Manufacturing Simulation with Plant Simulation and Simtalk Usage and Programming with Examples and Solutions Manufacturing Simulation with Plant Simulation and SimTalk Steffen Bangsow Manufacturing Simulation with Plant Simulation and SimTalk Usage and Programming with Examples and Solutions ABC Steffen Bangsow Freiligrathstraße 23 08058 Zwickau Germany E mail steffenbangsow de ISBN 978 3 642 05073 2 e ISBN 978 3 642 05074 9 DOI 10 1007978 3 642 05074 9 Library of Congress Control Number 20109.
Uses
You can use simulation during planning, implementation, and operation of equip- ment Possible questions can be:
Identification of bottlenecks in derivation of potential improvement Uncover hidden, unused potentials
Minimum and maximum of utilization
Juxtaposition of different planning alternatives
Test of arguments regarding capacity, effectiveness of control, performance limits, bottlenecks, throughput speed, and volume of stocks Visualization of planning alternatives for decision making
Problem analysis, performance test on future requirements
Simulation of exceptional system conditions and accidents
Training new employees (e.g., incident management)
Simulation of ramp up and cool-down behaviors
Review of emergency strategies and accident programs
Proof of quality assurance and fault management
Dispatching of orders and determination of the probable delivery dates
Definitions
Simulation involves creating a model that replicates a real system and its dynamic processes, with the goal of deriving insights that can be applied to real-world scenarios More broadly, it encompasses the preparation, execution, and assessment of targeted experiments using a simulation model.
A system is defined as a separate set of components which are related to each other
Model: A model is a simplified replica of a planned or real system with its proc- esses in another system It differs in important properties only within specified tolerance from the original
A simulation run is the image of the behavior of the system in the simulation model within a specified period
An experiment is a targeted empirical study of the behavior of a model by re- peated simulation runs with systematic variation of arguments.
Procedure of Simulation
Formulation of Problems
To ensure effective simulation outcomes, the simulation expert must collaborate closely with the customer to define the simulation requirements This collaboration should culminate in a written agreement, such as a technical specification, outlining the specific issues to be addressed through the simulation process.
Test of the Simulation-Worthiness
To assess the simulation-worthiness you can, for example, examine:
• The lack of analytical mathematical models (for instance, many variables)
• High complexity, many factors to be considered
• Gradual exploration of system limits
• Repeated use of the simulation model
Formulation of Targets
Every organization establishes a target system, typically centered around a primary objective like profitability, which then branches into various interconnected sub-targets Defining this target system is a crucial preparatory step, as it lays the groundwork for effective simulations Common targets for these simulations often include metrics related to financial performance and operational efficiency.
At the conclusion of the simulation runs, it is essential to collect and statistically analyze all defined targets, which necessitates a specific level of detail in the simulation model Consequently, this analysis defines the scope of the simulation study.
Data Collection
The data required for the simulation study can be structured as follows:
The following overview is a small selection of data to be collected:
Working time organization Break scheme
Modeling
The modeling phase includes building and testing the simulation model
Modeling usually consists of two stages:
1 Derive an iconic model from the conceptual model
2 Transfer the model into a software model
To effectively engage with a simulated system, it is crucial to first establish a comprehensive understanding of its components Depending on the testing objectives, decisions regarding the simulation's accuracy must be made This accuracy then informs which elements can be simplified The initial stage of modeling involves two key activities that lay the groundwork for successful simulation.
System analysis allows for the breakdown of complex systems into their fundamental elements, aligning with original investigation goals Through abstraction, the specific attributes of the system are minimized to create a clear and concise representation Common abstraction techniques include reduction, which eliminates irrelevant details, and generalization, which simplifies essential information.
A simulation model will be constructed and evaluated, with the results documented to facilitate future modifications Unfortunately, this critical documentation step is frequently overlooked, leading to models that are unusable due to unclear functionality To address this issue, it is essential to comment on the models and source code throughout the programming process, ensuring that explanations of the functionality remain accessible even after development is complete.
Executing Simulation Runs
The simulation study's objectives dictate the execution of experiments outlined in a comprehensive test plan, which specifies the output data, model parameters, goals, and anticipated results Establishing a time frame for these simulations is crucial, taking into account the findings from preliminary test runs Extended computer runs or repeated experiments for statistical accuracy are common, and utilizing a separate programmed object for batch runs can enhance control over the experiments To maximize computing resources, some experiments may be scheduled during nighttime hours Additionally, thorough documentation of input and output data, along with the parameters of the simulation model, is essential for each experiment.
Result Analysis and Result Interpretation
The values that change in a modeled system are derived from simulation results, making accurate interpretation crucial for the success of a simulation study When results contradict initial assumptions, it is essential to analyze the influencing factors behind these unexpected outcomes Additionally, complex systems typically undergo a ramp-up phase, which may differ between the simulation and real-world scenarios Consequently, results from this phase are often not applicable to the modeled system unless the ramp-up phase of the original system is fully represented in the model.
Documentation
A project report is the recommended format for documenting a simulation study, providing a comprehensive overview of the study's timeline and the work conducted It is essential to include documentation of any failed system variants and configurations The main focus of the report should be on presenting the simulation results in alignment with the customer requirements Additionally, it is beneficial to incorporate actionable proposals derived from the simulation findings Lastly, the report should detail the structure and functionality of the simulation model.
S Bangsow: Manufacturing Simulation with Plant Simulation, Simtalk, pp 7 – 15, 2010 © Springer Berlin Heidelberg 2010
First Steps
Online Tutorial
The online tutorial provides a systematic guide for quickly creating a simple simulation model To begin, open Plant Simulation and navigate to the Explorer window by clicking on the I NFO P AGES tab, followed by E XAMPLES and T UTORIAL.
Examples
The sample model features a diverse collection of small, thematically organized models that demonstrate the various settings for utilizing components and functions To access these models in Plant Simulation, simply navigate to the INFO PAGES tab, then select EXAMPLES and finally choose EXAMPLES.
Help
The "Step-by-Step Help" section of our online assistance offers detailed descriptions of essential steps required to effectively model various tasks This comprehensive guide is designed to facilitate users in navigating through the necessary procedures with ease.
