Unit 24: Controlling Systems Using IT Theory Handbook 2014-2015 With Owen Name Group
Introduction to Unit 24 Embedded control systems are appearing in every area of life. They include toys, TV remote controls, many devices with numeric displays and push button inputs such as digital clocks, microwave ovens and heating controllers. In industry, control systems can be found in assembly lines, environmental control, security and CCTV systems. This unit focuses on the techniques typically found in small embedded systems. Control systems are increasingly found in many manufacturing processes. Although the fundamental principles of control systems have not changed significantly over the years, the increasing sophistication and range of devices has enabled wider application. This unit considers the actual hardware devices available. Learners will carry out practical activity using control mechanisms to confirm their understanding of theoretical concepts. Developing an understanding of number systems such as binary and hexadecimal as well as logical operators, is essential to the operation of control systems and appropriate content is included. Learners will spend a significant amount of time in practical workshops developing the necessary knowledge and understanding. Theory will be necessary in order to complete the unit, but this should always be supported by practical demonstrations. Learners will ultimately design and assemble a control system with different sensors and test it for functionality and performance. 2
Keep this book safe! it is designed to help you with you assessment. During lesson follow along and take notes Reports MUST: Have a cover page with your name, date and the unit title A table of contents Header on every page with your name and unit Footer with the page numbers Clear Titles and Sub titles If you reference a website, book, magazines etc. You MUST use the Harvard referencing system. More information is available at the LRC or at: http://libweb.anglia.ac.uk/referencing/harvard.htm Thought out the unit you will take part in several practical assessments You are required to take pictures of theses practical's to use in your assessment Reports must be made of your own work. Pictures and diagrams should be all your own work and must be made by you in the appropriate software. 3
A Control System is,,,,,, What is a Control System? There are many different types of control systems but they all control something. They are becoming more common every day and people tend to use them without thinking or recognising what they are. Most control systems are combinations of the various types. There are 4 Types of Control Systems.. 1 2 3 4 4
Types of Control Systems 1 What is the purpose of the system? State the processing that the system will need to carry out Examples of the System Complete Circuits 02 in the Practical Handbook. Take pictures and make notes 5
Types of Control Systems 2 What is the purpose of the system? State the processing that the system will need to carry out Examples of the System Complete Circuits 03 in the Practical Handbook. Take pictures and make notes 6
Types of Control Systems 3 What is the purpose of the system? State the processing that the system will need to carry out Examples of the System Complete Circuits 04 in the Practical Handbook. Take pictures and make notes 7
Types of Control Systems 4 What is the purpose of the system? State the processing that the system will need to carry out Examples of the System Complete Circuits 05 in the Practical Handbook. Take pictures and make notes 8
Control Systems Input and Output Control System Inputs (Sensors) Outputs Thermostat Smoke Detectors Remote Control Microwave Burglar Alarm DVD Player 9
Digital and Analogue Control Systems Draw a Analogue Signal. Draw a Digital Signal. Lesson Notes 10
Digital and Analogue Control Systems Which of theses systems is Analogue and Which is Digital? Analogue Analogue Digital Digital Analogue Analogue Digital Digital Analogue Analogue Digital Digital Analogue Analogue Digital Digital Remember there is a difference between system and signal. 11
Digital and Analogue Control Systems Analogue Audio Amplifier Digital Clock 12
Digital and Analogue Control Systems Characteristics of analogue control systems Example of analogue control systems Characteristics of digital control systems Example of digital control systems 13
Signal Waves Errors Response to Noise Memory Signal Degradation Analogue Digital Comparing analogue and digital signals 14
