turned off, which is the zero point weight value near the time point t4 when the power is turned off in the same power on period T _ON , are calculated and stored. Then, in the next power-on period T _ON3 , the zero-point fluctuation amount in the power-on period T _ON is calculated as the difference between the stored zero-point weight value in the power-on period T _{ON and} the zero-point weight value in the power-off period T _ON . Is calculated. The zero-point fluctuation amount during the power-on period does not necessarily have to be calculated during the next power-on period, and the zero-point fluctuation amount during the power-on period may be calculated at the same time when the zero weight value at the time of power-off is calculated. Good.

  As described above, the zero point weight when the power is turned on, which is the zero point weight value in the vicinity of the time when the power is turned on, is used to calculate both the zero point fluctuation amount during the power off period and the zero point fluctuation amount during the power on period. The zero point weight value when the power is off, which is the zero point weight value near the time when the value and the power source are turned off, is required.

  Therefore, calculation of the zero weight value when the power is turned on and calculation of the zero weight value when the power is turned off will be described.

  First, calculation of the zero point weight value when the power is turned on will be described.

  Some types of weighing devices perform the following two types of operations depending on the application.

  That is, there are weighing devices that perform automatic zero adjustment when the power is turned on, and weighing devices that do not perform automatic zero adjustment when the power is turned on.

  The weighing device 1 of this embodiment is a platform scale as described above. The platform scale is normally turned on when no power is placed on the weighing platform when the power is turned on, like a truck scale. Occasional automatic zero adjustment.

  Therefore, as a work procedure, usually, an operator confirms that an object to be weighed is not placed on the weighing table, turns on the power, and when the power is turned on, the measured weight by the digital load signal Wad read. The value K · (Wad−Wi) is calculated as the zero point weight value when the power is turned on, and is used for calculating the zero point fluctuation amount during the power on period or the power off period.

  At this time, the calculated zero-point weight value at the time of power-on is stored in the nonvolatile memory of the memory 7, and the date / time data from the real-time clock element 11 at that time is read, together with the memory as the date / time data storage means 7 is stored in the nonvolatile memory.

  Note that in weighing devices that do not perform automatic zero adjustment when the power is turned on, for example, combination weighers, the power is highly likely to be turned on with the object to be weighed placed on the weighing platform (weighing hopper). When it is on, automatic zero adjustment is not performed.

  In the case of a weighing device that does not perform automatic zero adjustment when the power is turned on, the weight value K · (Wad measured by the digital load signal Wad read when manual zero adjustment or automatic zero adjustment is first performed after the power is turned on. -Wi) is used to calculate the zero point weight value when the power is on, and is used to calculate the zero point fluctuation amount during the power off period or during the power on period.

  Or, when the absolute value | Wn | of the displayed weight value becomes equal to or smaller than the weight value Wt near the predetermined zero point for the first time in a stable state after the power is turned on, that is, when | Wn | ≦ Wt is satisfied. The measured weight value K · (Wad−Wi) based on the read digital load signal Wad may be calculated as the zero point weight value when the power is turned on.

  Alternatively, after the power is turned on, the measured weight value K · (Wad−Wi) by the digital load signal Wad read at the earliest point of time when manual zero point adjustment, automatic zero point adjustment, or | Wn | ≦ Wt is established, You may calculate as a zero point weight value at the time of power-on.

  Even in a weighing device that does not perform automatic zero adjustment at power-on, the calculated zero-point weight value at power-on is stored in the nonvolatile memory of the memory 7 and the date / time data from the real-time clock element 11 at that time is stored. The data is read and stored in the nonvolatile memory of the memory 7 together.

  Next, calculation of the zero point weight value when the power is off will be described.

  Regardless of whether or not automatic zero adjustment is performed when the power is turned on, the manual weight adjustment immediately before the power is turned off, or the measured weight value K · by the digital load signal Wad read when the automatic zero adjustment is performed (Wad-Wi) is calculated as a zero point weight value when the power is off, and is used for calculating the zero point fluctuation amount during the power off period or the power on period. At the same time, the date / time data from the real-time clock element 11 is read and stored in the nonvolatile memory of the memory 7 together with the zero point weight value K · (Wad−Wi).

  Or, when the absolute value | Wn | of the displayed weight value Wn in a stable state immediately before the power is turned off is less than the weight value Wt near the predetermined zero point, that is, when | Wn | <Wt. The measured weight value K · (Wad−Wi) based on the digital load signal Wad read in may be calculated as the zero point weight value when the power is turned off. The calculated zero weight value when the power is turned off may be stored in the nonvolatile memory of the memory 7 together with the date / time data from the real time clock element 11.