Version 9's complete functionality is detailed in the online documentation, with manuals available as Adobe Acrobat PDF files on the Plant Simulation installation CD, which can be printed if needed Additionally, context-sensitive help is accessible within object dialogs; simply click the question mark in the top right corner and then select the dialog element for further explanations The context-sensitive help window will also reference the corresponding SimTalk attribute at the end.
Website
For the latest updates on Tecnomatix and Plant Simulation, visit Siemens' official website at http://www.plm.automation.siemens.com You can also access detailed information about Plant Simulation directly through this link: http://www.plm.automation.siemens.com/en_us/products/tecnomatix/plant_design/plant_simulation.shtml.
Introductory Example
The Program
Start Plant Simulation by clicking on the icon in the program group or the desktop icon
To customize the layout in Plant Simulation, navigate to the menu item VIEW – TOOLBOX, where you can select the elements displayed on your screen A typical Plant Simulation window may include various components that enhance your user experience.
The class library contains all necessary objects for simulation, allowing users to create custom folders, derive and duplicate classes, create frames, and load objects from other simulation models.
To show the class library, you can use the command:
V IEW – V IEWERS – E XPLORER or the icon
You can hide the class library by clicking the X in the title bar
The Console displays important information, such as error messages, during the simulation To output messages, you can utilize the Print command If the Console is not needed, it can be hidden by clicking the X in the title bar.
Show the console with the icon: in the toolbar or in the menu with V IEW –
The Toolbox offers convenient access to the class library, allowing users to effortlessly create custom tabs filled with their own objects To display the toolbox, simply click the designated button.
First Simulation Example
As a first example, a simple production line is to be build with a source (material producer), two workstations, and a drain (material consumer) Start Plant Simula- tion, and select the menu command:
It opens the Plant Simulation class library with the basic objects and a Frame (window) Simulation models are created in the object Frame
2.2.2.2 Insert Objects into the Frame
To insert objects into the Frame, you have two options:
• Click on the object icon in the toolbox, and then click in the Frame The object will be inserted into the Frame at the position, at which you clicked
• Another way: Drag the object from the class library to the Frame and drop it there (drag and drop)
Insert the following objects in the Frame:
To ensure efficient transportation of various parts between objects, it is essential to connect them along the material flow This functionality is provided by the Object Connector, which can be easily identified by its specific icon in the toolbar.
To connect objects within a Frame, click the Connector in the toolbar, then select the desired object; the cursor will change to indicate the Connector mode For adding multiple Connectors in succession, simply hold down the CTRL key while clicking on additional objects.
2.2.2.4 Define the Settings of the Objects
To optimize object configurations, it is essential to define settings such as processing times, capacity, setup information, failures, and breaks These properties can be conveniently adjusted through the object's dialog, which can be accessed by double-clicking on the object.
Example 1: Properties of the SingleProc
Set the following values: SingleProc stations: processing time: 2 minutes, Drain: Processing time: zero seconds, Source: 2-minute interval
The APPLY button retains the values while keeping the dialog open, whereas the OK button saves the values and closes the dialog Additionally, it is essential to insert an event controller to manage the processes occurring during a simulation.
Click on the event controller in the toolbox, then in the Frame
Open the control panel by double-clicking on the icon of the event controller
To initiate the simulation, click the START button, and to halt it, click the STOP button The graphical display in the frame illustrates the movements of the material Feel free to modify the model to observe the resulting changes.
Modeling
Object-Related Modeling
When modeling real installations, a limited range of model objects is typically available to represent the system's properties To create effective hierarchical system models, a top-down approach is recommended, allowing for the decomposition of the real system into distinct functional units or subsystems If the existing model objects do not provide adequate precision, further decomposition is necessary to enhance the model's accuracy.
Each object must be described precisely:
The individual objects and their operations are interconnected within a comprehensive framework, known as a Frame This integration allows for the modeling of various logistical systems using the objects and the established Frame.
Object-Oriented Modeling
The hierarchical structure of an object enables precise addressing, similar to a file path For instance, a robot named Rob1 can be located within this hierarchy using the notation production1.press_hall.section1.cell1.Rob1, where each level is delineated by a period.
Rob1 itself is described by a number of properties such as: type of handling, speed, capacity, lead times, etc All properties, which describe Rob1, are called
“object” An object is identified by its name (Rob1) and its path:
(production1.press_hall.section1.cell1.Rob1)
The properties are called attributes They consist of a property description (attrib- ute type), for example Engine type and a property value (attribute value) for in- stance: HANUK-ZsR1234578
In object-oriented programming, a class is defined as follows:
A class is a user-defined data type It designs a new data type to create a definition of a concept that has no direct counterpart in the fundamental data types
To develop a unique transport unit that transcends conventional classifications, one must establish a "class," which encompasses all necessary definitions, including properties, methods, and behaviors essential for its creation.
An instance of a class refers to a specific manifestation of that class, such as a general category like Transport, which can include a concrete example like Forklift 12/345 Each instance shares the fundamental properties of its class while also possessing unique characteristics, including a distinct name.
In Plant Simulation, you can derive a new subclass from an existing base class, allowing you to expand a data type without redefining it This process enables you to utilize the fundamental objects of the class through inheritance, streamlining your modeling efforts.
When managing multiple machines of the same type, it is efficient to create a basic machine definition that encompasses shared properties This foundational machine serves as a template, allowing all other machines to be derived from it As a result, subclasses inherit the properties of the base class, applying them seamlessly as if they were defined within each subclass.
Select the SingleProc in the class library Click the right mouse button to open the context menu Select D UPLICATE from the context menu
Plant Simulation names the duplicate SingleProc1 Change the processing time in the class SingleProc to 2 minutes Open the dialog of the SingleProc1 The proc- essing time has not changed
A duplicate retains all the features of the original object, yet it operates independently without any inheritance link To create a duplicate using your mouse, simply hold down the Control key, drag the object to your desired location, and release it.
Now do the same with D ERIVE Select the SingleProc again, click the right mouse button and select D ERIVE from the context menu
In Plant Simulation, a new class named SingleProc2 has been created using D ERIVE to instantiate it, which can either be a new class in the library or an object within a Frame This instance initially inherits all characteristics from the original SingleProc class By modifying the processing time of the SingleProc class to 10 minutes, these changes are saved, and upon opening the dialog for SingleProc2, it reflects the updated processing time inherited from SingleProc.
To derive in the class library, use CTRL + SHIFT while dragging the mouse This allows you to navigate to the original class from an object or a derived class Simply double-click the class or object to proceed.
