(Đồ án hcmute) monitoring and controlling chiller system by computer use plc siemen s7 1200

TECHNOLOGY AND EDUCATION QUALITY TRAINING ******************************* ******************* UNDERGRADUATE THESIS TASK DEPARTMENT: FACULTY OF VEHICLE AND ENERGY ENGINEERING SUBJECT: HE

FACULTY FOR HIGH QUALITY TRAINING

ADVISOR: LAI HOAI NAM STUDENT: NGUYEN HO CONG THANH

SKL 0 1 0 5 6 3

GRADUATION PROJECT THERMAL ENGINEERING TECHONOLOGY

MONITORING AND CONTROLLING CHILLER

SYSTEM BY COMPUTER USE PLC SIEMEN S7 - 1200

TECHNOLOGY AND EDUCATION

FACULTY OF HIGH QUALITY TRAINING

- -

UNDERGRADUATE THESIS

Student: Nguyen Ho Cong Thanh

ID: 19147053

Lectures: Lai Hoai Nam

MONITORING AND CONTROLLING CHILLER SYSTEM BY COMPUTER USE PLC SIEMEN S7 - 1200

HO CHI MINH CITY UNIVERSITY OF

TECHNOLOGY AND EDUCATION

FACULTY OF HIGH QUALITY TRAINING

TECHNOLOGY AND EDUCATION QUALITY TRAINING

******************************* *******************

UNDERGRADUATE THESIS TASK

DEPARTMENT: FACULTY OF VEHICLE AND ENERGY ENGINEERING SUBJECT: HEAT - REFRIGERRATION TECHNOLOGY

MAJOR: THERMAL ENGINEERING TECHNOLOGY

NAME OF STUDENT: NGUYEN HO CONG THANH ID: 19147053

ACADEMIC YEAR: 2019-2023 CLASS: 19147CLA

 Topic name:

MONITORING AND CONTROLLING CHILLER SYSTEM BY

COMPUTER USE PLC SIEMEN S7 – 1200

 Commission:

Create archetype using S7 1200 for Monitoring and controlling chiller

system

Demonstration value of temperature and pressure on PC screen

Controlling combine inverter technology on PLC S7 1200

Simulation principle of chiller system on WinCC screen

 Assignment date: 1/11/2022

 Exhaustive date: 19/2/2023

 Instructor : LAI HOAI NAM

Department chairman Instructor

(sign and write full name) (sign and write full name)

OF TECHNOLOGY AND

EDUCATION

QUALITY TRAINING

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FEEDBACK FOR UNGERGRADUATE THESIS (Instructor's comment) Full name of student: Nguyen Ho Cong Thanh Student ID:19147053 Major: Thermal Engineering Topic: “Monitoring and controlling chiller system by computer use PLC S7 - 1200’’ Full name of the instructor: Lai Hoai Nam FEEDBACK 1 Comment on work spirit and attitude ………

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(Theoretical basis, practicality and applicability of the project, research directions can continue to develop)

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3 Evaluate :

score

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1 Form and texture of thesis 30

Correct format with full form and content of

Objectives, tasks, overview of the topic 10

Ability to perform/analyze/synthesize/evaluate 10 The ability to design and manufacture a system,

component, or process that meets a given

requirement with realistic constraints

15

Ability to use technical tools, specialized

3 Evaluate the applicability of the topic 10

4 Conclude:

☐ Allowed to defend the thesis

☐ Dissertation defense is not allowed

Ho Chi Minh, …./…/2023

Instructor

(Signature)

HO CHI MINH CITY UNIVERSITY

OF TECHNOLOGY AND

EDUCATION

FACULTY OF HIGH QUALITY TRAINING

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FEEDBACK FOR UNGERGRADUATE THESIS (Reviewer’s comment) Full name of student: Nguyen Ho Cong Thanh Student ID: 19147053 Major: Thermal Engineering Topic: “Monitoring and controlling chiller system by computer use PLC S7 - 1200’’ Full name of the reviewer: ………

FEEDBACK 1 Structure, way of presentation ………

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1 Form and texture of thesis 30

Correct format with full form and content of

Objectives, tasks, overview of the topic 10

Ability to apply knowledge of mathematics,

science and engineering, social sciences… 5

Ability to perform/analyze/synthesize/evaluate 10

The ability to design and manufacture a system,

component, or process that meets a given

requirement with realistic constraints

15

Ability to use technical tools, specialized

3 Evaluate the applicability of the topic 10

7 Conclude:

☐ Allowed to defend the thesis

☐ Dissertation defense is not allowed

Ho Chi Minh, …./…/2023

Reviewer

(Signature)

HO CHI MINH CITY UNIVERSITY

OF TECHNOLOGY AND

EDUCATION

FACULTY OF HIGH QUALITY TRAINING

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CONFIRMATION OF COMPLETE THE UNDERGRADUATE THESIS

Topic: “Monitoring and controlling chiller system by computer use PLC S7 - 1200’’