  Alternatively, immediately before the power is turned off, the measured weight value K · (Wad− based on the digital load signal Wad read at the latest time of manual zero point adjustment, automatic zero point adjustment, or establishment of | Wn | ≦ Wt. Wi) may be calculated as a zero point weight value when the power is off.

  In short, the latest zero weight value is always updated and stored in the nonvolatile memory of the memory 7 together with the date / time data at which the zero weight value was obtained during the power-on period, and these values remain in the nonvolatile memory when the power is turned off. You can do it.

  Next, calculation of the zero point fluctuation amount during the power-off period and determination of the presence or absence of abnormality will be described.

  As described above, the zero point weight value when the power is turned on is calculated and stored in the nonvolatile memory together with the corresponding date / time data, while the zero point weight value when the power is turned off is calculated and the corresponding date / time is calculated. It is stored in the nonvolatile memory together with the data.

Thus, for example, zero point variation of the power supply off period T _OFF period of FIG. 2 (a), and zeros weight value at power-on in the current power-on period T _ON2, power off at the previous power-on period T _ON1 It can be calculated by reading the time zero weight value from the nonvolatile memory and taking the difference. That is, the zero point fluctuation amount only during the power-off period (during the operation suspension period) can be calculated. In this way, each time the power is turned on and the power on period is started, the zero point fluctuation amount during the immediately preceding power off period is calculated.

  In this embodiment, the date / time data at the time of turning off the power supply that defines the power-off period and the date / time data at the time of turning on the power supply and the zero point fluctuation amount during the operation stop period that is the power-off period are nonvolatile. And is displayed on the display unit 9. Moreover, this is stored in the non-volatile memory and displayed on the display unit 9 up to N sets, for example, the latest plural sets, or in order of increasing difference in zero point weight value. Thereby, the magnitude of the zero point fluctuation amount during the operation suspension period can be easily visually evaluated and determined.

  In this way, the value of the zero point fluctuation amount, which is the difference between the zero point weight values, and the date and time corresponding thereto are displayed, so that it is possible to grasp how much zero point fluctuation has occurred during the operation suspension period. Therefore, for example, when the weighing table is not properly attached or removed during the operation suspension period, and the zero point variation amount is less than the allowable value, the cause is a large change. It is possible to review and improve the work of attaching and detaching the weighing platform and the cleaning work during the operation suspension period.

  Further, if the date of the large zero fluctuation is during the transportation period or the relocation period of the weighing device 1, it is easily apparent that the cause of the zero fluctuation is due to transportation or relocation.

  Furthermore, in this embodiment, the CPU 6 as the determination unit determines that the load sensor or the like is abnormal when the calculated zero fluctuation amount during the operation suspension period is equal to or greater than a predetermined allowable value, and notifies the notification unit. Is displayed on the display unit 9 as an alarm, and the operator is not required to visually check and evaluate the magnitude of the zero point variation during the operation stop period. .

  Next, calculation of the zero point fluctuation amount during the power-on period and determination of the presence or absence of abnormality will be described.

For example, the zero point fluctuation amount in the power-on period T _ON shown in FIG. 2B is obtained from the non-volatile memory by calculating the zero-point weight value when the power is turned on and the zero-point weight value when the power is off in the same power-on period T _ON . It can be calculated by reading out each difference and taking the difference. That is, the zero point fluctuation amount only during the power-on period (during the operation period) can be calculated. In this way, each time the power is turned on and the power on period is started, the zero point fluctuation amount during the previous power on period is calculated.

  In this embodiment, as in the case of the power-off period, the date / time data at the time of turning on the power that defines the power-on period, the date / time data at the time of turning off the power, and the power-on period. The zero point fluctuation amount during the operation period is stored in the nonvolatile memory and displayed on the display unit 9. Moreover, this is stored in the non-volatile memory and displayed on the display unit 9 up to N sets, for example, the latest plural sets, or in order of increasing difference in zero point weight value. Thereby, the magnitude of the zero point fluctuation amount during the operation period can be easily visually evaluated and determined.

  As for the zero point fluctuation amount during the power-on period, every time the power is turned on and the power-on period starts, the zero point fluctuation amount during the previous power-on period is calculated and displayed. The weight value is memorized, and every time zero point adjustment is performed during the power-on period and the zero point weight value is obtained, the zero point is determined by the zero point weight value at the time of zero point adjustment and the zero point weight value at power on. The fluctuation amount is calculated and displayed as the current zero point fluctuation amount together with the date / time data at power-on and the date / time data at power-on when the zero adjustment was performed during the power-on period. In other words, each time a new zero adjustment is performed, the zero fluctuation amount and the date / time data when the zero adjustment is performed may be updated.