It will open the dialog of the original class If you drag a class from the class li- brary into a Frame object, the new object is derived
To begin, open a Frame object and incorporate a SingleProc by dragging and dropping it from the library Next, modify the processing time of the SingleProc within the library and verify that the updated processing time reflects in the Frame This demonstrates that the values are inherited from the library object.
Duplicating Objects in the Frame
To duplicate an object within the Frame, simply hold down the Ctrl key and drag the object to an available area, indicated by a “+” symbol on the mouse pointer Additionally, you can enable inheritance from the original class for the duplicated object.
To modify the processing time of a SingleProc in the library, note that changes will also affect the processing time of both SingleProcs within the Frame However, adjusting one SingleProc's processing time does not alter the other, as they do not share an inheritance relationship; instead, they relate to the original class In the object dialogs, you can easily discern inherited values from those entered in the instance, with each attribute featuring a green toggle button indicating inheritance and a yellow button with a minus sign denoting discrepancies with the original class values.
Value inherited Value changed (inserted)
To restore inheritance of a value, click the button after the value and then click
S Bangsow: Manufacturing Simulation with Plant Simulation, Simtalk, pp 17 – 74, 2010 © Springer Berlin Heidelberg 2010
Overview
The standard classes can be classified into six categories:
Material Flow Objects
General Behavior of the Material Flow Objects
Active material flow objects are capable of receiving and temporarily storing mobile objects before automatically transferring them to the next destination In contrast, passive material flow objects do not facilitate automatic transfers; for instance, a mobile unit (MU) will remain in storage until manually retrieved Additionally, the passive object "track" is effectively utilized only in conjunction with an object transporter, allowing the MU to move along the track at a defined speed.
Example 5: Material Flow – Time Consumption
To demonstrate a small example, model the following Frame:
An object receives MUs when it has free capacity and is neither failed nor paused
If any conditions are unmet or the gate is closed due to recovery or cycle times, the object will reject the MUs The moving object will then be placed at the end of a blocking list Once the object is ready to accept MUs again, the first MU on the blocking list will be processed in a First In, First Out manner.
To open the source, double-click on the object This action generates MUs (entities by default) You can adjust the interval between individual MUs here, with the default set to 0 minutes To change the interval, set it to 1 minute.
Set the processing time of the next object (SingleProc1) to 2 seconds Double-click on the SingleProc1 in the Frame In the dialog select the tab T IMES
To set the processing time, enter "2" in the Processing Time field and click Apply If the subsequent station has a processing time exceeding one minute, ensure that the MUs accumulate Configure the processing time for SingleProc2 to 2 minutes (2:00) Allow the simulation to run for a period, then stop it using the Event Controller Finally, double-click on SingleProc1 and navigate to the STATISTICS tab to view the results.
The station frequently experiences blockages caused by the successor, preventing the transfer of material units (MUs) to the next station, which is still processing and unable to store the MUs This duration of obstruction is referred to as blocked time.
At the entrance of an object, there are two “gates”:
1 The object is empty, not failed or paused
2 An entire multiple of a cycle time
Cycle time plays a crucial role in synchronization, ensuring that even if the previous station is ready sooner, the part must wait until the cycle is complete before being transferred to the next station The processing duration of a part at a station is divided into three components.
Setup time refers to the duration needed to prepare a basic object for processing a different type, which is identified by the name of a Manufacturing Unit (MU) MUs sharing the same name are classified under the same type Additionally, setup time can be utilized after a specified number of parts have been processed, such as during routine tool changes.
Recovery time is a crucial aspect of basic object functionality, as it involves a gate that closes for a designated period after a Manufacturing Unit (MU) enters This mechanism effectively simulates the operation of robots, which need a specific duration to insert components into the machine.
PROCESSING TIME: The processing time determines how long an MU stays on the object after the setup time, before Plant Simulation tries to move the MU to a succeeding object
Cycle times are essential for synchronizing production processes, as they define the specific intervals at which new units can enter a workstation, such as every 32.4 seconds This means that the gate opens at these regular intervals, allowing a new material unit (MU) to enter only after the previous one has completed processing and the gate has reopened.
The capacity of an object dictates the maximum number of MUs that can be accommodated simultaneously Once this capacity is reached, no additional MUs can be transferred Typically, the dimensions of MUs are not considered, except for specific objects such as Track, Line, AngularConverter, and Turntable, which factor in the length of MUs through the attribute 'length'.
MUs attempting to enter a full object will be denied access and added to a blocking list When an object has multiple successors, the transfer request will be processed sequentially to the subsequent objects The MU will then be moved to the next available object.
Create the following Frame Processing times: Mach1 and Mach4 every 2:30 min, Mach2 und Mach3: 5 min, the source produces one part every 2:30 min
Block Mach2 (check the box Failed, then click Apply) and look, what happens!
You can change the behavior of the distribution of Mach1 on the tab E XIT
S TRATEGY It provides a number of strategies:
Blocking refers to the process where, if the B LOCKING option is selected and a transfer request cannot be fulfilled, the request will be added to the object's blocking list This request will remain pending until the next available object is ready to receive MUs again Conversely, if blocking is not selected, the MU will be transferred to another available successor.
The objects provide the following types of blocking:
When an object fails, it cannot receive MUs, and any completed MUs will continue to be processed During the failure period, both setup and processing times are paused, allowing you to simulate the impact of a machine failure Additionally, failed objects are easily identifiable as they are marked with a red LED.
The device can be paused, indicated by a blue LED, which interrupts processing or setup time and prevents the reception of MUs, while completed MUs continue to be processed Similarly, the Unplanned feature allows for the simulation of times outside regular working hours To resolve any blockages, the reset button on the Eventcontroller can be used, but pauses must be manually cleared by deselecting the Pause option.
Entrance locked: It is not possible to move MUs; the MUs will be entered in the blocking list After the end of the failure, the MUs will be processed
For a highly realistic simulation, it's essential to incorporate events that disrupt the typical flow of materials These disruptions can be strategically placed or randomized, considering factors such as retooling times, maintenance periods, accidents, and machine failures.
