Weighing device and method for weighing a product

Abstract

Weighing device (1), in particular price marking device or checkweigher, - with a scale (2) for weighing a product (3) in a weighing section (AW), - with a conveying device (4) for transporting the product (3) along a conveying area (F) from a starting position (PStart) via the weighing section (AW) to a target position (PZiel), wherein the weighing device (1) further comprises a control device (5) which is configured such that the conveying device (4) can be automatically stopped during its operation in one direction from the start position (PStart) to the target position (PZiel) and then automatically operated in one direction from the target position (PZiel) to the start position (PStart), wherein the control device (5) is configured such that, with a product (3) placed on it, a weighing process can be carried out automatically using the scale (2) in a first work step sequence during the operation of the conveying device (4) in the direction from the start position (PStart) to the target position (PZiel), wherein the control device (5) is configured such that the first work step sequence with the product (3) placed on it can be carried out automatically multiple times, characterized by that the control device (5) is configured such that, with the product (3) placed on it, in a second work step sequence that follows or precedes the first work step sequence, after the operation of the conveying device (4) has ended, a weighing process can be carried out automatically using the scale (2) in the direction from the start position (PStart) to the target position (PZiel) in the stopped state of the conveying device (4). that an average of several measured values ​​can be formed from the first work step sequence and compared with a measured value or average of several measured values ​​from the second work step sequence.

Description

[0001] The present invention relates to a weighing device, in particular a checkweigher or price marking device, comprising a scale for weighing a product in a weighing section, and a conveying device for transporting the product along a conveying area from a starting position through the weighing section to a target position.

[0002] Furthermore, the invention relates to a method for weighing a product, in particular using a weighing device as defined above.

[0003] Various weighing devices are known from the prior art, which are used, for example, as price marking devices or checkweighers. Weighing devices of this type have a conveying system, often a single or multi-section conveyor belt, which transports products between a starting position and a destination position. Between the starting and destination positions, the respective product is weighed: in the case of a price marking device, to determine the weight for subsequent labeling, or in the case of a checkweigher, to verify the weight.

[0004] The scale is located in a section of the conveyor belt over which the product is transported at a predetermined speed. Therefore, with these weighing devices, the product is not weighed while stationary (i.e., statically), but rather dynamically during its movement.

[0005] A known problem with weighing devices of this type is that the measured values ​​for the same product differ between static and dynamic weighing (static-dynamic offset). These differences arise, among other things, from the air resistance of the moving product, which can cause a slight increase in buoyancy, making the product appear "lighter." Another reason for these discrepancies is that the conveyor belt in the section where the product is weighed can sag or give way slightly under the product's weight, causing it to accelerate in the direction of gravity. Unevenness in the conveyor belt can also contribute to this acceleration. Consequently, the measured values ​​from a static weighing always differ by a certain amount from those from a dynamic weighing.

[0006] To compensate for the static-dynamic offset in a weighing device of the type mentioned above, it is known to determine a correction value by first weighing a test item statically and then repeatedly weighing it dynamically. An average value is then calculated from the measured values ​​of the multiple dynamic weighings. This average value is then subtracted from the measured value obtained with the same test item during the static weighing process, resulting in a correction value. When products are dynamically weighed on the weighing device during regular operation, the previously determined correction value is automatically added to the respective measured value by a control unit, thereby determining the actual weight of the product relatively accurately. A weighing device operating according to the above-described principle is known, for example, from DE 32 06 061 C1.

[0007] One disadvantage of the current state of the art, however, is that the previously described calibration process for compensating for static-dynamic offset can lead to fluctuations in dynamic measurements. Therefore, these measurements must be performed multiple times to determine an average value. For this to work, however, the test specimen must be manually removed from the conveyor belt by an operator after each dynamic weighing process and then placed back onto the conveyor belt in its starting position. This is relatively cumbersome and time-consuming, especially when a large number of dynamic measurements are to be carried out, and always requires the presence and attention of an operator.