  Further, in this embodiment, when the calculated zero fluctuation amount during the operation period is equal to or greater than a predetermined allowable value, it is determined that the load sensor or the like is abnormal, and the display unit 9 determines that the abnormality is present. An alarm display specifying the operation period is performed.

  Next, the operation of this embodiment will be described based on the flowcharts of FIGS.

  First, when the power is turned on and the program is started as shown in FIG. 3, the zero point fluctuation amount during the operation period which is the previous power on period is changed from the zero point weight value at the previous power off time to the previous power on time. It is calculated by subtracting the zero point weight value (step n1).

  Next, the calculated zero fluctuation amount during the previous operation period and the latest zero fluctuation amount during the operation period including the date / time data of the operation period are updated and stored in the display table of the nonvolatile memory. At the same time, it is displayed on the display unit 9 and updated and stored in the memory table (step n2).

  Next, whether or not the calculated zero fluctuation amount during the previous operation period is abnormal, that is, whether or not the absolute value of the zero fluctuation amount during the previous operation period is equal to or greater than a predetermined allowable value Wst. (Step n3), and if it is equal to or greater than the allowable value Wst, an alarm display indicating that there was an abnormality in the amount of zero fluctuation during the previous operation period is displayed on the display unit 9 for notification (step n4). ).

  Further, when the absolute value of the zero point fluctuation amount during the previous operation period is not equal to or greater than the allowable value Wst, the timer for waiting for the circuit or load sensor to warm up is activated (step n5), and the filter processing is performed after the timer operation is completed. A digital load signal Wad is acquired (step n6). For example, the digital load signal Wad is read every 1 msec to perform the filter processing. This filtering process is performed by a processing program (not shown) having a higher priority than the process of FIG.

  Next, stability determination processing is performed (step n7), and it is determined whether or not it is stable (step n8). The stability determination process is performed as follows, for example. That is, the latest M of the filtered digital load signals Wad are stored in the shift register SR in the order of occurrence, and the oldest digital load signal Wad is discarded, and all ( When the difference between the maximum value and the minimum value of the M digital load signals Wad is equal to or less than a predetermined maximum width R (maximum value−minimum value ≦ R), it is determined that the value is stable.

  If it is determined in step n8 that it is not stable, the process returns to step n7 and waits until it becomes stable.

  If it is determined in step n8 that it is stable, the average value of the M digital load signals Wad stored in the shift register SR is calculated, and the calculated average value is again used as the digital load signal Wad to turn on the power. The measured weight value K · (Wad−Wi) is calculated as the zero-point weight value at the time, and the displayed weight value Wn is calculated by Wn = K · (Wad−Wi) −Wz (step n9). Move to n10.

  In step n10 of FIG. 4, in order to determine whether or not the displayed weight value Wn is a weight value near the zero point, the absolute value | Wn | of the displayed weight value Wn is less than or equal to a preset boundary value Wt. When it is less than or equal to the boundary value Wt, it is the weight value near the zero point, so the date / time data from the real-time clock element 11 is read (step n11), and the display weight value Wn is obtained. The calculated zero point weight value at the time of power-on is stored in a nonvolatile memory together with K · (Wad−Wi), and the zero-point weight value and date / time data at the time of the current power-on are obtained (step n12). Here, the zero point weight value and date / time data at the previous power-on time are updated to the current zero-point weight value and date / time data to prepare for the calculation of the zero point fluctuation amount at the next power-on period.

  Next, the zero point weight value at the time of power-off stored at the time of the previous power-off is subtracted from the zero-point weight value at the time of the current power-on to calculate the zero-point fluctuation amount during the operation stop period during the previous power-off period. (Step n13).

  The calculated zero point fluctuation amount during the operation stop period and the latest zero point change amount during the operation stop period including the date / time data of the operation stop period are updated and stored in the display table of the nonvolatile memory, The data is displayed on the display unit 9 and updated and stored in the memory table (step n14).

  Next, whether or not the calculated zero point fluctuation amount during the operation stop period, which is the power-off period immediately before, is abnormal, that is, the absolute value of the zero point fluctuation amount during the previous operation stop period is greater than or equal to the allowable value Wst. (Step n15), and if it is equal to or greater than the allowable value Wst, an alarm display indicating that there was an abnormality in the zero point fluctuation amount during the previous operation stop period is displayed on the display unit 9. Notification is made (step n16). Further, when the value is not equal to or greater than the allowable value Wst, automatic zero adjustment is performed so that the display weight value Wn = 0 is obtained by adding the value of the display weight value Wn to the contents of the zero point change value Wz and updating the zero point change value Wz. The process ends (step n17).