Full name: Nguyen Ho Cong Thanh Student ID: 19147053

Major: Thermal Engineering Chairman of the Council

After absorbing and adjusting according to the comments of the Instructor, Reviewer and members of the Defence Council

Chairman of the Council:

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Ho Chi Minh, …./…/2023

Introduction

Today's world has entered the 4.0 era, where devices, machines, and

artificial intelligence work instead of humans If in the old days people had to

work hard to carry heavy objects on very high places, today there are cranes

and cranes to help carry those heavy objects to those high places Or for a

refrigeration system when refrigeration productivity decreases, the engineer

will spend a lot of time determining why the cold yield is reduced But now

thanks to the rapid development of technology, those problems no longer take

much time By means of sensors, the algorithm written by the user will be able

to quickly indicate the reason why the cold power is reduced or even the

location where the problem is on the system (mechanically), reducing the

amount of downtime of the system to increase the capacity of the system,

achieve many values and profits to develop the country Therefore, the

development of technology is now also one of the top priorities

As a student of thermal engineering technology, after a long time studying at

Ho Chi Minh City University of Technical Education, guided by the teachers, I

chose for myself the graduation topic "Monitoring and controlling Chiller

system by computer use PLC Siemen S7 1200" This topic is a new direction

that teachers and teachers are now directing students to gradually follow,

especially Mr Hoai Nam, Mr Hung Son and Mr Minh Hung So in this

project, I focus most on the operation and monitoring of the operating system,

reporting common problems in a chiller system Use the TIA Portal V15

programming language to control the Siemen S7 1200 PLC

After 3 months of research and reference, with my own efforts and the

dedicated help of Mr Lai Hoai Nam, I can complete this project Through this

project, I would like to express my sincere thanks to Mr Lai Hoai Nam and the

teachers in the department of thermal engineering technology at the University

of Technical Education in Ho Chi Minh City

Sincerely thank everyone!

Acknowledgments

In order to be able to complete this project, I would like to thank the School Board, the teachers in the school and especially the teachers of Thermal Engineering Technology for their dedication to fanning the flame of love for the profession and love for the industry that has rekindled in our hearts since the beginning of the industry as well as imparting professional knowledge, major for us

I would like to express my deepest thanks to Mr Lai Hoai Nam You have been dedicated to guiding me throughout the process of implementing the topic Not only that, he is also the one who helped me find my strengths in this area of automation and exploit those strengths to operate large refrigeration systems later

In addition, I would like to thank my friends and friends who have supported me throughout the process of implementing this topic Although there are many mistakes, I hope the teachers will wholeheartedly guide me so that I can get better and better

Thank you very much!