[0008] EP 1 116 941 A2 discloses a weighing device comprising a scale for weighing a product in a weighing section, a conveying device for transporting the product along a conveying area from a starting position through the weighing section to a target position, and a control device. The control device is configured such that the conveying device can be automatically stopped during operation in one direction from the starting position to the target position and then automatically operated in the opposite direction from the target position to the starting position. The control device enables a weighing operation to be carried out automatically using the scale in a first step sequence while the conveying device is operating in the direction from the starting position to the target position, with a product placed on the device. After an incorrect measurement, the control device performs another dynamic or static measurement.However, one disadvantage of this system is that the second measurement overwrites the value of the first measurement, so that only a single measurement value is available.

[0009] Further prior art relevant to the subject matter of the invention can be found, for example, in DE 198 60 296 A1, DE 10 2007 013 333 A1 and DE 32 06 061 C1.

[0010] It is therefore an object of the present invention to further develop a weighing device of the type mentioned above in such a way that calibration for compensating for a static-dynamic offset is simplified. It is also an object of the invention to provide a corresponding method for weighing a product.

[0011] The problem previously derived and demonstrated is solved according to a first teaching of the present invention in a weighing device, in particular a price marking device or checkweigher, according to the preamble of claim 1 by the features of the characterizing part of claim 1.

[0012] According to the invention, a weighing device is provided with a scale for weighing a product in a weighing section, and with a conveying device for transporting the product, wherein the product rests, in particular, on the conveying device, along a conveying area (i.e., transport area) from a starting position through the weighing section to a target position. The weighing device further comprises a control device configured such that the conveying device can be automatically stopped during its operation in one direction from the starting position to the target position and then automatically operated in one direction from the target position to the starting position. The conveying area refers to the area of ​​the conveying device available for transporting a product, i.e., the area in which a product can be transported.

[0013] By providing a control device according to the invention that can automatically stop the moving conveying device and then automatically reverse the direction of movement, it is possible for a product placed on the conveying device (which also includes a test specimen) to first be conveyed from the starting position towards the target position, to be weighed in an area between the starting position and the target position, and after weighing to be automatically conveyed back towards the starting position by the aforementioned reversal of movement. The weighing section, which is a section of the conveying area in which the product can be weighed, is provided in the area between the starting position and the target position. In this way, a product or test specimen can be weighed.Test items can be weighed automatically multiple times without the need for an operator to repeatedly pick them up from the conveyor and place them back on the starting position.

[0014] According to the invention, the control unit is configured such that, in a first work step sequence during the operation of the conveying device in the direction from the starting position to the target position, a weighing process can be carried out automatically using the scale. Since the conveying device and thus also the product move during this weighing process, it is a dynamic weighing process.

[0015] Furthermore, according to the invention, the control device is configured such that, in a second work step sequence that follows or precedes the first work step sequence, a weighing process can be automatically carried out using the scale while the conveyor is stopped after the operation (movement) of the conveyor in the direction from the starting position to the target position has ended, and in particular, the conveyor can then be automatically operated in the direction from the target position to the starting position. In this case, the conveyor and thus also the product are stationary during the weighing process, resulting in a static weighing process.

[0016] Ideally, both work step sequences are performed sequentially, preferably automatically (without operator intervention). It is irrelevant whether the first work step sequence is performed before or after the second. The crucial point is that an average value is calculated from several measurements in the first work step sequence and compared with a measurement or average of several measurements from the second work step sequence. The difference between the (average) values ​​determined by the two work step sequences is the correction value, which must always be added to the measurements from future dynamic weighing processes to determine the actual weight of the weighed product as accurately as possible. This correction value is preferably stored by the control unit.It is preferred that the described calibration for compensating the static-dynamic offset is performed for different weights or weight ranges, and that corresponding correction values ​​are determined and stored in a database of the control unit. Additionally or alternatively, different correction values ​​can also be determined and stored in this way for different packaging shapes (different length and / or width and / or height and / or outer contour), for different packaging contents (differentiation between solid and liquid), or for different transport speeds. In particular, to determine a correction value for a specific product, not just a single package (unit) is weighed as an example, but a representative selection of packages (units) of the same product.

