INTRODUCTION
Project background & Problem Statement
The production line serves as the backbone of any manufacturing facility, with efficient operations being crucial for success Schneider Electric Manufacturing Vietnam boasts over 110 production lines, exemplifying a commitment to streamlined and effective manufacturing processes.
Figure 1: Layout of SEMV Plant [24]
SEMV offers a diverse range of 450 products across 70 families, primarily distinguished by switches and sockets However, the reliance on manual processes in many of these product lines has resulted in significant manufacturing errors, posing a major challenge for SEMV and businesses globally.
Figure 2: Overview of some of the company’s products [24]
Human manual processes can lead to various errors, including missing packaging, malfunctioning products, absent components or accessories, incorrect product types being packed, and misapplied labels.
Figure 3: Mass pre-printed labels
Figure 5: Example of wrong label pasting
The plant has developed various solutions to enhance quality control, including automated printing applications, Operation Work Standards (OWS), and notification cards for product lines Additionally, manual and semi-automated testers are utilized to identify non-conforming products Despite investing in automation machines and applications to manage failure modes, reliance on expensive supplier-made equipment is not the most efficient approach for process control.
Figure 6: Iconic Assembly + Packaging Line
Solution for the current situation of SEMV
Implementing an automated production line can significantly enhance productivity and cycle time by relying on a robust data network for logical analysis Effective communication between robots and databases is crucial for seamless operations, a strategy already adopted by leading factories worldwide However, these systems are typically designed for specific products or similar types, making them more suitable for mass production The substantial costs associated with designing, manufacturing, and operating such automated lines pose challenges for emerging businesses, particularly in the SEMV sector Without automation, manual processes increase time consumption and decrease efficiency, ultimately leading to lower performance and reduced profits.
SEMV offers a diverse range of products with various designs and styles tailored to meet the unique requirements and standards of markets like Australia, the USA, China, Malaysia, Thailand, and Indonesia Given the varying quantities and product specifications received from regional divisions, SEMV's production lines operate on a work order basis, making automated production lines unsuitable for their operations.
In response to the urgent challenges at Schneider, our team has developed an Interlocking System designed to seamlessly integrate with current systems and equipment, effectively reducing common failure modes for individual cells This innovative solution aims to enhance operational efficiency and will be implemented across the entire factory, as well as in other Schneider facilities.
The expected transformation of those lines and changes in the working flow is described in Figures 1.7 and 1.8 respectively:
The new production line layout will feature additional PCs at the three main stations—Printing, Testing, and Packaging—to facilitate communication between workers, machines, and the database Each computer will have a dedicated application that performs specific tasks, such as generating QR codes from production orders, updating product testing results, and verifying product status before printing packaging labels To enhance accuracy, each station will be equipped with a QR scanner for product identification and status updates The Modicon M221 PLCs are recommended for the testing machine due to their Ethernet connection, enabling efficient transmission of Not Good (NG) control signals to our system.
In the current workflow for processing new orders, the initial step involves printing a week-code label by the production team, which serves solely to indicate the product's manufacturing date without retaining any product history Laborers then proceed with assembly processes 1 and 2, followed by quality control testing using a specific tester to identify any non-conforming (NG) products Workers have the option to retest as needed or use a functioning product as a benchmark for testing others Once testing is complete, products are finalized at stations 3 and 4, where the week-code label is applied before moving to the packaging station If the line lacks a proper packaging system, there is a risk of product and accessory loss, compounded by the fact that packaging labels are also mass-printed and poorly regulated.
The Interlocking system streamlines the work order process by requiring workers to print a QR label from the first station, which is generated using data from the company's LDS system This label automatically adjusts the order quantity according to the number of printed labels, ensuring cost efficiency and comprehensive product information storage Laborers typically begin the assembly process at stages 1 and 2, applying the QR label to the product before testing To initiate testing, operators scan the QR label, allowing the system to verify data against the database and permit testing if it aligns Following successful testing, the system updates the status to ensure each QR label can only be tested once, allowing the product to proceed to the next assembly stages after passing inspection.
Before reaching the Packaging station, products must be scanned again using their QR labels This scan allows the system to verify the product's status in the database, ensuring it has undergone testing and determining whether it has passed or failed Each successful validation is crucial for the packaging process.
Implementing QR scanning technology will enhance productivity by increasing the number of finished products Once a designated quantity is scanned for either a group box or an outer box, the system verifies the box's weight If the weight matches the predetermined standard, it automatically generates a label according to the storage path stored in the database Additionally, all labels printed by the system will seamlessly update the database, ensuring accurate inventory management.
Objective and Research Method
The idea Interlocking System was created with the idea of improving the old system, giving control over the entire product-making process, the team wanted to do:
• Interlocking System will include 3 different applications which connect through conditions for 3 main stations (Printing, Testing, and Packaging) to create a clear process
• Create User Interfaces based on the old application to create a similar feeling for Operators
• Build label templates database for using references (One product family usually contains many markets)
• Modify the PLC of the tester to be compatible with the new Testing Station
• Create a database on the company’s SQL server to auto-store all the data during production as well as the necessary data used for the system
The Interlocking System operates on a principle designed to prevent conflicting movements at junctions and crossings by arranging signal apparatus strategically This method utilizes available devices and datasets to establish conditions that determine whether a product can proceed to the next processing step, with these conditions verified through scanning.
QR code on the stamp which is printed at Printing Station To make it possible, the plan to approach this topic is as follows:
• Study the popular semi-automatic solutions that are being applied by others From that, evaluate which one is suitable and within the ability to implement (Technology, time, and budget)
• Investigate the common issues at each station and based on that come out with ideas as well as suitable conditions to overcome the problems
• Observe, study, and clarify the current manual processes to analyze and find out the operation steps that can cause the above errors
To achieve the set goals, this semester we need to archive the following targets:
- Cooperate with other departments to collect necessary resources:
+ PE: Products database, and current template using 🡪 Create label database for each reference which will connect with the system through the plant’s SQL server
+ IT: Raise tickets to request administrator 🡪 Permission to install required software for PCs at stations and change the tester’s PLC IPs and computer IPs
+ Maintenance: Request to change the tester's control mechanism from relay to PLC
+ Finance: Negotiate and request budgets to buy and install the necessary equipment for the system (Ethernet cables, Scales, scanners, computers, and printers)
+ Customer Satisfaction & Quality (CS&Q): Evaluate and give a conclusion to see whether the system is stable and can be used for production
- Set up production line as designed (Devices, Ethernet, etc.)