  If the absolute value | Wn | of the displayed weight value Wn is not less than or equal to the preset boundary value Wt in step n10, the weight value Wn is not near zero immediately after the power is turned on. A weighing platform confirmation alarm signal for prompting confirmation of whether an object to be weighed or the like is not placed on is output and displayed on the display unit 9 (step n18). In this case, either an object to be weighed was placed on the weighing platform before the power was turned on, or the zero point weight value fluctuated greatly during the power off period, or both occurred. It will be. When an object to be weighed is placed on the weighing table, the operator removes the object to be weighed and operates the confirmation alarm reset key of the input unit 8.

  Accordingly, in step n19, the alarm is reset, and the process returns to step n6 in FIG. When the above alarm signal is output and displayed even though an object to be weighed is not placed on the weighing table, the operator checks the weighing table or the load sensor.

  Although not shown in FIGS. 3 and 4, the zero point weight value when the power is turned off is stored as follows. For example, if the weighing device 1 stores the zero point weight value at the time of manual zero adjustment immediately before turning off the power as the zero point weight value at the time of turning off the power, every time there is a command corresponding to the manual zero adjustment operation, the digital load When the signal Wad is determined to be stable in the above-described stability determination process, a stable measured weight value K · (Wad−Wi) is calculated. The calculated measured weight value K · (Wad−Wi) is set as the zero point weight value when the power is turned off, and the date / time data is read from the real-time clock element 11 at the calculated timing to obtain the zero point weight value K · (Wad− Along with Wi), it is stored in the nonvolatile memory as the zero point weight value and the date / time data when the power is turned off this time. Here, the zero point weight value and date / time data at the time of the previous power-off are updated to the current zero point weight value and date / time data.

  Since the zero point weight value and date / time data are updated every time manual zero point adjustment is performed during the operation period, when the power is turned off at a certain timing, the zero point weight value and date stored at the time of turning off are stored.・ Time data becomes zero point weight value and date / time data when the power is turned off.

  FIG. 5 is a table showing a display example of the zero point fluctuation amount and the date / time data. FIG. 5A shows an example of the zero point fluctuation amount and the date / time data during the operation period, and FIG. The example of the zero point variation | change_quantity and date / time data during a driving | operation stop period is shown.

  First, display during the operation period will be described with reference to FIG.

  The weighing device 1 is turned on at 08:30:05 on July 01, 2013, and starts storing the zero-point weight value wzs1 and date / time data when the power is turned on. The operation ends at 18:02:10 on the same day, the power is turned off, and the zero point weight value wze1 and date / time data at the time of power off are stored.

  When the power is turned on at 8:31:20 on July 2 of the following day, the zero point fluctuation during the operation period of July 1 of the previous day is displayed in the column of order 1 corresponding to the previous operation period at that time. For example, a value of wze1-wzs1 = 5.2 (g) is calculated and displayed on the display unit 9 and stored as the amount. At the same time, as the date and time data at the time of power-on corresponding to the start of the operation period, 08/01/13 08:30:05 is displayed, and the date / time at the time of power-off corresponding to the end of the operation period is displayed. As time data, July 01, 2013, 18:02:10 is displayed. Then, the zero point weight value wzs2 and the date / time data when the power is turned on this time are stored. The operation ends at 18:07:15 on the same day, the power is turned off, and the zero point weight value wze2 and the date / time data at the time of power off are stored.

  When the power is turned on at 8:30:50 on July 3 of the next day, the zero point fluctuation during the operation period of July 2 of the previous day is displayed in the column of order 2 corresponding to the previous operation period at that time. As an amount, for example, a value of wze2−wzs2 = 3.5 (g) is calculated and displayed on the display unit 9 and stored. At the same time, as the date / time data at the time of power-on corresponding to the start of the operation period, 08:31:20 on July 02, 2013 is displayed, and the date / time at the time of power-off corresponding to the end of the operation period is displayed. As time data, July 02, 2013 18:07:15 is displayed. Then, the zero point weight value wzs3 and the date / time data when the power is turned on this time are stored. The operation ends at 18:03:18 on the same day, the power is turned off, and the zero point weight value wze3 and date / time data at the time of power off are stored.

  When the power is turned on at 8:30:42 on July 4, the following day, the zero point fluctuation during the operation period on July 3 of the previous day is displayed in the column of order 3 corresponding to the previous operation period at that time. For example, a value of wze3−wzs3 = 2.6 (g) is calculated and displayed on the display unit 9 and stored as the amount. At the same time, as the date / time data at the time of power-on corresponding to the start of the operation period, 08/03/13 08:30:50 is displayed, and the date / time at the time of power-off corresponding to the end of the operation period is displayed. As time data, July 07, 2013, 18:03:18 is displayed. Then, the zero point weight value wzs4 and the date / time data when the power is turned on this time are stored. The operation is finished at 18: 4: 20 on the same day, the power is turned off, and the zero point weight value wze4 and date / time data at the time of power off are stored.

