HK1144600B - Kontrollgewicht, verfahren und system zur rueckverfolgbarkeit solcher gewichte - Google Patents

Description

Check weight and method and system for making it traceable

Technical Field

The invention belongs to the field of metrology, and relates to weights for testing balances and testing or measuring other weights.

Background

High-sensitivity balances, such as, in particular, microbalances and microbalances, analytical balances or precision balances, are subject to influences which lead to measurement deviations over time. Such balances must therefore be tested according to the normal standards to ensure that they produce accurate weighing results. Such tests are so-called routine tests carried out in a defined institution, in particular for balances used in the fields of pharmacology, biotechnology and food technology, which tests are officially required and are recorded in the FDA regulations (food and drug administration, department of health and human services). However, manufacturers of balances also recommend to their customers that balances used for commercial applications be regularly checked.

Check weights with well-defined nominal values were used to determine the deviation. According to a normative standard, for example the internationally accepted rule R111 published by the international legal metrology Organization (OIML), check weights of these kinds have a tolerance limit within which the actual weight value must lie in relation to the nominal weight value. With this tolerance system, the weights are divided into different weight classes according to different accuracy requirements. For example, the tolerance limit for a one-mg weight is 0.003mg at the E1 level (highest accuracy level), and 0.2mg at the M1 level (lowest accuracy level applicable to a one-mg weight).

Check weights, as the term is used herein, should be understood to include all kinds of weights for checking and/or calibrating and/or proving balances or weights that are particularly within the scope of a prescribed control. These check weights are sometimes also referred to as check weights or calibration weights.

The check weight can be made of a solid piece or several parts of material. The individual check weights are made from one piece of material, while the more-part check weight has a cavity therein, which is filled with a so-called adjusting material to the point where it reaches the nominal weight, and is then closed. It should be noted, however, that a multipart check weight is not allowed within the highest accuracy class according to OIML.

Since the actual weight values of check weights can change over time due to wear, this can also have the consequence that the weighing result or the industrial process exceeds its tolerance limits when these weights are used to check weather. It must therefore be determined that the check weight tolerance is met in any given case. To achieve this, the check weight itself is regularly checked against other check weights (called check standards). The time intervals between such verification checks are dependent on the respective accuracy class of the weight or on the application range and the particular application environment.

For each individual check weight, a certificate is issued on demand, which specifies the actual weight value, the nominal weight value, the accuracy class associated with the given class limit, and the calibration ID number and the calibration certificate number at a specific time. Each time another check, called recalibration, is made at a later date, a new voucher is issued, wherein a new voucher number is assigned to the same weight, but the same calibration ID number is still assigned to the weight.

The check weights or sets of check weights with different weight values are stored in dedicated weight container boxes for sorting and later storage by the user at the place of their application. In such a case, a well of suitable dimensions is prepared for each weight type, so that a weight of, for example, 100g can only be placed exactly fittingly into the recess of a weight of 100g, but not into the recess of a weight of 50 g, and at the same time it cannot completely fill the recess of a weight of 200g, so that an association between the weight and the recess is possible depending on the dimensions. The documents of the individual weight pieces are placed in these container boxes, so that in principle a connection is established between the documents and the check weights. This is usually evident by a label affixed to the container box, on which the calibration ID number is printed, and another label, on which the voucher number is printed.

Due to the manual handling of the weights during the aforementioned routine checks, the connection between the weight piece and the voucher associated therewith and/or the calibration ID number thereof is easily lost. This can occur, for example, in: it is assumed that a balance suitable for 400g will be certified or calibrated and that this is assumed to be achieved-since no 400g weight is currently available-with one 200g weight piece and 2 100g weight pieces. Whether the two 100g weight pieces are stored in the same container box or from two different container boxes, operational errors may occur in the process, resulting in confusion of the two 100g weight pieces. The result is an incorrect match between the document and the weight piece, which cannot even be checked effectively, so that this error remains undetected.

A problem with this approach is that there is no definite association of the credentials to the check weight, for example to the actual weight piece itself. The handling of these check weights therefore requires extreme care to ensure that the correct match between the certificate and the calibrated weight piece is maintained permanently. Nevertheless, this goal cannot be guaranteed to be achieved. Inadvertent confusion cannot be ruled out and reliably detected thereafter.