Ho Chi Minh city, February 19th, 2023

Perform Student

Nguyen Ho Cong Thanh

TABLE OF CONTENT

CHAPTER I: OVERVIEW 21

1.1 Introduction 21

1.2 Topic tasks 22

1.3 Research objectives 23

1.4 Subjects of study 23

1.5 Contents 23

CHAPTER II: INTRODUCTION TO PLC S7-1200 AND TIA PORTAL V15 SOFTWARE 24

2.1 Overview about PLC 24

2.1.1 Invention and early development 24

2.1.2 Architecture 25

2.1.3 Mechanical design 25

2.1.4 Discrete and analog signals 26

2.1.5 Simulation 26

2.1.6 Functionality 26

2.1.7 Process of a scan cycle 27

2.1.8 Security ……… 28

2.1.9 PLC compared with other control systems 28

2.2 Overview about TIA Portal software 30

CHAPTER III: DESIGN OF PISTON CHILLER REFRIGERATION SYSTEM MONITORING AND CONTROL SYSTEM 33

3.1 Introduction of refrigeration system at the thermal workshop 33

3.2 Introduction PLC S7 – 1200, circuit and analog input 38

3.2.1 Introduction of PLC S7-1200 1212C AC/DC/Rly 38

3.2.2 Design of supervisory operation system using PLC S7-1200 41

3.2.2.2 Equipment used to operate the system 41

3.2.2.3 Program to operate the system by PLC S7-1200 42

3.2.2.4 Compressor operating circuit 42

3.2.2.5 Cooling tower pump and fan control circuit 43

3.2.2.6 Control circuit for cold water pump 44

3.2.2.7 Low pressure protection circuit 44

3.2.2.8 High pressure protection circuit 46

3.2.2.9 Oil pressure protection circuit 47

3.2.2.10 Cooling tower pump protection circuit 48

3.2.2.11 Cold water pump protection circuit 49

3.2.2.12 Compressor overheating protection circuit 50

3.2.2.13 Alarm circuit 51

3.2.2.14 Overload protection 53

3.2.2.15 Circuit of the phase protector 54

3.2.2.16 Star and triangular circuit 55

3.2.2.17 Temperature sensor circuit 56

3.2.2.18 Diagnostic flowchart pane circuit 57

3.2.2.19 The list of tag using in the system 61

3.3 Processing analog signal from sensor 65

3.3.1 What is signal? 65

3.3.2 What is an analog signal? 66

3.3.3 Commonly used analog signal types: 68

3.4 Introduction some of sensor, equipment using in system 81

3.4.1 Pressure Sensor 81

3.4.1.1 Characteristic 82

3.4.1.2 Application 82

3.4.1.3 Form 82

3.4.1.4 Connection 83

3.4.2 Analog input ( siemens SM 1231 AI – 6ES7231 - 4HD32 – 0XB0 ) 84

CHAPTER IV: ACTUAL OPERATION OF THE SYSTEM BY CONTROL ON PC/LAPTOP 87

4.1 Operating manual 89

4.2 Wiring diagram 90

4.3 Main Screen ( Home ) 91

4.4 Set up screen 97

4.5 Water chiller system screen 100

4.6 Parameter screen 101

CHAPTER V: CONCLUSION AND FUTURE WORK 105

5.1 Conclusion 105

5.2 Future Work 105

Reference 107

LIST OF FIGURE

Figure 3 1: Water chiller system diagram 33

Figure 3 2: Thermostatic expansion valve 38

Figure 3 3: Wiring diagram ( 1: power supply 24V DC for input, 2: input door of PLC, 3: power supply AC 220V for PLC running, 4: relay output for equipment outside.) 38