  Similarly, the zero weight value wzs and date / time data when the power is turned on are stored, and the zero weight value wze and date / time data when the power is turned off are stored. The zero point fluctuation amount during the driving period is calculated and stored, and displayed on the display unit 9 together with date / time data indicating the driving period.

  In addition, the determination result of the presence / absence of abnormality is displayed in the column of abnormality sign. When the number of table columns becomes N, the oldest data is discarded, and the display column is moved up by one and new data is placed in the Nth.

  Next, the display of the zero point fluctuation amount during the operation suspension period will be described based on FIG.

  As described above, the weighing device 1 was turned on at 08:30:05 on July 01, 2013, and started operation at 18: 2: 10 on the same day. Zero point weight value wze1 and date / time data when the power is turned off are stored.

  When the power is turned on at 8:31:20 on July 2, the next day, the zero point weight value wzs2 and the date / time data at the time of power on are stored as described above. At that time, in the column of order 1 corresponding to the previous operation stop period, as the zero point fluctuation amount during the operation stop period from the end of the previous day operation to the start of the current operation, for example, wzs2-wze1 = 2.8 (g ) Is calculated and displayed on the display unit 9 and stored. At the same time, the date and time data at the time of power-off corresponding to the start of the operation stop period is displayed as 01/07/13 18:02:10, and the power-on time corresponding to the end of the operation stop period is displayed. As of the date / time data, 08:31:20 on July 02, 2013 is displayed. The operation is finished at 18: 7: 15 on the same day, the power is turned off, and the zero point weight value wze2 and the date / time data when the power is turned off are stored as described above.

  When the power is turned on at 8:30:50 on July 3, the following day, the zero point weight value wzs3 and the date / time data at the time of power on are stored as described above. At that time, in the column of order 2 corresponding to the previous operation stop period, as the zero point fluctuation amount during the operation stop period from the end of operation on July 2 of the previous day to the start of the current operation, for example, wzs3-wze2 = 10 .3 (g) is calculated and displayed on the display unit 9 and stored. At this time, if 10 g is set as the allowable value Wst of the zero point fluctuation amount during the operation suspension period, for example, a cross mark is displayed in the column of an abnormal sign as an alarm display. When the x mark is displayed, the operator checks the contents of removal work and cleaning work of the weighing platform during the operation suspension period, and immediately checks the dew condensation state on the surface of the load cell LC.

  Simultaneously with the display of the zero point fluctuation amount during the previous operation stop period, the date and time data at the time of power-off corresponding to the start of the operation stop period are displayed as 02/07/13 18:07:15. At the same time, 08:30:30 on July 03, 2013 is displayed as the date / time data at the time of power-on corresponding to the end of the operation suspension period. The operation ends at 18: 3: 18 on the same day, the power is turned off, and the zero point weight value wze3 and the date / time data when the power is turned off are stored as described above.

  When the power is turned on at 8:30:42 on July 4, the following day, the zero point weight value wzs4 and the date / time data at the time of power on are stored as described above. At that time, in the column of order 3 corresponding to the previous operation stop period, as the zero point fluctuation amount during the operation stop period from the end of the operation on July 3 of the previous day to the start of the current operation, for example, wzs4-wze3 = 5 .2 (g) is calculated and displayed on the display unit 9 and stored. At the same time, the date and time data at the time of power-off corresponding to the start of the operation suspension period is displayed as 03/07/18 18:03:18, and the power-on time corresponding to the end of the operation suspension period is displayed. As the date / time data, 08/07/2013 08:30:42 is displayed.

  Similarly, the zero point weight value wzs and date / time data when the power is turned on are stored, and the zero point weight value wze and date / time data when the power is turned off are stored. The zero point fluctuation amount during the operation stop period is calculated and stored, and displayed on the display unit 9 together with the date / time data indicating the operation stop period.

  In FIG. 5, N pieces may be displayed in order from a value with a large zero point fluctuation amount during the operation period and the operation suspension period.

  In the above embodiment, the attachment of the object to be weighed to the weighing table is not considered, but as another embodiment of the present invention, the presence or absence of abnormality is detected in consideration of the object to be weighed to the weighing table. You may do it.

  Next, detection of the presence / absence of an abnormality in consideration of adhesion of an object to be weighed to the weighing table will be described.