There are two possiblities to model failures:
• Using the Mean Time To Repair (MTTR) and the availability
The dialogs of the material flow objects provide the tab F AILURES : Clear the op- tion A VAILABILITY
A machine needs maintenance every 1,000 operating-hours with duration of 3 hours It requires these settings:
Active: The check box turns all kinds of failure events on or off
Start: With “Start”, you can define the beginning of the failure You can also se- lect a statistical distribution
The Source
The source generates mobile objects (MUs) based on your specifications, capable of producing various types of parts either sequentially or in a mixed arrangement To define batches and establish timing, the program offers multiple methods As an active entity, the source endeavors to transfer the produced MUs to the connected successor.
Mode: Mode determines how to proceed with MUs, which cannot be transferred
Blocking prevents the generation of new MUs, ensuring that existing ones are saved In contrast, selecting "Non-blocking" allows the Source to create an additional MU at the specified time of creation.
The production schedule is defined by three key parameters: start time, stop time, and interval Initially, parts are produced at the designated start time, followed by additional parts produced at specified intervals until the production concludes at the stop time Users have the option to input statistical distributions for each of these three values.
Number Adjustable: Number and interval (a certain number at specified interval) determine the production dates
The settings above will produce 10 parts after 10 minutes simulation time only once
The delivery table outlines the production times and types of parts to be manufactured, with each row representing a specific production order To implement this, it is essential to incorporate a table into your Frame.
Create the following Frame You can change the length of the line by draging the corner points at the right-hand side
To duplicate the object Entity three times in the class library, rename the duplicates to part1, part2, and part3 The source will generate five parts of type part1 after 2 minutes, two parts of type part2 after 10 minutes, and four parts of type part3 after 15 minutes In the dialog of the source, select the TIME OF CREATION – DELIVERY TABLE, then click the button with three points at the bottom of the window Finally, choose the appropriate table from the subsequent dialog.
To finalize the process, click OK to enter the table name into the source dialog Next, double-click the table in the Frame to open it and proceed to input the necessary information.
The source now produces parts as specified in the table After the last part has passed the drain, the simulation will be finished
MU-Selection: The following settings are available:
Constant: Only one MU-type will be produced Select the path to the respective
MU in the dialog (Object Explorer)
In Sequence Cyclical production, items are manufactured based on the specified order in a delivery table To initiate this process, simply input the table's path into the designated text box If the "GENERATE AS BATCH" option is selected, the entire quantity will be produced simultaneously Once the sequence is fully completed, the production cycle will restart.
Sequence: See Sequene cyclical; after the end of processing the entries no repeti- tion will take place
Random: The production is based on a random table
To create the required content, produce Part1, Part2, and Part3 with a distribution ratio of 30% for Part1, 60% for Part2, and 10% for Part3 Begin by establishing these parts within the class library, and customize their appearance by changing the color using the right mouse button and selecting the EDIT ICONS option.
Now select the following settings in the source:
Confirm your changes with Apply or Ok
Open the table by double-clicking it Enter the following data:
Now start the simulation The parts will be produced in a “mixed” order.
The Drain
The Drain serves as an active material flow object that processes and destroys manufacturing units (MUs) at a designated location To optimize efficiency, set the processing time to either zero seconds or the duration required for the subsequent process Additionally, the Drain gathers crucial statistical data, including throughput and the count of destroyed parts, which can be accessed by clicking on the TYPE STATISTICS tab.
The SingleProc
The SingleProc processes one MU at a time, accepting it from its predecessor before transferring it to a successor after completing setup, recovery, and processing While an MU is being handled, any new MUs will be blocked until a successor becomes available This setup allows for the simulation of machines and jobs that manage one part sequentially, ensuring that only one part occupies the workplace or machine at any given moment.
The ParallelProc
The ParallelProc operates similarly to a SingleProc but with multiple locations In the absence of control, a newly arriving MU is assigned to the location that has been vacant the longest When an MU with a different name arrives, the entire object undergoes setup.
After the deburring process, parts undergo a coloring treatment Due to the lengthy processing time associated with deburring, multiple workstations are utilized Source1 efficiently delivers one part every two seconds, and the deburring station is equipped with five processing locations to enhance productivity.
10 seconds per place and part Coloring takes 2 seconds The Frame with Sin- gleProcs could look as follows:
To simplify the simulation, you can use a station with five processing stations (ParallelProc)
The processing stations of a parallel station are arranged in a matrix (tab A TTRI -
Every “row” takes on x places (x-dimension) in y “columns” (y-dimension) The number of places results from the multiplication of x-Dimension and y-Dimension
If you want to reduce the dimension of the ParallelProc, then it may not find MUs on the places (otherwise, you get an error)
Normally, each place of a ParallelProc has the same processing time Neverthe- less, it is possible to define different times for each place
1 Define the number of places (x-dimension, y-dimension)
2 Insert a table in the Frame (folder InformationFlow)
Select in the tab “T IME ” in the list “P ROCESSING TIME ”: List (place)
3 Enter the name of the table into the field
4 Enter the processing times for the individual stations into the table (analo- gous to the position of the places in x- and y-dimension)
In Plant Simulation versions up to 8.2, users were required to manually format tables by allocating a number of columns based on the x-dimension of the ParallelProc, specifically for the time data type However, starting from version 9, the software automatically formats tables according to the dimensions of the ParallelProc, adjusting to the specified x columns and y rows when there is a mismatch in the data type of the table columns Therefore, it is essential to set the x-dimension and y-dimension values for the ParallelProc prior to assigning the table.
Example 13: ParallelProc; Different Processing Times
The production line features four deburring stations, each equipped with distinct technical equipment, resulting in varying processing times Specifically, station 1 and station 4 each take one minute, station 2 requires two minutes, and station 3 has a processing time of four minutes.
Settings: Source: interval 20 seconds, Line: length 12 meters, speed 0.08 m/s; Drain: 0 seconds processing time To define the processing times, follow these steps: Set the dimension of the ParallelProc
To begin, choose “LIST (PLACE)” from the processing time options Next, input the table name “times” into the text box, or alternatively, you can drag the table directly from the Frame into the designated field.
Confirm your changes by clicking OK
Open the table and enter the times.
The AssemblyStation
The AssemblyStation enhances assembly simulations by adding mounting components to main parts or by disassembling individual components to create an assembled part This tool streamlines the simulation of assembly operations, making the process more efficient and effective.