Figure 3 4: System operation panel 41

Figure 3 5: Control compressor circuit (part 1) 42

Figure 3 6: Control compressor circuit (part 2) 42

Figure 3 7: Control pump,fan of cooling tower circuit 43

Figure 3 8: Control cold water pump circuit 44

Figure 3 9: Low pressure protection circuit 44

Figure 3 10: Block processing analog input for low pressure 45

Figure 3 11: Calculation circuit for low pressure 45

Figure 3 12: High pressure protection circuit 46

Figure 3 13: Block processing analog input for high pressure 46

Figure 3 14: Calculation circuit for high pressure 46

Figure 3 15: Block processing of oil pressure sensor 47

Figure 3 16: Calculation circuit for oil pressure 47

Figure 3 17: Cooling tower pump waterpressure protection 48

Figure 3 18: Block processing analog input for flow switch 48

Figure 3 19: Cold water pump pressure protection 49

Figure 3 20: Block processing analog input for flow switch of cold water pump 49

Figure 3 21: Compressor overheating protection circuit 50

Figure 3 22: Block processing analog input for temperature sensor 50

Figure 3 23: Alarm circuit (part 1) 51

Figure 3 24: Alarm circuit (part 2) 51

Figure 3 25: Alarm circuit (part 3) 52

Figure 3 26: Overload compressor protection 53

Figure 3 28: Overload cold water pump 53

Figure 3 29: Phase control relay (part 1) 54

Figure 3 30: Phase control relay (part 2) 54

Figure 3 31: Star and triangular circuit (part 1) 55

Figure 3 32: Star and triangular circuit (part 2) 55

Figure 3 33: Star and triangular circuit (part 3) 55

Figure 3 34: Star and triangular circuit (part 4) 55

Figure 3 35: Block processing of temperature sensor 56

Figure 3 36: Calculation for temperature signal 56

Figure 3 37: Pressure value circuit 57

Figure 3 38: Superheated temperature circuit 57

Figure 3 39: Subcooling temperature circuit 58

Figure 3 40: Temperature difference of valve circuit 58

Figure 3 41: Chilled water temperature difference circuit 58

Figure 3 42: Cold water temperature difference circuit 59

Figure 3 43: Diagnostic flowchart pane circuit (part 1) 59

Figure 3 44: Diagnostic flowchart pane circuit (part 2) 59

Figure 3 45: Diagnostic flowchart pane circuit (part 3) 60

Figure 3 46: List of tag using in the system (part 1) 61

Figure 3 47: List of tag using in the system (part 2) 62

Figure 3 48: List of tag using in the system (part 3) 62

Figure 3 49: List of tag using in the system (part 4) 63

Figure 3 50: List of tag using in the system (part 5) 63

Figure 3 51: List of tag using in the system (part 6) 64

Figure 3 52: List of tag using in the system (part 7) 64

Figure 3 53: List of tag using in the system (part 8) 65

Figure 2 54: Digital signal 66

Figure 2 55: Analog signal 67

Figure 3 56: Table choosing equipment 69

Figure 3 57: List of analog input 70

Figure 3 58: Connecting analog input 71

Figure 3 59: General imformation of analog input 72

Figure 3 60: Catalog imformation of analog input 72

Figure 3 61: Overall of analog input 72

Figure 3 62: Choosing measurement type of analog input 73

Figure 3 63: Choosing range of analog input 73

Figure 3 64: Input and output addresses in analog input 74

Figure 3 65: Channel 0 of analog input 74

Figure 3 66: Channel 1 of analog input 74

Figure 3 67: Channel 2 of analog input 75

Figure 3 68: Channel 3 of analog input 75

Figure 3 69: List of instructions 76

Figure 3 70: Choosing command block by table 76

Figure 3 71: Choosing command block by quick command 76

Figure 3 72: Choosing NORM_X block 77

Figure 3 73: Choosing SCALE_X block 77

Figure 3 74: NORM_X block 77

Figure 3 75: SCALE_X block 78

Figure 3 76: PLC value and measuring range 78

Figure 3 77: Set up for NORM_X block 79

Figure 3 78: Specifications of Beamex IPRT-300 Pt100 probe 79

Figure 3 79: Specification Pt100, thermocouple of C-mac 80

Figure 3 80: Set up for SCALE_X block 80

Figure 3 81: Example for processing NORM_X and SCALE_X block 81

Figure 3 82: Pressure sensor 81

Figure 3 83: Current connection 83

Figure 3 84: Voltage connection 84

Figure 3 85: Analog input SM1231 84

Figure 4 1: Electric cabinet 87

Figure 4 2: Controlling screen 88

Figure 4 3: Simulation screen 89

Figure 4 4: Control wiring diagram 90

Figure 4 5: Motor wiring diagram 91

Figure 4 6: Main screen 91

Figure 4 7: Set up screen 97

Figure 4 8: High pressure set up 97

Figure 4 9: Low pressure set up 98

Figure 4 10: oil pressure set up 99

Figure 4 11: Cold water temperature 99

Figure 4 12: Water chiller system screen 100

Figure 4 13: Parameter screen 101

LIST OF TABLE

Table 1: List of Thermal power plant 22

Table 2: Information about PLC S7-1200 1212C AC/DC/Rly 39

Table 3: Table of equipment 41

Table 4: Table of output and connector of model M52 82

Table 5: Table of range of sensor 83

Table 6: Information of analog input 84

Table 7: List key and description of main screen 92

Table 8: List key and description of water chiller system screen 100

Table 9: List key and description of parameter screen 101

CHAPTER I: OVERVIEW

The thermal engineering technology industry has indeed grown rapidly and has become an important player in supporting various industries The development of this industry has resulted in better comfort for people in the office, increased labor productivity, improved quality of exported goods, and better food preservation

The thermal engineering industry requires a significant amount of manpower to operate its large systems, and this has created job opportunities in many areas Additionally, the industry provides support to other industries, such as the automotive industry, by offering air conditioning systems for vehicles and engine cooling solutions In the chemical industry, thermal engineering technology helps to store drugs and vaccines at the right temperature to preserve their properties

The growth of the thermal engineering technology industry is a testament to the advances made in technology, and it is exciting to see how this industry will continue to evolve and support other industries in the future The continued development of this industry will likely result in even more advancements and benefits for society as a whole

The thermal engineering technology industry is divided into two main areas: refrigeration and heat The refrigeration sector is further divided into two sub-sectors: freezing and air conditioning Currently, air conditioning is the most popular field due to the construction of large houses and commercial centers that require air conditioning The freezing sector is important for preserving food and chemicals that can change in properties when exposed to positive temperatures

The heat sector is also important and is focused on thermal power plants, which are large plants that generate heat and electricity These plants require strict processes and rules to ensure the safety of workers and proper operation

of the large systems In Vietnam, there are several large thermal power plants that are known for their size and capacity

It is clear that the thermal engineering technology industry is a complex and multi-faceted field that plays a critical role in supporting other industries and improving the quality of life for people The continued development of this industry will likely result in even more advancements and benefits for society

as a whole

Table 1: List of Thermal power plant

Name of thermal power plant Capacity (MW)

Phu My Thermal Power Plant 3,900

Vung Ang Thermal Power Plant 6,300

Song Hau Thermal Power Plant 5,200

Coastal Thermal Power Plant 4,400

Long Phu Thermal Power Plant 4,400

Kien Luong Thermal Power Plant 4,400 - 5,200

Vinh Tan thermal power plant 5,600

Mong Duong Thermal Power Plant 3,400

O Mon Thermal Power Center 2,800

Characteristics of refrigeration system control requirements:

The equipment in the water chiller control system includes: 1 piston compressor, 2 or more indoor units, 1 cooling tower, 2 capacity pumps

to pump cold water to the indoor unit and to pump cooling water to the

cooling tower external equilibrium thermal throttle valve and solenoid valve

Joystick equipment: solenoid valve, indoor unit fan, outdoor unit fan, compressor and 2 pumps