- Research the LDS system and SQL database to decide what data to use and link information between datasets or stations through the database
To establish a robust data management system, create a database on the plant server for efficient storage and querying of all relevant data Utilize SQL to connect various applications, leveraging the SQL Client add-on within the C# library to facilitate seamless connections across the entire system.
- Learn how to use the Bartender application to create all individual, group, and box label templates for each running reference
- Study the logic and operation principle of the previous application – Traceability
- Create a familiar User Interface display based on Traceability using Windows Form by C# language on NET 6.0
- Study EcoStruxure Machine Expert – Basic application and modify the PLC program of each tester to decide where to put the Interlock signal to prevent the skip process.
Scope and Limitations
Initially, the system was intended for just three production lines, but it is now anticipated to address Schneider's current challenges Furthermore, the Interlocking System will be implemented across an additional 14 high-volume production lines, which are crucial to the factory's operations, once its stability and reliability are confirmed.
The project operates concurrently with production activities, making it challenging to install, code, test, and modify PLC testers during active production orders To facilitate this process, the team must coordinate with the production manager to schedule time for utilizing production lines and testers.
To be able to complete the project, requires a combination of departments, especially during a project period Therefore, the goal set for this project is to apply for one line only
The timeline for ordering and shipping the system equipment exceeded the team's initial expectations, while the process of requesting an administrator involves a complex procedure that must adhere to company policy.
LITERATURE REVIEW
Theory of Interlocking
Olsen and Borit have redefined traceability, aligning it with ISO definitions as the capability to access all relevant information concerning an item throughout its entire lifecycle, utilizing recorded identifications.
Product traceability software varies in functionality but consistently includes two key components: product identification and documentation through a database Unique identifiers, such as QR codes or RFID tags, are used to differentiate products and link them to their data QR technology, first utilized by Denso Wave in 1994 for tracking automotive parts, has become a common identification method However, QR codes pose security risks that can lead to breaches in automated systems.
The SQL database is a dependable choice for product documentation, offering robust security and adaptability for businesses of all sizes In 2004, Pinto, D.B created PaniGest, an application designed to enhance traceability and food safety management, utilizing Visual Basic and an SQL database Meanwhile, blockchain technology has emerged as a promising alternative in production lines, providing enhanced transparency and security for product information.
The second system to implement together with traceability is interlocking which prevents bypassing processes in the production line Interlocking was first introduced in England in
The interlocking system, first developed by John Saxby in 1856 for the railway system at Bricklayers Arms Junction, has undergone significant advancements over the years Various methods for constructing interlocks have emerged, tailored for diverse industrial applications In 2015, researchers T Hakulinen, F Havart, P Ninin, and F Valentini identified four primary technologies for building interlock systems, evaluating the advantages of each Among these, PLC technology stands out as an optimal choice for Schneider Electric's production line due to its software-based reconfiguration capabilities, which streamline maintenance for QC machines, making it faster and less labor-intensive.
A significant limitation of Programmable Logic Controllers (PLC) is their inability to adapt to recent technological advancements, particularly in sophisticated networks and complex microprocessor architectures Modern industries often demand more I/O points than traditional PLCs can accommodate, which typically support only a few hundred Although there have been efforts to enhance PLCs over the years, most developments have concentrated on integrating improved hardware rather than fundamentally changing the programming model Martin A Sehr highlights that a paradigm shift is essential for PLCs to meet the complexities and extensive network integration required by Industry 4.0 Consequently, for Schneider Electric's production line to facilitate future enhancements, further research and analysis are needed to either refine the PLC design or explore superior alternatives.
Application Analysis
Windows Form Application, part of Microsoft’s Visual Studio IDE, enables developers to create various applications, including GUI, console, web, mobile, and cloud-based solutions Specifically, Windows Forms, also known as WinForms, is a GUI class library within the NET Framework designed to simplify desktop application development for PCs, tablets, and other devices Applications built using WinForms are exclusively desktop applications, featuring a range of controls such as labels, list boxes, and tooltips, making it a focused tool for Windows Forms Application development.
Build rich, interactive user interfaces
Windows Forms offers a variety of advanced UI controls that replicate functionalities found in premium applications like Microsoft Office By utilizing ToolStrip and MenuStrip controls, developers can design toolbars and menus that incorporate text and images, showcase submenus, and accommodate additional controls such as text boxes and combo boxes.
The drag-and-drop Windows Forms Designer in Visual Studio simplifies the creation of Windows Forms applications by allowing users to easily select and position controls on the form With helpful tools like gridlines and snap lines, aligning controls becomes effortless Additionally, advanced layout options such as FlowLayoutPanel, TableLayoutPanel, and SplitContainer enable developers to design sophisticated forms more efficiently.
The DataGridView control in Windows Forms offers a versatile solution for displaying data from various sources, including databases, XML or JSON files, and web services, in a structured row and column format This control allows for extensive customization, enabling users to modify the appearance of individual cells, lock specific rows and columns, and incorporate complex controls within cells, enhancing the overall data presentation.
Windows Forms makes it easy to connect to data sources over a network through the BindingSource component, which facilitates data binding to controls and offers methods for navigating, editing, and saving records Additionally, the BindingNavigator control enhances user experience by providing a straightforward interface for navigating between records in conjunction with the BindingSource.