DE4006375a1 discloses the concept of providing a coded marking on a check weight that represents a weight value. This is achieved by storing the weight value electronically in an electronic circuit which is accommodated in the weight piece itself. This method has the disadvantage that electrical contacts must be used for the data transmission from the weight part to the balance or vice versa, and because of these contacts the weight must be placed in a defined position and, in particular, requires the use of special equipment, making manufacture and use an error-prone process. Electronic data storage also does not completely avoid errors, so that data errors due to improper handling of the check weight or also due to fatigue of the material, and consequently calibration errors, cannot be completely ruled out in this case either. Furthermore, such check weights are expensive to produce.

Since only the original actual values are included in the discerning marks, this coding system does not provide a single discerning mark for each weight piece, but merely scales according to weight values. In the method described in said reference a single weight piece can be tracked, each weight check being calculated until said upper limit is reached, only within the highest possible range of the number of weight checks to be performed entered into the electronic data storage of the weight. Traceability beyond the time limit or for other reasons, such as the place or date of manufacture, the product lot number, etc., is not possible. For example, if a manufacturing error occurs in a product lot, a recall that may be necessary for check weights identified in this way is therefore not possible.

Disclosure of Invention

It is therefore an object of the present invention to improve the design of check weights so that the weights can be permanently and independently tracked.

The above object is achieved by the concept of detecting that the weight itself carries an identification mark, in particular by means of a machine-readable identification code mark on the exterior of the weight, so that each weight piece can be individually identified.

The advantage of this concept is that the check weight can be permanently and reliably matched to its certificate and that all data can be read and manipulated by machine and also be stored centrally if required. Confusion in the operation of the weight or reliable detection after this has occurred can thus be largely avoided. Furthermore, if a check weight rated as grade E of OIML is found to be out of tolerance, for example, the weight can be reassigned to a lower accuracy grade without any problems.

Such an identification system is advantageous for check weights of unitary construction and those assembled from a plurality of pieces. The check weights are made of metal or of a metal alloy of constant material density, which is specified in the applicable specification standards.

An advantage of placing the identification code on the outer surface of the weight piece is that the process of attaching the code and reading the code can be realized in a simple manner.

In an advantageous embodiment, it is designed to implement the identification code in the form of a binary representation, in particular a data matrix code or a miniaturized bar code.

In a preferred embodiment, the identification code comprises a weight number which is uniquely assigned to the weight piece.

In a practical further developed embodiment, the identification code comprises more data about the respective weight piece, including for example a product lot number and a detailed date, in particular a production date, a date on which the marking is applied and/or an initial calibration date. The method has the advantages that in the weight detection process, the data of the detected weight can be obtained without connecting an external database or data backup on an internal storage medium, so that the processes are simplified and speeded up.

A further object of the invention is to provide a method by means of which the aforementioned check weights can be tracked in time, which is achieved by the following steps:

1) the identification code is established and the identification code is established,

2) converting the identification code into a machine-readable code format, and

3) the code in machine-readable format is placed on the weight piece as a marking or recognition means.

The identification code essentially comprises the weight number which is uniquely assigned to the check weight. However, it is also conceivable to arrange the identification code in any other desired way. The only essential requirement is that the identification code thus established must be suitable for conversion into the desired machine-readable code, which is placed as a marking on the weight piece. This procedure can be carried out immediately after the production of the check weight or else at a later point in time. The advantage of including the markers within the scope of the production process is that each individual weight piece is already identifiable and thus traceable at the completion of the production process. On the other hand, the advantage of applying the marking at a later time is that check weights already in use, in particular when there is a loss of correlation with their respective vouchers, can be identified later, making them traceable again.

It is desirable in practice to perform transcoding by converting the identification code into a matrix code or a miniaturized bar code.

In an advantageous implementation of the marking method with a binary representation, the marking process is carried out with a laser. The advantage is that the marking process can be carried out without loss of material or, in the worst case, with only minimal loss, while the marking can be permanently attached to the weight piece. Known laser marking processes can produce the identification code pattern by matte finishing or by a method known as annealing color.

Other writing methods suitable for label application include, for example, needle, etching, or electron beam lithography. More methods than those mentioned here are equally conceivable.

According to an advantageous further development, after the application of the marking to the check weight, the respective identification code is permanently stored in the database. This creates an advantageous possibility for systematically processing and managing the registered identification codes and the data of their marked weight pieces. The credential data can advantageously also be registered and stored in a database together with the identification code. The credential data of the individual check weights can thus be automatically kept available and transmitted on request in a simple and reliable manner.