[0017] In the weighing device according to the invention, the control unit is configured such that the first operation sequence (dynamic weighing process) can be executed automatically multiple times. The second operation sequence (static weighing process) can preferably also be executed automatically multiple times. In other words, the control unit performs several successive static weighing processes and / or several successive dynamic weighing processes. For example, the first operation sequence, in which the weighing is dynamic, is executed 2 to 40 times, preferably 10 to 30 times, and particularly preferably 15 to 25 times. The second operation sequence, in which the weighing is static, is executed less frequently than the first operation sequence, for example, 2 to 10 times, preferably 2 to 5 times, and particularly preferably 2 to 3 times. The number of weighing processes can be fixed.However, it is also conceivable that the number of weighing processes is variable and, in particular, dependent on the dispersion of the measured values ​​(standard deviation), possibly linked to the error limits of the weighing device, and adjustable by the control unit or manually.

[0018] According to a further embodiment of the weighing device according to the invention, it further comprises at least one movable guide element, preferably two movable guide elements, wherein the respective guide element is movable between a projecting position, in which the guide element is particularly partially adjacent to the conveying area or at least partially projects into the conveying area, and a recessed position, in which the guide element is particularly spaced away from the conveying area, i.e., located outside the conveying area. "Projecting" means that the guide element is arranged closer to the center of the belt or the center of the conveying device than in the recessed position. The movement between the projecting and the recessed positions can also be carried out automatically, in particular controlled by the control unit of the weighing device.The respective guide element is arranged such that the product is guided past the guide element along the conveying area. In other words, the respective guide element is arranged along a section of the conveying area that lies between the starting position and the target position, specifically between the starting position and the weighing section where the respective product is weighed. The respective guide element may also extend partially into the weighing section.

[0019] A corresponding guide element allows the product to be oriented in a specific way as it moves along the conveyor from the starting position towards the target position. This ensures that the product is always positioned in the same way on the conveyor, even after multiple passes through the conveyor from the starting position towards the target position. This guarantees that the product is always transported onto and across the scale in the same orientation. In turn, this minimizes the risk of discrepancies between individual measurements and allows for a more accurate and faster determination of the average value of a dynamic weighing process on the one hand and a static weighing process on the other.

[0020] In this context, according to a further embodiment of the weighing device according to the invention, the control unit is configured such that the guide element is arranged in the projecting position when the conveying device is operated in the direction from the starting position to the target position and / or in the retracted position when the conveying device is operated in the direction from the target position to the starting position. In other words, it is possible to move the respective guide element, or, if two guide elements are present, both guide elements, into a retracted position outside the conveying area when the product is conveyed back to the starting position after the weighing process. By moving the product back to the starting position, the respective guide element is moved into a retracted position outside the conveying area.Since the guide elements are located outside the conveying area, there is no risk of the product coming into contact with a guide element and, in the worst case, being moved to a different position. Therefore, when the product is moved back to its starting position, its orientation remains unchanged, or at least largely unchanged.

[0021] Before the product is moved from the starting position back towards the weighing section, the respective guide element is preferably moved back into its protruding position to ensure that the product is aligned as precisely as possible, just as it was during the previous measurement. While this isn't strictly necessary, especially if the conveyor with the product on it is moved back and forth relatively slowly, it can be desirable to move the product and thus the conveyor back and forth as quickly as possible to shorten the calibration process for static-dynamic compensation. In such cases, the product may shift slightly when returning to the starting position and during the subsequent reversal of movement, but this position is then corrected by the guide elements, which are then back in their protruding position.