  Depending on the weighing device and the object to be weighed, the object to be weighed may adhere to a weighing table, for example, a weighing hopper, and cleaning work such as washing of the weighing table may be performed during the operation suspension period.

  In this way, when the object to be weighed adheres to the weighing table of the weighing device and the weighing table is cleaned during the operation suspension period, the amount of the object to be weighed when the power is turned off after the operation is completed Since it is cleaned and removed during the power-off period, which is the suspension period, the amount of the object to be weighed appears as a negative zero point fluctuation amount during the operation suspension period when the power is turned on next time.

  Therefore, for example, a value of ± 2% of the rated load is set as the zero point fluctuation amount due to the attachment of the object to be weighed. When the power is turned on, the presence or absence of abnormality is determined based on the zero point fluctuation amount during the previous operation suspension period. This determination is performed as follows.

  If the object to be weighed does not have the property of adhering to the weighing platform, if the absolute value of the zero point variation during the operation suspension exceeds ± 2% of the rated load, the zero point due to the object to be weighed will be Since it is not a fluctuation, an alarm signal indicating that the zero point fluctuation amount during the operation suspension period is excessive and abnormal is output, and an alarm is displayed on the display unit 9.

  When the object to be weighed has a property of adhering to the weighing platform and cleaning work is performed to remove the adhering substance during the operation suspension period, the amount of the object to be weighed during the operation period is measured in advance. Understand and set the average amount of adhesion (average amount of adhesion).

  For example, if the average adhesion amount is 0.5% of the rated load, the zero point fluctuation amount is 0.5% of the rated load in the negative direction due to the removal of the adhering substance during the operation stop period even if there is no zero point fluctuation of the load sensor. Therefore, the allowable value in the negative direction is -2.5% of the rated load, and the allowable value in the positive direction is + 1.5% of the rated load. That is, for the determination of the presence / absence of abnormality, the adhesion amount of the object to be measured is corrected. In order to correct the amount of the object to be weighed, the input unit 8 is operated in advance to determine whether or not the object has a property of adhering to the weighing table. In some cases, the average adhesion amount and whether or not the cleaning operation is performed during the operation stop period are set.

  In addition, you may make it correct | amend the zero point variation | change_quantity calculated with the average adhesion amount of a to-be-measured object. That is, when performing a cleaning operation to remove the adhesion of the object to be weighed during the operation stop period, the preset average adhesion amount is added to the value calculated as the zero point fluctuation amount during the operation stop period, and the allowable value is larger or smaller. Compare.

  Also, in many weighing platforms such as combination weighers, that is, weighing devices that use many weighing hoppers, even during cleaning operations to remove deposits during the operation suspension period, If the magnitude of the zero variation of each weighing platform is determined based on the average value of the zero variation of each weighing platform, the object to be weighed will adhere to any weighing platform by the same amount. If this is the case, the presence or absence of an abnormality can be determined by evaluating the magnitude of the zero-point fluctuation amount by relative comparison without specially setting the adhesion amount.

  In using the relative comparison, it is assumed that the probability of occurrence of zero point fluctuation anomalies simultaneously on a plurality of weighing platforms is small. In addition, when there are a large number of weighing platforms as a whole, it is possible to determine the presence or absence of an abnormality by evaluating the magnitude of the zero point fluctuation amount even if an abnormality occurs simultaneously on a small number of weighing tables.

  In other words, the average value of the zero point variation during the operation suspension period of all the weighing platforms is such that there is no abnormality at the zero points of almost all weighing platforms, and the property that the object to be weighed adheres to the weighing platform (weighing hopper). If there is, it becomes a value almost equal to the average adhesion amount. When the cleaning operation is performed during the operation stop period, the deposits are removed, and thus a negative value is obtained. This value becomes a reference value as a normal zero point fluctuation amount during the operation suspension period.

  If the object to be weighed does not have the property of adhering to the weighing table, the average zero point fluctuation amount becomes a value near zero, and this value becomes the reference value.

  Compare the absolute value of the difference between the zero point fluctuation amount of each weighing platform and any of these reference values with a preset tolerance, for example, 2% of the rated load, and the zero point fluctuation amount exceeding 2% If there is, an alarm signal indicating that the zero point fluctuation amount is excessive and abnormal is output to the weighing table, and an alarm is displayed on the display unit 9.

  Next, the handling which considered adhesion of the to-be-measured object to the weighing platform during an operation period is demonstrated.

  If the object to be weighed does not have the property of adhering to the weighing platform, the factors causing the zero point fluctuation in each period can be estimated by continuously comparing the zero point fluctuation amount during the operation period and the operation suspension period. To help. Further, it can be easily determined which period the amount of zero point fluctuation is large.

