MINISTRY OF EDUCATION AND TRAINING HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION GRADUATION THESIS AUTOMATION AND CONTROL ENGINEERING TECHNOLOGY CONTROL AND MONITORING THE AUT
OVERVIEW
Introduction
Vietnam is an agricultural country, and many of its high-yield agricultural products-like coffee, rice, beans, and others - are exported Therefore, quantification is becoming more and more in demand by businesses For this method, high accuracy and large output are becoming increasingly important There is considerable usage of the quantitative weighing system
A system for product weighing and packing has been constructed in the packaging workshop In such a workshop, there will be several weighing systems, and two or three workers will be assigned to each system to ensure proper and secure operation There are various processes involved in the weighing and packing process, such as placing the materials first into distinct tanks on each weighing machine, then packing the small bags once the weight is appropriate
To quantitatively weigh materials for the immediate production of items on a conveyor system, a device known as a "weighing scale" is utilized The adoption of a quantitative weighing scale will improve the production line since it will allow the factory's production system to function continuously and ensure the standard volume of raw materials for the finished product By helping product quality standards to meet the highest levels, product value is raised
Through a mechanical component on the load cell, the material enters the weighing scale There, it passes through a force sensor, which generates an electrical signal and transmits it to the central controller
The central controller sends signals to the actuators to reduce the material flow or to stop the feed entirely after computing and comparing against the predetermined threshold
There are many different subcategories of packaging machines Machines are typically categorized by their level of automation, their intended use, and the types of packaged items they produce
• Sort by type of packaged product
Patient safety is the foremost necessity for the pharmaceutical sector The medicine cannot be significantly impacted by the packing Pharmaceutical packaging must also adhere to regulations so that it is possible to tell real products from fakes, track their origin, and recall them immediately
Figure 1 VINACOMM 's pesticide packaging machine
Figure 2 JIMEI VIETNAM's 3in1 carbonated soft drink filling machine
We will select the best packaging method given the variety of packaging options available and the cost and kind of goods to be packaged
For this topic, we chose to weigh the items for this issue using a loadcell and pack them using heat sealing Since rice is made up of small, many grains, it must be weighed and packaged in a certain amount based on the demands of the consumer Plastic bags are used to package goods, make sealing easier, and save expenses
The quantitative weighing system has many uses and advantages, therefore I decided to focus my research on "Control and monitoring the automatic rice weighing and packaging system"
Objectives
Control and monitor the automatic rice bagging weighing system in accordance with the following specifications:
− Dimensions: (Length x Width x Height) 80 x 60 x 110 (cm)
− Weight of 1 bag: from 100 gram to 600 gram Depends on weight rating setting Because the system is small and simple, it can only weigh and pack small volumes of rice, less than 600 grams Finished product error: 5%
− Materials that can be weighed: rice
− Material of rice bag: nylon
− Size of 1 bag: (Width x Length) 17 x 27 cm, no handle, size 1kg
− Count the number of completed
− Build Weintek HMI interface to help users easily monitor and operate.
Main contents
The project is divided into 6 chapters with the following main contents:
This section is an overall view of the whole project It introduces the objectives and limitations of the topic
This section covers the ground theories and working methods that are used in the system
This section includes all the hardware devices, components and their crucial function to the rice weighing and packaging system
This section introduces the SIEMENS TIA software and Weintek HMI which were used for programming and designing the UI for the project
This section shows how the experiments were conducted In addition, it indicates the final hardware and software results, and the remaining errors of the system
This section lists all the achievements and drawbacks of the automatic rice weighing and packaging system Therefore, future improvements for the project were proposed
Limitations of the topic
Control and monitoring of the automatic weighing and packaging rice system is a long- researched and developed issue There are various systems in factories nowadays that are ideal for both quality and aesthetics However, within a study subject, given knowledge, time, and money constraints, the following research limits apply:
• Must manually insert the bags because there is no automatic bag feeding mechanism currently available
• The device merely weighs and packs the product; it does not identify product errors.
The applicable ability of this project
Because of the growing need for weighing and packing, the project is critical to manufacturing With the purposes of:
• Automate the line production process in the manufacturing industry More precisely, a method of packing and weighing rice
• Improved ability to control online errors
• A smaller worker force, less boredom at work, better working conditions, access to scientific and technical developments, and employment in a more civilized environment brighten and decrease labor costs
• Measuring the little errors that can occur in the weight of each product allows for a more precise determination of whether the weight of each final item is slightly wrong, missing, or excessive in comparison to the set requirements
• Simplifies administration and control by potentially reducing the number of workers while changing their working condition
THEORETICAL PRINCIPLE
Product weighing theory
Electronic scales utilize load cells, which employ strain gauges in a Wheatstone bridge configuration The deformation caused by load creates an electrical output These transducers provide precise weight measurements, inaccessible through other technologies due to commercial limitations Accurate results rely heavily on proper system calibration, transforming weight into electrical outputs.