Signal Conversion - Analogue to Digital Wave Complete the diagram... Name the steps for Analogue to Digital conversions 15
Signal Conversion Draw a Digital to Analogue conversion Why do we need Signal Conversion. 16
Control Loop and Process Control Operations P W M Using a Resistor to control a motor speed - What happens? Using PWM - Why is this a better idea? 17
Control Loop and Process Control Operations Duty cycle - Complete the graphs 0% Duty Cycle 25% Duty Cycle 50% Duty Cycle 75% Duty Cycle 100% Duty Cycle 18
Data representation in control systems - Binary A system of numbers using ten digits, 0 and 1-9 Is this describing Denary (Base-10) or Binary? Tick the Correct Binary Denary A system of numbers using only two digits, 0 and 1 Is this describing Denary (Base-10) or Binary? Tick the Correct Binary Denary 128 64 32 16 8 4 2 1 0 0 0 1 0 1 0 1 What base 10 Number is this? Convert 45 to binary 128 64 32 16 8 4 2 1 128 64 32 16 8 4 2 1 1 0 0 1 0 0 1 1 What Base 10 number is this? 19
Data representation in control systems - Binary 128 64 32 16 8 4 2 1 1 1 0 0 1 0 0 0 What base 10 Number is this? 128 64 32 16 8 4 2 1 1 1 1 1 1 1 1 1 What Base 10 number is this? Convert 72 to binary 128 64 32 16 8 4 2 1 Convert 235 to binary 128 64 32 16 8 4 2 1 Convert 131 to binary 128 64 32 16 8 4 2 1 20
Data representation in control systems - Logic Gates Name theses Logic Gates. 1 2 3 4 Truth Tables Complete the Truth Table for a NOT Logic Gate A Q Do the Minecraft Logic Gate Practical in the Practical Handbook and complete the Truth Tables 21
Data representation in control systems - Logic Gates Complete theses Truth Tables for each of your logic gates A B Q Name: A B Q Name: A B Q Name: A B Q Name: 22
Data representation in control systems - Hexadecimal What is a Hexadecimal? Base 10 Base 2 Base 16 0 0 0 1 1 1 2 10 2 3 11 3 4 100 4 5 101 5 6 110 6 7 111 7 8 1000 8 9 1001 9 10 1010 A 11 1011 B 12 1100 C 13 1101 D 14 1110 E 15 1111 F 23
Data representation in control systems - Hexadecimal Converting Hex to Base-10. 25 in Hex is. 16 1 2 5 2 x 16 = 32 3 x 1 = 5 32 + 5 = 37 in Base 10 Convert 3C from Hex to base 10 16 1 3 C 3 x 16 = 48 12 x 1 = 12 48 + 12 = 60 in Base 10 Convert 5F from Hex to base 10 16 1 5 F 5 x 16 = 80 12 x 1 = 15 80 + 15 = 95 in Base 10 Convert A5 from Hex to base 10 16 1 24
Data representation in control systems - Hexadecimal Converting Base 10 to Hex Convert 45 in Base-10 to Hex 45 16 = 2 Remainder 13 = D 2 16 = 0 Remainder 2 45 in Binary = 2D in Hex Convert 235 in Base-10 to Hex 235 16 = 2 Remainder 11 = B 14 16 = 0 Remainder 14 = E 235 in Binary = EB in Hex An easier way. 45 in Binary is 32 + 8 + 4 + 1 128 64 32 16 8 4 2 1 0 0 1 0 1 1 0 1 Split into 2 nibbles (4-bits) 8 4 2 1 8 4 2 1 0 0 1 0 1 1 0 1 2 8 + 4 + 1 2 13 = D 45 in Binary (00101101) = 2D in Hex 25
Data representation in control systems - Hexadecimal Convert 01010101 to Hexadecimal 128 64 32 16 8 4 2 1 Split into 2 nibbles (4-bits) 8 4 2 1 8 4 2 1 Convert 11111111 to Hexadecimal 128 64 32 16 8 4 2 1 Split into 2 nibbles (4-bits) 8 4 2 1 8 4 2 1 26
Data representation in control systems - ASCII What is ASCII? All the main alphabetic characters, upper and lower case 52 Characters All the numeric symbols, 0-9 10 Characters 32 punctuation and other symbols and space 33 Characters 32 codes reserved for non-printable control code 32 Characters Binary Hex Base-10 ACSII 0100000 20 32 space 1000001 41 65 A 1000010 42 66 B 1011010 5A 90 Z 1100001 61 97 a 1111001 79 121 y 1111010 7A 122 Z 11111111 7F 127 delete http://www.asciitable.com/ has the full ASCII table 27
Data representation in control systems - Numbers Binary, Hexadecimal and Base-10 only store What about fractions, decimals and negative numbers? Control systems need to use these for such quantities as weights and temperatures. Integers Integers are like whole numbers, but they also include negative numbers... but still no fractions or decimals. So, integers can be negative {-1, -2,-3, -4, -5, }, positive {1, 2, 3, 4, 5, }, or zero {0} On the Arduino Uno (and other ATMega based boards) an int stores a 16 -bit (2-byte) value. This yields a range of -32,768 to 32,767 Floating point numbers Floating-point numbers are numbers that have a decimal point. Floatingpoint numbers are often used to approximate analogue and continuous values because they have greater resolution than integers. Floating-point numbers can be as large as 3.4028235E+38 and as low as -3.4028235E+38. They are stored as 32 bits (4 bytes) of information. The Ariane 5 disaster was caused by a badly coded Floating Point. It caused an overflow, witch is when a number is to big for the memory to store 28