When a control weight is certified, it includes a unique association with the identification code. In particular when the identification code comprises a weight number which is uniquely assigned to the weight, said weight number is also specified in the certificate.

Since the checking, calibration or recalibration procedure may also comprise a comparison of the further check weight with the first check weight, in particular in accordance with a calibration standard. Advantageously, if the identification code of the first check weight, in particular the check standard, is also recorded in the database, it is also specified in the certificate. Thus, a higher level of traceability can be achieved.

The voucher data further comprises the calibration ID number, the voucher number, the date of issuance of the voucher, the shape and material of the check weight, the identity of the person performing the weight check, the conditions under which the weighing takes place, the environmental conditions such as temperature and atmospheric pressure, the present weight value, and also statistical data about the weight check.

The weight pieces are recalibrated from time to time, the preferred practice being to create a history file for a particular weight based on chronological order of the credential data. From the history file, the measured and/or stored data can be compared with the data of the preceding voucher, the result can be further processed and, if desired, the result can be used to predict the future range in which the weight is still usable.

When a routine check is performed, for example to check the balance with a check weight, a program is executed in the processor of the balance to investigate and confirm the identity of the check weight before the weighing check begins.

It is a further object of the invention to provide a system such that check weights can be tracked individually on a permanent basis. This is achieved by the features of claim 22 and the embodiments of the claims referring to claim 22. An advantage of these embodiments is that all individually marked weight pieces can be systematically managed and maintained, in particular under central control, whereby all data belonging to a given individual weight piece can be accessed at any time. The one or more processors may convert the marker code back to the original identification code and utilize the latter directly. The at least one memory unit serves to store the identification code belonging to the respective weight piece and advantageously also further registration data, including for example voucher data, in a permanent and traceable/retrievable memory. These data are ideally kept available in a database that provides centralized access and fast system processing capabilities. Thus, a basis is established for the traceability of a given weight, which allows, for example, a traceable assessment of past wear and thus also an inference of the future during the entire service life of the check weight. This may for example include changing the recalibration interval or assigning it to a lower level of advice when the weight is found to be out of its applicable tolerance. Thereby ensuring the highest possible quality supervision of the check weights to increase the reliability of balances and/or weights checked with these check weights.

According to a further advantageous embodiment of the system, the at least one processor is equipped with functionality to send a report, e.g. a notification about the expiration of a check time interval, depending on the result and/or the inference of the occurrence. The advantage of this is that the supervision of the check weights and the measurements made on them can be systematically and reliably controlled from a central location, for example by the weight manufacturer. A direct and reliable warning of the user of the check weight about any action to be taken is thus ensured, which improves the quality of the respective measuring system.

Drawings

The invention will be explained in more detail subsequently with reference to the drawings, as follows:

FIG. 1 shows a side view of an example check weight;

fig. 2 illustrates an example check weight as seen from above, in which a machine-readable identification code in the form of a marking according to the invention is schematically shown;

FIG. 3 shows an enlarged view of a matrix type mark placed on a weight;

FIG. 4 is a schematic representation of a system for detecting traceability of a weight; and

fig. 5 shows a flowchart showing the timing of routine checks.

Detailed Description

Fig. 1 shows an example of a check weight 1. Of course, the scale of the check weight 1 can vary, or the weight 1 can have a completely different shape, in particular in terms of a nominal weight value. For example, the weight with the smallest nominal value is usually provided as a so-called string weight or a sheet metal weight.

Fig. 2 shows a check weight 1 according to the invention of the same type as shown in fig. 1, with a marking in the form of a matrix code 2, the matrix code 2 comprising an identification code. The shape and size of the matrix code 2 are not true to scale. The shape and size of the marks may vary depending on the type of mark used. However, in the case of more precise weight classes E and F, the maximum dimensions are specified by the specification standards. The method of arranging the markings on the weight piece can likewise be varied. Advantageously, the indicia is placed on top for ease of reading. However, it is also conceivable to place the markers in some other position, for example laterally or underneath.

