Electronic scale abnormity control method for tobacco primary processing production line

Abstract

The invention discloses an electronic scale abnormity control method for a tobacco primary processing production line, and the main design concept of the method is that a data collection system is used for collecting indexes such as a belt speed value and a material weight value of an electronic scale, and historical data of the key indexes of the electronic scale are processed and analyzed, so that the abnormity of the electronic scale is determined. Establishing an abnormal early warning mechanism of the belt indexes; during real-time production, an early-stage early warning mechanism is updated based on actual data acquisition, dynamic control upper and lower limit values are obtained, and abnormal judgment and early warning are carried out according to the dynamic control upper and lower limit values. The problem that faults of the electronic scale are difficult to find or cannot be found to cause major quality accidents is effectively solved, and the production quality of water adding, perfuming, material adding and other procedures of a tobacco shred making workshop is comprehensively improved.

Description

Technical Field

[0001] The invention relates to the field of cigarette manufacturing, and in particular to an abnormality control method of an electronic scale used in a tobacco shred production line. Background Art

[0002] The electronic belt scale (hereinafter referred to as the electronic scale) is an important metering equipment in the silk production process. In the silk production control process, the PLC collects analog signals to obtain the instantaneous flow and cumulative amount of the electronic scale, and then uses the collected values ​​for the precision control of flavoring and feeding and the precise control of the blending amount of stem silk, expanded silk, thin silk and air-flow silk.

[0003] According to tobacco processing requirements, the measurement accuracy of electronic scales must be controlled within ±0.5%. In the actual production process, electronic scales may exceed the measurement accuracy due to malfunctions, such as obvious malfunctions: damage to electrical components, serious belt deviation, mechanical structure failure, etc. These more prominent faults can be discovered and resolved in a timely manner by experienced operators.

[0004] However, when the weight detection signal of the electronic scale changes and there is no alarm (that is, a hidden fault as referred to in the present invention may occur), it is difficult for operators to discover it through normal measures during production inspections. If such faults are not discovered in time, the electronic scale measurement errors caused by them will have a cumulative effect, resulting in more serious consequences and even leading to major production quality accidents. Summary of the invention

[0005] In view of the above, the present invention aims to provide an abnormal control method of an electronic scale for a tobacco shred production line to solve the above-mentioned technical problems.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The present invention provides an abnormality control method of an electronic scale for a tobacco shred production line, which comprises:

[0008] Determine the target electronic scale on the production line as the data collection point;

[0009] Acquire historical data of electronic scale indicators used to construct an early warning model from the data collection point;

[0010] Based on the historical data, the standard deviation of the electronic scale indicator is obtained, and the abnormal control range is obtained;

[0011] Recalculating the standard deviation based on the real-time acquired data, and updating the abnormal control range using the secondary calculation result;

[0012] Use the updated abnormal control range to issue abnormal warnings for electronic scales.

[0013] In at least one possible implementation, the updating of the abnormal control range includes observing the upper control limit and the lower control limit of the electronic scale indicator using an EWMA control chart:

[0014] Observe the actual value data of the electronic scale indicator;

[0015] The EWMA statistic is obtained after transforming the observed values;

[0016] Based on the EWMA statistic, the dynamic threshold for abnormality determination is obtained in real time.

[0017] In at least one possible implementation, obtaining the standard deviation of the electronic scale indicator based on the historical data and obtaining the abnormal control range includes: calculating the standard deviation of the electronic scale indicator of the target electronic scale by analyzing the historical data, and determining the fluctuation of the electronic scale indicator; and obtaining the normal value range and alarm value range of the standard deviation based on the fluctuation.

[0018] In at least one possible implementation, the abnormality control method further includes:

[0019] Based on the historical production batch statistics of the target electronic scale, the production time of a single batch is segmented, and the standard cumulative time of each segment is obtained;

[0020] In actual production, the countdown is triggered according to the segment duration;

[0021] After the countdown ends, the corresponding real-time cumulative amount is obtained;

[0022] According to the comparison result between the real-time cumulative amount and the standard cumulative amount, an abnormal warning is issued to the electronic scale.

[0023] In at least one possible implementation, the abnormal control method also includes: obtaining a current process capability index of the electronic scale indicator, wherein the current process capability index is used to determine the degree of deviation of the electronic scale indicator relative to the center value, and correcting the deviation based on the degree of deviation and the current process capability index.

[0024] In at least one possible implementation manner, the electronic scale indicators include at least: a belt speed value and a material weight value.