Master the command blocks, operating rules of the Seimen S7 1200 PLC through defining the instructions, scripting the requirements of the input value and output value of the system before passing through the processing system of the PLC Write the program to control and monitor the system through the TIA Portal V15 programming language

Monitoring and control parameters: Room temperature to be cooled (To), medium temperature at the suction head and thruster of the compressor (To, Tk), thruster pressure of the compressor (Pk), compressor suction head pressure (Po)

The subjects of the study were refrigeration systems, PLC siemen S7

1200 TIA Portal software that simulates WinCC, high pressure sensors, low pressure sensors, temperature sensors and others From there, build a program

to operate and monitor the refrigeration system by PLC siemen

The history of the formation and development of PLC through stages, writing programs to operate PLC, studying how to use PLC in a large system, using analog to encode signals brought back from sensors The specific contents I will present in Chapter I below

CHAPTER II: INTRODUCTION TO PLC S7-1200

AND TIA PORTAL V15 SOFTWARE

2.1 Overview about PLC

A programmable logic controller (PLC) or programmable controller is

an industrial computer that has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, machines, robotic devices, or any activity that requires high reliability, ease of programming, and process fault diagnosis Dick Morley is considered as the father of PLC as he had invented the first PLC, the Modicon 084, for General Motors in 1968

PLCs can range from small modular devices with tens of inputs and outputs (I/O), in a housing integral with the processor, to large rack-mounted modular devices with thousands of I/O, and which are often networked to other PLC and SCADA systems

They can be designed for many arrangements of digital and analog I/O, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact Programs to control machine operation are typically stored in battery-backed-up or non-volatile memory

PLCs were first developed in the automobile manufacturing industry to provide flexible, rugged and easily programmable controllers to replace hard-wired relay logic systems Since then, they have been widely adopted as high-reliability automation controllers suitable for harsh environments

A PLC is an example of a hard real-time system since output results must be produced in response to input conditions within a limited time, otherwise unintended operation will result

2.1.1 Invention and early development

PLCs were initially developed to replace the cumbersome and inflexible relay logic systems used in manufacturing, which were difficult to modify and prone to failure The development of PLCs allowed for greater flexibility and extensibility in control logic, as well as easier troubleshooting and maintenance

Early PLCs were programmed using ladder logic, which closely resembled the schematic diagrams used in relay logic systems, making it easier for engineers and technicians to understand and work with As technology advanced, newer programming formats such as state logic and Function Block emerged, but ladder logic remains the most popular format for programming PLCs

Proprietary programming panels and terminals were initially used to program PLCs, but as technology advanced, programming software became available that allowed for programming on personal computers Today, PLCs are widely used in industrial control applications and are an essential component of modern manufacturing processes

2.1.2 Architecture

A PLC is a microprocessor-based controller that is commonly used in industrial control applications It consists of several components, including a CPU, power supply unit, memory unit, input and output interface, and communications interface The CPU interprets inputs, executes the control program stored in memory, and sends output signals to control external devices

PLCs require programming devices, such as personal computers, to develop and download programs into the memory of the controller Modern PLCs often contain a real-time operating system, which enables them to perform tasks with precise timing and respond quickly to changes in input signals

A modular PLC, on the other hand, consists of a chassis or rack that provides space for different modules with different functions, such as power supply, processor, I/O modules, and communication interfaces These modules can be customized to meet the specific requirements of the application, and additional modules can be added as needed

Modular PLC systems are more flexible and scalable than single-box PLCs and can support larger numbers of inputs and outputs They also allow for easy expansion and upgrading of the system In addition, modular PLC systems can be distributed across a plant, reducing wiring costs and simplifying installation

2.1.4 Discrete and analog signals

Discrete signals are binary, meaning they can only be either on or off, while analog signals can take any value within their range PLCs are designed

to handle both types of signals, with discrete signals often used for simple on/off controls, and analog signals used for more complex control systems where continuous monitoring and adjustments are required Proper signal conditioning and filtering are crucial to ensure accurate and reliable operation

of the PLC system

2.1.5 Simulation

PLC simulation is a valuable feature in PLC programming software that enables testing and debugging of PLC programs in a virtual environment before the actual deployment of the control system It provides a safe and cost-effective way to ensure that the PLC program is functioning correctly, reducing the risk of lost productivity, equipment damage, and safety hazards

2.1.6 Functionality

PLCs have been designed specifically for industrial environments where they can handle more severe conditions such as high temperatures, dust, and moisture They also offer extensive input/output options to connect to a wide range of sensors and actuators Over the years, PLCs have evolved to include

advanced functionalities like motion control, process control, distributed control systems, and networking Although desktop computers can overlap some of the functionalities of PLCs in certain applications, they have not been widely accepted in heavy industry because of their less stable operating systems and hardware not designed to withstand the harsh environments of industrial settings

