Siemens SIMATIC S7-1200 Manual page 22

Getting started
Create a simple network in your user program
You have created a network of LAD instructions. You can now associate the tag names with
these instructions.
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Your program code consists of instructions that the PLC executes in
sequence. For this example, use ladder logic (LAD) to create the
program code. The LAD program is a sequence of networks that
resemble the rungs of a ladder.
To open the program editor, follow these steps:
1. Expand the "Program blocks" folder in the Project tree to display
the "Main [OB1]" block.
2. Double-click the "Main [OB1]" block.
The program editor opens the
program block (OB1). Use the
buttons on the "Favorites" to insert
contacts and coils onto the network:
1. Click the "Normally open contact"
button on the "Favorites" to add a
contact to the network.
2. For this example, add second
contact.
3. Click the "Output coil" button to
insert a coil.
The "Favorites" also provides a
button for creating a branch:
1. Click the "Open branch" icon to
add a branch to the rail of the
network.
2. Insert another normally open
contact to the open branch.
3. Drag the double-headed arrow to
a connection point (the green
square on the rung) between the
open and closed contacts on the
first rung.
To save the project, click the "Save
project" button in the toolbar. Notice
that you do not have to finish editing
the rung before saving.
Manual, 11/2009, A5E02486774-01
Easy Book