[0025] Compared with the prior art, the main design concept of the present invention is to use a data acquisition system to collect indicators of the electronic scale, such as belt speed value, material weight value, etc., and establish an abnormal warning mechanism for belt indicators by processing and analyzing the historical data of these key indicators of the electronic scale; in real-time production, the early warning mechanism is updated based on the actual data acquisition, and dynamic upper and lower limit values ​​of control are obtained, and abnormal judgment and warning are performed accordingly. The present invention can effectively prevent quality accidents caused by hidden faults of electronic scales, and effectively solves the problem that electronic scale faults are difficult to find or are not found in time to cause major quality accidents, and comprehensively improves the production quality of processes such as adding water, adding fragrance, and adding materials in the silk-making workshop. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described below with reference to the accompanying drawings, in which:

[0027] Figure 1 A schematic diagram of an abnormality control method for an electronic scale in a tobacco shred production line provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0029] The present invention proposes an embodiment of an abnormal control method for an electronic scale in a tobacco shred production line. Specifically, Figure 1 shown, including:

[0030] Step S1, determining a target electronic scale on the production line as a data collection point;

[0031] Take the blade feeding section of a production line as an example. The blade feeding section of the production line has one electronic scale (electronic scale before blade feeding). The required data variable table is as follows:

[0032]

[0033] Step S2, acquiring historical data of electronic scale indicators for building an early warning model from the data collection point;

[0034] Specifically, after establishing the OPC connection, the PLC data of the electronic scale is read, from which at least the belt speed value and the material weight value of the four indicator data in the above table can be obtained.

[0035] Step S3, based on the historical data, obtaining the standard deviation of the electronic scale index and obtaining the abnormal control range;

[0036] Specifically, by analyzing and processing historical data, the standard deviation of the material weight value and the belt speed value of the target electronic scale can be calculated (refer to the following formula), and the actual fluctuations of the material weight value and the belt speed value can be determined. According to the actual fluctuations, the normal value range and the alarm value range of the standard deviation can be obtained.

[0037]

[0038] Among them, S is the standard deviation of the electronic scale indicator, n is the number of samples, xi is the current data value, is the sample mean.

[0039] Step S4: recalculate the standard deviation based on the data acquired in real time, and update the abnormal control range using the recalculation result.

[0040] To elaborate, the present invention proposes in some preferred embodiments that an EWMA control chart can be introduced to observe the upper and lower control limits of electronic scale indicators, wherein the "upper and lower control limits" are calculated based solely on the actual value data of the above electronic scale indicators, and specifically can be obtained by transforming the observed values ​​to obtain the EWMA statistic, and thereby calculating the dynamic threshold for abnormality determination (i.e., the aforementioned upper and lower control limits) in real time. The calculation process can refer to the following formula:

[0041]

[0042] Where: Zt is the EWMA statistic at the current moment, φ is the weight (usually [0.05, 0.25]), Xt is the observed value of the material weight or belt speed at the current moment, UCL is the upper control limit, LCL is the lower control limit, is the mean of the observation sequence, is the standard deviation of the observation sequence.

[0043] Step S5: Use the updated abnormal control range to issue an abnormal warning for the electronic scale.

[0044] It can be understood that when the EWMA statistic is between the upper control limit (UCL) and the lower control limit (LCL), the result is judged to be normal; when it is greater than the upper control limit (UCL) or less than the lower control limit (LCL), an abnormal alarm is output.

[0045] In addition, as a supplementary explanation, in some other embodiments of the present invention, the method for determining an abnormality of an electronic scale may further include:

[0046] Based on the production batch statistics of the target electronic scale, the production time of a single batch is divided into segments, and the standard cumulative amount of each segment is obtained;

[0047] Assume that after counting a large number of production batches, it is found that the average production time for each batch is 1 hour, and the cumulative amount on the electronic scale is 1000 kg. Therefore, a single batch can be divided into 10 sections, but is not limited to it. Then the production time for each section is 6 minutes, and the corresponding standard cumulative amount is 100 kg.

[0048] Next, the real-time accumulated amount of the target electronic scale is segmented and a countdown is triggered;

[0049] After the countdown ends, the corresponding real-time cumulative amount is obtained;

[0050] In actual operation, the real-time cumulative amount of each batch of operation can be segmented according to the brand on the electronic scale before adding the blades, that is, the entire actual operation range is divided into several sub-ranges, and the real-time cumulative amount when the corresponding segment time (such as the 6 minutes obtained in advance) is recorded.

[0051] An abnormality warning is issued to the electronic scale based on the comparison between the real-time cumulative amount and the standard cumulative amount.

[0052] That is, after each section of production is completed, the real-time cumulative volume of this section is compared with the standard cumulative volume. If the difference is too large, an alarm is triggered. At the same time, the alarm data can be sent to the IFIX alarm system, which will pop up a window to remind on-site personnel to deal with the fault in time. Based on this idea, a PLC program can be written to trigger the sound and light alarm through electronic control at the workshop site to remind the inspection personnel to deal with the fault in time.