Heat sealer theory
Plastic beads are used to seal the intersections of interlocking closures and side edges of plastic containers This bead seal barrier protects the joint that holds the fastener from liquid infiltration and contamination by microorganisms The process of creating this seal involves forcing plastic into and over the joint using specific techniques and equipment.
In order to cut and seal plastic film that is transported between the two machine parts in a horizontal route, a plastic bag manufacturing machine with vertically aligned upper and lower machine sections that move toward and away from one another has three key features:
The first characteristic is a streamlined holding and feeding system for each machine component that feeds Teflon sheets that are regularly worn without requiring users to manipulate countless screws or other machinery
The second element is a cutter/sealer that continually cuts and seals both films to create plastic bags as they move through the machine on a pre-formed tubular or split plastic film
The third characteristic is the heating and sealing bars of the top and lower parts of the machine include mechanisms to prevent and correct for buckling in their two planes [4][5]
Building a model about rice weighing and packing system
To initiate the automatic rice weighing and packaging process, the rice tank is first loaded with rice Operators then input the desired weight on the HMI screen, which controls and monitors the system Subsequently, the loadcell measures and weighs the predetermined quantity of rice from the tank, transferring it to the hopper Upon completion of the weighing process, the discharge cylinder closes and the hopper lid opens to release the rice into the packaging unit.
During the packaging process, the plastic bag is opened and inserted into the funnel mouth, allowing rice to enter the bag The bag's mouth is then sealed using a heating method Subsequently, the packaged product is released onto a support plate and conveyed to the barrel via a conveyor belt To ensure quality control, the final product passes through a sensor that sends weight and count data to the PLC for analysis and classification.
- Also, there are 2 mains operation mode: Auto and Manual When pressing the “Auto” mode, the system will run automatically through the predetermined processes to create the complete product after entering the amount of rice to HMI screen and enter the Start button to run the system In the Manual mode, users can control each process by activating cylinders separately or testing the stability of each cylinder or the conveyor belt
- The push buttons and sensors in this project will transmit the signal into the PLC controller for processing before being transmitted into the conveyor and the cylinder respectively
- There is a temperature controller with the thermal sensor to control the temperature of the heat welding knife It will display the temperature into the digital clock Also, users can adjust the temperature in the heater rod by using rheostat in the controller to have the best quality for packaging process
- The idea uses a DC motor instead of an inverter to control the motor’s rotational speed because the transmission is small, and the motor just need to transfer the completed products from the support plate into the barrel So, controlling the speed of the motor is not necessary and useful in this system
- In this system, the conveyor belt will be controlled by two main modes: automatic and manual In manual mode, users can control and run the conveyor by clicking on the HMI screen Also, manual mode can be used for checking the stability of the conveyor belt before running the system On the HMI screen, users can check all the parameters through each process, like the weight of the rice contained in the hopper, the amount of finished plastic bags, and the signal of each piece of equipment by the indicator light on the screen Also, users can give the value of the rice that needs to be weighed on the screen and the suitable temperature to the controller for the heat welding duration
- On the HMI panel, there are some different features like Alarm and Trend In the “Alarm” feature, there is a notice board that will describe the details of each process in the system
It will be shown when users press the “Alarm” button on the main screen The “Trend” display screen shows the pattern or fluctuation of the amount of rice that has to be weighed
GRADUATION THESIS 7 using a loadcell to help monitor the stability of the system and weighing inaccuracy for quick adjustment and processing time
- Users can easily operate the system, monitor operations, and maintain it when a problem arises by creating an interface to control and check the stability of the system on the HMI screen.
The block diagram of the system
Figure 3 Block diagram of the system
- Signal block: This is the place to receive information from devices into the processor This signal devices can be identified as switch, sensor, …
- Power supply: This is the 24V power supply connected to the PLC to activate it
- Control block: The control block contains Input Modules, Program Memory and Output Module This is the central block with the main control function In this system, PLC has been used as a Control Block
- Display block: This is the equipment used to control and monitor each process of the system
- Output block: This output block contains rice weighing scale, sealing and packing the mouth of plastic bags and conveyor running The signal after processing will be sent to the control devices Some control devices can be motors or inverters
Figure 4 Block diagram of the system in specific
- From the diagram block of the system, the 24VDC source is needed to supply for the work of the PLC The control block with the controlling of PLC will control all the main process of the system Firstly, the display block through HMI screen will connect to the control block via Ethernet The HMI screen will support users to follow the process easily
GRADUATION THESIS 9 and follow all the equipment used in each process Secondly, the PLC will receive the signal from buttons, sensors and the transmitter received from loadcell After receiving the signal, the PLC will send it into the electric valve From there, the electric valve will supply gas to cylinders from pneumatic equipment to carry out some main processes such as rice weighing, welding and classify types of products process Finally, PLC will give the signal into the inverter to control the speed of the 3-phase motor to activate the conveyor When the conveyor starts to run, the classify process will be completed and all the finished products will be put into the bin However, in this project, the conveyor is exclusively utilized for the conveyance of completed, packaged goods due to the relatively small installed scale In this project, the conveyor speed does not need to be adjusted, hence an inverter is not required We chose to operate the conveyor with a DC motor rather than an inverter to regulate its rotational speed.