Before applying color to a component, it must first be attached to a support frame, as coloring cannot be completed without this essential structure The assembly process for the frame takes just 2 minutes, followed by another 2 minutes required for the coloring itself The primary element involved is the support frame (Container), while the component being mounted is referred to as the part (Entity).
To begin the assembly process, first connect the source_support_frame to the source_part Ensure that you persuade the support_source_frame to generate support_frames, with the default setting being Entity To proceed, double-click on the source and choose the MU Container option.
The object AssemblyStation has the following attributes:
Assembly table with: Select the parts, which you want to assemble, according to different points of view:
If you do not select an assembly list, one of each part will be assembled
To select predecessors, open the predecessor table by clicking the designated button Input the predecessor number and the quantity of assembled parts into the list Note that if you choose the assembly mode "Attach MUs," the main part should not be included in the list For instance, if one part of predecessor 2 is to be assembled, select the assembly table with "Predecessor" and then click "Open" to enter the required information.
If you select MU-types, enter the name of the MU-class and the respective number of parts into a table
You can show the numbers of the predecessors Select V IEW –O PTIONS –S HOW
P REDECESSORS in the Frame window
The number of the predecessor will be displayed on the connector
The main MU from the predecessor is determined by identifying which workstation supplies the primary component, based on the order of established connections It's essential to ensure that the main MU can accept parts, such as a container, if you choose the option to attach MUs.
In assembly mode, users can either load components onto a primary part, which must have adequate capacity to function as a container, or dismantle all existing parts to create a new assembly part.
Exiting MU: The main part (with the loaded components) or a new part can be moved from the assembly If you create a new part, you have to select it.
The Buffer
Plant Simulation distinguishes between two types of buffers:
In the processing time within the PlaceBuffer, MUs pass sequentially without the ability to overtake one another Movement is only permitted once an MU reaches the highest numbered position, allowing the last MU to be passed on and enabling all preceding MUs to advance by one place The processing time is defined for the entire buffer, such as a dwell time of 20 minutes, rather than for individual positions The attribute ACCUMULATING indicates whether the buffer exit is blocked due to an occupied successor, determining if subsequent MUs can move up (Accumulating = TRUE) or must remain stationary.
The buffer does not have a place-oriented structure After the processing time is over, you can remove the MU again You can determine a mode for unloading:
• Buffer type Queue: First in First out
• Buffer type Stack: Last in First out
Capacity: number of places in the Buffer; enter -1 for an infinite capacity
Times: Processing time (dwell time of a part in the buffer), recovery time, cycle time
The DismantleStation
The DismantleStation dismantles added parts from the main part or creates new parts It facilitates modeling dismantling operations
A machine efficiently handles a palette containing 12 parts, unloading them at a designated position using an internal loader Once the unloading process is complete, the parts are stored on a separate palette at a second location The palettes are transported to and from the machine via a three-meter-long conveyor system, ensuring smooth operations A DismantleStation facilitates the unloading of parts onto the machine while transferring empty palettes to the area for finished parts Additionally, an AssemblyStation is utilized for loading parts onto the palette, which is defined in the class library as a container with a capacity of 12, featuring dimensions of 3 meters in length and 4 meters in width, each measuring 0.5 meters.
To configure the simulation, set the Source_part to generate entities at an interval of 1:05 and the Source_pallet for containers at 12:00 The AssemblyStation has a processing time of 0, with the main part being the pallet and an assembly mode of attaching MUs Ensure twelve parts from predecessor 2 connect first with the Source_pallet, followed by the Source_part and the assembly station Both line1 and line2 should be 3 meters long with a speed of 1 m/s The machine has a processing time of 1 minute and requires the main part to be loaded from unloading, which takes 4 seconds To initiate the simulation, an empty pallet must be prepared at the loading station, ideally created on line1 The DismantleStation will fetch the empty pallet positioned next to the loading station To ensure the assembly station receives the pallet at the correct connector, create a method object named INIT within the folder InformationFlow This method is triggered by clicking INIT in the Eventcontroller If you encounter a grayed-out font in the editor preventing code entry, deactivate inheritance by clicking the appropriate button.
To incorporate your palette class into the editor, simply drag it from the class library and place it between the 'do' and 'end' keywords This action will automatically input the absolute path of the class into the editor, allowing you to complete the source code effectively.
MUs.pallet.create(line1); end;
Then close the window and save your changes
Select how the DismantleStation distributes MUs to its successors from the drop- down list sequence
When using the Dismantle mode in the drop-down menu, selecting "Create MUs" will prompt the DismantleStation to generate a new MU for each successor and transfer it accordingly Alternatively, choosing "MUs detach" will lead the DismantleStation to distribute the MUs evenly among the successors It is important to remember that the DismantleStation will also transfer the primary portion to the successor identified in the "Main successor to MU" field.
For the following three menu commands, Plant Simulation requires entries into the dismantle list
MUs exiting independent of other MUs: Each MU is trying to move as soon as possible to the given successor
Main MU after other MUs: The mounted parts exit the DismantleStation first followed by the main part
In simulations involving the unloading of parts, it is crucial to ensure that the empty palette exits the dismantle station only after all individual components have been successfully delivered to the next stage, rather than prematurely This scenario highlights the importance of timing in the delivery process to maintain efficiency.
Example 16: Dismantle Station, Exit Sequence
Palettes have to be loaded and unloaded The parts are weighed after unloading and then destroyed by a drain Weighing takes 5 seconds Create the following Frame:
In this setup, the source generates one part every four seconds (Entity) Begin by connecting L2 to the source, followed by linking the source to the assembly station Configure the container capacity in the class library to hold 10 parts and ensure the assembly station is set to load 10 parts onto the main part from L2 Notably, assembly and dismantling processes have a processing time of zero seconds Both L1 and L2 operate at a speed of 1 m/s Next, establish a connection from the station unload to L2, and subsequently connect to the weighing station The initialization method should create two containers on line L2, completing the init method accordingly.
Select the following settings in the DismantleStation (unload):
To ensure proper operation, the palette should exit the dismantling station only after all individual parts have been processed This adjustment aligns with realistic functioning, necessitating a change in the dismantling station settings to achieve the correct sequence of operations.
In the dismantle table you have to define how many of which parts are to be trans- ferred to any successor
Now all parts will be unloaded first, before the main part will be transferred
Select how Plant Simulation deals with mounted parts
In Plant Simulation, the process of detaching MUs involves unloading mounted parts from the main component and transferring them to successors listed on the dismantle table Additionally, the DismantleStation is responsible for creating new parts, enhancing the overall efficiency of the dismantling process.
