Navigation BarPresents groups of pushbutton controls.docx

1、Navigation Bar Presents groups of pushbutton controlsNavigation Bar Presents groups of pushbutton controls for programming features:View桽elect this category to display pushbutton controls for the Program Block, Symbol Table, Status Chart, Data Block, System Block, Cross Reference, and Communications

2、.Tools桽elect this category to display pushbutton controls for the Instruction Wizard, Text Display Wizard, Position Control Wizard, EM 253 Control Panel, and the Modem Expansion Wizard. Note: When the Navigation Bar contains objects that cannot be shown because of the current window size, the Naviga

3、tion Bar displays scroll buttons to let you move up or down to the other objects.Instruction Tree Provides a tree view of all project objects and all the instructions that are available for your current program editor (LAD, FBD, or STL). You can right-click folders in the Projects portion of the tre

4、e to insert additional Program Organizational Units (POUs); you can right-click an individual POU to open it, delete it, edit its property sheet, password-protect it, or rename subroutines and interrupt routines. You can right-click a folder or individual instruction in the Instructions portion of t

5、he tree in order to hide the entire tree. Once you open an instruction folder, you can drag and drop individual instructions or double-click to automatically insert the selected instruction at the cursor location in the Program Editor window as desired. You can organize frequently used instructions

6、by dragging and dropping them in a Favorites folder. Cross Reference Allows you to view Cross Reference and Element Usage information for your program.Data Block Window Allows you to display and edit the content of your data block.Status Chart Window Allows you to track the status of program inputs,

7、 outputs, or variables by putting them into the chart. You can create multiple status charts in order to view elements from different portions of your program. Each status chart has its own tab in the Status Chart window.Symbol Table/Global Variable Table Window Allows you to assign and edit global

8、symbols (in other words, symbolic values that can be used in any POU, not just the POU where the symbol was created). You can create multiple symbol tables. A pre-defined table of S7-200 System Symbols can be added to your project.Output Window Provides informational messages when you compile your p

9、rogram or instruction library. When the output window lists program errors, you can double-click on an error message and the appropriate network is displayed in the program editor window.Status Bar Provides information about the status of the operations that you perform in STEP 7-Micro/WIN.Program E

10、ditor Window Contains the Local Variable Table and the program view for the editor (LAD, FBD, or STL) that you are using for this project. You can drag the split bar to expand the program view and cover up the Local Variable Table if desired. When you create subroutines or interrupt routines in addi

11、tion to the main program section (OB1), tabs appear at the bottom of the program editor window. You can click on the tabs to move between the subroutines, interrupts, and OB1.Local Variable Table Contains assignments that you have made to local variables (in other words, variables that are used by y

12、our subroutines and interrupt routines). Variables created in the Local Variable Table use temporary memory; address assignment is handled for you by the system; use of the variable is restricted to the POU where it was created.Menu Bar Allows you to perform operations using either a mouse or keystr

13、okes. You can customize the Tools menu to add your own tools.Toolbars Provides easy mouse access to the most commonly used STEP 7-Micro/WIN operations. You can customize the content and appearance of each of the toolbars. 360毕业设计网友情提供-In STEP 7-Micro/WIN, the project provides you with a means of ass

14、ociating your program with all the information that is needed in order for you to communicate with a PLC and download the given program to that particular PLC.A project is composed of these fundamental components:Program Block The program block is composed of executable code and comments. The execut

15、able code consists of a main program (OB1) and any subroutines or interrupt routines. The code is compiled and downloaded to the PLC; the program comments are not.Symbol Table The symbol table is a means for allowing the programmer to use symbolic addressing. Symbols are sometimes more convenient fo

16、r the programmer, and make program logic easier to follow. The compiled program that is downloaded to the PLC converts all symbols to absolute addresses. Symbol table information is not downloaded to the PLC.Status Chart Status charts allow you to observe how process values are affected as your prog