HARDWARE DESIGN
Hardware requirements
The automated rice packaging system operates through four levels to fulfill three key functions: measuring rice, sealing bags, and sorting products The first level discharges the material, while the second level uses load cells for precise weighing The third level utilizes a cylinder for efficient bag sealing, and the fourth level pushes sealed bags onto a conveyor belt, sorts them, and counts them via a sensor These sequential operations ensure efficient and accurate rice packaging.
• Dimensions: (Length x Width x Height) 80 x 60 x 110 (cm)
• Weight of 1 bag: from 100 grams to 600 grams Depends on weight rating setting
• Size of 1 bag: (Width x Length) 17 x 27 cm, no handle, size 1kg
• The sensor returns a fast signal to avoid noise and errors
• Sufficient power supply for the system to operate
• The motor has enough torque to pull the load
• The supply pneumatic is enough for the cylinder to work well and quickly
• Align the loadcell for accurate and sensitive readings
• The pack sealer heats up well, can seal the mouth of the bag, leaving no black marks on the bag.
Design system
System is designed on SOLIDWORKS 2021 software
Figure 5 Symbol of SOLIDWORKS software 2023
SolidWorks is a 3D design application designed for the Windows operating system, first introduced in 1997 It is developed by Dassault Systems SolidWorks Corp, a subsidiary of Dassault Systems, S.A., headquartered in Vélizy, France Presently, SolidWorks boasts a user base exceeding 2 million engineers and designers, spanning over 165,000 companies globally
SolidWorks was established in December 1993 by Hirschtick, a graduate of the renowned Massachusetts Institute of Technology (MIT) Hirschtick utilized the $1 million he
GRADUATION THESIS 11 garnered as a member of the MIT Blackjack Team to kickstart the company Initially headquartered in Waltham, Massachusetts, USA, Hirschtick assembled a team of engineers with the goal of developing user-friendly 3D Computer-Aided Design (CAD) software that was not only affordable but also customizable for Windows desktops The company later relocated to Concord, Massachusetts In 1995, SolidWorks achieved a significant milestone with the release of its first version, SolidWorks 95 Two years later, in 1997, Dassault, renowned for its CATIA software, acquired SolidWorks for $310 million in stock Since then, SolidWorks has continually evolved, enhancing its features, performance, and its ability to address 3D design requirements in the engineering and industrial sectors Notably, SolidWorks has expanded its reach into various industries, including but not limited to pipelines, architecture, interior design, and construction This diversification is attributed to its robust 3D design capabilities and a versatile portfolio of supporting solutions
As of now, SolidWorks offers several versions, including SolidWorks CAD, which focuses on 3D design, eDrawings as a support tool, and DraftSight, a product specializing in 2D Computer-Aided Design (CAD)
Leadership at SolidWorks has seen transitions over the years John McEleney served as the head from 2001 to July 2007, followed by Jeff Ray, who led the company from 2007 to January 2011 The current Chief Executive Officer is Bertrand Sicot
SOLIDWORKS is equipped with a range of features, including the capability to design precise 3D models, assemble parts, export drawings, incorporate machining features, and perform dynamic analysis These functionalities contribute to its widespread use in various industries for comprehensive 3D design needs
Figure 6 Main interface of SOLIDWORKS 2023
In this project, we use SOLIDWORKS version 2023 to design the system
Machine body: is essentially a rack designed for the arrangement of components such as the rice hopper, a filter for controlling the volume of rice, a cylinder, a load cell weight sensor, and a heat-sealing machine for sealing the bag's opening To construct the frame for the system, we employ shaped aluminum with dimensions specified in Figure 7 and 8 The chosen aluminum type, measuring 20x20, is selected for its suitability in assembling the frame This specific type features slots that facilitate the easy installation of equipment, ensuring a well-organized setup for air ducts and electrical wiring, resulting in a neat and tidy arrangement
Figure 7 Shaped aluminum 20x20 length 20cm
Figure 8 Shaped aluminum 20x20 length 110cm
The entire installed system frame is displayed in Figure 9 Four shaped aluminums with a length of 110 cm and fourteen shaped aluminums with a length of 20 cm are used to install the system Dimensions of the frame: (Length x Width x Height) 20 x 20 x 110 (cm)
Figure 10 2D version of machine body
Load cell holder: A U-bar was built to attach the loadcell because if it is mounted directly under the rice quantitative filter, the hopper mouth will close after weighing enough cylinders since the cylinder movement will affect the weight
Rice hopper: The rice hopper, which is made up of six parts, is used to store rice a/ Simulated b/ 2D drawing
Figure 11 Simulated of rice hopper o Piece 1 of rice hopper: Use two pieces 1 to create the rice hopper's front and rear
Figure 12 Simulated piece 1 of rice hopper o Piece 2 of rice hopper: To make the rice hopper's left and right, use two pieces 2 a/ Simulated b/ 2D drawing
Figure 13 Simulated piece 2 of rice hopper o Piece 3 of rice hopper: To build the rice hopper's bottom, use two pieces 3 This part opens and closes the hopper
Figure 14 Simulated piece 3 of rice hopper
Filter hopper the volume of rice: used to store the amount of rice to be weighed a/ Simulated b/ 2D drawing
Figure 15 Simulated filter hopper the volume of rice