This successor number may not be contained in the dismantle table (error message)
Here, you determine how Plant Simulation handles the main parts
The cycle object enables the synchronization of multiple objects, ensuring that material units (MUs) are only passed on when all stations in a balanced line are completed, neither failed nor paused, and the subsequent station is prepared to receive MUs It is essential to connect the stations within the balanced line, and the first and last objects of this line must be entered into the cycle object to function correctly An example illustrates the operational mechanics of the cycle object effectively.
Three machines will be synchronized Create the following Frame:
In a simulation with a source interval of 2 minutes and processing times of 2 minutes for stations M1 and M2, and 1 minute for station M3, an 8-meter line operates within an 8-minute timeframe After running the simulation, it is observed that station M3 completes its tasks more quickly than the other stations, resulting in temporary idleness To analyze the cycle, double-click the cycle object, activate it, and input the first and last stations for further evaluation.
The part on the object M3 remains on the station until all other stations are finished too.
The Store
The store features an unlimited number of storage locations organized in a matrix, allowing for the reception of material units (MUs) whenever a space is available In the absence of a control method, MUs are placed in any free location within the matrix Unlike active material flow objects, the store does not require setup or processing time, nor does it implement exit controls MUs remain stored until they are removed through a designated control process.
To effectively reduce the dimensions of a store, it's essential to eliminate any empty spaces However, if there are MUs occupying the areas you intend to remove, you'll need to either delete these MUs or relocate them to other available spaces within the newly defined smaller dimension.
If the store is failed, it cannot receive MUs, but it can move MUs out of it.
The Line
The Line is a dynamic material flow system that transports material units (MUs) at a constant speed along a designated route, similar to an accumulating conveyor such as a gravity-roller or chain conveyor MUs are unable to overtake one another on this line By default, the Line distributes MUs to its successors unless an output control is activated or an alternative behavior is selected If an MU cannot exit due to the successors being occupied, it will remain on the Line until it can proceed.
“Accumulating” determines whether the MUs maintain their distance or move up
Length: Length of the line (the maximum number of MUs on the line is calculated by dividing the length of the line by the length of the MUs)
Speed: The line has the same speed along the entire length You can set the speed to zero to stop the line
Time: Enter the time, a MU needed for transportation from the beginning until the end of the line (the speed is calculated thereof)
Capacity: The capacity determines the maximum number of MUs, which can be positioned entirely or in part on the Line (-1 for an unlimited capacity)
Accumulating: See the following example
Create the following Frame: Source: each 6 seconds one part, Line: length 18 m,
1 m/s speed, Drain: processing time 0 seconds
The default setting of the Line is A CCUMULATING (a checkmark in the box)
To initiate the simulation, check the "FAIL" box for the drain and save your changes As the MUs begin to move upward, the line functions as a buffer, allowing the simulation to continue until the entire line is filled with MUs.
Remove the MUs from the simulation model ( ), then clear the checkbox
A CCUMULATING in the dialog of the Line and confirm your changes by clicking
OK Now restart the simulation The parts on the line keep their distance With this setting, the line cannot be used as a buffer
The behavior of a conveyor line is determined by its technical design; typically, conveyor belts and roller conveyors are designed for accumulation, while chain conveyors are usually non-accumulating.
Backwards: The line can move forward or backward If it should move forward, the checkbox B ACKWARDS is cleared
Work stations are arranged around a conveyor belt
One part arrives every 5 seconds, the processing time of the APs is 10 seconds, and the last job requires 5 seconds The speed of the conveyor is 1 m/s
To enhance the speed of a conveyor belt, it's essential to adjust the speed of each line segment, similar to how workstations operate A straightforward solution involves defining an object in the class library and modifying its properties By dragging this object into the Frame, you create child objects through derivation The primary object is referred to as the base object or base class, while the derived objects are known as child objects These child objects inherit all properties and methods from their base class, establishing a link through inheritance Consequently, any changes made to the base object's properties in the class library will also reflect in the child objects, provided inheritance is enabled.
Plant Simulation enables users to design complex line courses that accurately reflect real layouts Lines can be extended by dragging when inserted into a Frame, and their shapes can be modified using the context menu command "APPEND POINTS." The software calculates line length based on a ratio of meters to pixels, with the default grid spacing set at 20 x 20 pixels Users can customize the grid spacing in the Plant Simulation window under TOOLS – PREFERENCES – MODELING.
You can adjust the ratio of grid and dimensions for each Frame individually Se- lect T OOLS –S CALING FACTOR … in the Frame window
Enter the required size ratio into the following dialog:
Define the visual appearance of the curved object on the tab CURVE
Clear the checkbox A CTIVE if you want to use a separate icon for the line (e.g., from an icon library) If you append points (right mouse button – A PPEND
P OINTS ) and hold Ctrl + Shift, you can draw arc segments:
AngularConverter and Turntable
AngularConverter and Turntable facilitate the modeling of curves or junctions on lines Often, independent technical solutions are necessary, each demanding a significant investment of time for implementation Plant Simulation provides three distinct options to address these needs.
1 Append a corner point to the line, and extend the line in a 90-degree angle Without SimTalk you cannot implement a special (higher) time for the transfer
2 You can use the object AngularConverter You can simulate processes in which the part is transported to a certain point, stops, and then accelerates again at an angle of 90 degrees Retarding and acceleration times will be considered as time (e.g., 4 seconds) The entity will not be rotated during this process
3 If the part is to be rotated while transferring (via a robot or a turntable, for example), you can use the object TurnTable
For comparing the various solutions, here is a small example: Duplicate an entity, and rename it to partarrow Change the icon so that it matches the following picture:
To initiate the simulation, configure the source to generate the MU partarrow at one-minute intervals while keeping the default settings for all other objects Begin the simulation and monitor the movements of the part closely.
You can select different lengths and the associated speeds:
The M OVING T IME (Tab Times) is the time which the converter needs to switch from one direction to the other
The Turntable rotates a part by 90 degrees before moving it towards the connector By selecting "GO TO DEFAULT POSITION" and entering an angle, the turntable will return to its original position after transferring the part If this option is not chosen, the turntable will only rotate when the next part is prepared for movement.