2.1.7 Process of a scan cycle

A PLC works in a program scan cycle, where it executes its program repeatedly The simplest scan cycle consists of 3 steps:

Read inputs,

Execute the program,

And write outputs

The program follows the sequence of instructions It typically takes a time span of tens of milliseconds for the processor to evaluate all the instructions and update the status of all outputs If the system contains remote I/O—for example, an external rack with I/O modules—then that introduces additional uncertainty in the response time of the PLC system

As PLCs became more advanced, methods were developed to change the sequence of ladder execution, and subroutines were implemented This enhanced programming could be used to save scan time for high-speed processes; for example, parts of the program used only for setting up the machine could be segregated from those parts required to operate at a higher speed Newer PLCs now have the option to run the logic program synchronously with the IO scanning This means that IO is updated in the background and the logic reads and writes values as required during the logic scanning

Special-purpose I/O modules may be used where the scan time of the PLC is too long to allow predictable performance Precision timing modules, or counter modules for use with shaft encoders, are used where the scan time would be too long to reliably count pulses or detect the sense of rotation of an

encoder This allows even a relatively slow PLC to still interpret the counted values to control a machine, as the accumulation of pulses is done by a dedicated module that is unaffected by the speed of program execution

2.1.8 Security

To mitigate these security concerns, manufacturers have begun implementing security features such as access control, encryption, and intrusion detection systems PLC programmers are also encouraged to follow secure programming practices and use secure communication protocols Regular security audits and updates to firmware and software are recommended

to ensure that vulnerabilities are addressed and that systems remain secure In addition, organizations should have incident response plans in place to respond

to any security breaches or incidents

2.1.9 PLC compared with other control systems

PLC installed in a control panel

Control center with a PLC for an RTO

PLCs are well adapted to a range of automation tasks These are typically industrial processes in manufacturing where the cost of developing and maintaining the automation system is high relative to the total cost of the automation, and where changes to the system would be expected during its operational life PLCs contain input and output devices compatible with industrial pilot devices and controls; little electrical design is required, and the design problem centers on expressing the desired sequence of operations PLC applications are typically highly customized systems, so the cost of a packaged PLC is low compared to the cost of a specific custom-built controller design

On the other hand, in the case of mass-produced goods, customized control systems are economical This is due to the lower cost of the components, which can be optimally chosen instead of a "generic" solution, and where the non-recurring engineering charges are spread over thousands or millions of units PLC Chip / Embedded Controller

Nano ACE PLC & Chip PLC for small machine builders / small or medium volumes

For small machines with low or medium volume PLCs that can execute PLC languages such as Ladder, Flow-Chart/Grafcet, Similar to traditional PLCs, their small size allows developers to design them into custom printed circuit boards like a microcontroller, without computer programming knowledge, but with a language that is easy to use, modify and maintain It's between the classic PLC / Micro-PLC and the Microcontrollers

Single-board computers

Very complex process control, such as those used in the chemical industry, may require algorithms and performance beyond the capability of even high-performance PLCs Very high-speed or precision controls may also require customized solutions; for example, aircraft flight controls Single-board computers using semi-customized or fully proprietary hardware may be chosen for very demanding control applications where the high development and maintenance costs can be supported "Soft PLCs" running on desktop-type computers can interface with industrial I/O hardware while executing programs within a version of commercial operating systems adapted for process control needs

The rising popularity of single-board computers has also had an influence on the development of PLCs Traditional PLCs are generally closed platforms, but some newer PLCs (e.g groove EPIC from Opto 22, ctrlX from Bosch Rexroth, PFC200 from Wago, PLCnext from Phoenix Contact, and Revolution Pi from Kunbus) provide the features of traditional PLCs on an open platform

PID Controllers

PLCs may include logic for single-variable feedback analog control loop, and a PID controller A PID loop could be used to control the temperature of a manufacturing process, for example Historically PLCs were usually configured with only a few analog control loops; where processes required

hundreds or thousands of loops, a distributed control system (DCS) would instead be used As PLCs have become more powerful, the boundary between DCS and PLC applications has been blurred

2.2 Overview about TIA Portal software

TIA Portal stands for Totally Integrated Automation Portal is a composite

of many operating software that manages automation, electrical operation of the system Understandably, TIA Portal is the first automation software, using

1 environment/ platform to perform tasks and control the system

TIA Portal was developed in 1996 by Siemens engineers, it allows users

to develop and write individual management software quickly, on 1 unified platform The solution minimizes the time it takes to integrate separate applications to unify the creation of the system

TIA Portal - Comprehensive automatic integration is the basis for all other software development: Programming, device configuration integration in the product range TIA Portal characteristics allow software to share the same 1 database, creating unity and integrity for the application system to manage and operate

TIA Portal creates an easy environment for programmers to perform operations:

The interface design pulls information easily, with a variety of support languages

Manage decentralized User, Code, Project in general

Perform go online and Diagnostic for all devices in the project to identify diseases and system errors

Integrated system simulation

Easily configure and link between Siemens devices

Currently, TIA Portal software has many versions such as TIA Portal V14, TIA Portal V15, TIA Portal V16 and the latest is TIA Portal V17 Depending on the needs of use, users will choose to install the corresponding version of TIA portal

Pros - cons of using TIA Portal

TIA Portal is a familiar term applied in the fields of automation, integrating many other popular software such as HMI, PLC, Inverter of Siemens TIA Portal software has its pros and cons in operating automation systems

Advantage: Integrate all software in 1 platform, share a common database to easily manage and unify the configuration The solution operates the equipment quickly and efficiently, looking for troubleshooting in a short time

All elements: PLC programmer, HMI screen are programmed and configured on TIA Portal, allowing specialists to save time manipulating and setting up communication between devices With only 1 variable of the PLC programmer dropped into the HMI screen, the connection is established without any programming operations

Limitations: Due to the integration of many software, the system database is large, so the memory capacity is huge High technical requirements

of programmers, managers, take a long time to get used to

Components in the TIA Portal installer

TIA Portal software is developed by Siemens with many components to help users manage and program PLCs and HMI effectively Components included in the TIA Portal suite:

Simatic Step 7 professional and Simatic step 7 PLCSIM: PLC programming and simulation solutions S7-300, S&-400, Simatic S7-1200, Simatic S7-1500

Simatic WinCC Professional: Used to program HMI display, and SCADA interface

Simatic Start Driver: Programmed Siemens configuration

Sirius and Simo code: Flexible configuration and fault diagnosis

Control single-axis and multi-axis motion with Scout TIA support The full-data Simatic Robot library allows users to set up configurations and systems quickly

Set up security for PLCs with TIA Portal: Perform settings in the Hardware configuration of PLC Users select Protection & security, continue to select Access Level Inside:

o Full access: Corresponds to a security block that anyone can read and write without a password

o Read Access: Security of the writing section for PLC, password required HMI and SCADA or user can read the program without a password

o HMI access: Securing the read and write part of the PLC requires a Password HMI and SCADA readers do not need a password

o No Access: All applications accessing the PLC need a Password

install TIA Portal

Security of the S7 PLC programming function block with TIA: go to the Properties section of that function block, select protection Now you will see 3 types of security: Write, Read / write and copy protection

TIA Portal software application in the field of automation is very popular Technicians need to understand what the essence of TIA Portal is? Characteristics and how to apply programming effectively Hope the above sharing will be useful for users who are learning about TIA Portal software in automation system programming

CHAPTER III: DESIGN OF PISTON CHILLER

REFRIGERATION SYSTEM MONITORING AND

CONTROL SYSTEM

3.1 Introduction of refrigeration system at the thermal

workshop

Figure 3 1: Water chiller system diagram

The principle of operation of the system:

a) Compressor Automation The pressure at the discharge end (Pk) indicates the pressure of the

refrigerant after it has been compressed by the compressor The low pressure (P0) represents the pressure of the refrigerant after it has been cooled and

condensed in the condenser The medium temperature at the discharge end (T2)

is a measure of the temperature of the refrigerant after it has been compressed The temperature of the lubricating oil (delta Toil) is important for monitoring

the temperature of the oil used to lubricate the compressor and ensure its

smooth operation The oil pressure (P) performance indicates the pressure of the lubricating oil in the compressor, and the compressor cooling mode

indicates the method used to cool the compressor These parameters provide valuable information about the operation of the compressor and the

refrigeration system, and help identify any potential issues that may arise

b) Automatic reduction of compressor load by triangular star circuit

In refrigeration compressors often use asynchronous AC motor squirrel cage rotor can be 3 phase or 1 phase Compressors with a capacity of 3HP or more are powered by a 3-phase motor with 3 or 6 output ends It is important to

do so that the starting current does not exceed the permissible value If the machines have medium and large power, if we choose an inappropriate starting option, it causes the starting current to increase This causes the grid voltage drop to overload the line and the motor winding wire overheating causes the compressor life to decrease So choosing a startup option is very important The method of starting by star-triangle connection is applied when the compressor motor has 6 output wires When the compressor is energized, at this time the compressor motor is starred (Y) after a period of 5 ÷ 10 seconds the compressor motor automatically switches to triangular () This method gives a 3-fold decrease in the compressor starting current

c) Compressor overload protection:

As mentioned above, the compressor is one of the important equipment

in a refrigeration system, it acts as the heart of the whole system and is also the highest cost device in the whole system, so there will be measures to protect this equipment during operation in the system

d) Protection of high Pk compression pressure:

High compression pressure protection is an important safety feature in a refrigeration system The purpose of this protection is to prevent damage to the compressor in the event of a high compression pressure

