Computer measurement and control

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of Physics 2017/2018 spring semester Copyright

1 Computer measurement and control Instructors: András Magyarkuti, Zoltán Kovács-Krausz BME TTK, Department of Physics 2017/2018 spring semester Copyright András Magyarkuti, Attila Geresdi, András Halbritter

2 Outline Basics Concept of object oriented programming Data acquisition and measurement control Analyze and display acquired data Programming assignments using Visual Studio development environment Graphical user interface Data Analysis nonlinear curve fitting by Monte Carlo method Connecting instruments via serial port Communication with instrument Display acquired data Solving complex measurement control and data analysis tasks NI mydaq data acquisition device

3 Website Informations Visual Studio 2017 Visual Studio 2017 Community - free to use Other resources: John Sharp: Microsoft Visual C# 2008 Tutorial:

4 Requirements Presence requirements: In order to successfully complete the course, students have to be present on the all classes (6 occasions) and submit all tasks / reports. Mid-term tests: Completing the laboratory assignments requires self-preparation. Preparation of the students is checked at the beginning of each laboratory exercise with a short written test. Grades: Test 20 point + report 100 point Final Grade 0% 40% 1 40% 55% 2 55% 70% 3 70% 85% 4 85% 100% 5 If a submitted report, program, or part of a written report is proven not to be a stand-alone work, it will be evaluated automatically, irrespective of the amount of the copy, by -100 points!

5 Computer measurement and control Tasks: automated measurement, data acquisition, real time data analysis Devices: Instrument: measures a physical quantity; Computer: data acquisition, display and analysis

analysis Devices: Instrument: measures a physical

6 Computer measurement and control Tasks: automated measurement, data acquisition, real time data analysis Devices: Instrument: measures a physical quantity; Computer: data acquisition, display and analysis

7 Computer measurement and control Communication protocols: - RS USB - LPT - GPIB

8 C# - C sharp Object oriented, event driven, general purpose,.net Framework Class Library CLR Common Language Runtime MONO (LINUX)

9 Basics of Object Oriented Programming Object-oriented programming (OOP) is a programming paradigm based on the concept of "objects", which may contain data, in the form of fields, often known as attributes; and code, in the form of procedures, often known as methods. Source: Wikipédia

10 Basics of Object Oriented Programming Example: drawing program Class: Formation Property: color Method: draw Event: onclick Property: thickness Subclass: rectangle circle... Property: a, b Property: r - fast development - modular - event driven

11 Basics of Object Oriented Programming Example: generating random numbers Class: type of the object Random rand01; rand01 = new Random(); Name of the individual object Constructor: creating object Double FloatRandomNumber = rand01.nextdouble(); Int32 IntRandomNumber = rand01.next(maxrandomnumber); Method: returns the next random number.

12 Basics of Object Oriented Programming Example: button Property: Text displayed on the button. StartButton.Text= Start! private void StartButton_Click(object sender, EventArgs e) Event: Function, called when the user clicks on the StartButton.

13 Visual Studio

14 Visual Studio

15 Basics of Object Oriented Programming Hello World! program: namespace proba public partial class Form1 : Form public Form1() InitializeComponent(); private void Form1_Load(object sender, EventArgs e) StartButton.Text = "Start!"; private void StartButton_Click(object sender, EventArgs e) MessageBox.Show("Hello World!");

16 Basics of Object Oriented Programming Hello World! program: event namespace namespace proba public partial class Form1 : Form public Form1() function InitializeComponent(); private void Form1_Load(object sender, EventArgs e) StartButton.Text = "Start!"; property private void StartButton_Click(object sender, EventArgs e) MessageBox.Show("Hello World!"); method

17 Basics of Object Oriented Programming Example: drawing program Class: Formation Property: color Method: draw Event: onclick Property: thickness Subclass: rectangle circle... Property: a, b Property: r Summary: - Class: definitions for the data format and available procedures; - Object: instance of a class; - Method: procedure associated with a message and an object; - Property: data stored in the object; - Event: an action or occurrence recognized by software like user input.