Figures 15 illustrate the configuration and dimensions of the rice weighing hopper The design choice for this hopper involves a round shape The rice, contained within the hopper's funnel, represents the quantity slated for weighing The round shape of the hopper facilitates the straightforward transfer of the weighed rice into the bag for subsequent sealing once the necessary weighing process is completed This design enhances the efficiency of the system by providing an easily pourable and seamless transition from weighing to the sealing phase
Discharge hopper foot: composed of aluminum that has been trimmed to size as previously described and utilized to open and close the rice hopper to measure rice One metal plate is sufficient because the funnel's mouth is rounded a/ Simulated b/ 2D drawing
Figure 16 Simulated discharge hopper foot
Rice bag support plate: utilized, following welding, to support the rice bag The completed rice will land on this support plate after it has been sealed, and the cylinder will force it out onto the conveyor belt and into the barrel
Figure 17 Simulated rice bag support plate
Simulate types of Cylinders to assemble for the system a/ Discharge cylinder b/ Finished product push cylinder c/ Bag holding cylinder d/ Bag mouth welding cylinder
3.2.2.3 Other devices a/ Symbolic simulation for loadcell b/ Heating rod c/ Product sensor simulation d/ Conveyor simulation
The equipment is arranged in the electrical cabinet design in a way that facilitates a simpler, quicker, and more convenient installation
Figure 20 Top view electrical cabinet drawing
Figure 21 Front view electrical cabinet drawing
Figure 22 Inside view electrical cabinet drawing
Figure 23 SOLIDWORKS simulated weighing and packing rice system
The mechanism in SOLIDWORDS after it has been fully assembled is shown in Figure
23 With the least amount of error possible, we build and install the system rapidly using SOLIDWORKS drawings
Material
A list of the system’s components was created based on the design
Table 1 List of devices used in the system
Numerical order Device Quantity Price
11 Electric circuit breaker (CB) 1 70.000 VND
Total estimated budget to complete the project is 15.375.000 VND.
Devices used in the project
Figure 24 Power supply 24V 20A, with fan
• Function: Supply power to PLC, Weintek HMI and active load
• Features: Over-current, over-voltage, overload, and short-circuit protection
3.4.2 Programmable Logic Controller 1214C DC/DC/DC
A programmable logic controller is a control device that can be programmed using a programming language to enable the flexible implementation of logic control algorithms The user can program the corresponding events based on each system's requirements The program runs these actions repeatedly and one after the other In order to control actuators, motors, and lights, the programmable controller's CPU will read a program from memory, verify memory areas holding input values, and then carry out the program's instructions This will have an impact on memory areas storing output values
Programmable Logic Controllers (PLCs) offer significant advantages over wired controllers, making them a highly versatile and efficient solution for industrial automation Their wireless nature eliminates the need for extensive wiring, simplifying installation and maintenance They facilitate effortless device expansion, allowing systems to grow and adapt as needed When program modifications are required, PLCs enable quick and convenient updates, reducing downtime Additionally, their modular design eases maintenance and repairs, ensuring minimal disruption to operations PLCs boast high reliability, minimizing unplanned downtime and outages Moreover, their communication capabilities enable seamless integration with other devices, facilitating data sharing and enhancing overall system functionality.
Figure 25 PLC Siemens S7-1200 CPU 1214C DC/DC/DC
• Specifications: PLC Siemens S7-1200 CPU 1214C DC/DC/DC
Product code: CPU 1214C – 6ES7214-1AG40-0XB0
• Connection diagram of the device:
Figure 26 Diagram of PLC Siemens S7-1200 CPU 1214C DC/DC/DC in the system
For this project, the system’s frame is made of mica and aluminum Mica plastic sheet has exceptional qualities such as being a flexible material that can be easily constructed: processing, installation, bending, pressing, assembling, cutting, or shaping; flat, smooth, smooth surface; high strength, good heat resistance, corrosion resistance by chemical substances; these qualities make aluminum a very suitable choice for system frameworks Aluminum is also used for automation and mechanical components, real molds, products, and molds for processing and manufacturing Because it is non-conductive, non-heating, and reasonably priced, it is ideal for usage in square hoppers that hold rice and product plates
A conveyor belt is a tool used to carry goods and commodities quickly, accurately, and efficiently from one place to another Conveyor belt types are made of a wide variety of rich and varied materials
Figure 27 General structure of the conveyor belt
(1) – Traction unit with working elements directly carrying the object
(2) – Tensioner, which creates and holds the necessary tension for the pulling unit
(3) – Driving station, transmitting motion for traction unit
Additionally, a support system that slides the puller and the working elements is under it and consists of rollers, supports, etc
• Systems have distinct large and small scales depending on how sophisticated the product needs are As a result, for the conveyor belt to work with the system, it must also come in various sizes Acknowledging this fact, the project team will develop and build a little version that serves the same purpose as the actual thing—that is, a conveyor belt that moves goods based on their previously achieved sizes