In a refrigeration system, the compressor compresses the refrigerant, which increases the pressure of the refrigerant If the compression pressure becomes too high, it can cause damage to the compressor and affect the performance of the system

To protect the compressor from high compression pressure, a high pressure sensor is installed in the discharge line of the compressor This sensor takes a pressure signal and sends it to the programmable logic controller (PLC)

If the pressure signal exceeds a certain limit set by the PLC, the PLC will stop the compressor to prevent further damage

This way, the high compression pressure protection ensures that the compressor is protected against damage and the system operates smoothl

e) Low pressure protection P0:

A low suction pressure in a refrigeration system can negatively impact its efficiency and cause damage to the compressor To prevent low suction pressure, a low pressure sensor is often used to monitor the pressure in the suction line or suction drill of the compressor

The low pressure sensor sends a signal to the programmable logic controller (PLC), which compares the pressure reading with a set value If the pressure falls below the set value, the PLC stops the compressor to prevent further damage

By monitoring the suction pressure, the low pressure sensor helps ensure that the refrigeration system operates within safe and efficient conditions By stopping the compressor when the pressure is too low, it also helps prevent damage to the system and prolong the life of the compressor

f) Oil pressure protection:

In a compressor with a forced oil lubrication system, oil pressure is an important parameter for evaluating the quality of the lubrication process The oil pressure is determined by the difference between the oil pump pressure

(Poil) and the crankcase pressure (P0), as described in your equation: ΔP = Poil – P0

A lack of oil pressure in the compressor can indicate a malfunction in the oil pumping system or a shortage of oil in the crankcase, which can result in poor lubrication and increase the risk of wear and damage to the compressor parts

To prevent this, the pressure signals from the oil pump and the crankcase are monitored by the PLC If the oil pressure falls below a certain set value, the PLC stops the compressor to prevent further damage This is known

as oil pressure protection

By monitoring the oil pressure, the system can ensure that the lubrication process is functioning properly and that the compressor is protected from damage This helps prolong the life of the compressor and ensure stable and efficient operation of the refrigeration system

g) Automation of condensers The condenser is an important component in a refrigeration system, and proper control of the condenser can improve the system's performance and reduce operating costs

The fans and pumps in the cooling tower of the condenser need to be automatically controlled Like the compressor's pump, the cooling tower's pump is also protected through water flow in the tube Problems such as scale buildup in the tube or a lack of water flow can reduce the system's performance and cause cavitation in the pump

To prevent this, sensors are placed at the outlet of the condenser to monitor the water flow If there is no water flow, the programmable logic controller (PLC) will disconnect the pump and stop the system This helps prevent damage to the pump and prolong the life of the system

h) Automation of evaporators

The evaporator plays an important role in a refrigeration system by pumping cold water to the fan coil units (FCUs), air handling units (AHUs), packaged air handling units (PAUs), etc

To ensure that the cold water supplied to the AHUs, PAUs, etc has the required temperature, the temperature of the water in the evaporator needs to be limited This is done by using a temperature sensor installed at the inlet or outlet of the evaporator

The temperature signal from the sensor is then processed by the programmable logic controller (PLC), and if the temperature of the cold water

is less than or equal to the set value, the system will pause to ensure that the water supply temperature is appropriate for the AHUs, PAUs, etc

This way, the evaporator can provide a constant supply of cold water to the other components in the system, helping to maintain a comfortable environment and ensuring that the system is operating efficiently

i) Automatic fluid supply by thermal throttle:

In a refrigeration system, the refrigerant flow rate is regulated by a thermal expansion valve (TEV) in order to maintain a constant superheat at the evaporator outlet Superheat refers to the temperature difference between the refrigerant gas temperature and its saturation temperature

When the heat load increases, the refrigerant entering the indoor unit decreases, leading to an increase in suction superheat This increase in superheat is sensed by the temperature sensor, which converts the temperature signal into a pressure signal The pressure signal then affects the valve stem, causing the valve to open and allow more liquid refrigerant to enter the evaporator

On the other hand, when the refrigerant entering the indoor unit increases, the suction superheat decreases The pressure in the temperature sensor bulb decreases, causing the valve to close and supply less liquid refrigerant to the evaporator In this way, the TEV regulates the refrigerant

flow rate and maintains a constant superheat at the evaporator outlet, ensuring efficient and stable operation of the refrigeration system

Figure 3 2: Thermostatic expansion valve

3.2 Introduction PLC S7 – 1200, circuit and analog

Table 2: Information about PLC S7-1200 1212C AC/DC/Rly

General information Product type

Engineering with Programming

Inrush current,

Output current for backplane bus

Memory Work memory

6; HSC (High Speed Counting)

Number of simultaneously controllable inputs

— up to 40 °C,

Input voltage