Fig. 3 shows an example of the design of the label 2 in relation to the matrix form. The matrix 2 shown is, for example, a 12 x 12 array of matrix cells 3, 3 'in which two binary values are represented by a black matrix cell 3 and a white matrix cell 3', respectively. The border cell rows 4 and 4 'meet at one corner of the matrix and the border cell rows 5 and 5' meet at the opposite corner, each forming a pattern that allows a reading device to find the matrix code and read and interpret it in the correct orientation. The rows of border cells with uniform binary values (black) running in the direction of the arrows 4, 4 'represent a so-called probe (finder) pattern, while the two rows of border cells with selectable values running along respectively opposite borders of the matrix in the direction of the arrows 5, 5' represent a so-called azimuth pattern. The detection patterns 4, 4 'are used to find the matrix code on the weight, while the orientation patterns 5, 5' along the respectively opposite boundaries provide the correct orientation in the reading and evaluation of the code. The cells surrounded by the two boundary patterns 4, 4 'and 5, 5' represent the actual identification code.

The shaded representation of the binary bits may be achieved during manufacture, for example by applying a matte finish (matte finish) to an initially polished surface to obtain the black matrix elements 3 shown in the figure. Other techniques may also be used to generate the binary representation. An example is the creation of serrations, such as discoloration by needle-scribing or surface annealing with a laser, or alternatively by etching.

Fig. 4 shows a general diagram of a system for establishing the traceability of a check weight 1 manufactured according to the invention. A reading device 6, equipped with a processor 10, reads the markings on the weights, here the matrix code 2. The processor 10 converts the matrix code into an identification code and transmits the latter to the computer 7, which is also equipped with one or more processors. The computer 7 is connected to a database 8, the database 8 containing all data needed to issue the voucher 9. From the identification code, the computer 7 is now able to retrieve (retrieve) the required data from the database 8 and issue the voucher 9.

To ensure that each identification code is issued only once, a writing device (not shown here) which generates the marking (for example the matrix code 2) and comprises for example a laser is equipped with suitable software modules.

The database 8 has the function of accepting further data associated with the stored identification code, in particular data required by the certificate, but also data which are only generated at a later time, for example data relating to the recalibration of the check weight.

Further comprising means or measures allowing error detection of the matrix code 2 which has been read into the system.

Data can be transmitted from the processor 11 of the computer 7 to or received by other processors and/or computers (not shown in the figures) via a data connection 12, which is only symbolically shown. These processors may be directly connected to the processor 11, or they may be part of a local area network or accessible via the internet. The computer may be installed, for example, at the customer's location or other authorized metering laboratory, so that the credential data can be communicated thereto. Said identification code obtained by the reading device 6 can be transmitted directly, for example without intermediate storage in the database 8, to a processor (not shown) at a remote location, via a data connection 12. Further data connections, for example to a balance (not shown) performing calibration tests, allow data from the test balance, for example weighing result data, to be transferred to the processor 11 of the computer 7, or data from the computer 7, for example voucher data, to be transferred to the test balance. Further system configurations are also conceivable.

The flow chart in fig. 5 shows the chronological sequence of a routine examination of the balance with the aid of the marked weight piece 1 according to the invention. A machine-readable identification code on the weight piece 1, for example in the form of a matrix code 2 shown in fig. 2, is used here for verification and validation purposes. For example, it is possible to determine whether the specific weight piece 1 matches a weight piece described in a test procedure, which may be an internally generated or an externally commanded procedure.

A program executed in the processor of the balance controls the performance of the weighing detection and guides the user accordingly. Initially, in a first step, the weight piece 1 is presented to the reading device 6, the reading device 6 reads the matrix code 2 and compares the corresponding identification code with the data stored in the computer 7 for weighing detection. The computer 7 can be a computer located separately from the balance or can be incorporated in the balance, which can essentially consist of the processor of the balance. If the identification code matches an allowable, e.g. registered, code of the weight piece 1, the weight checking procedure is allowed to be performed and the routine check can continue. If no match is found with the identification code, the weight checking procedure is interrupted and a failure message is issued. A record of the result may be generated by a printer connected to the balance and/or the computer 7. It is also conceivable to provide a corresponding portal in the database 8 which is connected to the computer 7.

The above-described figures represent schematic illustrations of embodiments, which are meant to be exemplary only. In addition to different arrangements of the markings on the individual weight pieces, different kinds of markings are also conceivable. To make the central traceable system more comprehensive it is also possible to include any other desired information items in the code.