  For example, if the zero point fluctuation amount during the operation period is continuously larger than the zero point fluctuation amount during the operation stop period even though the object to be weighed does not have the property of adhering to the weighing platform, The influence of the load is estimated, and the supply operation of the object to be weighed can be reviewed and improved.

  On the contrary, when the zero point fluctuation amount during the operation suspension period is continuously larger than the zero point fluctuation amount during the operation period, it is estimated that the influence of dew condensation or the work of removing the weighing platform from the load sensor during cleaning is affected. Therefore, countermeasures for condensation will be taken, and the cleaning work method will be reviewed and improved.

  In this way, it is possible to find a problem before the load sensor becomes completely unusable, and to use it for failure prevention measures.

  Note that an evaluation value may be calculated based on the zero point fluctuation amount, and the presence or absence of abnormality may be determined based on the evaluation value.

  For example, the zero point fluctuation amount during the operation period and the operation suspension period is integrated for L times that is the latest predetermined number, and the average value is calculated as the evaluation value, respectively, and the respective allowable values are set and compared, or It is preferable to calculate the difference between the zero point fluctuation amount during the operation period and the operation stop period as an evaluation value and compare the magnitudes thereof because the difference between the zero point fluctuation amounts during the operation period and the operation stop period becomes clearer. That is, the frequent fluctuations in the zero point weight value that occur frequently are offset, and continuous one-way zero point fluctuations due to special factors such as repeated overload and condensation clearly appear.

  When the object to be weighed has a property of adhering to the weighing platform and cleaning work is performed to remove the adhering substance during the operation suspension period, the amount of the object to be weighed is measured in advance and the average adhesion The average adhesion amount, which is the amount, is set beforehand.

  In this case, in order to remove the influence of the adhesion amount of the object to be measured from the zero point fluctuation amount, the average adhesion amount is subtracted from the zero point fluctuation amount during the operation period and the zero point fluctuation amount during the operation suspension period. Each value added with is compared with an allowable value.

  Further, as another embodiment of the present invention, whether or not there is a zero fluctuation peculiar to any period during the operation suspension period or the operation period is evaluated as follows, and whether or not there is an abnormality is determined. Good.

  That is, the ratio R1 between the zero point fluctuation amount during the operation stop period and the zero point fluctuation amount during the operation period, or the difference between the zero point fluctuation amount during the operation stop period and the zero point fluctuation amount during the operation period is used as an evaluation value. Based on the evaluation value, the presence or absence of an abnormality is determined.

  For example, the ratio R1 is calculated as the evaluation value by the following equation.

R1 = Zero point fluctuation amount during operation stop period / Zero point fluctuation amount during operation period Here, the operation stop period and the operation period are adjacent in terms of time.

  For this ratio R1, for example, a determination level of an allowable value ± 0.2 is set, and each time the power is turned on, the zero point fluctuation amount during the previous operation period and the zero point fluctuation amount during the previous operation stop period Based on the above, the ratio R1 is calculated, and when the calculated ratio R1 is the allowable value +0.2, for example, 1.2 or more, or the allowable value -0.2, for example, 0.8 or less. In some cases, it is determined that a characteristic zero point fluctuation has occurred during either the operation period or the operation suspension period.

  In this case, the zero point fluctuation amount due to a common factor during the operation period and the operation suspension period does not affect the ratio R1.

  Even if the amount of fluctuation of the zero point is relatively small, if there is a specific zero point fluctuation factor in any period, for example, an alarm is displayed on the display unit 9.

  In addition, since the length of the operation suspension period that is the power-off period and the operation period that is the power-on period may be different in one day, the following zero point fluctuation amount in the operation suspension period and the operation period Thus, the zero point fluctuation rate, that is, the zero point fluctuation amount per unit time in the operation suspension period and the operation period may be calculated as an evaluation value and compared.

  That is, the zero point fluctuation rate (= per unit time) during the operation stop period is calculated based on the time length and the zero point fluctuation amount of the operation stop period obtained from the date / time data at the time of power off and the date / time data at the next power on. Of zero point fluctuation).

  Similarly, the zero point fluctuation rate during the power-on period can also be obtained. The zero point fluctuation rate during the operation suspension period and the operation period together with the date / time data is stored in the nonvolatile memory, read out and displayed on the display unit 9, for example, the latest N sets, or By storing the data up to N in the order of the magnitude of the zero point fluctuation rate in the nonvolatile memory and displaying it on the display unit 9, the zero point fluctuation per unit time only during the operation period and during the operation stop period The amount can be compared and used for evaluation and judgment.