Like all aspects of life, nothing is perfect Same for Windows Form Application, it has pros and cons:
• Ensure the safety and confidentiality of information
• Can run on different versions of Windows
• Windows Forms is a mature and well-established framework with a long history of use
• Windows Forms applications are easy to develop and can be created quickly using drag-and-drop tools
• Windows Forms is compatible with a wide range of systems, including older versions of Windows
The software is designed to operate on the Windows platform, requiring users to have it installed on their personal computers for effective use Therefore, individuals must ensure they have access to a suitable computer to facilitate their work.
• Winform is only suitable for desktop applications: information management applications, and applications that interact directly with users
• The graphics on winform are not high, so the software interface will lack intuitiveness, be a bit difficult to manipulate, and not be user-friendly
The Modbus protocol, developed by Modicon, Incorporated in 1979, has become an industrial standard for transferring discrete and analog I/O information between control and monitoring devices As an open, public-domain protocol, Modbus facilitates communication through a master-slave (client-server) architecture, where only the master can initiate transactions Slave devices, such as Acromag I/O Modules, respond to requests from the master, which can be a host computer with the necessary software While masters can address individual slaves or send broadcast messages, slaves only reply to specific queries and do not initiate communication.
Figure 9: Graphical conventions used to illustrate networks
What is Modbus TCP/IP? [14]
TCP/IP (Transmission Control Protocol/Internet Protocol), also referred to as the Internet
Protocol Suite, is the World Wide Web's core communication system that enables every
The internet protocol facilitates simultaneous communication between internet-connected devices, establishing a standardized language for both public and private networks This protocol's advancement has significantly contributed to the rapid growth of the internet and online commerce.
TCP/IP is a dual-layer protocol where the Transmission Control Protocol (TCP) breaks down messages into small data packets for transmission over the Internet, while the Internet Protocol (IP) manages addressing to ensure these packets reach their intended destinations Each computer within a network verifies IP addresses to facilitate the accurate forwarding of messages.
Figure 10: Autonomous System (AS) mapping
TCP/IP operates on a client-server model, where a client computer requests services, like accessing a web page, from a server or web hosting provider It utilizes point-to-point communication, allowing data to flow between host computers within a defined network boundary Additionally, TCP/IP is considered stateless, as each request is independent of previous ones, enabling efficient use of network pathways.
Figure 11: Network and internet addresses
TCP/IP and Higher-Level Applications
E-commerce businesses must be familiar with higher-level applications that operate on or utilize TCP/IP, as these applications represent a more advanced layer of protocol language and are typically bundled with TCP/IP in a comprehensive suite.
● HTTP (the Internet's Hypertext Transfer Protocol)
● FTP (the Internet's File Transfer Protocol)
● Telnet, which enables logging on computers from remote locations
● SMTP (Simple Mail Transfer Protocol)
Accessing the Internet through analog phone modems requires the use of specific protocols, namely SLIP (Serial Line Internet Protocol) or PPP (Point to Point Protocol) These protocols serve to encapsulate data packets, enabling their transmission over dial-up phone connections to the access provider's modem.
UDP (User Datagram Protocol) serves as a simpler alternative to TCP, designed for specialized applications It operates on a connectionless transmission model, requiring minimal protocol overhead This makes UDP ideal for low-latency, loss-tolerant connections in online applications.
TCP/IP-related protocols used in the exchange of router data include:
● ICMP (Internet Control Message Protocol)
“RS232C “Recommended Standard 232C” is the recent version of Standard 25 pins whereas, RS232D is 22 pins In the new PC’s male D-type which is of 9 pins.”
RS232 is a widely recognized standard protocol for serial communication, enabling the connection of computers to peripheral devices for efficient data exchange It operates over a distance of up to 50 feet and supports a data transmission rate of 1.492 kbps According to the Electronic Industries Alliance (EIA), RS232 facilitates communication between Data Transmission Equipment (DTE) and Data Communication Equipment (DCE).
The Universal Asynchronous Data Receiver and Transmitter (UART) facilitates data transfer between a printer and a computer via RS232 Since microcontrollers cannot manage the voltage levels associated with RS232, connectors are utilized to bridge these signals These connectors, commonly referred to as DB-9 connectors, come in two types: Male connectors (DTE) and Female connectors (DCE).
Currently process control application in SEMV
- Concept: Control quantity, weighting by Scanner and Printing online
+ Avoid missing parts by scanning barcodes
+ Application interface not familiar to the end-user
+ Big building cost from the supplier
+ Only apply for packaging station
- Concept: Scan barcode on component, tracking quantity & weight manual
+ Scan the barcode to control the quantity
+ Application interface not familiar to the end-user
+ Not to prevent small parts
+ Not control missing parts/product
+ Big building cost from the supplier
+ Only apply for packaging station
+ Use the scanner to scan the QR on the components
+ Use sensors to guide operation workflow for operators, and send the signal to the system for auto-printing labels after each sensor sequence
+ Connecting scale to control product quantity and weighing
+ Can ensure the flowchart to avoid missing parts
+ Scan the barcode to control the quantity
+ Application interface not close with the end-user
+ Big building cost from the supplier
+ Only apply for packaging station
Figure 20: Concept of system operation
Figure 21: Poka-Yoke Packaging Interface
Failure mode and effects analysis (FMEA) [21]
Failure Modes and Effects Analysis (FMEA) is a proactive tool used for systematic analysis of processes that may pose risks A multidisciplinary team comes together to identify potential failures, assess their likelihood and impact, and document these findings Experts then collaborate to develop strategies aimed at preventing these failures, particularly those that could result in significant harm to patients or staff.
The FMEA tool prompts teams to review, evaluate, and record the following:
• Failure modes (What could go wrong?)
• Failure causes (Why would the failure happen?)
• Failure effects (What would be the consequences of each failure?)
FMEA is utilized by teams to proactively assess processes for potential failures, enabling them to implement corrective measures before adverse events occur, thereby minimizing risks to both patients and staff This method is especially beneficial for evaluating new processes prior to their implementation and for analyzing the effects of proposed changes on existing processes.