[0022] According to yet another embodiment of the weighing device according to the invention, the conveying system is a belt conveyor or a roller conveyor. The term "belt conveyor" encompasses not only belt conveyors but also belt and chain conveyors, as well as plate belt conveyors and chain link conveyors. The belt conveyor can, in turn, consist of one or more individual belts arranged successively in the transport direction, with the scale being integrated into one of the conveyor belts or positioned between two conveyor belts. A roller conveyor, in particular, has a plurality of rollers, with the scale preferably arranged between two adjacent rollers. A combination of belt and roller conveyors is also conceivable, with the scale then preferably arranged between the belt and roller conveyors.

[0023] Furthermore, according to another embodiment of the weighing device according to the invention, the weighing device also includes a label application device, which in particular comprises a printer, wherein the conveying area from the starting position to the target position passes by or ends at the label application device. After calibration to compensate for the static-dynamic offset, regular operation of the weighing device can then commence, for example by dynamically weighing individual products one after the other and each being labeled with a label containing product information corresponding to the measurement result.

[0024] The problem is further solved according to a second teaching of the present invention by a method for weighing a product, in particular using a weighing device as defined above, according to claim 8, in which the following steps are carried out successively in the specified order: a) Placing a product on a conveyor system in a starting position, b) Operating the conveying device (in a first direction) so that the product is conveyed in the direction from the starting position to a target position along a conveying area, c) Weighing the product when the product is located in a weighing section on or above a scale, the weighing section being on the conveying area between the starting position and the destination position, d) Operating the conveying device (in a second direction) so that the product is conveyed in the direction from the target position to the starting position, e) Stopping the conveying device when the product is no longer in the weighing section and, in particular, when the product is back in the starting position.

[0025] In other words, particularly for the purpose of calibrating a weighing device to compensate for a static-dynamic offset, the method according to the invention involves conveying a product or test item from a starting position to a target position and weighing it in the process. The weighing process is carried out either statically or dynamically. The product is then transported back towards the starting position, i.e., in the opposite direction. Finally, the product can be conveyed again from the starting position to the target position, and another weighing process can be performed.

[0026] According to one embodiment of the inventive method, the conveying device is stopped for weighing the product, in particular automatically (static weighing process) or continues to operate during the weighing of the product (dynamic weighing process).

[0027] As previously explained, it is preferable to repeat the sequence of steps b) to e) several times in succession, particularly automatically. This repetition allows for the calculation of an average value from multiple measurements, the calculation of a correction value based on this average, and, subsequently, the most accurate possible determination of the product's actual weight during the later regular operation of the weighing device.

[0028] In particular, the method according to the invention provides that the mean value of the measured values ​​obtained when weighing the product while the conveyor device is stationary is compared with the mean value of the measured values ​​obtained when weighing the product while the conveyor device is in operation, i.e., while in motion. If the calibration process involves only a single static measurement or only a single dynamic measurement, the individual measured value is also understood as the mean value within the meaning of the invention.

[0029] Finally, as has already been explained, a movable guide element is provided which is moved automatically between a protruding position and a receding position, preferably such that when the product is moved in the direction from the starting position to the target position, the respective guide element is in the protruding position and when the direction of movement is reversed, it is in the receding position.

[0030] There are now numerous possibilities for designing and further developing the weighing device and the method for weighing a product according to the invention. In this regard, reference is made, on the one hand, to the claims subordinate to dependent claims 1 and 8, and on the other hand, to the description of an exemplary embodiment in conjunction with the drawing. The drawing shows: Fig. 1 a schematic view of a weighing device immediately after the start of a first or second work step sequence, Fig. 2 the weighing device Fig. 1 in the further course of carrying out the first work step sequence and Fig. 3 the weighing device Fig. 1 in the further course of carrying out the second work step sequence.

[0031] In Fig. Figure 1 schematically depicts a weighing device 1 in the form of a price marking device or a checkweigher in a top view. The weighing device 1 has a scale 2 for weighing a product 3 in a weighing section AW and a conveying device 4 for transporting the product 3 along a conveying area F from a starting position PStart via the weighing section AW to a target position PTarget.