18 Button using System.Windows.Forms; Properties Name Identifier of the object Text Text displayed on the button Methods Hide Hides Button on the user interface Show Shows Button on the user interface Events Click Function, called when user clicks on the button

19 Form using System.Windows.Forms; Properties Name Identifier of the object Text Text displayed in the header of the Form Methods Show Opens Form Close Closes Form (Exits the program) Events Load FormClosing Function, called when the program opens Function, called when the program exits

20 TextBox using System.Windows.Forms; Properties Name Identifier of the object Text Text displayed in the textbox Methods Hide Hides TextBox on user interface Show Shows TextBox on the user interface Events TextChanged Click Function, called when the input text is changed Function, called when the user clicks on the TextBox

21 Label using System.Windows.Forms; Properties Name Identifier of the object Text Text displayed on the Label Methods Hide Hides Label on the user interface Show Shows Label on the user interface Events VisibleChanged Click Function, called when the label becomes Hidden/Shown Function, called when the user clicks on the label

22 Constructor (Opening the file) File IO StreamWriter, StreamReader: using System.IO; StreamWriter FileWriter = new StreamWriter( File Name ); StreamReader FileReader = new StreamReader( File Name ); Methods Write( Text ) WriteLine( Text ) Read() ReadLine() Close() Properties EndOfStream Writes string to the file Writes string ending with a new line character to the file Reads next character from the file Reads next line from the file Closes file Bool value, signals when the end of the file is reached.

23 File Dialogs OpenFileDialog, SaveFileDialog : using System.Windows.Forms; Methods ShowDialog() Reset() Properties FileName Title InitialDirectory DefaultExt Opens the FileDialog window Clears the settings of the object Path and name of the chosen file. Header of the dialog window Default directory Default file extension

24 Read from File Example: using System.IO;... StreamReader reader = new StreamReader("filename.txt"); string line; while ((line = reader.readline())!= null) TextBox1.AppendText(line); reader.close();

25 Write to File StreamWriter, SaveFileDialog example: using System.IO;... // The SaveFileDialog object must be added in the designer... if(sfdialog.showdialog() == DialogResult.OK) StreamWriter writer = new StreamWriter(sfDialog.FileName); writer.writeline("your text"); writer.close();

26 C# basics Declaration: int i; Initialization: i = 5; Declaration + Initialization: double j=1.5; Int32 int, Int64 long Arrays: double[] data = new double[16]; data[0]=1.5; data[15]=2.3;

27 C# basics Functions: private Int32 Function(arglist)... Calling a function: Int32 x = Function(arglist); private: can only be accessed within the class public: can be accessed outside of the class Type conversion: x = Convert.ToDouble(Object); string = Convert.ToString(Object); i = Convert.ToInt(Object);... String: string Text = Hello ; int length = Text.Length; string Part = Text.Substring(start, length); int index = Text.IndexOf(char); Text = Object.ToString( Format );

28 string manipuláció string Text = apple ; string hossza: int length = Text.Length; C# basics Trim(): removes white space characters from the beginning and end of the string TrimStart(), TrimEnd(): removes whitespace characters only from the beginning or end of the string newtext = Text.Trim(); // apple newtext = Text.TrimStart(); // apple newtext = Text.TrimEnd(); // apple Substring(): // Text.Substring(start,length); newtext = Text.Substring(0,4) // ap Split(): string text = 6+3; string [] numbers = text.split('+'); // numbers[0] = 6 // numbers[1] = 3

29 C# basics string manipulation Concatenating strings: Hello World! = Hello + + World! IndexOf(): index of the searched character (returns -1 if character is not found). int index = Text.IndexOf( p ); // index=4 ToString(): // Text = Object.ToString( Format ); double num = ; Text = num.tostring( 0.00 ); // fix 2 decimal places, 5.01

30 C# basics Character: char c= g ; c=(char)103; //ASCII g character string Text=c.ToString(); char[] Text2=Text.ToCharArray(); Text2[0]=c; //indexing strings Special characters: char c; c= \t ; c= \n ; c= \r ; c= \\ ; c= \ ; c= \ ; // tabulator // new line // carriage return // backslash // quotation marks // double quotation marks