1/ Select a process to evaluate with FMEA
Evaluation using FMEA works best on processes that do not have too many sub-processes
To effectively assess the intricate process of medication management in a hospital, it is advisable to break it down into smaller components Conducting separate Failure Mode and Effects Analyses (FMEAs) for medication ordering, dispensing, and administration can provide clearer insights and enhance the overall evaluation.
Involving all relevant stakeholders in the analysis process is crucial, even if their participation is not required throughout the entire duration For instance, in a hospital setting, couriers responsible for transporting medications from the pharmacy to nursing units should be included in discussions related to the transport process Their insights are vital for the Failure Mode and Effects Analysis (FMEA), as they possess knowledge about specific steps that pharmacy or nursing personnel may not be aware of.
3/ Have the team list all of the steps in the process
Working with a team that represents every point in the process you’re evaluating, establish a mutually agreed upon, ordered list of all the steps in the process
4) Fill out the table with your team
To begin, list the steps of the process in the leftmost column Next, collaborate with team members responsible for each step to complete the other columns accordingly.
• Failure Mode [What could go wrong?]: List anything that could go wrong during that step in the process
• Failure Causes [Why would the failure happen?]: List all possible causes for each of the failure modes you’ve identified
• Failure Effects [What would be the consequences of the failure?]: List all possible adverse consequences for each of the failure modes identified
• Likelihood of Occurrence (1–10): On a scale of 1-10, with 10 being the most likely, what is the likelihood the failure mode will occur?
• Likelihood of Detection (1-10): On a scale of 1-10, with 10 being the most likely NOT to be detected, what is the likelihood the failure will NOT be detected if it does occur?
• Severity (1-10): On a scale of 1-10, with 10 being the most likely, what is the likelihood that the failure mode, if it does occur, will cause severe harm?
Table 3: Schneider Electric Manufacturing Vietnam’s RPN score rate
The Risk Priority Number (RPN) is calculated for each failure mode by multiplying three scores: the likelihood of occurrence, the likelihood of detection, and the severity of the failure The RPN can range from a minimum score of 1 to a maximum of 1,000 To obtain the overall RPN for the entire process, sum the individual RPNs of all failure modes.
• Actions to Reduce Occurrence of Failure: List possible actions to improve safety systems, especially for failure modes with the highest RPNs
5) Use RPNs to plan improvement efforts
To effectively enhance processes, it is crucial to prioritize failure modes with high Risk Priority Numbers (RPNs), as they significantly impact overall performance In contrast, failure modes with low RPNs have minimal effect on the process and should be considered lower on the priority list for improvement efforts.
Identify the failure modes with the top 10 highest RPNs These are the ones the team should consider first as improvement opportunities
• Use FMEA to plan actions to reduce harm from failure modes a) If the failure mode is likely to occur:
- Evaluate the causes and see if any or all of them can be eliminated
- Consider adding a forcing function (that is, a physical constraint that makes committing an error impossible, such as medical gas outlets that are designed to accept only those gauges that match)
- Add a verification step, such as independent double-checks, bar coding on medications, or alert screens
- Modify other processes that contribute to causes b) If the failure is unlikely to be detected:
- Identify other events that may occur before the failure mode and can serve as “flags” that the failure mode might happen
To enhance patient safety and minimize the risk of medication errors, it is crucial to implement a proactive step in the process that addresses potential failure modes early on For instance, incorporating pharmacy rounds to ensure the removal of discontinued medications from patient care units within one hour of discontinuation can significantly reduce the likelihood of these medications remaining available for use This timely intervention is essential for maintaining optimal patient care and preventing adverse drug events.
- Consider technological alerts such as devices with alarms to alert users when values are approaching unsafe limits c) If the failure is likely to cause severe harm:
To enhance early intervention, it is crucial to identify warning signs of potential failure modes and train staff to recognize them effectively Implementing drills that simulate events leading to failure can significantly improve staff's ability to detect these early indicators.
- Provide information and resources, such as reversal agents or antidotes, at points of care for events that may require immediate action
• Use FMEA to evaluate the potential impact of changes under consideration
Teams can use FMEA to discuss and analyze each change under consideration and calculate the change in RPN if the change were implemented This allows the team to
Before implementing changes in patient care, it is essential to "verbally simulate" the modifications and assess their impact in a controlled environment This process helps identify potential issues, as some proposed improvements may inadvertently raise the estimated Risk Priority Number (RPN).
• Use FMEA to monitor and track improvement over time
Teams should calculate the total Risk Priority Number (RPN) for their processes and establish improvement goals For instance, a team might aim to reduce the total RPN for the medication ordering process by 50% from its baseline measurement.
Ergonomic workbench systems for industrial & commercial use
An ergonomically designed workstation is essential for effective work organization, as it enhances efficiency, reduces fatigue, and minimizes health risks for employees By taking ergonomic principles into account, companies can significantly decrease work-related physical strain, even for employees who use the same workstation over extended periods.
An ergonomic workstation not only complies with occupational safety and health regulations but also enhances overall employee performance While it meets safety standards, ergonomics extends beyond mere compliance, focusing on creating working conditions that optimize productivity and prevent job-related health issues.
The main ergonomics criteria at a glance
Several requirements must be considered for ergonomic design:
• Ideal use of handling is to enable natural movements of the body and prevent those that cause strain
• Individual working height for standing and seated positions
• Chair that enables dynamic sitting
• Appropriate provision and positioning of tools and materials
• Lighting and visual conditions designed according to activities
During this process, it is important to note that every operator has skills and deficits that should be taken into account in designing the workbench
Comfort and well-being as factors in ergonomics
Research on the workplace integrates both medical and psychological insights, highlighting that a key aspect of ergonomics is the sense of physical comfort This comfort is derived from evaluating work objects and the user's subjective perception of them.
