Siemens SIMATIC S7-200 System Manual page 25

Example: Sample Program for getting started with STEP 7- - Micro/WIN
Timing Diagram
current = 100
current = 40
T33 (current)
T33 (bit)
M0.0
Opening the Program Editor
Click on the Program Block icon to open
the program editor. See Figure 2-6.
Notice the instruction tree and the
program editor. You use the instruction
tree to insert the LAD instructions into
the networks of the program editor by
dragging and dropping the instructions
from the instruction tree to the networks.
The toolbar icons provide shortcuts to
the menu commands.
After you enter and save the program,
you can download the program to the
S7-200.
Network 1
LDN M0.0
TON T33, +100
Network 2
LDW>= T33, +40
= Q0.0
Network 3
LD T33
= M0.0
0.4s 0.6s
Q0.0
Figure 2-6
Getting Started
//10 ms timer T33 times out after
//(100 x 10 ms = 1 s) M0.0 pulse is
// too fast to monitor with Status view.
//Comparison becomes true at a
//rate that is visible with
//Status view. Turn on Q0.0 after
//(40 x 10 ms = 0.4 s), for a
// 40% OFF/60% ON waveform.
//T33 (bit) pulse too fast to monitor with
//Status view. Reset the timer through
//M0.0 after the (100 x 10 ms = 1 s) period.
STEP 7- -Micro/WIN Window
Chapter 2
Program editor
Instruction tree
11