- Weight: highest volume of rice: 1kg
- Dimensions: (Length x Width x Height) 44 x 10 x 40 cm
- Material of the frame made of good anti-static aluminum profile
- Material of conveyor belt: bearing rubber band
- Maximum mass that the conveyor belt can load: 4kg
To control the speed of the motor, we use an inverter
− Serial communication port: RS-485, operated with USS protocol
− Communication: Profibus, Device Net, CANopen
• Block diagram of the inverter:
Figure 32 Block diagram of inverter
In this model, a large-capacity motor is not necessary because a belt conveyor is employed, don’t need to control the direction of rotation and a high load is not needed With quite simple requirements of the conveyor belt as:
- Conveyor belt runs continuously, can stop when needed
- Does not require high accuracy, light conveyor load
- Easy to control, low cost
Based on the requirements of the conveyor belt is 44cm long and 10cm wide, weight 4kg, we need a force of 40N
Conveyor speed = roller shaft circumference x number of rollerrevolutions per minute
• Number of rollerrevolutions per minute: 63 rpm
The roller shaft circumference= diameter of circle x π = 33 x π= 103.67 mm
So just use a DC motor with a small capacity with a DC voltage of 24 V
The DS400 engine has two primary uses: it can be used as a geared motor and a small generator Because the DS400 helps to enhance the torque of the shaft and decrease rotational speed, it is an essential motor for large-capacity machinery and is highly helpful for small power equipment during power shortages
Figure 33 Geared Motor-Generator Motor DS400
▪ Operation: 6VDC – 24VDC o Deceleration ratio: 1/40 o Power: 80 – 100W o Weight: 475g o Size:
Figure 34 Geared Motor-Generator Motor DS400 wiring diagram
2 output wires of the motor connected to the 24V source, regardless of the polarity (positive and negative poles connected to 2 different wires will reverse the motor)
Human Machine Interface (HMI) screens are devices that enable communication between an operator and a machine Weintek HMI screens are a widely used type of HMI, particularly in industrial settings The Weintek HMI touch screen is essential for human-machine interaction Weintek electrical equipment, including HMI displays, is known for its high quality and durability, making it a trusted choice in factories.
An overview of Weintek HMI includes:
− A part of the Weintek HMI application software that is put into the device and constructed using the Weintek HMI development software tool
− A place to store objects (Objects), variables (tags), contextual programs (scripts)
− Including internal variables in the Weintek HMI device's operating system, which are utilized as intermediary variables in calculations, and process variables in the devices connected to the control network, such as the PLC, the intelligent measurement device, and other embedded devices and controllers
− Tags are an intermediate object to link Weintek HMI and PLC
• Variable type (Tag type/Data type): Bit: 0/1 (true/false); Bytes: 0…255; Word: 2 bytes
= 0…65025; Interger (Original): -32512…+32512; Long, Float, BCD; String: abc
− Global Script: Script program code that affects the entire Weintek HMI system
− Object script: is a script that affects only that object The program code is often written for the object's events An example would be a button script with a "button click" event
− An illustration showing how a variable (tag) changes over time
− There are two main types of trends: current trends and history trends o Alarm: An object's ability to sound alarms or notify the system of issues o Bar Graph: Bar graph displays constant variations in pressure, water, and oil
Figure 35 Weintek MT8071iP HMI
- Communication ports: RS232, RS485, Ethernet, USB
- Communication protocols: Mobus, CANbus, PPI, MPI, Profielbus …
- Wide input voltage range: 10.5~28VDC
- Built-in flash memory and RTC
- NEMA4 / IP65 Compliant Front Panel
• Specifications: Weintek MT8071iP HMI
- There are 2 connection ports: USB and Ethernet to load programs from a computer or to connect to a PLC
- There are 2 wires: 1 wire to connect V+, 1 wire to connect V-
Figure 36 Connectivity – Communication of Weintek HMI a Power Connector c USB Host b COM1 RS232 4W,
➢ We need to use 10 cylinders for all system
Table 2 Cylinder used in the system
1 2 Open and close the lid of the rice hopper
2 1 Open and close the mouth of the rice quantitative filter
3 2 Hold the mouth of the bag
4 2 Attach the heat sealer to seal the mouth of the bag
5 1 Push the finished product to the conveyor
The authors decided to utilize a two-way acting cylinder in the system since the quick- acting cylinder's fixed and small stroke makes it unsuitable for use The system can be precisely and entirely automatically regulated thanks to the two-way action cylinder Structure of double acting cylinder:
Figure 37 Construction of double acting piston
1 Piston 2 Piston seal 3 Piston shaft 4 Guide
5 Shaft seal 6 Dust ring 7 Cylinder cover 8.13 Fluid door
9 Cylinder body 10 Shaft chamber 11 Piston chamber 12 Cylinder base
Gas is delivered to the cylinder's port 8 upon receiving an action signal, at which point the piston is inserted Gas is delivered to port 13 in response to a return signal, which pushes the piston out in the opposite direction
• Choose cylinder for the lid of the rice hopper: CXSL15-10
Horizontal movement cylinder o Mass: 1 kg o Operating pressure (Mpa): 0.7 o Load Factor: 0.5
• Choose cylinder for the mouth of the rice quantitative filter: CXSL10-30
Horizontal movement cylinder o Mass: 0.7 kg o Operating pressure (Mpa): 0.7 o Load Factor: 0.5