[0032] In this case, the conveying device 4 is a multi-part belt conveyor, with the scale 2 being integrated into a middle section of the multi-part belt conveyor.

[0033] The weighing device 1 further comprises a control unit 5, which, among other things, controls the conveying device 4, in particular its speed and direction of travel. The control is time- and / or distance-dependent and / or takes into account position data of the moving product. The position data can be determined, for example, by an optical system (not shown) connected to the control unit 5, such as a camera or light barrier.

[0034] Furthermore, the weighing device 1 has two movable guide elements 6 and 6' arranged along a section of the conveying area F located between the starting position PStart and the weighing section AW. The guide elements 6 and 6' can each be moved, in particular independently of each other or simultaneously, between a projecting position PV and a receding position PZ. The projecting position PV is in Fig. 1 and the preceding position PZ in the Fig. 2 and Fig. 3 shown. As in the comparison of the Fig. 1 on the one hand with the Fig. 2 and Fig. 3, on the other hand, it is clearly evident that the guide elements 6 and 6' in the projecting position PV protrude at least partially into the conveying area F, whereas the two guide elements 6 and 6' in the recessed position TZ lie outside the conveying area F.

[0035] Finally, the weighing device 1 also has a label application direction 7 with a printer 8, which is arranged such that a product 3 can be guided along the conveyor area F from the starting position PStart to the target position PZiel past the label application device 7 and / or be labeled. In this way, after calibration of the weighing device 1 according to the invention, which will be described below, a price marking process can be carried out in which several products 3 are weighed successively while moving from the scale 2 and the respective measurement result is taken into account when printing the label assigned to the product 3.

[0036] The calibration process for compensating the static-dynamic offset is now described in more detail below.

[0037] The control unit 5 is configured such that the conveying device 4, in this case the belt conveyor or at least one transport belt, can be automatically stopped during operation in one direction from the start position PStart to the target position PTarget and then automatically operated in the opposite direction from the target position PTarget to the start position PStart. The control unit 5 allows a dynamic weighing process to be automatically carried out using the scale 2 in a first step sequence during the operation of the conveying device in the direction from the start position PStart to the target position PTarget.

[0038] In addition, the control unit 5 allows a static weighing process to be carried out using the scale 2 in another work step sequence when the conveying device 4 is stopped.

[0039] Both the first and second work step sequences can be automatically repeated multiple times to obtain several measurement results, from which an average is then calculated.

[0040] In Fig. Figure 1 illustrates how, at the beginning of one of the two work step sequences, product 3 is conveyed from the starting position PStart towards the weighing section AW and the target position PTarget. In the depicted state, product 3 is still in a first section of the conveying device 4, along which the aforementioned guide elements 6 and 6' are arranged laterally. Here, the guide elements 6 and 6' are in the position PV projecting towards the center of the belt, in which they can contact and thus align product 3.

[0041] Product 3 is produced by the in Fig. The item is conveyed from position 1 shown to the weighing section AW and there either dynamically (during the first work step sequence, see Fig. 2) or static (during the second work step sequence, see Fig. 3) weighed.

[0042] In the case of a dynamic weighing process, product 3 is conveyed over scale 2 and weighed during the time period in which the product is vertically above scale 2. In this case, product 3 is then, as Fig. Figure 2 shows that the product is transported in one direction from the target position Ptarget to the starting position Pstart by reversing the direction of rotation of the conveyor device 4, until it has left the weighing section AW and, in particular, has returned to the starting position Pstart. This dynamic weighing process can be repeated several times, with the product 3 being weighed, in particular, at the same speed and / or orientation as in the preceding weighing process.

