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Balancing Complexity and Simplicity: The Role of Python in Work Scheduling

Aktualisiert: 7. Aug.

In today's manufacturing landscape, Manufacturing Execution Systems (MES) have become integral for managing production processes, ensuring quality, and maintaining regulatory compliance. However, when it comes to specific tasks like work scheduling, simplicity can sometimes offer advantages over the complexity of a full-fledged MES.

Scheduling Work

The Power of Complex MES Systems

MES systems are designed to provide comprehensive oversight of manufacturing operations. They integrate data from various sources, support real-time monitoring, and facilitate complex decision-making processes. Key benefits include:

  • Real-Time Data Integration: MES systems pull data from different stages of production, offering a holistic view of operations.

  • Regulatory Compliance: They ensure adherence to industry standards and regulations.

  • Detailed Reporting: Complex MES solutions provide in-depth reporting capabilities, aiding in analytics and decision-making.

  • Integration with Other Systems: They often integrate seamlessly with ERP and other enterprise systems, enhancing overall business processes.

While these systems offer robust capabilities, their complexity can also lead to challenges such as high implementation costs, longer setup times, and potentially cumbersome interfaces for specific tasks.


Leveraging SAP Data with Python for Efficient Work Scheduling

While complex MES systems offer a broad array of functionalities, the use of Python for work scheduling, particularly when combined with data extracted from an SAP system, presents a compelling alternative. By tapping into SAP’s robust data management capabilities, Python can provide a streamlined and cost-effective solution for scheduling tasks efficiently.


Requirement 1: You have the appropriate authorization

In order to be able to execute an SAP query or an InfoSet query, you need authorization for transaction SQ01. If you do not have this permission, contact your system administrator.


Requirement 2: You are assigned to a user group

All users who want to create or carry out queries must be assigned to at least one user group. The respective system administrator is usually responsible for managing user groups. If you just want to execute a query, you do not need any further authorizations. Special authorization is only required if you want to create a query and save it. Even then, contact your system administrator.


Requirement 3: Suitable InfoSets are available

An InfoSet is a special view of a data source. The design of an InfoSet depends on the information needs of the user.


Special authorization is usually required to create an InfoSet and maintain its properties, so contact your system administrator to identify or have the InfoSet required for your tasks created. InfoSets can be assigned to different user groups. Under certain circumstances, a suitable InfoSet for another user group already exists, so only the assignment of this InfoSet needs to be adjusted.


As soon as a suitable InfoSet is available for your user group, you have the option of generating a query on it:


  • Using transaction SQ01 you get to the initial screen of the SAP Query. Here you will be presented with all the queries that have been created and saved for your user group in a table.

  • To execute an existing query, select it from the table and click the Execute button (F8).

  • To create a new query, enter a name for it and click the Create button.

  • All available InfoSets will be offered to you in a new dialog window. Select the InfoSet required for your query here and confirm the dialog.

  • On the Create Query screen, you enter a title and a description for your query. All other input options are optional and are provided with preset values as long as you do not provide any information.

  • Click the Basic List button.

  • On the following screen you can select the fields for the selection or for the list display in the tree structure that appears at the top left. On the right side you have the option to influence the appearance of the list output if necessary.

  • Click the Test button and confirm the following variant dialog without making any entries.

  • The selection fields you just selected are ready for input on the next screen. Enter valid values there and then click the Run button (F8).

  • If you want to save this SAP query, you must first maintain a so-called variant for it. You can then save the entire SAP query in a suitable package.


The process listed above describes the basic steps that need to be completed when working with SAP queries. If you work with SAP queries more often and would like to take advantage of the diverse possibilities, you will find detailed information in the following chapters on the individual components of SAP Query.


Advanced Scheduling with Python: Implementing and Evaluating Key Algorithms

While integrating SAP data with Python for work scheduling offers a streamlined approach, the real power comes from applying advanced scheduling algorithms to optimize performance. By leveraging Python, we can implement and evaluate various algorithms to identify the most effective solution for specific scheduling needs. This section delves into the application of several key algorithms, including HEIJUNKA, Shortest Processing Time (SPT), First-Come, First-Served (FCFS), Longest Processing Time (LPT), Smallest Lateness First (SLK), and Critical Ratio (CR). We will also discuss the results of these implementations and why a heuristic algorithm ultimately proved to be the most effective.


Implementing HEIJUNKA for Work Scheduling

HEIJUNKA, or production leveling, is a strategy used to smooth out production schedules and avoid fluctuations in workload. Implementing HEIJUNKA involves organizing tasks in a way that balances the workload across the production period, aiming to achieve a more consistent and predictable production flow.


Evaluating Key Scheduling Algorithms

To find the most effective scheduling approach, we implemented and evaluated several well-known algorithms:

  • Shortest Processing Time (SPT): This algorithm prioritizes jobs with the shortest processing times first. It aims to minimize the average job completion time, potentially leading to increased efficiency in job processing.

  • First-Come, First-Served (FCFS): FCFS schedules jobs in the order they arrive. While this method is straightforward and easy to implement, it may not always optimize overall performance, especially in complex scheduling environments.

  • Longest Processing Time (LPT): LPT schedules the longest jobs first. This approach can be useful for balancing workloads across multiple resources and preventing long jobs from delaying the completion of shorter tasks.

  • Smallest Lateness First (SLK): SLK prioritizes jobs based on their lateness, aiming to minimize overall tardiness and ensure that jobs are completed as close to their due dates as possible.

  • Critical Ratio (CR): CR schedules jobs based on the ratio of time remaining to process to the time remaining until the due date. This method helps prioritize jobs that are most critical to meet their deadlines.


Optimization with Multi-Machine Operations

In addition to these algorithms, we explored multi-machine scheduling to optimize job assignments across multiple resources. This approach helps balance the workload and reduce idle times, improving overall production efficiency.


Heuristic Algorithm: The Optimal Solution

After evaluating the aforementioned algorithms, it became clear that a heuristic approach provided the best results for our specific scheduling needs. Heuristic algorithms are designed to offer practical solutions in complex scenarios by using approximate methods to find optimal or near-optimal solutions.


 

By integrating SAP data with Python and applying a range of scheduling algorithms, we were able to determine the most effective approach for our needs. Each algorithm has its strengths, but the heuristic method ultimately proved to be the most efficient, providing an optimal balance of performance and practicality. For detailed implementations and further exploration of these algorithms, please refer to my GitHub repository here.



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