Specifications

IEC 1131-3 Instructions
10-3
S7-200 Programmable Controller System Manual
C79000-G7076-C233-01
Positive, Negative Transition
The Positive Transition contact allows power to flow for
one scan for each off-to-on transition.
The Negative Transition contact allows power to flow
for one scan, for each on-to-off transition.
In LAD, the Positive and Negative Transition instructions
are represented by contacts.
In FBD, the instructions are represented by the POS and
NEG boxes.
Inputs/Outputs Operands Data Types
IN (FBD) I, Q, M, SM, T, C, V, S, L, Power Flow BOOL
OUT (FBD) I, Q, M, SM, T, C, V, S, L, Power Flow BOOL
Contact Examples
Network 1
%Q0.0
LAD
%I0.0 %I0.1
Network 2
%Q0.1%I0.0
NOT
Network 3
%Q0.2%I0.1
N
Timing Diagram
I0.0
I0.1
Q0.0
Q0.1
Q0.2
On for one scan
FBD
Network 1
Network 2
Network 3
AND
%Q0.0
%I0.1
%I0.0
=
%I0.0
N
OUTIN%I0.1
%Q0.1
%Q0.2
Figure 10-1 Examples of Boolean Contact Instructions for LAD and FBD
P
N
P
N
IN OUT
IN OUT
222 224
333
221
L
A
D
F
B
D