Bit Logic Input Examples - Siemens SIMATIC S7 System Manual

Program instructions
7.1 Bit logic
7.1.11

Bit logic input examples

LAD
Run-mode timing for input example
182
Normally-open contacts I0.0 AND I0.1 must be ON
(closed) to activate Q0.0. The NOT instruction acts
as an inverter. In RUN mode, Q0.0 and Q0.1 have
opposite logic states.
(Normally-open contact I0.2 must be ON) or (Normal-
ly-closed contact I0.3 must be OFF), to activate
Q0.2. One or more parallel LAD branches (OR logic)
must be true to make the output active.
A positive Edge Up input on a P contact or a nega-
tive Edge Down input on an N contact outputs a
pulse with a 1 scan cycle duration. In RUN mode, the
pulsed state changes of Q0.4 and Q0.5 are too fast
to be visible in program status view. The Set and
Reset outputs latch the pulse state into Q0.3 and
make the state change visible in program status
view.
STL
Network 1
LD I0.0
A I0.1
= Q0.0
NOT
= Q0.1
Network 2
LD I0.2
ON I0.3
= Q0.2
Network 3
LD I0.4
LPS
EU
S Q0.3, 1
= Q0.4
LPP
ED
R Q0.3, 1
= Q0.5
System Manual, V2.3, 07/2017, A5E03822230-AF
S7-200 SMART