A workbench's comfort stems primarily from its functionality, which determines how easy it is to use, and secondarily from its design, impacting its perceived quality The effectiveness of a workbench is crucial, as it must meet the specific needs of its intended purpose, ensuring optimal performance for users.
Figure 23: Example workbench Requirements for a workbench system
A business workbench system must fulfill both company requirements and employee needs, ensuring ergonomic workstations are provided, even in specialized cases like full ESD (electrostatic discharge) protection This section outlines essential criteria for workstation design based on ergonomic principles, categorized into seven key areas applicable to a wide range of businesses.
A workbench must be technically suitable for its intended purpose while also adhering to essential ergonomic requirements to ensure user comfort and efficiency.
1 The workbench system should offer fastening options for securing all working materials It should be possible to expand it by adding suitable uprights and overhangs Fixtures for tools or parts containers should be arranged efficiently on the workbench They should also be sturdy enough for the purpose, but also easy to remove if fast reconfiguration is necessary The upright and overhang offer options for attaching components to the workbench for purposes such as providing electricity and data, materials, tools, or lighting
2 The workbench should be electrically height adjustable With an electric height adjustment system, the working position can be adjusted precisely to accommodate the specific employee’s physical proportions Ideally, employees should be able to switch as desired between standing and seated work positions This helps counter lopsided strain profiles and those with adverse health consequences If having a height-adjustable workstation is not favored because of the production environment (for instance because multiple workstations are interlinked together), an appropriate height-adjustable footrest is required in addition to easy-to-use seat height adjustment
3 The workbench should be available in various sizes The optimum width and depth of the workbench, which depends on the work task and the physical space available, should be feasible with the standard dimensions offered by the manufacturer If the standard dimensions do not fit in a certain case, the manufacturer must be willing to supply the individual dimensions requested by the customer
4 The workbench surface must be adequately sturdy and resistant to mechanical strain as well as resistant to any fluids used in the process It should also be non-reflective and able to absorb noise The workbench should offer adequate legroom As a result, parts such as clamping elements in the leg area are not considered favorable.
DESIGN AND IMPLEMENTATION
System Overall Block diagram
Table 4: Devices used in the Interlocking System Devices Models Specifications
CPU: Intel Core i7-10700 Processor RAM: 8GB RAM bus 2666MHZ Hard disk: SSD 512GB Nvme VGA: Integrated Intel UHD Graphics 630 Connection: WLAN + Bluetooth
Model: Xenon XP 1952g Operating Temperature: 0°C to 50°C Connection: Bluetooth, RS-232, IBM 46xx, USB, Keyboard Wedge
Communication Type: Bluetooth Communication Range: 33 ft
Capacity (kg):6 Division (g): 0.5 Display: 6/5/6digits,19mm digit height, LCD with LED backlight
Weighing pan(mm): 294×228 (stainless steel) Dimension(mm): 341×249×104
Weight: N 4.48kg, G 5.01kg Power supply: AC 110V/220V or rechargeable battery (6V/4Ah) Operation: -5℃ ~ 40℃
Air Interface Protocol: EPCglobal UHF Class
1 Gen 2 V2 (ISO 18000-63) Operating Frequency: 865-928 MHz Data Interface: USB 2.0, RS-232, Bluetooth 4.1, Dual USB Host
Power Source: 100-240 VAC, 50-60 Hz Dimensions: 495 x 269 x 324 mm
Dimension(mm): 267x202x192 mm Weight: 2.5Kg
Memory: 512 MB Flash, 256 MB SDRAM Operation: 4.4° to 41° C
Power Supply: 100-240VAC Display Screen: Color LCD (320 x 240 resolution), 10-button user interface Connection: USB 2.0, USB Host, Serial, Ethernet, BTLE
Output Voltage: 24 V DC Output Current: 2 Amp
Input Voltage: 140-260 V AC Ripple Voltage: 50-80 mV DC Efficiency: 90%
PCB Size (HXWXL): 31x65x119mm Frame Size (HXWXL): 55x71x154mm Tester Sign
Range of product: Modicon M221 Discrete input number: 9
Discrete input voltage: 24V DC Output Type: Digital
Input Type: Discrete Discrete output number: 7 relays Program Capacity: 10000 steps Mounting Type: Panel Mount Programming Interface: Mini USB Programming Language Used: CoDeSys Depth: 75.9mm
RS232 To USB DB9 Pin male converter cable
Connection: + USB port; Type A male + RS232 port; 9-pin male Transfer Rate: up to 255 kbps
Bus-powered Prolific PL2303 Chipset Weight: 165g
Figure 25: Interlocking System Connection Diagram
Figure 26: Interlocking Process Overall Diagram
The printers, scanners, scale, and tester use a 220V power supply Operators need to open
Three primary applications operate on interconnected computer stations, where parameters and hardware are configured to initiate the system These applications facilitate data connectivity to an SQL database, enabling efficient data retrieval and collaboration.
At the printing station, operators utilize a computer linked to a printer and scanner to generate QR labels from the app's code and database information This process allows operators to automatically input essential data, such as the WO Number, using scanners, minimizing the risk of errors.
At the testing station, a switched-mode power supply connects to 220V AC to supply 24V
The DC to PLC M221 is installed within the tester, enabling a connection to the PC and testing application via an Ethernet cable Operators initiate the testing process by scanning the QR label on the products, and upon completion of each product's testing, the data is transmitted to a database for storage.
After testing is complete, operators must rescan the QR label with a scanner Two printers are utilized to print three types of labels: individual, group, and outer, all connected to a PC The scale measures the weight of the box to ensure proper packaging Once a product is fully packed and weighed, the system updates the scale's status in the database.
Layout design
Safety is the most important factor when working for a company specializing in the production of electrical equipment We will design the line layout according to the company's regulations:
- Ensure safety factors for operators
- An ergonomic workstation should be established
- Devices should be installed in suitable locations for ease of operation
Creating an ergonomic workstation requires conducting an anthropometric analysis and evaluating the work area to optimally position parts boxes and equipment, ensuring operators can access tools easily while minimizing fatigue Anthropometric analyses take into account variations in human body size, shape, joint motion, and strength, utilizing data from diverse global populations to ensure designs align with the physical capabilities of intended users.
