Power Flow In A Ladder Diagram - Siemens SIMATIC S7-200 Getting Started

1.3

Power flow in a ladder diagram

Getting Started - Advanced
Training Documents, 09/2007, A5E01469795B
Quick review
1.3 Power flow in a ladder diagram
In this example, output Q0.3 would
be active or "1", if the contact at
I0.1 is closed, or bit value "1" (24 V
DC at input I0.1) AND
simultaneously, the timer bit T37 is
active, or "1".
Input I0.1 is now "1", and contact
I0.1 is closed. T37 is not active in
the figure, and it is a "0". Q0.3
remains inactive or "0"
If timer T37 is also "1" (T37 has
elapsed), the result of the AND
operation is "1" and so output Q0.3
is also "1".
The output bit is then also "true", in
other words, it takes the value "1"
(gray background).
This corresponds to the LAD
status view that you have already
used in the Getting Started -
Beginnners for debugging your
program.
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