17、ram executes. Status charts are not downloaded to the PLC; they are simply a means of monitoring PLC (or simulated PLC) activity.Data Block The data block is composed of data (initial memory values; constant values) and comments. The data is compiled and downloaded to the PLC; the comments are not.S

18、ystem Block The system block consists of configuration information such as communications parameters, retentive data ranges, analog and digital input filters, output values for a STOP transition, and password information. The system block information is downloaded to the PLC.Cross Reference The Cros

19、s Reference window lets you examine tables that list where operands are used in your program, and also which areas of memory have already been assigned (Bit Usage and Byte Usage). During a program edit in RUN mode, you can also examine the edge numbers (EU, ED) that are currently in use by your prog

20、ram. Cross reference and usage information is not downloaded to the PLC.Ladder ProgramsIn LAD programs, the basic elements of logic are represented with contacts, coils, and boxes. A set of interconnected elements that make a complete circuit is called a network.A hard-wired input is represented by

21、a symbol called a contact. A normally-open contact enables power flow when closed. A contact can also be normally closed. In this case, power flow occurs when the contact is opened. A hard-wired output is represented by a symbol called a coil. When a coil has power flow, the output is turned on.A bo

22、x is a symbol for a complex operation performed within the PLC. The box simplifies programming of the operation. For example, timers and counters are represented by boxes.STL ProgramsSTL program elements are represented by a set of instructions for performing the desired functions. Instead of using

23、the graphic display as shown by ladder programs, the STL program is shown in text format. FBD ProgramsFBD program elements are represented by boxes. AND/OR boxes (gates) are used to manipulate Boolean signals in the same manner as ladder contacts.The different representations are shown in an example

24、 below.Ladder logic (LAD) is a graphical language that resembles electrical relay diagrams. When you write a program in LAD, you use graphical components and arrange them to form a network of logic. The following types of elements are available for you to use in creating your program:?Contacts Repre

25、sent a switch through which power can flow. Power flows through a normally open contact only when the contact is closed (a logical value of one); power flows through a normally closed or negated (NOT) contact only when the contact is open (a logical value of zero).?Coils Represent a relay or output

26、that is energized by power flow.?Boxes Represent a function (for instance, a timer, counter, or mathematical operation) that is executed when power flow reaches the box.A network is composed of these elements and represents a complete circuit. Power flows from the left power rail (represented in the

27、 LAD editor by a vertical line on the left side of the window) through the closed contacts to energize the coils or boxes.The STEP 7-Micro/WIN Function Block Diagram (FBD) editor allows you to view the instructions as logic boxes that resemble common logic gate diagrams:You can use the AND button (o

28、r the instruction tree) to insert an AND instruction.You can use the OR button (or the instruction tree) to insert an OR instruction.You can use the BOX button (or the instruction tree) to select any other FBD box.The program logic is derived from the connections between these box instructions. That

29、 is, the output from one instruction (such as an AND box) can be used to enable another instruction (such as a timer) to create the necessary control logic.This topic describes several ways that you can modify the inputs and outputs of FBD instructions:Negating Inputs You can negate a boolean (bit v

30、alue) input, creating an inverted logic condition (the input becomes normally closed/ON instead of normally open/OFF).Making Inputs or Outputs Immediate You can turn a boolean (bit value) input or output into an immediate input/immediate output, so that the address is updated immediately instead of

31、being updated at a fixed interval during the regular scan cycle of the program.Adding or Removing Extra Inputs You can also add extra inputs to an AND or OR instruction if your program logic requires. If you change your mind, you can remove the extra inputs and return the instruction to its default

32、of 2 inputs.Negating Inputs (Back to Top)You can negate a boolean (bit value) input, or toggle it back to a normal input:1. Select the desired instruction (by clicking on it or pressing the ENTER key until a selection box appears around the instruction).2. Use the TAB key to move to the input that you want to change (or click directly on the input).Note: The selected input line is colored red; the lines of the inputs that are not selected are colored black.3. Click on the Toggle Negate button, or press the F11 shortcut key, to toggle the input between normal an