Data representation in control systems - Numbers Fixed-point numbers A fixed point number has a specific number of bits (or digits) reserved for the integer part (the part to the left of the decimal point) and a specific number of bits reserved for the fractional part (the part to the right of the decimal point). No matter how large or small your number is, it will always use the same number of bits for each portion. For example, if your fixed point format was in decimal EEEEE.FFFFF then the largest number you could represent would be 99999.99999 and the smallest would be 00000.00001. Every bit of code that processes such numbers has to have built-in knowledge of where the decimal point is. Take the number 123.456789 What is this an integer? What is this as a fixed point (2)? What is this as a floating point? Answer Take the number 123.456789 As an integer, this number would be 123 As a fixed point (2), this number would be 123.46 (Assuming you rounded it up) As a floating point, this number would be 123.456789 Floating point lets you represent most every number with a great deal of precision. Fixed is less precise, but simpler for the computer.. 29
Control Loop and Process Control Operations Systems Diagrams Input: The input starts the system, such as a switch or sensor. Process: The mind of the system, which considers the inputs and decides what to do. Common process blocks include comparators, latches, logic gates, counters, timers and pulse generators. Output: The system's response to being activated - e.g. a flashing light or a buzzer. Each box in the system diagram has a specific function, and they are joined by a signal. Each box is normally a physical item: this could be a single component or a collection of components. Systems Diagram of a Vending Machine Next time you use a electronic system think of the process it goes though 30
Control Loop and Process Control Operations Control Loops - Open Loop Example Boiler On/Off Switch Boiler Radiator Input: An on-off switch Process: Boiler (water heater) and pump Output: Radiator What is an Open-Loop System and what is the disadvantage of the system? 31
Control Loop and Process Control Operations Control Loops - Close Loop Example Boiler On/Off Switch Boiler Radiator Thermostat Input: An on-off switch Process: Boiler (water heater) and pump Process: Thermostat Measures room temperature and turns on the heating if the room is to cold or turns off if its hot Output: Radiator 32
Control Loop and Process Control Operations Proportional Integral Derivative (PID) loop What is an Closed-Loop System Is this a Open or Closed Loop System? A Toaster Open Closed Driving a Car Open Closed A Rocket Open Closed 33
Control Loop and Process Control Operations Proportional Control (Fill in the Blanks) ( ) Temperature Sensor Controller = 70 C = 100 C should be:100 Heater Should Be: Increased (+) Decreased (-) ( ) Temperature Control Heater Controller Output What makes Proportional Control Special Controlled increase in Temperate over time. Compares (SP) and (PV) The Gap between the two is known as the When to use Proportional Control 34
Developing and Implementing Projects Idea Server room temperature monitor Temperature with visual output Alarm for a room An alarm with audio output Electronic Dice An electronic dice using LEDS Camera Gimbal Control Controllable remote camera gimbal Research Use your Practical Handbook to help research ideas for your project Useful link: Plan https://learn.adafruit.com/category/learn-arduino http://hackaday.com/ http://www.instructables.com/id/arduino-projects/ Your planning should involve: A list of requirements the project will achieve Schematics Systems diagrams Drawings Develop During the build process you should be taking pictures and keeping a log. The log should show each step as you build your project. Remember to note down any problems you have and how you have overcome them. 35
Build a testing table. Like the one below Has the project meet the requirements laid out in the Planning stage What could it be improved? What went right with the project? What is different from the original plans? Test No. Part of the System Example Temperature Sensor Testing Developing and Implementing Projects What is being Tested Test Expected Result Actual Result Pass Does the temperature sensor show the correct temperature in the serial monitor Analysis Place fingers over the sensor The temperate goes up The temperature went up Fail Pass 36