• Choose cylinder for hold the mouth of the bag: CXSM10-10-Y7BW
• Choose cylinder for the heat sealer to seal the mouth of the bag: AIRTAC TN 16x100
• Choose cylinder for push the finished product to the conveyor and cylinder for classifying packages: CXSM15-100
Use the piston cylinder to push the pneumatically controlled product
− Fmsmax is the maximum friction force between the product surface and the conveyor belt
With: o K is the coefficient of friction between the product surface and the conveyor belt, choose K = 0.8 o N is the reaction of the conveyor belt with the product N=G=mg=7N
• The highest weight of a bag of rice: 600g
A pneumatic reversing valve is a component utilized for closing, disconnecting, and reversing the compressed air flow, thereby altering the direction of movement of the pneumatic actuator Within the model of the product classification system, the project team employs a 5/2 reversing valve
Valve 5/2 is a valve with 5 working ports and 2 working states:
- Door P is the power supply door
- Door A is fitted with the left chamber of the actuator cylinder
- Door B is fitted with the right chamber of the actuator cylinder
- Gate T and gate R: energy discharge gates
Uses: Valve 5/2 has the effect of reversing the control of the double acting cylinder
Working principle: When the valve slider shifts to the right, port P establishes a connection with port A, while port B connects to port T Conversely, when the valve slider moves to the left, port P links with port B, and port A establishes a connection with port R
A quartet of SMC valves and an independent Koganei valve were used for heat sealing, enabling effortless monitoring of the bag's mouth temperature
Cylinder area = bore size mm x0.5x0.0394 π = 15x0.5x0.0394 π= 0.2743 in
Cylinder stroke = 100x0.0394=3.94 in cylinder stoke 100
Figure 39 Valve SMC SYJ3143-5LOZ
Cylinder area = bore size mm x0.5x0.0394 π = 16x0.5x0.0394 π= 0.3121 in Cylinder stroke = 100x0.0394=3.94 in cylinder stoke 100
Koganei Solenoid Valve A110-4E1-83-PSL-3L DC24V 0.15~0.7MPa Solenoid Valve
Figure 41.Solid state relay RM1A48D50
Solid state relays (SSRs) are an ideal alternative to electromagnetic relays due to their unique advantages SSRs are switching relays that eliminate the need for mechanical components, ensuring higher dependability and durability They also boast extended lifespans compared to their electromagnetic counterparts Furthermore, SSRs provide superior performance with faster switching speeds and resistance to interference Their compact size and robust design make them a reliable choice for diverse applications.
Nevertheless, solid state relays are expensive; so, in order to save money and utilize the system, the Omron MY4N relay was used
Hardware construction
• Diagram of PLC connection with devices
The phrases "sinking”, and "sourcing" refer to how a load's direct current flow is controlled Whereas a sourcing digital I/O gives the load a voltage source, a sinking digital I/O (input/output) provides a grounded connection Think of a straightforward circuit that has a single digital input and a digital output attached to it
We are using source digital I/O in this project since NPN sensors are used in the system
A negative excitation signal is called an NPN signal In other words, level 0 (level 0 = 0V, level 1 = voltage source) corresponds to an output that is active, and level 1 corresponds to no effect In a normal state, the output of an NPN sensor equals the voltage source Moreover, the output will now be 0V when the sensor is impacted
For devices utilizing this voltage level, the connection diagram uses a single 24VDC-20A switching power supply as the only source The cylinder, light, and conveyor control motor are connected to the PLC's output, while other devices like buttons and sensors are attached
GRADUATION THESIS 51 to its input The PLC's analog input is connected to both the weight transmitter and the loadcell
No Name Adress Type Note
1 I_Start I0.0 Bool Start the system
2 I_Stop I0.1 Bool Stop the system
4 I_Sensor I0.3 Bool Product counting sensor
5 I_Analog_loadcell AI Bool Weight sensor
No Name Adress Type Note
1 Q_XL1 Q0.0 Bool Cylinder holds the mouth of the bag
2 Q_XL2 Q0.1 Bool Cylinder opens and closes the lid of the rice hopper
3 Q_XL3 Q0.2 Bool Cylinder opens and closes the mouth of rice quantitative filter
4 Q_XL4 Q0.3 Bool Cylinder attaches the heat sealer to seal the mouth of the bag
6 Q_light_Start Q0.5 Bool Start light
7 Q_light_Stop Q0.6 Bool Stop light
8 Q_XL5 Q0.7 Bool Cylinder pushes the finished product
9 Q_XL6 Q1.0 Bool Cylinder classifies type 1 product
10 Q_XL7 Q1.1 Bool Cylinder Classifies type 2 product
We utilize Koganei and SMC valves We decided to use an SMC valve cluster, which consists of 4 valves, in place of a single valve in order to make installation easier and improve the system's appearance To make it easier to change the timing of correctly sealing the bag's mouth and create a completed product without spilling rice, use a separate AIRTAC valve for the heating bar
Figure 69 Weighing and packing rice system after actual completion
Figure 70 Control panel above electrical cabinet
Monitor screens, push buttons and lights are installed above the switchboard for easy operation and observation of the system The devices include power, CB, loadcell transmitter, relay, dominos are arranged and wired in electrical cabinets a/ Wiring inside electrical cabinets b/ In front of the electrical cabinet
The construction system is similar to the design The power cord is neatly attached to the trough, has a cos end and a label for easy identification and repair when there is a fault.