We distinguish between the provision of information, tools, and materials All three factors need to be coordinated and aligned to the employee’s physical proportions and the process
The optimal location for material provision is within the singlehanded zone, where using pivot arms with two or three joints can enhance accessibility This design minimizes the time employees spend reaching for items and reduces physical strain The same principles apply to the arrangement and positioning of tools, ensuring efficiency and comfort in the workplace.
In this setup, each tool is assigned a specific location based on ergonomic principles, featuring holders designed for easy retrieval and storage Additionally, optimizing the horizontal and vertical angles of parts containers enhances employee efficiency and comfort.
Figure 28: Top view working zone [22]
Zones determined as semicircular for "seated" or "high-seated" workstations become linear for "standing" workstations, the operator being able to move in front of the workstation
Figure 30: Printer setup for easy operation
Electrical Design
Table 5: Devices used in the electrical block diagram
In the block diagram, various devices such as printers, scanners, testers, and computers are connected to a 220V AC power supply To operate the PLC within the tester, which requires 24V DC, an SMPS is utilized to convert the 220V AC to 24V DC Additionally, the Ethernet splitter in the electrical cabinet also needs 24V DC, necessitating another SMPS for conversion Once powered, the splitter receives an Ethernet signal from the cloud network and distributes it to three computers across different stations and the PLC in the tester.
A 220 AC voltage will be supplied to the electronic cabinet This will be used for the SMPS to create a 24 DC output voltage to supply to the Ethernet splitter
Figure 32: Electrical cabinet circuit schematic
Printing Application Design
+ The application must be able to generate QR labels based on information in MySQL A serial number of products include production line ID, printed date, and 6-digit number
+ The application must be able to upload the QR label into the SQL database after the QR code is generated
+ The ability to communicate with a QR printer to print out the generated QR code
The printing station features two login modes: Production and QAS When accessing the application, the default production account and password are automatically filled in In Production mode, operators can manage and print existing work orders and calibrate labels, although manual printing requires an admin account for security This setup is designed to enhance efficiency for line leaders Conversely, QAS mode necessitates an engineer-level account, as determined by the database, enabling the Interlocking team to access a "copy" database for testing operating procedures and quality assurance tasks without impacting production work orders.
Interlocking systems utilize SQL databases, where tables are interconnected through columns with matching headers A unique requirement at this station involves gathering WO data from the LDS system, achieved through a command executed in SSMS This command will be integrated into the code to automatically generate results when a production line is selected and applied.
SEMV processes two types of orders: internal orders initiated by employees to assist with their tasks, which are managed by the Warehouse department, and customer orders received by the SE organization and recorded in the LDS system The combined data from both the LDS and WH databases is accessible through the itl_view_WO table (Figure 3-10), providing a comprehensive view of all orders.
Figure 34: Table itl_view_WO
The Itl_view_WO table serves as a connection between the LDS system and the Warehouse data, summarizing existing orders in SEMV by displaying order numbers, references, quantities, and planning times Since the LDS system permits only viewing and not editing, it is necessary to export this data to a separate table, itl_printing_header.
Figure 35: Load Data for Printing Station code
Figure 36: Code result in SSMS & explanation
Figure 37: Code result when assuming choosing line A01_FG
Figure 38: Table itl_printing_header
The Itl_printing_header table is designed to store all active and closed data, enabling operators using printing applications to easily access the remaining quantities of each order along with their start and finish times.
The printers connect with the computer via Zebra Setup Utilities
Figure 39: Zebra Setup Utilities Interface
Zebra Setup Utilities automatically detects connected printers and facilitates the download of necessary drivers, ensuring optimal printer functionality Additionally, it offers valuable tools for users to print labels, connect, and configure devices seamlessly.
Figure 40: Online viewer website (Labelary.com)
Zebra Setup Utilities facilitate the use of ZPL codes for printing QR labels, while an accompanying website allows users to pre-draw these codes for easy modifications and export them in various file formats.
This document serves as a training resource for the maintenance team during the handover process at SEMV, based on my learnings For additional details, please follow the provided link.
Table 6: Proposal for a new design of traceability label
- Testing results based on the unique serial number & week-code
- More details on manufacturing time
Figure 42: QR labels from Printing Station
The four characters displayed at the top of the label serve as a reference for both the line station and the product These characters are automatically generated through the integration of databases and visual codes as the application operates.
Figure 43: Databases use for information transfer
The label data can be automatically updated using system codes, including the plant code, production time, and serial number The plant code is typically set as a default, eliminating the need for a database The application utilizes the PC's date and time, along with C# code, to display this information on the labels Additionally, each label printed will feature a unique serial number, which increments based on the last serial recorded in the database, managed through C# code.
The system is linked to an SQL server database, which aggregates data from both the LDS system and the Warehouse's database Once sufficient information is gathered, it triggers a signal to Zebra Setup Utilities (ZSU), which decodes the print request and forwards it to the printer Each successful print updates the system's print history and quantity records.
To utilize the application, users must first log in Each application within the system offers the option to access either the live database, which supports ongoing production, or the test database, designated for engineers and technicians to conduct various testing and modifications.
Figure 45: Login form of the first station After login, the operator can work with the program with different functions displayed in the main UI
Figure 46: UI design of the first station Table 7: Function of the First station
The “Apply” button and the combo box
To let the cell leaders, choose the name of the current cell in the combo box and click apply to display on the table
The “Refresh Data” button To refresh the data displayed in the table with the latest one
“Print Rework” button To reprint the manually printed labels as the production order will disappear from the table when manually printed
“Calibration” button To set the origin of the coordinate of the printed label
To print a label with a QR code specialized for each product from the SQL database
“Sign out” button To log out from the form
“Search” button and text box Find the production order number typed in the text box Table To display the detailed production order at the chosen cell
To effectively use the program, users must first choose the cell name from the drop-down combo box, which retrieves data from the production line cells.