The PickAndPlace Robot
Starting from version 9, Plant Simulation introduces the PickAndPlace object, enabling users to effortlessly model robots that can pick up parts from one location, rotate them, and place them at another The software automatically calculates the required rotation angles based on the positions of the subsequent parts, or users have the option to manually input these angles into a table.
The source generates one part every minute, while all other components operate at their default settings Upon initiating the simulation, the pick and place robot efficiently moves parts from the source to the drain.
By connecting the pick and place robot to other objects using Connectors, Plant Simulation creates a table that lists the positions and corresponding objects This table can be accessed in the A TTRIBUTES tab by clicking the A NGLES T ABLE button.
The position of 0° corresponds to the so-called 3 o'clock position The angles are specified clockwise
The TIMES table regulates the duration of movement between various rotation positions, with a default setting of one second To modify these time settings, simply click the TIMES TABLE button located in the ATTRIBUTES tab.
The default angle designates a waiting position, which the PickAndPlace robot takes when you select the respecitve option on the tab A TTRIBUTES
Enter the duration of the rotations like this:
The PickAndPlace robot operates by remaining at the unloading position until a new part is ready at the loading position Once the part is available, the robot turns to the loading position to retrieve it After successfully loading the part, selecting "GO TO STANDARD POSITION" prompts the robot to move to its designated position.
A Pick-and-place robot is designed to sort mixed parts, specifically red, green, and blue components Its primary function is to categorize these parts based on a user-defined attribute called “col.” In the class library, three parts—part1, part2, and part3—are created, each assigned the attribute “col” with the string value set to “red.” This setup enables the robot to effectively distribute the parts according to their color attributes.
“green”, and “blue” Color the parts accordingly Create the following Frame:
In a dynamic setting, the source generates part1, part2, and part3 at equal intervals of 2 seconds To optimize the process, connect the PickAndPlace object sequentially with Line_red, Line_green, and finally Line_blue The distribution of parts by color can be customized through the exit strategy of the PickAndPlace robot.
MU A TTRIBUTE on the Tab E XIT S TRATEGY Then click Apply The dialog shows additional dialog items:
To define a user-defined attribute, select the ATTRIBUTE TYPE as String and click OPEN LIST Here, you can input the attributes, their corresponding values, and the successors that need to be transferred.
Finally, the robot should place the parts assorted by color to the lines.
The Track
The track serves as a passive model for transport routes, with only the transporter actively moving along it Dwell time is calculated based on the track's length and the transporter's speed, while multiple transporters must adhere to a first-in, first-out (FIFO) order, preventing them from passing each other When a faster transporter approaches a slower one, it automatically reduces its speed to avoid collision The track's maximum capacity is determined by its length and the size of the transporters, allowing for a maximum of 10 transporters if each is 1 meter long and the track is 10 meters long, unless a different capacity limit is specified.
Plant Simulation determines the length of the track if you activated the check- boxes A CTIVE and T RANSFER L ENGTH on the tab curve
Backward/Forward destination list: A track can connect several workstations You can specify which stations have to be covered on the route (forward and back- ward)
To initiate the production of transporters, double-click on the source to open it Set the production interval to 1 minute and select MUs.Transporter as the manufacturing unit.
Upon initiating the simulation, a new transporter is generated every minute by the source and placed onto the track The transporter travels at the specified speed along the track, ultimately reaching the drain, where it is destroyed.
Clear the option R OTATE MU S on the tab Curve, and test what happens:
The R OTATE MU S option animates the transporter, ensuring it consistently faces forward in the direction of movement, causing the transporter icon to rotate To see this in action, experiment with a curve by accessing the Line: Context menu, attaching corner points, and inserting the curve using CTRL + SHIFT.
The Sorter
The sorter efficiently processes multiple MUs by rearranging their removal order based on predefined priorities MUs with the highest priority are transferred first, regardless of their entry time, ensuring an optimized workflow.
The following selection criteria are offered:
The content of the sorter is sorted, if either
• a MU enters the sorter or
• the content of the sorter is accessed
When several MUs have the same value within a sort criterion, then the order of these MUs remains undefined You can use the sorter for simulating queue logics
Effective queue management is essential for optimizing production efficiency, with several key rules guiding the process One crucial factor is the throughput time of an order, which measures the duration from production entry to customer delivery Special orders from major customers are prioritized to ensure faster delivery, often resulting in longer wait times for other orders Additionally, orders that incur the least retooling costs are typically processed first The most straightforward approach to queue management adheres to the first come, first served principle, ensuring a fair and organized workflow.
Capacity: Enter the number of stations in your sorter “-1” stands for an unlimited capacity You can access individual stations by their index ([…])
Order: The sort order determines whether the MUs are sorted in ascending or in descending order (Priority 1 very high; capital commitment, …)
Sorting MUs occurs at specific times based on the selected option If "ONE ENTRY" is chosen, new MUs will be integrated into the current order without updating the sequence, even if the sort criteria values change Conversely, selecting "ON ACCESS" allows for dynamic sorting, where MUs are reordered with each new entry.
MU or before moving it, the MUs will be reordered (taking into account the cur- rent values of the sort criterion)
Sort criterion: Sort criteria can be:
• Occupation Time: The MUs will be sorted according to their occupation time in the sorter (descending: first in-first out or ascending: first in-last out)
• MU-Property: You can enter order attributes and statistical values (statisti- cal values only if statistics for the MUs is active)
In this simulation, a process with 50% availability will be implemented, featuring a large buffer positioned in front of it The processing of parts will occur after blockages, prioritized by their urgency The goal is to ensure that higher-priority parts experience significantly lower throughput times compared to those with lower priority To organize the project, create a folder named "color_sorting" within the "models" directory, and then establish a Frame inside this folder by right-clicking the folder icon and selecting "NEW" followed by "FRAME." Finally, duplicate all necessary objects into this folder to complete the setup.
