Using Step 7--Micro/Win To Create Your Programs - Siemens SIMATIC S7-200 System Manual

Using STEP 7- -Micro/WIN to Create Your Programs
To open STEP 7--Micro/WIN, double-click on the STEP 7--Micro/WIN icon, or select the Start >
SIMATIC > STEP 7 MicroWIN V4.0 menu command. As shown in Figure 5-1, the
STEP 7--Micro/WIN project window provides a convenient working space for creating your control
program.
The toolbars provide buttons for shortcuts to frequently used menu commands. You can view or
hide any of the toolbars.
The navigation bar presents groups of
icons for accessing different
programming features of
STEP 7--Micro/WIN.
The instruction tree displays all of the
project objects and the instructions for
creating your control program. You can
drag and drop individual instructions
from the tree into your program, or you
can double-click an instruction to insert it
at the current location of the cursor in the
program editor.
The program editor contains the program
logic and a local variable table where
you can assign symbolic names for
temporary local variables. Subroutines
and interrupt routines appear as tabs at
the bottom of the program editor window. the bottom of the program editor window.
Click on the tabs to move between the
subroutines, interrupts, and the main
program.
STEP 7--Micro/WIN provides three editors for creating your program: Ladder Logic (LAD),
Statement List (STL), and Function Block Diagram (FBD). With some restrictions, programs
written in any of these program editors can be viewed and edited with the other program editors.
Program
Editor
Features of the STL Editor
The STL editor displays the program as a text-based language. The STL editor allows you to
create control programs by entering the instruction mnemonics. The STL editor also allows you to
create programs that you could not otherwise create with the LAD or FBD editors. This is because
you are programming in the native language of the S7-200, rather than in a graphical editor where
some restrictions must be applied in order to draw the diagrams correctly. As shown in Figure 5-2,
this text-based concept is very similar to assembly language programming.
The S7-200 executes each instruction in
the order dictated by the program, from
top to bottom, and then restarts at the
top.
STL uses a logic stack to resolve the
control logic. You insert the STL
co t o og c ou
instructions for handling the stack
operations.
Consider these main points when you select the STL editor:
STL is most appropriate for experienced programmers.
-
STL sometimes allows you to solve problems that you cannot solve very easily with the
-
LAD or FBD editor.
You can only use the STL editor with the SIMATIC instruction set.
-
While you can always use the STL editor to view or edit a program that was created with the
-
LAD or FBD editors, the reverse is not always true. You cannot always use the LAD or FBD
editors to display a program that was written with the STL editor.
Programming Concepts, Conventions, and Features
Figure 5-1
se t t e S
Figure 5-2
Instruction tree
Navigation bar
STEP 7- -Micro/WIN
LD I0.0 //Read one input
A I0.1 //AND with another input
= Q1.0 //Write value to output 1
Sample STL Program
Chapter 5
Program Editor
55