[0043] In Fig. Figure 3 is part of the second work step sequence, namely the static weighing process. In the second work step sequence, product 3 is placed by conveyor 4 exactly vertically above the scale 2, and the conveyor 4 is stopped in this position. Product 3 is then weighed while stationary. Subsequently, product 3 is, as Fig. 3 shows that the product is transported back again by reversing the direction of rotation of the conveyor 4 until it has left the weighing section AW and, in particular, has returned to the starting position PStart. This static weighing process can also be repeated several times, whereby the product 3 is fed to the weighing section AW at the same speed and / or orientation as in the preceding weighing process. If necessary, however, a single static weighing process may suffice for calibration purposes. In principle, with the proposed weighing device 1 or the proposed method, it is also conceivable to manually enter / store the static weight value after the (static) weight has been determined using a checkweigher. When the product 3 is moved back from the target position PZiel to the starting position PStart, the two movable guide elements 6 and 6' are moved into the positions shown in the Fig. 2 and Fig. The product 3 is moved to the back position PZ shown in Figure 3, so that it cannot come into contact with the guide elements 6 and 6' when passing them. Before the first or second work step sequence is repeated, the guide elements 6 and 6' are moved back to the projecting position PV as shown in Figure 3. Fig. 1 procedure. This is done automatically by the control unit 5.

[0044] Finally, the invention will be explained in more detail using the following exemplary process sequence, in which the following step is first carried out, in particular by an operator or automatically by the control device 5 using a feeding device (not shown): a) Placing a product 3 on a conveyor 4 in a starting position PStart,

[0045] The control unit 5 of the weighing device 1 then allows the following steps to be carried out in the specified order: b) Operating the conveying device 4 such that the product 3 is conveyed in the direction from the starting position PStart to a target position PZiel along a conveying area F and past two projecting guide elements 6 and 6' which align the product 3, c) Weighing the product 3 when the product 3 is located in a weighing section AW above a scale 2, wherein the weighing section AW is located on the conveying area F between the starting position PStart and the target position PTarget, wherein according to a first work step sequence the conveying device 4 continues to run while weighing the product 3 and is only stopped after weighing or wherein according to an alternative work step sequence the conveying device 4 is already stopped for weighing the product 3, d) Operating (i.e. restarting) the conveying device 4 so that the product 3 is conveyed in the direction from the target position PTarget to the starting position PStart, e) Stopping the conveying device 4 after the product 3 has partially or completely passed the retracted guide elements 6 and 6'.

[0046] To obtain multiple measurements, steps b) to e) are automatically repeated several times in succession in each of the two processing sequences. In a further step, an average value for the dynamic measurement process and an average value for the static measurement process are then calculated from the individual measurements. In yet another step, the average values ​​are compared, and the difference is stored as a correction value for the static-dynamic compensation.

[0047] In the subsequent regular weighing procedure, that is, after calibration of the weighing device, in which several products are dynamically weighed one after the other, the previously determined correction value is then added to each measurement result in order to conclude the actual weight.