31 C# basics if branching: int seconds = 0; int minutes = 0;... if (seconds == 59) seconds = 0; minutes++; else seconds++; Multiple branches: if (day == 0) dayname = Sunday ; else if (day == 1) dayname = Monday ;... else if (day == 6) dayname = Saturday ; else dayname = unknown ; switch branching: switch (day) case 0 : dayname = Sunday ; break; case 1 : dayname = Monday ; break; case 2 : dayname = Tuesday ; break;... default : dayname = Unknown ; break; Only for internal datatypes (pl. int, string) Value has to be compared to a constant

32 C# basics while loop: int i = 0; while (i < 10) MessageBox.Show(i.ToString()); i++; Do while loop: int i = 0; do MessageBox.Show(i.ToString()); i++; while (i < 10); for loop: for (int i = 0; i < 10; i++) Console.WriteLine(i); Initializing multiple variables: for (int i = 0, j = 10; i <= j; i++, j--)...

33 C# basics Math class Mathematical functions: Math.Cos(rad): cosine function Math.Sin(rad): sine function Math.Min(num1, num2): returns the smaller number Math.Abs(num): absolute value Math.Pow(base, exponent): Exponential function Math.Exp(x): e x Math.Round(num, int decimals): rounding numbers Math.Sqrt(num): square root... Mathematical constants: Math.PI: π Math.E: e

34 Pitfalls 1. Dividing integers: double d; d = 4/5; // d = 0 d = (double) 4/5; // d = Convert.ToDouble() depends on the Windows locale settings (decimal separator). 3. Textbox.Textchanged() event is generated every time a character is changed. 4. Objects cannot be converted, pl. Convert.ToDouble(TextBox1). Correctly: TextBox1.Text. 5. Correct usage of SubString() method: start index and length of substring (not start index and end index).

35 Debugging Debug QuickWatch: Evaluating expressions Manipulating objects breakpoint Tracking the value of a variable: In debug mode, right click on the variable > Add watch

36 Scope of variables namespace helloworld Can be accessed by every function in the Class public partial class Form1 : Form string globaltext = "Hello World!"; public Form1() InitializeComponent(); private void Form1_Load(object sender, EventArgs e) MessageBox.Show(globalText); private void button1_click(object sender, EventArgs e) string text = "Message"; MessageBox.Show(text); Can only be accessed from the button1_click() function

add(30); numlist.add(50); numlist.add(70); int length = numlist.

37 Lists: dynamic arrays in C# Example: list containing integer numbers Lists using C#: <list> List<int> numlist = new List<int>(); numlist.add(20); numlist.add(30); numlist.add(50); numlist.add(70); int length = numlist.count; // length = 4 int item = numlist[2]; // item = 50 numlist.removeat(3); Further methods: Clear(), Find(), Sort()

38 Programming Tasks 1. Modify the Hello World! program, so that it displays the contents of a TextBox in a MessageBox when the user pushes a button. Add another button and display a property (like Text, Font, TextAlign, ) of the StartButton in a MessageBox. 2. Wait for the user to input two numbers separated with a + character in a TextBox, then display the result in a second TextBox. 3. Create a file with integers from 1 to 100 separated by a comma. Use a SaveFileDialog object for choosing the file path. 4. The XY_data.txt file contains [X,Y] data points. Read the data from the file and calculate the mean and standard deviation separately for the X and Y datasets. Use the OpenFileDialog object when opening the file. Calculating standard deviation:

C# 2008 and.net Programming for Electronic Engineers - Elektor - ISBN

C# 2008 and.net Programming for Electronic Engineers - Elektor - ISBN Contents Contents 5 About the Author 12 Introduction 13 Conventions used in this book 14 1 The Visual Studio C# Environment 15 1.1 Introduction 15 1.2 Obtaining the C# software 15 1.3 The Visual Studio