After clicking the apply button, it accesses different tables in the database to get different information and display it on the table
Figure 47: UI of first station
After the table appears, the operator initiates the printing of the label with the specified quantity by clicking the print button At this stage, the program generates a unique serial number for each product, retrieves data from the database, and updates the table for the testing station.
The program utilizes the built-in ZPL printing function to initiate label printing, employing the generated serial number It then produces labels that include a QR code based on this information.
Furthermore, calibrates are used for adjusting the label size and space between labels and selecting the correct printer
Testing Application Design
1 The application must be able to communicate with the PLC inside the testing machine by extracting the data of the product (product status) and controlling the PLC by triggering the interlocking signal to seize the operation of the testing machine
2 After scanning the QR code of the product, the application will compare it with the
The system utilizes a QR code stored in a database; if a scanned QR code does not match the database entry, the interlocking mechanism is triggered, causing the testing machine to halt its operations.
3 The ability to record and update the product status (pass/fail) on the database after the testing machine completes the product scanning operation
• Aside from an invalid QR code, the application also triggers an interlocking mechanism in the following scenarios:
• Product already passed the corresponding machine
• Product already passed all required attempts
The user interface for operators is designed to be intuitive and easy to navigate The testing station features two login modes: Production and QAS To initiate the testing application, operators must log in using a prefilled production account After logging in, they can select the running cell and view the available testers configured in the database It is crucial for operators to choose the correct tester, as a mismatch between the PLC hardware IP and the database IP will prevent connection establishment An Ethernet connection between the PC and PLC is necessary to upload testing history to the database Both Production and QAS modes operate under the same functions and processes, with the QAS login specifically created for engineers to test and validate the process The QAS mode utilizes a separate database and requires a QR label printed at the first station.
Figure 57: Table itl_master_dummy_data
In quality control, dummy samples are essential for ensuring that testers function correctly before assessing actual products A tester must first pass a dummy mode, indicated by a yellow light, to confirm its reliability To facilitate this process, a table has been created to generate "dummy QR labels" specifically for testing these samples While the testing procedure remains consistent, the dummy samples do not upload any data to the database, allowing for effective quality assurance without compromising the integrity of actual product testing.
Figure 58: table itl_master_tester_data
The master tester data table is a crucial component of the testing station, containing essential information such as the tester's name, production line, and the IP addresses of each PLC associated with the tester This table stores all interlocking bits as global bits in the SQL database utilized by the system When operators select a production line, they are presented with a list of available testers Additionally, the PLC IPs are stored as global values to accommodate the diverse range of machines, enabling the system to effectively connect with the PLCs.
Figure 59: Table itl_master_testing_result_history
The Itl_master_testing_result_history table stores QR label data along with testing history, serving as a crucial reference for comparison in subsequent processes To initiate a test, users must provide the QR label, which the system verifies against the database If the label has no prior test history, it is deemed valid, prompting the system to update the status of interlocking PLC bits accordingly.
Prior to implementing the Interlocking system, product testers primarily focused on quality checks, often leading to issues with untested products reaching the packing station and resulting in customer complaints about functionality To address this, the Interlock System was introduced, requiring an Ethernet connection for accessing the SQL server and facilitating communication between the PLC and the testing application For successful integration, both the computer and PLC must operate on the same network layer and DNS server Discussions with the IT team have determined the appropriate network layer and compiled a list of usable IP addresses for the setup.
We used the AVEVA network layer (10.187.212.XXX)
Figure 61: Database alignment with PLC IP (E83426-T01)
Figure 62: Change Ethernet TCP/IP to the same layer with PLC
The testing station will verify the PLC's IP by connecting to the SQL server database Once the user selects the appropriate test machine, the results will be returned accordingly.
IP of that machine will be uploaded and successfully connected to the system
To connect with the Interlocking System, various testers will be employed, each equipped with its own program It is essential to comprehend when a tester initiates testing and how it determines if a product is classified as NG (No Good) or PASS We will select a specific tester to illustrate the process of modifying a PLC (Programmable Logic Controller).
Operators must simultaneously press two green buttons on the tester to activate the pushing cylinder This action will temporarily halt operations until the QR label is scanned The Interlock signal will be implemented immediately before the pushing cylinder signal to ensure safety and proper functionality.
Figure 66: Interlocking signal in the PLC program
To accurately tally the total number of passed and failed products, as well as the overall count of tested items, we will replicate the tester's set condition for counting purposes However, the output generates a continuous Q signal, resulting in uncontrolled counting To address this issue, we implement a memory bit alongside the lighting signal, utilizing it as a pulse (P) signal that ensures counting occurs only once each time the status changes.
Figure 67: Pass and Fail conditional
“SB_FirstRun” is a system bit that will be only enabled one time whenever the PLC is connected which is used to reset all the counting signals
Figure 68: Pulse signal for counting bits
Figure 69: Memory word used for counting bits
When choosing a test machine, the application retrieves tester information from the SQL database and establishes a connection to the PLC using the MODBUS TCP/IP communication protocol After each product test, the application uploads historical data to the database based on signals from the PLC.
The uniform login UI across all three stations will streamline the process and lessen the coding workload for the team.
Figure 71: Login form of the testing station
Figure 72: UI of testing station
Table 8: Function of the testing station
“Cell/Chuyền” Combo box To let the user choose the cell and find the tester’s name
“TesterID/Tên máy test” textbox and “Connect” button
To let the user choose the name of the testing machine on the cell and connect the application with the tester
“Scan QR/Quét mã QR”
Combobox and the enter button
To enter the QR code scanned from the label on the product
“Message/Thông báo” textbox Display errors, notifications, and operation instruction
“Result log/Nhật kí kết quả” textbox
Display test result history of all products
“Product info/Thông tin sản phẩm” textboxes
Display information on the recently scanned product
When signing in, users have the option to choose between a Live run and a Test run (QAS) Selecting the Live run uploads testing results to the main database, whereas the Test run uploads results to a testing database.