Claims (16)

1. The method for timely tracking the recognizable check weight comprises the following steps:

establishing a recognizable check weight by the following substeps:

-providing a specific weight piece;

-forming a recognition code so as to give a specific weight piece an individual identity by which it can be recognized;

-converting the identification code into a machine-readable code format; and is

-affixing the translation code in machine-readable format as a marker on a specific weight piece;

-storing the identification code in a database;

-generating a calibration voucher associating a specific weight piece with the identifying code;

recalibrating the check weight with the identification code stored in the database;

generating a new certificate for the recalibrated test weight based on the recalibrating step;

based on the chronological order of the credential data in the database, a history file is created in the database for the recalibrated check weights.

2. The method of claim 1, wherein: the converting step includes converting the identification code to a matrix code or a miniaturized bar code.

3. The method of claim 1, wherein: the attaching step comprises applying the machine-readable code format to the weight piece by laser beam, needle, etching or electron beam lithography.

4. The method of claim 1, further comprising the steps of:

calibrating a further check weight with respect to the first check weight with the identification code stored in the database;

storing the identification code of the further check weight in a database, associating it with the identification code of the first check weight;

a credential is generated that associates the further check weight with the identification code of the first check weight.

5. The method of claim 1, further comprising the steps of:

establishing a set of credential data for each of a plurality of check weights;

inputting each credential data set into a database;

the identification code of each check weight is uniquely associated with the corresponding credential data set in the database.

6. The method of claim 5, wherein: the credential data set comprises at least one of:

a credential number;

calibrating the ID number;

the date of issuance of the voucher;

description of the shape and material of the check weight;

operating the identity of a person detecting the weight;

the conditions under which weighing occurs;

ambient conditions such as temperature and atmospheric pressure;

the current weight value; and

statistical data on weight measurements.

7. The method of claim 1, further comprising the steps of:

comparing, in at least one computer associated with the database, the data resulting from the recalibration step with the data of at least one previous certificate of check weights;

further processing the results from the comparing step in the at least one computer.

8. The method of claim 7, further comprising the steps of: in the computer, a prediction is made of the further usage permitted by the check weight on the basis of the result.

9. The method of claim 1, further comprising the steps of:

transmitting, from the computer, at least one of:

credential data; and

and (4) reminding and informing about expiration of the deadline of the calibration check weight.

10. The method of claim 1, further comprising the steps of:

a routine check is performed to check the balance, which comprises the following substeps:

executing a program in a processor of the balance, wherein the program is used for verifying and confirming the identity of the detection weight;

the check and confirmed check weight is weighed to check the balance.

11. A system for timely tracking identifiable weights based on time sequence, comprising:

check weights with electronically processable identification codes in the form of machine-readable markings applied to the check weight, and

a processor connected to a database which associates an identification code of a check weight with a first set of data relating to the check weight with said identification code when the check weight is calibrated for weighing and with at least one second set of data relating to the check weight with said identification code when the check weight is recalibrated for weighing, said processor being adapted to be connected to a balance for performing the recalibration.

12. The system of claim 11, further comprising: a machine readable program in the processor to receive and process other data associated with the check weight than the identification code, the processed other data being recorded and stored in the database.

13. The system of claim 11, further comprising means, operatively connected to the processor, for generating a credential associated with the check weight.

14. The system of claim 13, wherein:

the database stores data associated with the generated credentials, the data including at least one of:

a credential number;

calibrating the ID number;

the date of issuance of the voucher;

detecting the shape and the material of the weight;

operating the identity of a person detecting the weight;

the conditions under which weighing occurs;

ambient conditions such as temperature and atmospheric pressure;

the current weight value;

and statistical data about weight detection.

15. The system of claim 12, further comprising a communication device operatively coupled to the processor for communicating the results of the processing by the machine-readable program to other devices.

16. The method for timely tracking the recognizable check weight comprises the following steps:

providing a recognizable check weight comprising a specific weight piece having a machine-readable code attached thereto, the machine-readable code produced by the identification code providing the specific weight piece with an individual identity by which it can be recognized;

providing a path to access a database, storing in the database an identification code and a calibration credential associating a particular weight piece with the identification code;

recalibrating the check weight with the identification code stored in the database;

generating a new certificate for the recalibrated test weight based on the recalibrating step;

based on the chronological order of the credential data in the database, a history file is created in the database for the recalibrated check weights.