1 Insert three entities, and name them red, green, and blue Assign them different colors (recommended: 5x5 pixels, colors according to the names) to better distin- guish them Open the source, and set the following values: Interval: constant 2 seconds, MU-Selection: random, table: allocation, enter the following values into the table allocation (Note: You can insert the addresses using drag and drop; Drag the relevant parts from the class library to the table, and drop them there):
SingleProc: Processing time: 1 second, Availability: 50%, 30 minutes MTTR (based on the simulation time), Line: length 8 meters, 1 m/s speed, accumulating, Drain: 0 seconds processing time
Create a user-defined attribute for each part (Double-click the part in the class li- brary, tab C USTOM ATTRIBUTES ):
Set the following values for the attribute “importance”: red: 1, blue: 2, green: 3 The parts in the sorter should be sorted according to the attribute “importance”
In the sorter, you have to select the criteria by which it sorts (default on entrance of a new part into the sorter)
To initiate the sorting process, click "Start Sorting." The items will be organized in ascending order based on their importance, with the least significant elements moving to the forefront The sorting criterion is determined by the customer's attribute related to importance.
To analyze the simulation results, run the simulation for a period In the event of a failure, observe the series of red parts exiting the SingleProc, which will appear in a mixed order as they enter the sorter For detailed insights, access the type-specific statistics of the drain by clicking on the "DETAILED STATISTICS TABLE" under the "TYPE SPECIFIC STATISTICS" tab.
The value LT_Mean shows the average throughput time of the parts The part red has a much lower throughput time than the part green:
The FlowControl
FlowControl does not directly process MUs; instead, it acts as an intermediary between multiple objects, regulating the flow behavior among them Additionally, you have the option to combine multiple FlowControl objects for enhanced functionality.
When evaluating scrap rates in a workplace, it's essential to understand that scrap indicates a deviation in the material flow, such as when quality control identifies and sorts out defective parts In a simulation, these defective parts are categorized using a property labeled "io," which can be either true or false, allowing for effective branching of the material flow based on these values.
To create a quality assurance frame, set a processing time of 1 minute, a line length of 3 meters, and a speed of 1 m/s The sequence of connector insertion affects the number of successors; first, connect FlowControl to line_io, then FlowControl to line_nio Duplicate an entity and name it "part," then create a user-defined attribute labeled "io" with a boolean data type Randomly assign 10% of the parts the value "false" for the "io" attribute, while the remaining parts will be assigned "true." Use the source for allocation by selecting the MU-SELECTION – RANDOM option in the source dialog and choose TableFile for the allocation process.
Open the TableFile by double-clicking it Enter the following values into the table:
To create a table in Plant Simulation, enter the same part twice and input a name in the ATTRIBUTES column Press the F2 key in the ATTRIBUTES field to open a new window, where you can enter the attribute name (e.g., "io") and its corresponding value (true/false) in the appropriate boolean data type field.
To evaluate the attribute io in the flow control, proceed with the second row for the boolean false part Then, navigate to the Exit Strategy tab and select the Method option.
To access the respective part within the specified method, use the @ symbol; to move the successor, an integer must be returned (for example, either 1 or 2) Enter the provided source code into the method.
(r : integer) : integer is do if @.io=true then return 1; else return 2; end; end;
Run the simulation and check the results using the type-specific statistics of the drain
The EXIT STRATEGY tab allows you to define the exit behavior of the FlowControl When set to BLOCKING, the FlowControl will pause and wait until the successor is able to receive parts again if it is currently unable to do so.
Here is a short selection of the strategies:
Flow control prioritizes passing the MU to successor number 1 If successor 1 is consistently available, all MUs will be directed to it The MU will only be forwarded to the next successor if successor 1 is unavailable due to faults or being occupied.
• C YCLIC : The FlowControl tries to move the MU based on the recent pass- ing on the next object (in the list of successors)
• S ELECTION : The FlowControl tries to move the MUs onto the successor that meets a certain property
To distribute the MUs effectively, specify a method that returns the successor's number Access the MU to be transferred using the @ symbol If the MU cannot be moved to the designated successor, the method will be invoked again to attempt the transfer.
MUs must be organized by their names, with three components—part1, part2, and part3—stored together in a single location known as buffer1 Subsequently, these distinct parts will be processed on separate machines.
The system features a buffer with a capacity of 100 parts and a processing time of 2 minutes for Mach1 Each source, including Source1 (part1), Source2 (part2), and Source3 (part3), operates at an interval of 6 minutes Mach1, Mach2, and Mach3 each require 6 minutes for processing Failures are not taken into account To implement the exit strategy, select "Method" in the flow control dialog and choose the appropriate method in your Frame Use "@" to access the current MU and specify the successor's number The provided source code serves as an example for implementation.
(r : integer) : integer is do if @.name="part1" then return 1; elseif @.name="part2" then return 2; elseif @.name="part3" then return 3; end; end;
Percentage: You can select a percentage distribution The basis of this is a distri- bution table In this table you enter the percentage for each successor
Random: You can define a distribution function for the transfer The distribution function is used to determine the successor
Cyclic sequence: If you select Cyclic sequence, then the MUs will be passed in a defined sequence to the successors The order is entered in the corresponding table
To all Successors: This distribution creates duplicates of MUs Any successor will receive a duplicate (always blocking)
Assignment: There is only one successor You can set a property of the MU using a method …
MU Attribute: Here is the successor chosen by the value of an attribute of the MUs Tab Entrance Strategy
Under this tab you set the reunification strategy of the FlowControl (several pre- decessors)
FlowControl enables the modeling of sequential processes, where components from various sources are utilized in a specific order for production and assembly For instance, in a scenario involving three distinct sources, parts must be arranged sequentially—two from Source_r, one from Source_g, and two from Source_b—before being transported to the assembly station At this station, five parts are placed on each palette, ensuring an organized workflow.
In this setup, three entities—red, blue, and green—are represented as 5x5 pixel segments The red entity is produced every 4 seconds by Source_r, while Source_b also generates blue parts every 4 seconds, and Source_g produces green parts every 8 seconds Each part requires 10 seconds to travel through Lines 1, 2, and 3, and Line 4 has a travel time of 20 seconds Additionally, Source_pal creates a container with a capacity of 5 parts every 8 seconds, and the assembly station is configured to load 5 parts from Line 4 into the container, taking 8 seconds for assembly To manage the flow effectively, select the Cyclic Sequence strategy under the Entrance Strategy tab in the flow control dialog.
To begin, clear the inheritance by clicking the button next to "OPEN LIST" (the green button) Then, proceed by clicking "OPEN LIST" and input the sequence of "predecessors" into the provided list For instance, the correct order in this example is 1-1-2-3-3.
So that the sequence will remain intact even if a part is temporarily not available, select B LOCKING