To ensure proper operation, users must first input the testing machine's name and click "Enter." The program will then search the database for the tester's name to retrieve the corresponding IP address It utilizes a Modbus Client to establish a connection to the PLC, and if the connection fails, all other operations will be disabled.
After that, the user can start using the testing machine:
The interlocking system is activated by default When it is connected, the program immediately disables the testing machine
Packing station
Can communicate with an electrical scale to check the weight of the packaging box
The application must be able to generate QR codes for packaging in the following scenarios:
• The weight of the packaging box is equivalent to its required weight which is in the database (±5% tolerance)
• The product status in the database passed the testing station
• The ability to communicate with the QR printer to print out the QR code generated
The login user interface for all three stations is identical, offering two modes: Production and QAS, which share the same functionality but differ in that QAS accesses a test database After logging in, users must configure connected devices by selecting test print and verifying connections through the "Configuration" button They should then choose the running line to display the applicable product codes set in the database Accurate selection of product references, work orders, and QR labels is essential, as the system will utilize the chosen reference and the product weight from an electronic scale to automatically print three types of labels.
The Itl_packing table serves as the central repository for essential information in the packaging application, encompassing details such as family classifications, commercial references, box quantities, and label template directories.
Figure 79: Table itl_standard_weight
The Itl_standard_weight feature offers precise weighing for each product reference, including the weight of the packaging This data enables the application to multiply the quantity of each box to accurately determine the total preset weight.
Figure 80: Table itl_packing_history
The Itl_packing_history table is essential for storing historical manufacturing data, allowing for the tracking of each product's history based on its serial number This table provides valuable insights, such as the production time and box weight of each item.
The relationship among multiple tables relies on the similarity of data and matching column headers across those tables This allows for data selection from any table, provided that the table contains the relevant column.
Figure 82: Connection between database and template directory
Our database contains a comprehensive directory of all label templates, and we utilize the application to initiate the print command whenever the scale measures close to the standard weight.
The printers used at the Packing Station, specifically the ZT411 and GK420t models, connect to the PC through Zebra Setup Utilities, similar to the Printing Station setup.
Figure 83: Zebra Setup Utilities UI
Zebra Setup Utilities automatically detects printers connected to your computer and simplifies the process of downloading the necessary drivers, ensuring optimal printer functionality Additionally, it offers valuable tools to assist users in printing labels and configuring devices efficiently.
Bartender is the leading software solution for designing, printing, and managing barcodes, labels, RFID tags, and documents Schneider Electric has acquired the Bartender license from Seagull Scientific, solidifying its commitment to utilizing this trusted technology.
With bartender, we can easily build all the product templates (Barcode, Pictures, database connection, etc.)
Figure 84: Three types of label templates
Figure 86: Example of an outer box label template
The printing application utilizes data from SQL Server to function effectively After the packaging process, operators place the product on a scale to verify its weight against the system's standard If the weight matches, the application sends a print signal to Bartender, which uses the label templates stored in the database to print the required label through the connected printer.
The packaging station operates similarly to the first station, generating QR codes by concatenating digits from various SQL tables to create unique serial numbers Additionally, user login is required for access to the packaging station.
Figure 89: Login form of Packaging Station
Figure 90: UI of Packaging Station
The packaging application typically comes with pre-set default settings for each production line, which are secured with engineer-level login permissions to prevent errors However, line leaders or maintenance personnel can access the system to modify parameters when there are changes in equipment or order specifications.
The print manual mode, akin to the Printing station, is exclusively utilized by line leaders for printing stamps that are defective, such as those that are faulty, blurred, or torn, as well as for cases where the system fails to print labels Access to this mode necessitates a higher-level account for login.
Figure 92: Print Manual User Interface Table 9: Function of Packaging Station
“Select cell name” Combobox To let the user choose the cell and find product reference
“Select reference” Combobox To let the user choose the product reference
To let the user choose the amount of product packed in an unfinished box for the program to continue to count and print the label
“Scan serial number” textbox To let the user scan in the product they want to pack
Other “scan” textboxes To let the user scan in the information if required to check if they picked the right component or not
“Weight” and “Standard weight” label display
Display the current weight of the scale and the weight to compare with
“Notification” textbox Display errors, notifications, and operation instruction
“Packing log” textbox Display test result history of all products
“Subs”, “Inner”, “Outer”, and “Total” label display
Display the current number of subs in 1 product, the number of products in the current inner, and outer box, and the total packed products
The “Setting” button To let the authorized user set the printer and COM port for the app
The “Print manual” button To let the authorized user print manually the labels of the products
To use this app, users must select a cell name and product reference, as the program retrieves information only from the SQL Database for existing cells and products Upon pressing enter, the app verifies the existence of the label template by checking the location link in SQL for each product's label, as well as confirming the connection status of the scale.
When connected, the user inputs the initial number of products, representing those that are successfully packed but not yet in a completed carton box This input allows the program to accurately calculate the number of products for printing labels once a box is finished.
Layout Implementation
Based on the ergonomic research mentioned above, we’ve finished the re-layout as below:
Figure 95: Assembly station before Figure 96: Assembly station after
Figure 97: Testing station before Figure 98: Testing station after
Figure 99: Packing station before Figure 100: Packing station before
We applied a 220 AC voltage into the electric cabinet to supply the SMPS which has an output voltage of ~24VDC This output will be applied to the network splitter
MCSESU053FN0, which has a total of 5 Ethernet ports to split out
Figure 101: Outside of the electric cabinet
Figure 102: Inside of the electric cabinet
Thanks to the support from the improvement team, we’ve successfully done the wiring following the industrial standard as an important requirement from the 5S standard
Figure 103: Tidy Wiring Figure 104: Electric wires go inside the electric gutter