[0053] Finally, it can be added that in the early modeling stage, the current process capability index Cpk of the electronic scale indicator can also be obtained. It can be understood that the current process capability index can be used to determine the degree of deviation of the aforementioned values ​​such as material weight and belt speed relative to the center value, so that in the actual use of the scheme of the present invention, when deviations occur, they can be compensated in combination with the Cpk obtained in the early stage to correct the deviations. Specifically, the calculation process of Cpk can be analyzed by analyzing the historical production batch data to obtain the corresponding specification center value, specification upper limit and specification lower limit, so as to calculate the current Cpk. The following formula can be used as a reference. Of course, the following parameters can also be changed according to actual process requirements:

[0054]

[0055] T=USL-LSL

[0056] C pk =C p ·(1-|C a |)

[0057] in: is the process average, μ is the specification center value, USL is the upper specification limit, LSL is the lower specification limit, σ is the standard deviation, and T is the specification tolerance.

[0058] To sum up, the main design concept of the present invention is to use a data acquisition system to collect indicators of the electronic scale, such as belt speed value, material weight value, etc., and establish an abnormal warning mechanism for belt indicators by processing and analyzing the historical data of these key indicators of the electronic scale; in real-time production, the early warning mechanism is updated based on the actual data acquisition, and dynamic upper and lower limit values ​​of control are obtained, and abnormal judgment and warning are performed accordingly. The present invention can effectively prevent quality accidents caused by hidden faults of electronic scales, and effectively solves the problem that electronic scale faults are difficult to find or are not found in time to cause major quality accidents, and comprehensively improves the production quality of processes such as adding water, adding fragrance, and adding materials in the silk-making workshop.

[0059] If the expressions expressing orientation are mentioned in the embodiments of the present invention, they are relative concepts based on the embodiments. In addition, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, a and b, a and c, b and c, or a and b and c, wherein a, b, c can be single or multiple.

[0060] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings, but the above is only a preferred embodiment of the present invention. It should be noted that the technical features involved in the above embodiments and their preferred methods can be reasonably combined and matched into a variety of equivalent schemes by those skilled in the art without departing from or changing the design ideas and technical effects of the present invention; therefore, the present invention is not limited to the scope of implementation shown in the drawings, and all changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the specification and drawings, should be within the protection scope of the present invention.

Claims

1. A method for controlling abnormality of an electronic scale in a tobacco shred production line, characterized in that: include: Determine the target electronic scale on the production line as the data collection point; Acquire historical data of electronic scale indicators used to construct an early warning model from the data collection point; Based on the historical data, the standard deviation of the electronic scale indicator is obtained, and the abnormal control range is obtained; Recalculating the standard deviation based on the real-time acquired data, and updating the abnormal control range using the secondary calculation result; Use the updated abnormal control range to issue abnormal warnings for electronic scales.

2. The method for controlling abnormality of an electronic scale for a tobacco shred production line according to claim 1, characterized in that: The updating of the abnormal control range includes observing the upper and lower control limits of the electronic scale indicators using the EWMA control chart: Observe the actual value data of the electronic scale indicator; The EWMA statistic is obtained after transforming the observed values; Based on the EWMA statistic, the dynamic threshold for abnormality determination is obtained in real time.

3. The method for controlling abnormality of an electronic scale for a tobacco shred production line according to claim 1, characterized in that: The method of obtaining the standard deviation of the electronic scale indicator based on the historical data and obtaining the abnormal control range includes: calculating the standard deviation of the electronic scale indicator of the target electronic scale by analyzing the historical data, and determining the fluctuation of the electronic scale indicator; and obtaining the normal value range and the alarm value range of the standard deviation according to the fluctuation.

4. The method for controlling abnormality of an electronic scale for a tobacco shred production line according to claim 1, characterized in that: The abnormality control method further includes: Based on the historical production batch statistics of the target electronic scale, the production time of a single batch is segmented, and the standard cumulative time of each segment is obtained; In actual production, the countdown is triggered according to the segment duration; After the countdown ends, the corresponding real-time cumulative amount is obtained; According to the comparison result between the real-time cumulative amount and the standard cumulative amount, an abnormal warning is issued to the electronic scale.

5. The method for controlling abnormality of an electronic scale for a tobacco shred production line according to claim 1, characterized in that: The abnormality control method also includes: obtaining a current process capability index of the electronic scale indicator, wherein the current process capability index is used to determine the degree of deviation of the electronic scale indicator relative to the center value, and correcting the deviation based on the degree of deviation and the current process capability index.

6. The method for controlling abnormality of an electronic scale used in a tobacco shred production line according to any one of claims 1 to 5, characterized in that: The electronic scale indicators at least include: a belt speed value and a material weight value.

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