Claims

[1] Weighing device (1), in particular price labelling device or checkweigher, - with a scale (2) for weighing a product (3) in a weighing section (AW), - with a conveyor device (4) for transporting the product (3) along a conveyor area (F) from a start position (PStart) via the weighing section (AW) to a target position (PZiel), wherein the weighing device (1) further comprises a control device (5) configured such that the conveyor device (4) can be automatically stopped during its operation in a direction from the start position (PStart) to the target position (PZiel) and then automatically operated in a direction from the target position (PZiel) to the start position (PStart), wherein the control device (5) is configured such that with a product (3) placed on it, a weighing process can be carried out automatically by means of the scale (2) in a first work step sequence during the operation of the conveyor device (4) in the direction from the start position (PStart) to the target position (PZiel), wherein the control device (5) is configured such that the first work step sequence with the product (3) placed on it can be run through automatically several times, characterized by , that the control device (5) is configured such that with the product (3) placed on it in a second work step sequence which follows or precedes the first work step sequence, after completion of the operation of the conveyor device (4) in the direction from the start position (PStart) to the target position (PZiel) in the stopped state of the conveyor device (4), a weighing process can be carried out automatically by means of the scale (2), that an average value from several measured values can be calculated from the first work step sequence and compared with a measured value or average value from several measured values from the second work step sequence. [2] Weighing device (1) according to claim 1, characterized by that the control device (5) is configured such that the second work step sequence can be automatically run through several times. [3] Weighing device (1) according to one of the preceding claims, characterized by that the weighing device (1) further comprises at least one movable guide element (6, 6') which can be moved between a projecting position (PV), in which the guide element (6, 6') in particular borders at least partially on the conveying area (F) or at least partially projects into the conveying area (F), and a rearward position (PZ), in which the guide element (6, 6') is in particular spaced apart from the conveying area (F). [4] Weighing device (1) according to claim 3, characterized by that the guide element (6,6') is arranged such that the product (3) is guided past the guide element (6,6') along the conveying area (F). [5] Weighing device (1) according to claim 3 or 4, characterized by that the control device (5) is configured such that the guide element (6, 6') is arranged in the projecting position (PV) during operation of the conveyor device (4) in the direction from the start position (PStart) to the target position (PZiel) and / or in the backward position (PZ) during operation of the conveyor device (4) in the direction from the target position (PZiel) to the start position (PStart). [6] Weighing device (1) according to one of the preceding claims, characterized by that the conveying device (4) is a belt conveyor or a roller conveyor. [7] Weighing device (1) according to one of the preceding claims, characterized bythat the weighing device (1) further comprises a label application device (7), which in particular has a printer (8), wherein the conveying region (F) leads from the start position (PStart) to the target position (PZiel) past or ends at the label application device (7). [8] Method for weighing a product (3), in particular using a weighing device (1) according to one of the preceding claims, in which the following steps are carried out successively in the specified order: a) placing a product (3) on a conveyor (4) in a start position (PStart), b) operating the conveyor device (4) so that the product (3) is conveyed in the direction from the start position (PStart) to a target position (PZiel) along a conveyor area (F), c) weighing the product (3) when the product (3) is located in a weighing section (AW) above a scale (2), the weighing section (AW) being located on the conveyor area (F) between the start position (PStart) and the target position (PZiel), d) operating the conveyor (4) so that the product (3) is conveyed in the direction from the target position (PZiel) to the start position (PStart), e) stopping the conveyor (4) when the product (3) is no longer in the weighing section (AW), wherein in a first work step sequence, the conveyor device (4) continues to be operated during the weighing of the product (3), wherein the first work step sequence with the product (3) placed on it is automatically run through several times, wherein an average value is formed from the measured values determined in step c), which were determined when weighing the product (3) during the operation of the conveyor device (4), wherein in a second work step sequence following or preceding the first work step sequence, the conveyor device (4) is stopped for weighing the product (3), wherein a measured value determined in step c) or an average value of the measured values determined from the measured values determined in step c), which was / are determined when weighing the product (3) in the stopped state of the conveyor device (4), is compared with the average value of the measured values determined when weighing the product (3) during operation of the conveyor device (4). [9] Method according to claim 8, characterized byin step b) a movable guide element (6, 6') in a projecting position (PV) adjoins the conveying area (F) or at least partially projects into the conveying area (F) in such a way that a product (3) guided past the guide element (6, 6') on the conveying device (4) comes into contact with the guide element (6, 6') and / or is aligned by the guide element (6, 6'). [10] Method according to claim 9, characterized by that in step d) the movable guide element (6,6') is located in a rearward position (PZ) outside the conveying area (F) in such a way that a product (3) guided past the guide element (6,6') on the conveying device (4) does not come into contact with the guide element (6,6'). [11] Method according to claim 9 or 10, characterized bythat the movable guide element (6,6') is automatically moved into the projecting position (PV) in or before step b) and / or automatically into the retracted position (PZ) in or before step d).

Images