  For example, when the zero point fluctuation rate during the operation stop period is larger than that during the operation period, it is not zero point fluctuation due to condensation during the operation stop period, or the zero point change rate during the operation period is not during the operation stop period. When larger than that, the factor of the zero point fluctuation amount can be estimated for each period such as whether there is a problem in the supply of the object to be weighed to the weighing table.

DESCRIPTION OF SYMBOLS 1 Weighing device 2 Weighing device 3 Indicator 4 Operational amplifier 5 A / D converter 6 CPU
7 Memory 8 Input section 9 Display section 11 Real-time clock element LD Load cell

Claims (10)

In a weighing device comprising a measuring instrument for measuring the weight of an object to be weighed, and capable of measuring a zero point weight value which is a weight value in a state where there is no object to be weighed in the measuring instrument,
Zero point weight value calculating means for calculating a zero point weight value at a time in the vicinity of the time when the power is turned on during a power on period in which the power of the weighing device is turned on;
Zero point weight value calculating means for calculating a zero point weight value at a time point after the vicinity time point when the power source is turned on during the power on period, as a zero point weight value other than when the power source is turned on;
Storage means for storing the zero point weight value when the power is turned on;
The same power supply the zero weight value at power-on in the on period and the power-on period zero point variation calculating means for calculating a zero point fluctuation amount in the power-on period is the difference between the zero point weight value other than the power-on Prepared ,
The zero-point weight value calculating means for calculating a zero-point weight value at a time point after the vicinity time point when the power source is turned on in the power-on period as a zero-point weight value other than when the power source is turned on. The zero point weight value near the time point when the power is turned off is calculated as the zero point weight value when the power is turned off.
The storage means stores the calculated zero point weight value at the time of power-off,
The power-on period zero point fluctuation amount calculating means calculates a difference between the zero point weight value when the power is turned on and the zero point weight value when the power is off in the same power-on period as the zero-point fluctuation amount during the power-on period. To
A weighing device characterized by that. In a weighing device comprising a measuring instrument for measuring the weight of an object to be weighed, and capable of measuring a zero point weight value which is a weight value in a state where there is no object to be weighed in the measuring instrument,
Zero point weight value calculating means for calculating a zero point weight value at a time in the vicinity of a time point when the power is turned off during a power on period in which the power of the weighing device is turned on;
Zero point weight value calculating means for calculating a zero point weight value at a time in the vicinity of the time when the power is turned on in the next power on period after the power source is turned off in the power on period as a zero point weight value at the time of power on. When,
Storage means for storing the zero point weight value when the power is off;
A power source that calculates a difference between the zero point weight value when the power is turned off stored in the storage means and the zero point weight value when the power is turned on during the next power on period as a zero point fluctuation amount during the same power off period Off period zero point fluctuation amount calculating means;
A weighing apparatus comprising: The zero-point weight value calculating means for calculating a zero-point weight value at a time point after the vicinity time point when the power source is turned on in the power-on period as a zero-point weight value other than when the power source is turned on. The weight value at the time of zero point adjustment is calculated as the zero point weight value at the time of zero point adjustment ,
The power ON period zero point fluctuation amount calculating means calculates a difference between the zero point weight value at the time of power ON and the zero point weight value at the time of zero adjustment as the zero point fluctuation amount during the power ON period in the same power ON period. To
The weighing device according to claim 1. Output means for outputting the zero point fluctuation amount during the power on period or the zero point fluctuation amount during the power off period calculated by the power on period zero point fluctuation amount calculating means or the power off period zero point fluctuation amount calculating means;
The weighing device according to any one of claims 1 to 3 . The presence / absence of abnormality is determined based on the zero point fluctuation amount during the power on period or the zero point fluctuation amount during the power off period calculated by the power on period zero point fluctuation amount calculating means or the power off period zero point fluctuation amount calculating means. A determination means ,
The weighing device according to any one of claims 1 to 4. The determination means determines the presence or absence of the abnormality by comparing the zero point fluctuation amount with a predetermined allowable value.
The weighing device according to claim 5 . The determination means determines the presence or absence of abnormality based on an evaluation value calculated based on the zero point fluctuation amount.
The weighing device according to claim 5 or 6. Provided with a notifying means for notifying when it is determined to be abnormal by the determining means;
The weighing device according to any one of claims 5 to 7 . A time measuring means for measuring the date and time and generating date and time data;
Date / time data for storing at least one of date / time data by the timing means corresponding to a time near the time when the power is turned on and date / time data corresponding to a time near the time when the power is turned off Storage means;
Weighing apparatus according to any one of claims 1 to 8 comprising a. Display means for displaying the date and time data of at least one of the date and time data storage means in correspondence with the zero point fluctuation amount during the power on period or the zero point fluctuation amount during the power off period;
The weighing device according to claim 9 .

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