SOFTWARE DESIGN
SOFTWARE REQUIREMENTS
Based on the requirements of the system, the software program fulfills the features that customers require to be convenient, including:
- Read the signal from the control block and process it through the HMI screen
- Simple interface design for easy operating
- User permission and alarm message will be appeared on the HMI screen to secure the system
- Show all the equipment run and activate through the process
- Fast update about the value that needed to follow in the system
SOFTWARE BUILDING
Because the system uses Siemens S7-1200 DC/DC/DC PLC for all the process, using Tia Portal to code is necessary Total Integrated Automation Portal, or TIA Portal, is a management tool for system automation and electrical operation that integrates several operational software Naturally, TIA Portal is the first automation program to operate the system and do activities on the same environment/platform [6]
TIA Portal, an automation programming software, caters to both novice and experienced users As the cornerstone software for Siemens' TIA product line, it simplifies the setup, programming, and integration of automation systems Its user-friendly design allows for efficient and seamless operations, making it a valuable tool for automation professionals of all skill levels.
1 Create a user-friendly, attractive information interface with a variety of supported languages
2 Manage User, Code, Project permissions in general
3 Perform go online and Diagnostic for all devices in the project to identify diseases and system errors
5 Easy to configure and link between Siemens devices
There are many versions of Tia Portal for users to use for the best experience for coding the PLC like Tia Portal V14, Tia Portal V15, Tia Portal V16… In this project, we seem to choose Tia Portal V17 because it will give us the best experience and function to build the project TIA Portal software is developed by Siemens with many components to help users manage and program PLC, Siemens Simatic HMI effectively Components included in the TIA Portal suite:
1 Simatic Step 7 professional and Simatic step 7 PLCSIM: PLC simulation and programming solution S7-300, S&-400, Simatic S7-1200, Simatic S7-1500…
2 Simatic WinCC Professional: Used to program the Siemens Simatic HMI display, and SCADA interface
3 Simatic Start Driver: Programmed to configure Siemens
4 Sirius and Simocode: Flexible configuration and diagnostics
5 Single- and multi-axis motion control with Scout TIA support The full data Simatic Robot library allows users to set up configurations and systems quickly
The official programming language for the Siemens S7-1200 PLC is the S7 programming language, also called LAD (Ladder Diagram), FBD (Function Block Diagram), SCL (Structured Control Language), STL (Statement List) or Graph The programmer can use any of these languages to program the S7-1200 PLC
When start the full process, there are 2 main modes of controlling: Manual and Auto If users press the manual button, it will transfer to the Manual mode and transfer to Auto mode when pressing the Auto button Also, an emergency button will be added to the system to stop the system immediately if errors appear
When pressing the Manual mode, users can check the status of each cylinder in the system by pressing each button of the cylinder For example, when pressing cylinder 1, the cylinder
1 will run to check if it works Also, if users want to run the process by pushing each cylinder, Manual mode will be the best choice So, before moving to the Auto mode, Manual mode will be used to test to have the best efficiency
4.2.4.1 WEIGHING AND CONTAINING RICE STEP FLOWCHART
Figure 74 Weighing and containing rice step flowchart
When pressing the auto mode, all the process will run automatically First, users will give the weight of rice that needed to weight After that, Cylinder 1 to stretch the pack and cylinder 2 to open the tank will run right after pushing the Start button At that moment, the conveyor also worked If the actual weight received from loadcells equal to the set weight, cylinder that opened the tank will close and cylinder 3 will open to give the weighed rice into the pack When the actual weight equal to 0, that means there is no rice inside the funnel, the cylinder that covered the mouth of the funnel will close after 6 seconds
Figure 75 Welding package step flowchart
As rice packaging concludes with weighing and containment, the subsequent step involves welding and containment Upon reaching capacity within the bag, Cylinder 4 initiates its operation Concurrently, the HMI screen determines the welding duration, which triggers the cessation of the welding and stretching cylinders once the predetermined high-temperature welding time has elapsed This action releases the welded package from the hook for its subsequent drop.
Figure 76 Classify package step flowchart
Upon completion of the welding process, the welded package descends to the floor Cylinder 5 promptly transfers the package to the conveyor within two seconds A sensor adjacent to the conveyor detects the presence of the package Depending on the package's weight, Cylinder 6 or Cylinder 7 redirects the package to the designated box containing type 1 or type 2 products, respectively The conveyor halts its operation four seconds after the sensor's initial detection of the package.
4.2.5 CONTROL AND MONITORING INTERFACE IN HMI
In this project, we use TIA Portal V17 software, and choose model corresponding to hardware PLC 1214C DC/DC/DC type 6ES7214-1AG40-0XB0
Figure 77 Device configuration in Tia Portal software
1 Name of the original save program
3 Main [OB1]: Where to write the main code
4 AUTO [FC1]: Program to run Auto
5 LOADCELL [FC4]: Programming for loadcell
6 MANUAL [FC3]: Program run Manual
7 OUTPUT [FC2]: Program output of the system
In the HMI, this system has set up permissions for users We divided into 3 main groups: Users, admin, and operator Engineers can activate the system with all the permissions like operate, follow the process, stop the system to maintain Users will have less permission like follow the process and run the auto mode Both users and engineers will use the username and password to the table 1 below
Figure 79 Set up permissions in HMI
The HMI is designed with 5 main screens: Main screen, Auto mode screen, Manual mode screen, Trend screen and Alarm screen In the Alarm screen, engineers can check the stability of the system If any problems happen, it will show in the Trend screen the error to help engineers to maintain it In the Trend screen, engineers can follow the input weight after several times in graph and compare with the actual weight in graph
Figure 80 The main screen of the system
RESULTS
Implementation result
• Calculate all the datasheet and select suitable devices for running the process.
• Draw the 3D system in SOLIDWORK software to have the best overview.
• Draw the wiring and block diagram of the system.
• Draw the connection circuit between PLC and sensors, pneumatic dynamic circuit to connect cylinders and valves.
Figure 85 The system in 3D drawing
• Control and display the weight in the weighing process
• Use the Tia Portal to control the signals using PLC
• Write a program based on the requirements of the system in flowcharts
• Control the welding and packing process
• Design a HMI screen to control each of the mode
Figure 87 The main screen of the system
• With the stable and the suitable power supply and pneumatic, the system run smoothly
• The motor is fast and stable to pull out finish packages into the bins
• Adjust the stable loadcell signal
• Successfully installed the heat sealer
• Complete all the requirements set up for the system
We will run in 3 different types of products: 200g for type 1, 400g for type 2 and 300g for the other type In each type, we will test 25 packages in each type to survey the percentage of error and stability of the operation and welding process
In this project, the weight error of the actual package is less than 5%
Yes No Achieved Not achieved
Percent age (%) of correct operatio n
Right Wrong Achieved Not achieved
Right Wrong Achieved Not achieved
Percenta ge (%) of correct operatio n (tried
➢ Other type test (300g): Error 5% - Range: 285g – 315g
Right Wrong Achieved Not achieved
Right Wrong Achieved Not achieved
Percenta ge (%) of correct operatio n (tried
After testing the system with different types, the results are listed on the table 1
Table 5 Statistics of the system Input weight (g) Actual weight (g) Error (%)
From the statistic of the system, we have
• The average weight error of 3 types is less than 5%
• The achieved welding rate is high and stable with 80% success
• The success rate when running the system is 100%
➔ The system operates stably at a high rate and responds to all the requirements.
CONCLUSION AND DEVELOPMENTS
Conclusions
• The system has automatically weighed, pack filled bags and classify them into several set up types
• The system responds successfully with high rate, making the quality of the package become higher
• Have the HMI to communicate with the system, which makes the control process easier to approach
• Easy to expand and upgrade to fit with modern technology
Manual handling of packaging materials leads to non-uniform welds, both in shape and alignment Moreover, inconsistencies in manual bag placement during welding can result in weld exposure, compromising the package integrity and product quality.
• The design of the rice hopper is smaller in width than the rice discharge tank, so sometimes small quantities of rice will drop out, making it difficult to check the total amount of rice inside the tank.
Developments
• Build the package supply automatically: The quality of the package will highly depend on where the bag is placed Therefore, building an automatic package supply system to support this process is necessary and convenient
• Design the hook can keep the package with high weight to diverse the weight inside each bag.
[1] Snehashis Das, Avijit Karmakar, Pikan Das, Biman Koley (2019), Manufacture of Electronic Weighing Machine Using Load Cell, IOSR Journal of Electrical and Electronics Engineering
[2] I VARSHITHA (2021), Arduino Weighing Machine using Load Cell and HX711 Module
[3] H Keith Howard (1974), Heat-Sealing Method for Plastic Containers
[4] Carlos R.D.S Copia (1982), Cutting/Sealing Device for Plastic Bag Making Machine [5] https://heatsealing.ceetak.com/heat-sealing-principles
[6] https://www.siemens.com/global/en/products/automation/industry- software/automation-software/tia-portal.html
➢ PLC Siemens S7-1200 code https://drive.google.com/drive/folders/1PV5VONaPXhryXrZtlSKxAHjjjZ0N4opE?usp=s haring